WORKING GROUP II CONTRIBUTION TO THE

FIFTH ASSESSMENT REPORT OF THE

INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE

WG II

I N T E RGOV E R N M E N TA L PA N E L O N climate change

Summary

for Policymakers

SPM

This Summary for Policymakers should be cited as:

IPCC

, 2014: Summary for policymakers. In: Climate Change 2014: Impacts, Adaptation, and Vulnerability.

Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the

Intergovernmental Panel on Climate Change [Field, C.B., V.R. Barros, D.J. Dokken, K.J. Mach, M.D. Mastrandrea,

T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken,

P.R. Mastrandrea, and L.L. White (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New

York, NY, USA, pp. 1-32.

Drafting Authors:

Christopher B. Field (USA), Vicente R. Barros (Argentina), Michael D. Mastrandrea (USA),

Katharine J. Mach (USA), Mohamed A.-K. Abdrabo (Egypt), W. Neil Adger (UK),

Yury A. Anokhin (Russian Federation), Oleg A. Anisimov (Russian Federation), Douglas J. Arent

(USA), Jonathon Barnett (Australia), Virginia R. Burkett (USA), Rongshuo Cai (China),

Monalisa Chatterjee (USA/India), Stewart J. Cohen (Canada), Wolfgang Cramer

(Germany/France), Purnamita Dasgupta (India), Debra J. Davidson (Canada), Fatima Denton

(Gambia), Petra Döll (Germany), Kirstin Dow (USA), Yasuaki Hijioka (Japan),

Ove Hoegh-Guldberg (Australia), Richard G. Jones (UK), Roger N. Jones (Australia),

Roger L. Kitching (Australia), R. Sari Kovats (UK), Joan Nymand Larsen (Iceland), Erda Lin

(China), David B. Lobell (USA), Iñigo J. Losada (Spain), Graciela O. Magrin (Argentina),

José A. Marengo (Brazil), Anil Markandya (Spain), Bruce A. McCarl (USA), Roger F. McLean

(Australia), Linda O. Mearns (USA), Guy F. Midgley (South Africa), Nobuo Mimura (Japan),

John F. Morton (UK), Isabelle Niang (Senegal), Ian R. Noble (Australia), Leonard A. Nurse

(Barbados), Karen L. O’Brien (Norway), Taikan Oki (Japan), Lennart Olsson (Sweden),

Michael Oppenheimer (USA), Jonathan T. Overpeck (USA), Joy J. Pereira (Malaysia),

Elvira S. Poloczanska (Australia), John R. Porter (Denmark), Hans-O. Pörtner (Germany),

Michael J. Prather (USA), Roger S. Pulwarty (USA), Andy Reisinger (New Zealand),

Aromar Revi (India), Patricia Romero-Lankao (Mexico), Oliver C. Ruppel (Namibia),

David E. Satterthwaite (UK), Daniela N. Schmidt (UK), Josef Settele (Germany), Kirk R. Smith

(USA), Dáithí A. Stone (Canada/South Africa/USA), Avelino G. Suarez (Cuba), Petra Tschakert

(USA), Riccardo Valentini (Italy), Alicia Villamizar (Venezuela), Rachel Warren (UK),

Thomas J. Wilbanks (USA), Poh Poh Wong (Singapore), Alistair Woodward (New Zealand),

Gary W. Yohe (USA)

Summary for Policymakers

Contents

Assessing and Managing the Risks of Climate Change ........................................................................................................ 3

Background Box SPM.1. Context for the Assessment ........................................................................................................................................ 4

Background Box SPM.2. Terms Central for Understanding the Summary .......................................................................................................... 5

Background Box SPM.3. Communication of the Degree of Certainty in Assessment Findings ........................................................................... 6

A: Observed Impacts, Vulnerability, and Adaptation in a Complex and Changing World ............................................... 4

A-1. Observed Impacts, Vulnerability, and Exposure .......................................................................................................................................... 4

A-2. Adaptation Experience ............................................................................................................................................................................... 8

A-3. The Decision-making Context .................................................................................................................................................................... 9

B: Future Risks and Opportunities for Adaptation ........................................................................................................ 11

B-1. Key Risks across Sectors and Regions ...................................................................................................................................................... 11

Assessment Box SPM.1. Human Interference with the Climate System ........................................................................................................... 12

B-2. Sectoral Risks and Potential for Adaptation ............................................................................................................................................. 14

B-3. Regional Key Risks and Potential for Adaptation ..................................................................................................................................... 20

Assessment Box SPM.2. Regional Key Risks .................................................................................................................................................... 21

C: Managing Future Risks and Building Resilience ....................................................................................................... 25

C-1. Principles for Effective Adaptation ........................................................................................................................................................... 25

C-2. Climate-resilient Pathways and Transformation ....................................................................................................................................... 28

Supplementary Material ..................................................................................................................................................... 30

SPM

ASSESSING AND MANAGING THE RISKS OF CLIMATE CHANGE

Human interference with the climate system is occurring,

and climate change poses risks for human and natural systems (Figure SPM.1). The

assessment of impacts, adaptation, and vulnerability in the Working Group II contribution to the IPCC’s Fifth Assessment Report (WGII AR5)

evaluates how patterns of risks and potential benefits are shifting due to climate change. It considers how impacts and risks related to climate

change can be reduced and managed through adaptation and mitigation. The report assesses needs, options, opportunities, constraints,

resilience, limits, and other aspects associated with adaptation.

Climate change involves complex interactions and changing likelihoods of diverse impacts. A focus on risk, which is new in this report, supports

decision making in the context of climate change and complements other elements of the report. People and societies may perceive or rank

risks and potential benefits differently, given diverse values and goals.

Compared to past WGII reports, the WGII AR5 assesses a substantially larger knowledge base of relevant scientific, technical, and socioeconomic

literature. Increased literature has facilitated comprehensive assessment across a broader set of topics and sectors, with expanded coverage of

human systems, adaptation, and the ocean. See Background Box SPM.1.

Section A of this summary characterizes observed impacts, vulnerability and exposure, and adaptive responses to date. Section B examines future

risks and potential benefits. Section C considers principles for effective adaptation and the broader interactions among adaptation, mitigation,

EMISSIONS

and Land-use Change

Vulnerability

Exposure

RISK

Hazards

Anthropogenic

Climate Change

Socioeconomic

Pathways

Adaptation and

Mitigation

Actions

Governance

IMPACTS

Natural

Variability

SOCIOECONOMIC

PROCESSES

CLIMATE

Figure SPM.1 | Illustration of the core concepts of the WGII AR5. Risk of climate-related impacts results from the interaction of climate-related hazards (including hazardous

events and trends) with the vulnerability and exposure of human and natural systems. Changes in both the climate system (left) and socioeconomic processes including

adaptation and mitigation (right) are drivers of hazards, exposure, and vulnerability. [19.2, Figure 19-1]

Summary for Policymakers

A key finding of the WGI AR5 is, “It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century.”

[WGI AR5 SPM Section D.3, 2.2, 6.3, 10.3-6, 10.9]

1.1, Figure 1-1

SPM

Summary for Policymakers

and sustainable development. Background Box SPM.2 defines central concepts, and Background Box SPM.3 introduces terms used to convey

the degree of certainty in key findings. Chapter references in brackets and in footnotes indicate support for findings, figures, and tables.

A: OBSERVED IMPACTS, VULNERABILITY, AND ADAPTATION IN A COMPLEX AND CHANGING WORLD

A-1. Observed Impacts, Vulnerability, and Exposure

In recent decades, changes in climate have caused impacts on natural and human systems on all continents and across the

oceans. Evidence of climate-change impacts is strongest and most comprehensive for natural systems. Some impacts on human systems have

also been attributed

to climate change, with a major or minor contribution of climate change distinguishable from other influences. See

Figure SPM.2. Attribution of observed impacts in the WGII AR5 generally links responses of natural and human systems to observed climate

change, regardless of its cause.

In many regions, changing precipitation or melting snow and ice are altering hydrological systems, affecting water resources in

terms of quantity and quality (medium confidence). Glaciers continue to shrink almost worldwide due to climate change (high confidence),

affecting runoff and water resources downstream (medium confidence). Climate change is causing permafrost warming and thawing in high-

latitude regions and in high-elevation regions (high confidence).

Many terrestrial, freshwater, and marine species have shifted their geographic ranges, seasonal activities, migration patterns,

abundances, and species interactions in response to ongoing climate change (high confidence).

See Figure SPM.2B. While only a few recent

species extinctions have been attributed as yet to climate change (high confidence), natural global climate change at rates slower than current

anthropogenic climate change caused significant ecosystem shifts and species extinctions during the past millions of years (high confidence).

Based on many studies covering a wide range of regions and crops, negative impacts of climate change on crop yields have

been more common than positive impacts (high confidence).

The smaller number of studies showing positive impacts relate mainly to

Background Box SPM.1 | Context for the Assessment

For the past 2 decades, IPCC’s Working Group II has developed assessments of climate-change impacts, adaptation, and vulnerability.

The WGII AR5 builds from the WGII contribution to the IPCC’s Fourth Assessment Report (WGII AR4), published in 2007, and the

Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX), published in

2012. It follows the Working Group I contribution to the AR5 (WGI AR5).

The number of scientific publications available for assessing climate-change impacts, adaptation, and vulnerability more than

doubled between 2005 and 2010, with especially rapid increases in publications related to adaptation. Authorship of climate-change

publications from developing countries has increased, although it still represents a small fraction of the total.

The WGII AR5 is presented in two parts (Part A: Global and Sectoral Aspects, and Part B: Regional Aspects), reflecting the expanded

literature basis and multidisciplinary approach, increased focus on societal impacts and responses, and continued regionally

comprehensive coverage.

1.2-3

1.1, Figure 1-1

The term attribution is used differently in WGI and WGII. Attribution in WGII considers the links between impacts on natural and human systems and observed climate change,

regardless of its cause. By comparison, attribution in WGI quantifies the links between observed climate change and human activity, as well as other external climate drivers.

18.1, 18.3-6

3.2, 4.3, 18.3, 18.5, 24.4, 26.2, 28.2, Tables 3-1 and 25-1, Figures 18-2 and 26-1

4.2-4, 5.3-4, 6.1, 6.3-4, 18.3, 18.5, 22.3, 24.4, 25.6, 28.2, 30.4-5, Boxes 4-2, 4-3, 25-3, CC-CR, and CC-MB

SPM

Summary for Policymakers

Background Box SPM.2 | Terms Central for Understanding the Summary

limate change

Climate change refers to a change in the state of the climate that can be identified (e.g., by using statistical tests)

by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer.

Climate change may be due to natural internal processes or external forcings such as modulations of the solar cycles, volcanic

eruptions, and persistent anthropogenic changes in the composition of the atmosphere or in land use. Note that the Framework

Convention on Climate Change (UNFCCC), in its Article 1, defines climate change as: “a change of climate which is attributed directly or

indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability

observed over comparable time periods.” The UNFCCC thus makes a distinction between climate change attributable to human

activities altering the atmospheric composition, and climate variability attributable to natural causes.

Hazard: The potential occurrence of a natural or human-induced physical event or trend or physical impact that may cause loss of

life, injury, or other health impacts, as well as damage and loss to property, infrastructure, livelihoods, service provision, ecosystems,

and environmental resources. In this report, the term hazard usually refers to climate-related physical events or trends or their physical

impacts.

Exposure: The presence of people, livelihoods, species or ecosystems, environmental functions, services, and resources, infrastructure,

or economic, social, or cultural assets in places and settings that could be adversely affected.

Vulnerability: The propensity or predisposition to be adversely affected. Vulnerability encompasses a variety of concepts and

elements including sensitivity or susceptibility to harm and lack of capacity to cope and adapt.

Impacts: Effects on natural and human systems. In this report, the term impacts is used primarily to refer to the effects on natural

and human systems of extreme weather and climate events and of climate change. Impacts generally refer to effects on lives,

livelihoods, health, ecosystems, economies, societies, cultures, services, and infrastructure due to the interaction of climate changes or

hazardous climate events occurring within a specific time period and the vulnerability of an exposed society or system. Impacts are

also referred to as consequences and outcomes. The impacts of climate change on geophysical systems, including floods, droughts,

and sea level rise, are a subset of impacts called physical impacts.

Risk: The potential for consequences where something of value is at stake and where the outcome is uncertain, recognizing the

diversity of values. Risk is often represented as probability of occurrence of hazardous events or trends multiplied by the impacts if

these events or trends occur. Risk results from the interaction of vulnerability, exposure, and hazard (see Figure SPM.1). In this report,

the term risk is used primarily to refer to the risks of climate-change impacts.

Adaptation: The process of adjustment to actual or expected climate and its effects. In human systems, adaptation seeks to moderate

or avoid harm or exploit beneficial opportunities. In some natural systems, human intervention may facilitate adjustment to expected

climate and its effects.

Transformation: A change in the fundamental attributes of natural and human systems. Within this summary, transformation could

reflect strengthened, altered, or aligned paradigms, goals, or values towards promoting adaptation for sustainable development,

including poverty reduction.

Resilience: The capacity of social, economic, and environmental systems to cope with a hazardous event or trend or disturbance,

responding or reorganizing in ways that maintain their essential function, identity, and structure, while also maintaining the capacity

for adaptation, learning, and transformation.

The WGII AR5 glossary defines many terms used across chapters of the report. Reflecting progress in science, some definitions differ in breadth and focus from the definitions

used in the AR4 and other IPCC reports.

high-latitude regions, though it is not yet clear whether the balance of impacts has been negative or positive in these regions (high confidence).

Climate change has negatively affected wheat and maize yields for many regions and in the global aggregate (medium confidence). Effects on

rice and soybean yield have been smaller in major production regions and globally, with a median change of zero across all available data,

which are fewer for soy compared to the other crops. Observed impacts relate mainly to production aspects of food security rather than access

SPM

Summary for Policymakers

or other components of food security. See Figure SPM.2C. Since AR4, several periods of rapid food and cereal price increases following climate

extremes in key producing regions indicate a sensitivity of current markets to climate extremes among other factors (medium confidence).

At present the worldwide burden of human ill-health from climate change is relatively small compared with effects of other

stressors and is not well quantified. However, there has been increased heat-related mortality and decreased cold-related mortality in some

regions as a result of warming (medium confidence). Local changes in temperature and rainfall have altered the distribution of some water-

borne illnesses and disease vectors (medium confidence).

Differences in vulnerability and exposure arise from non-climatic factors and from multidimensional inequalities often produced

by uneven development processes (very high confidence). These differences shape differential risks from climate change. See

Figure SPM.1. People who are socially, economically, culturally, politically, institutionally, or otherwise marginalized are especially vulnerable to

climate change and also to some adaptation and mitigation responses (medium evidence, high agreement). This heightened vulnerability is

rarely due to a single cause. Rather, it is the product of intersecting social processes that result in inequalities in socioeconomic status and

income, as well as in exposure. Such social processes include, for example, discrimination on the basis of gender, class, ethnicity, age, and

(dis)ability.

Impacts from recent climate-related extremes, such as heat waves, droughts, floods, cyclones, and wildfires, reveal significant

vulnerability and exposure of some ecosystems and many human systems to current climate variability (very high confidence).

Impacts of such climate-related extremes include alteration of ecosystems, disruption of food production and water supply, damage to

infrastructure and settlements, morbidity and mortality, and consequences for mental health and human well-being. For countries at all levels

of development, these impacts are consistent with a significant lack of preparedness for current climate variability in some sectors.

Climate-related hazards exacerbate other stressors, often with negative outcomes for livelihoods, especially for people living in

poverty (high confidence).

Climate-related hazards affect poor people’s lives directly through impacts on livelihoods, reductions in crop

Background Box SPM.3 | Communication of the Degree of Certainty in Assessment Findings

he degree of certainty in each key finding of the assessment is based on the type, amount, quality, and consistency of evidence (e.g.,

data, mechanistic understanding, theory, models, expert judgment) and the degree of agreement. The summary terms to describe

evidence are: limited, medium, or robust; and agreement: low, medium, or high.

Confidence in the validity of a finding synthesizes the evaluation of evidence and agreement. Levels of confidence include five

qualifiers: very low, low, medium, high, and very high.

The likelihood, or probability, of some well-defined outcome having occurred or occurring in the future can be described quantitatively

through the following terms: virtually certain, 99–100% probability; extremely likely, 95–100%; very likely, 90–100%; likely,

66–100%; more likely than not, >50–100%; about as likely as not, 33–66%; unlikely, 0–33%; very unlikely, 0–10%; extremely unlikely,

0–5%; and exceptionally unlikely, 0–1%. Unless otherwise indicated, findings assigned a likelihood term are associated with high or

very high confidence. Where appropriate, findings are also formulated as statements of fact without using uncertainty qualifiers.

Within paragraphs of this summary, the confidence, evidence, and agreement terms given for a bold key finding apply to subsequent

statements in the paragraph, unless additional terms are provided.

1.1, Box 1-1

7.2, 18.4, 22.3, 26.5, Figures 7-2, 7-3, and 7-7

11.4-6, 18.4, 25.8

8.1-2, 9.3-4, 10.9, 11.1, 11.3-5, 12.2-5, 13.1-3, 14.1-3, 18.4, 19.6, 23.5, 25.8, 26.6, 26.8, 28.4, Box CC-GC

3.2, 4.2-3, 8.1, 9.3, 10.7, 11.3, 11.7, 13.2, 14.1, 18.6, 22.3, 25.6-8, 26.6-7, 30.5, Tables 18-3 and 23-1, Figure 26-2, Boxes 4-3, 4-4, 25-5, 25-6, 25-8, and CC-CR

SPM

RCTIC

Distribution change (km per decade)

(90)

(20)

(46)

(29)

(9)

(3)

(13)

(29)

(9)

(111) (359)

CoolerWarmer

enthic

lga

Benthic

cnida

ria

enthic

mollusks

nthic crustacea

Benthic invert. (other)

Phytoplankton

Zooplankton

Larval bony ﬁshes

Non-bony ﬁshes

ﬁ

percentile

Median

percentile

Standard error

Mean

Standard error

UROPE

medlow

very

high

very

low

high

Glaciers, snow, ice,

and/or permafrost

indicates

conﬁdence range

Rivers, lakes, ﬂoods,

and/or drought

Terrestrial ecosystems

Regional-scale

impacts

Marine ecosystems

Coastal erosion

and/or sea level effects

Wildﬁre

Livelihoods, health,

and/or economics

Food production

Physical systems Biological systems Human and managed systems

Filled symbols = Major contribution of climate change

Outlined symbols = Minor contribution of climate change

Conﬁdence in attribution

to climate change

Observed impacts attributed to climate change for

SMALL ISLANDS

USTRALASIA

AFRICA

CENTRAL & SOUTH

MERICA

ORTH AMERICA

SIA

ANTARCTIC

(A)

−6

−4

–2

400

100

–20

Maize

Rice

SoyWheat

Te m p e r ate

Region Crop type

Tropical

(12)(13)(10)(18)(27)(19)

Yield impact (% change per decade)

Figure SPM.2 | Widespread impacts in a changing world. (A) Global patterns of impacts in recent decades attributed to climate change, based on studies since the AR4. Impacts

are shown at a range of geographic scales. Symbols indicate categories of attributed impacts, the relative contribution of climate change (major or minor) to the observed impact,

and conﬁdence in attribution. See supplementary Table SPM.A1 for descriptions of the impacts. (B) Average rates of change in distribution (km per decade) for marine taxonomic

groups based on observations over 1900–2010. Positive distribution changes are consistent with warming (moving into previously cooler waters, generally poleward). The

number of responses analyzed is given within parentheses for each category. (C) Summary of estimated impacts of observed climate changes on yields over 1960–2013 for four

major crops in temperate and tropical regions, with the number of data points analyzed given within parentheses for each category. [Figures 7-2, 18-3, and MB-2]

Summary for Policymakers

SPM

Summary for Policymakers

ields, or destruction of homes and indirectly through, for example, increased food prices and food insecurity. Observed positive effects for poor

and marginalized people, which are limited and often indirect, include examples such as diversification of social networks and of agricultural

practices.

Violent conflict increases vulnerability to climate change (medium evidence, high agreement). Large-scale violent conflict harms

assets that facilitate adaptation, including infrastructure, institutions, natural resources, social capital, and livelihood opportunities.

A-2. Adaptation Experience

Throughout history, people and societies have adjusted to and coped with climate, climate variability, and extremes, with varying degrees of

success. This section focuses on adaptive human responses to observed and projected climate-change impacts, which can also address broader

risk-reduction and development objectives.

Adaptation is becoming embedded in some planning processes, with more limited implementation of responses (high confidence).

Engineered and technological options are commonly implemented adaptive responses, often integrated within existing programs such as disaster

risk management and water management. There is increasing recognition of the value of social, institutional, and ecosystem-based measures

and of the extent of constraints to adaptation. Adaptation options adopted to date continue to emphasize incremental adjustments and co-

benefits and are starting to emphasize flexibility and learning (medium evidence, medium agreement). Most assessments of adaptation have

been restricted to impacts, vulnerability, and adaptation planning, with very few assessing the processes of implementation or the effects of

adaptation actions (medium evidence, high agreement).

Adaptation experience is accumulating across regions in the public and private sector and within communities (high confidence).

Governments at various levels are starting to develop adaptation plans and policies and to integrate climate-change considerations

into broader development plans.

Examples of adaptation across regions include the following:

• In Africa, most national governments are initiating governance systems for adaptation. Disaster risk management, adjustments in technologies

and infrastructure, ecosystem-based approaches, basic public health measures, and livelihood diversification are reducing vulnerability,

although efforts to date tend to be isolated.

• In Europe, adaptation policy has been developed across all levels of government, with some adaptation planning integrated into coastal

and water management, into environmental protection and land planning, and into disaster risk management.

• In Asia, adaptation is being facilitated in some areas through mainstreaming climate adaptation action into subnational development

planning, early warning systems, integrated water resources management, agroforestry, and coastal reforestation of mangroves.

• In Australasia, planning for sea level rise, and in southern Australia for reduced water availability, is becoming adopted widely. Planning for

sea level rise has evolved considerably over the past 2 decades and shows a diversity of approaches, although its implementation remains

piecemeal.

• In North America, governments are engaging in incremental adaptation assessment and planning, particularly at the municipal level. Some

proactive adaptation is occurring to protect longer-term investments in energy and public infrastructure.

• In Central and South America, ecosystem-based adaptation including protected areas, conservation agreements, and community

management of natural areas is occurring. Resilient crop varieties, climate forecasts, and integrated water resources management are

being adopted within the agricultural sector in some areas.

8.2-3, 9.3, 11.3, 13.1-3, 22.3, 24.4, 26.8

12.5, 19.2, 19.6

4.4, 5.5, 6.4, 8.3, 9.4, 11.7, 14.1, 14.3-4, 15.2-5, 17.2-3, 21.3, 21.5, 22.4, 23.7, 25.4, 26.8-9, 30.6, Boxes 25-1, 25-2, 25-9, and CC-EA

22.4

23.7, Boxes 5-1 and 23-3

24.4-6, 24.9 Box CC-TC

25.4, 25.10, Table 25-2, Boxes 25-1, 25-2, and 25-9

26.7-9

27.3

SPM

•

In the Arctic, some communities have begun to deploy adaptive co-management strategies and communications infrastructure, combining

traditional and scientific knowledge.

• In small islands, which have diverse physical and human attributes, community-based adaptation has been shown to generate larger

benefits when delivered in conjunction with other development activities.

• In the ocean, international cooperation and marine spatial planning are starting to facilitate adaptation to climate change, with constraints

from challenges of spatial scale and governance issues.

A-3. The Decision-making Context

Climate variability and extremes have long been important in many decision-making contexts. Climate-related risks are now evolving over time

due to both climate change and development. This section builds from existing experience with decision making and risk management. It creates

a foundation for understanding the report’s assessment of future climate-related risks and potential responses.

Responding to climate-related risks involves decision making in a changing world, with continuing uncertainty about the severity

and timing of climate-change impacts and with limits to the effectiveness of adaptation (high confidence). Iterative risk management

is a useful framework for decision making in complex situations characterized by large potential consequences, persistent uncertainties, long

timeframes, potential for learning, and multiple climatic and non-climatic influences changing over time. See Figure SPM.3. Assessment of the

widest possible range of potential impacts, including low-probability outcomes with large consequences, is central to understanding the benefits

and trade-offs of alternative risk management actions. The complexity of adaptation actions across scales and contexts means that monitoring

and learning are important components of effective adaptation.

Adaptation and mitigation choices in the near term will affect the risks of climate change throughout the 21st century (high

confidence).

Figure SPM.4 illustrates projected warming under a low-emission mitigation scenario and a high-emission scenario [Representative

Concentration Pathways (RCPs) 2.6 and 8.5], along with observed temperature changes. The benefits of adaptation and mitigation occur over

different but overlapping timeframes. Projected global temperature increase over the next few decades is similar across emission scenarios

(Figure SPM.4B).

During this near-term period, risks will evolve as socioeconomic trends interact with the changing climate. Societal

Scoping

Implementation

Review

& learn

Implement

decision

Monitor

Assess

risks

Identify

options

Evaluate

tradeoffs

Analysis

Identify risks,

vulnerabilities,

& objectives

Establish decision-

making criteria

Figure SPM.3 | Climate-change adaptation

as an iterative risk management process with

multiple feedbacks. People and knowledge shape

the process and its outcomes. [Figure 2-1]

Summary for Policymakers

28.2, 28.4

29.3, 29.6, Table 29-3, Figure 29-1

30.6

2.1-4, 3.6, 14.1-3, 15.2-4, 16.2-4, 17.1-3, 17.5, 20.6, 22.4, 25.4, Figure 1-5

WGI AR5 11.3

SPM

Summary for Policymakers

Observed Temperature Change

Based on trend over

1901–2012 (

C over period)

Diagonal Lines

rend not

statistically

signiﬁcant

White

Insufﬁcient

data

Solid Color

igniﬁcant

trend

Projected Temperature Change

02 46

–0.5 11.7

02 46

–0.5 11.7

Difference from

1986–2005 mean (

Solid Color

Strong

agreement

Very strong

agreement

Little or

no change

Gray

Divergent

changes

Diagonal Lines

White Dots

(A)

(B)

(C)

RCP8.5 2081–2100RCP2.6 2081–2100

Global mean temperature change

(

C relative to 1986–2005)

1900 1950 2000 2050 2100

–2

Figure SPM.4 | Observed and projected changes in annual average surface temperature. This ﬁgure informs understanding of climate-related risks in the WGII AR5. It illustrates

temperature change observed to date and projected warming under continued high emissions and under ambitious mitigation.

Observed

RCP2.6

RCP8.5

Overlap

SPM

responses, particularly adaptations, will influence near-term outcomes. In the second half of the 21st century and beyond, global temperature

increase diverges across emission scenarios (Figure SPM.4B and 4C).

For this longer-term period, near-term and longer-term adaptation and

mitigation, as well as development pathways, will determine the risks of climate change.

Assessment of risks in the WGII AR5 relies on diverse forms of evidence. Expert judgment is used to integrate evidence into

evaluations of risks. Forms of evidence include, for example, empirical observations, experimental results, process-based understanding,

statistical approaches, and simulation and descriptive models. Future risks related to climate change vary substantially across plausible

alternative development pathways, and the relative importance of development and climate change varies by sector, region, and time period

(high confidence). Scenarios are useful tools for characterizing possible future socioeconomic pathways, climate change and its risks, and policy

implications. Climate-model projections informing evaluations of risks in this report are generally based on the RCPs (Figure SPM.4), as well as

the older IPCC Special Report on Emission Scenarios (SRES) scenarios.

Uncertainties about future vulnerability, exposure, and responses of interlinked human and natural systems are large (high

confidence). This motivates exploration of a wide range of socioeconomic futures in assessments of risks.

Understanding future

vulnerability, exposure, and response capacity of interlinked human and natural systems is challenging due to the number of interacting social,

economic, and cultural factors, which have been incompletely considered to date. These factors include wealth and its distribution across

society, demographics, migration, access to technology and information, employment patterns, the quality of adaptive responses, societal

values, governance structures, and institutions to resolve conflicts. International dimensions such as trade and relations among states are also

important for understanding the risks of climate change at regional scales.

B: FUTURE RISKS AND OPPORTUNITIES FOR ADAPTATION

This section presents future risks and more limited potential benefits across sectors and regions, over the next few decades and in the second

half of the 21st century and beyond. It examines how they are affected by the magnitude and rate of climate change and by socioeconomic

choices. It also assesses opportunities for reducing impacts and managing risks through adaptation and mitigation.

B-1. Key Risks across Sectors and Regions

Key risks are potentially severe impacts relevant to Article 2 of the United Nations Framework Convention on Climate Change, which refers to

“dangerous anthropogenic interference with the climate system.” Risks are considered key due to high hazard or high vulnerability of societies

and systems exposed, or both. Identification of key risks was based on expert judgment using the following specific criteria: large magnitude,

Figure SPM.4 Technical Details

(A) Map of observed annual average temperature change from 1901–2012, derived from a linear trend where sufﬁcient data permit a robust estimate; other areas are white.

Solid colors indicate areas where trends are signiﬁcant at the 10% level. Diagonal lines indicate areas where trends are not signiﬁcant. Observed data (range of grid-point values:

–0.53 to 2.50°C over period) are from WGI AR5 Figures SPM.1 and 2.21. (B) Observed and projected future global annual average temperature relative to 1986–2005. Observed

warming from 1850–1900 to 1986–2005 is 0.61°C (5–95% conﬁdence interval: 0.55 to 0.67°C). Black lines show temperature estimates from three datasets. Blue and red

lines and shading denote the ensemble mean and ±1.64 standard deviation range, based on CMIP5 simulations from 32 models for RCP2.6 and 39 models for RCP8.5. (C)

CMIP5 multi-model mean projections of annual average temperature changes for 2081–2100 under RCP2.6 and 8.5, relative to 1986–2005. Solid colors indicate areas with very

strong agreement, where the multi-model mean change is greater than twice the baseline variability (natural internal variability in 20-yr means) and ≥90% of models agree on

sign of change. Colors with white dots indicate areas with strong agreement, where ≥66% of models show change greater than the baseline variability and ≥66% of models

agree on sign of change. Gray indicates areas with divergent changes, where ≥66% of models show change greater than the baseline variability, but <66% agree on sign of

change. Colors with diagonal lines indicate areas with little or no change, where <66% of models show change greater than the baseline variability, although there may be

signiﬁcant change at shorter timescales such as seasons, months, or days. Analysis uses model data (range of grid-point values across RCP2.6 and 8.5: 0.06 to 11.71°C) from

WGI AR5 Figure SPM.8, with full description of methods in Box CC-RC. See also Annex I of WGI AR5. [Boxes 21-2 and CC-RC; WGI AR5 2.4, Figures SPM.1, SPM.7, and 2.21]

Summary for Policymakers

WGI AR5 12.4 and Table SPM.2

2.5, 21.2-3, 21.5, Box CC-RC

1.1, 1.3, 2.2-3, 19.6, 20.2, 21.3, 21.5, 26.2, Box CC-RC; WGI AR5 Box SPM.1

11.3, 12.6, 21.3-5, 25.3-4, 25.11, 26.2

SPM

Summary for Policymakers

high probability, or irreversibility of impacts; timing of impacts; persistent vulnerability or exposure contributing to risks; or limited potential to

reduce risks through adaptation or mitigation. Key risks are integrated into five complementary and overarching reasons for concern (RFCs) in

Assessment Box SPM.1.

The key risks that follow, all of which are identified with high confidence, span sectors and regions. Each of these key risks

contributes to one or more RFCs.

WGI AR5 SPM, 2.2, 6.3, 10.3-6, 10.9

18.6, 19.6; observed warming from 1850–1900 to 1986–2005 is 0.61°C (5–95% confidence interval: 0.55 to 0.67°C). [WGI AR5 2.4]

Current estimates indicate that this threshold is greater than about 1°C (low confidence) but less than about 4°C (medium confidence) sustained global mean warming above

preindustrial levels. [WGI AR5 SPM, 5.8, 13.4-5]

19.2-4, 19.6, Table 19-4, Boxes 19-2 and CC-KR

Assessment Box SPM.1 | Human Interference with the Climate System

uman inﬂuence on the climate system is clear.

et determining whether such inﬂuence constitutes “dangerous anthropogenic

interference” in the words of Article 2 of the UNFCCC involves both risk assessment and value judgments. This report assesses risks

across contexts and through time, providing a basis for judgments about the level of climate change at which risks become dangerous.

Five integrative reasons for concern (RFCs) provide a framework for summarizing key risks across sectors and regions.

First identiﬁed in the IPCC Third Assessment Report, the RFCs illustrate the implications of warming and of adaptation limits for people,

economies, and ecosystems. They provide one starting point for evaluating dangerous anthropogenic interference with the climate system.

Risks for each RFC, updated based on assessment of the literature and expert judgments, are presented below and in Assessment Box

SPM.1 Figure 1. All temperatures below are given as global average temperature change relative to 1986–2005 (“recent”).

1) Unique and threatened systems: Some unique and threatened systems, including ecosystems and cultures, are already at risk

from climate change (high conﬁdence). The number of such systems at risk of severe consequences is higher with additional

warming of around 1°C. Many species and systems with limited adaptive capacity are subject to very high risks with additional

warming of 2°C, particularly Arctic-sea-ice and coral-reef systems.

2) Extreme weather events: Climate-change-related risks from extreme events, such as heat waves, extreme precipitation, and

coastal ﬂooding, are already moderate (high conﬁdence) and high with 1°C additional warming (medium conﬁdence). Risks

associated with some types of extreme events (e.g., extreme heat) increase further at higher temperatures (high conﬁdence).

3) Distribution of impacts: Risks are unevenly distributed and are generally greater for disadvantaged people and communities in

countries at all levels of development. Risks are already moderate because of regionally differentiated climate-change impacts on

crop production in particular (medium to high conﬁdence). Based on projected decreases in regional crop yields and water

availability, risks of unevenly distributed impacts are high for additional warming above 2°C (medium conﬁdence).

4) Global aggregate impacts: Risks of global aggregate impacts are moderate for additional warming between 1–2°C, reﬂecting

impacts to both Earth’s biodiversity and the overall global economy (medium conﬁdence). Extensive biodiversity loss with associated

loss of ecosystem goods and services results in high risks around 3°C additional warming (high conﬁdence). Aggregate economic

damages accelerate with increasing temperature (limited evidence, high agreement), but few quantitative estimates have been

completed for additional warming around 3°C or above.

5) Large-scale singular events: With increasing warming, some physical systems or ecosystems may be at risk of abrupt and

irreversible changes. Risks associated with such tipping points become moderate between 0–1°C additional warming, due to early

warning signs that both warm-water coral reef and Arctic ecosystems are already experiencing irreversible regime shifts (medium

conﬁdence). Risks increase disproportionately as temperature increases between 1–2°C additional warming and become high

above 3°C, due to the potential for a large and irreversible sea level rise from ice sheet loss. For sustained warming greater than

some threshold,

near-complete loss of the Greenland ice sheet would occur over a millennium or more, contributing up to 7 m of

global mean sea level rise.

SPM

i) Risk of death, injury, ill-health, or disrupted livelihoods in low-lying coastal zones and small island developing states and other small

islands, due to storm surges, coastal flooding, and sea level rise.

[RFC 1-5]

ii) Risk of severe ill-health and disrupted livelihoods for large urban populations due to inland flooding in some regions.

[RFC 2 and 3]

iii) Systemic risks due to extreme weather events leading to breakdown of infrastructure networks and critical services such as electricity,

water supply, and health and emergency services.

[RFC 2-4]

iv) Risk of mortality and morbidity during periods of extreme heat, particularly for vulnerable urban populations and those working outdoors

in urban or rural areas.

[RFC 2 and 3]

v) Risk of food insecurity and the breakdown of food systems linked to warming, drought, flooding, and precipitation variability and extremes,

particularly for poorer populations in urban and rural settings.

[RFC 2-4]

vi) Risk of loss of rural livelihoods and income due to insufficient access to drinking and irrigation water and reduced agricultural productivity,

particularly for farmers and pastoralists with minimal capital in semi-arid regions.

[RFC 2 and 3]

vii) Risk of loss of marine and coastal ecosystems, biodiversity, and the ecosystem goods, functions, and services they provide for coastal

livelihoods, especially for fishing communities in the tropics and the Arctic.

[RFC 1, 2, and 4]

viii) Risk of loss of terrestrial and inland water ecosystems, biodiversity, and the ecosystem goods, functions, and services they provide for

livelihoods.

[RFC 1, 3, and 4]

Many key risks constitute particular challenges for the least developed countries and vulnerable communities, given their limited ability to

cope.

°C

Undetectable

ery high

evel of additional risk due to climate change

Moderate

igh

Unique &

threatened

systems

Extreme

weather

events

Distribution

of impacts

Global

aggregate

impacts

Large-scale

singular

events

1900 1950 2000 2050

°C

(

C relative to 1850–1900, as an

approximation of preindustrial levels)

2003

–2012

2100

(

C relative to 1850–1900, as an

approximation of preindustrial levels)

°C

0.61

(

C relative to 1986–2005)

Global mean temperature change

°C

0.61

Assessment Box SPM.1 Figure 1 | A global perspective on climate-related risks. Risks associated with reasons for concern are shown at right for increasing levels of climate

change. The color shading indicates the additional risk due to climate change when a temperature level is reached and then sustained or exceeded. Undetectable risk (white)

indicates no associated impacts are detectable and attributable to climate change. Moderate risk (yellow) indicates that associated impacts are both detectable and attributable

to climate change with at least medium conﬁdence, also accounting for the other speciﬁc criteria for key risks. High risk (red) indicates severe and widespread impacts, also

accounting for the other speciﬁc criteria for key risks. Purple, introduced in this assessment, shows that very high risk is indicated by all speciﬁc criteria for key risks. [Figure 19-4]

For reference, past and projected global annual average surface temperature is shown at left, as in Figure SPM.4. [Figure RC-1, Box CC-RC; WGI AR5 Figures SPM.1 and SPM.7]

Based on the longest global surface temperature dataset available, the observed change between the average of the period 1850–1900 and of the AR5 reference period

(1986–2005) is 0.61°C (5–95% conﬁdence interval: 0.55 to 0.67°C) [WGI AR5 SPM, 2.4], which is used here as an approximation of the change in global mean surface

temperature since preindustrial times, referred to as the period before 1750. [WGI and WGII AR5 glossaries]

(

C relative to 1986–2005)

Global mean temperature change

Observed

RCP2.6 (a low-emission mitigation scenario)

RCP8.5 (a high-emission scenario)

Overlap

Summary for Policymakers

5.4, 8.2, 13.2, 19.2-4, 19.6-7, 24.4-5, 26.7-8, 29.3, 30.3, Tables 19-4 and 26-1, Figure 26-2, Boxes 25-1, 25-7, and CC-KR

3.4-5, 8.2, 13.2, 19.6, 25.10, 26.3, 26.8, 27.3, Tables 19-4 and 26-1, Boxes 25-8 and CC-KR

5.4, 8.1-2, 9.3, 10.2-3, 12.6, 19.6, 23.9, 25.10, 26.7-8, 28.3, Table 19-4, Boxes CC-KR and CC-HS

8.1-2, 11.3-4, 11.6, 13.2, 19.3, 19.6, 23.5, 24.4, 25.8, 26.6, 26.8, Tables 19-4 and 26-1, Boxes CC-KR and CC-HS

3.5, 7.4-5, 8.2-3, 9.3, 11.3, 11.6, 13.2, 19.3-4, 19.6, 22.3, 24.4, 25.5, 25.7, 26.5, 26.8, 27.3, 28.2, 28.4, Table 19-4, Box CC-KR

3.4-5, 9.3, 12.2, 13.2, 19.3, 19.6, 24.4, 25.7, 26.8, Table 19-4, Boxes 25-5 and CC-KR

5.4, 6.3, 7.4, 9.3, 19.5-6, 22.3, 25.6, 27.3, 28.2-3, 29.3, 30.5-7, Table 19-4, Boxes CC-OA, CC-CR, CC-KR, and CC-HS

4.3, 9.3, 19.3-6, 22.3, 25.6, 27.3, 28.2-3, Table 19-4, Boxes CC-KR and CC-WE

SPM

Summary for Policymakers

ncreasing magnitudes of warming increase the likelihood of severe, pervasive, and irreversible impacts.

ome risks of climate

change are considerable at 1 or 2°C above preindustrial levels (as shown in Assessment Box SPM.1). Global climate change risks are high to

very high with global mean temperature increase of 4°C or more above preindustrial levels in all reasons for concern (Assessment Box SPM.1),

and include severe and widespread impacts on unique and threatened systems, substantial species extinction, large risks to global and regional

food security, and the combination of high temperature and humidity compromising normal human activities, including growing food or

working outdoors in some areas for parts of the year (high confidence). The precise levels of climate change sufficient to trigger tipping points

(thresholds for abrupt and irreversible change) remain uncertain, but the risk associated with crossing multiple tipping points in the earth

system or in interlinked human and natural systems increases with rising temperature (medium confidence).

The overall risks of climate change impacts can be reduced by limiting the rate and magnitude of climate change. Risks are

reduced substantially under the assessed scenario with the lowest temperature projections (RCP2.6 – low emissions) compared to the highest

temperature projections (RCP8.5 – high emissions), particularly in the second half of the 21st century (very high confidence). Reducing climate

change can also reduce the scale of adaptation that might be required. Under all assessed scenarios for adaptation and mitigation, some risk

from adverse impacts remains (very high confidence).

B-2. Sectoral Risks and Potential for Adaptation

Climate change is projected to amplify existing climate-related risks and create new risks for natural and human systems. Some of these risks

will be limited to a particular sector or region, and others will have cascading effects. To a lesser extent, climate change is also projected to

have some potential benefits.

Freshwater resources

Freshwater-related risks of climate change increase significantly with increasing greenhouse gas concentrations (robust evidence,

high agreement). The fraction of global population experiencing water scarcity and the fraction affected by major river floods increase with

the level of warming in the 21st century.

Climate change over the 21st century is projected to reduce renewable surface water and groundwater resources significantly in

most dry subtropical regions (robust evidence, high agreement), intensifying competition for water among sectors (limited

evidence, medium agreement).

In presently dry regions, drought frequency will likely increase by the end of the 21st century under RCP8.5

(medium confidence). In contrast, water resources are projected to increase at high latitudes (robust evidence, high agreement). Climate

change is projected to reduce raw water quality and pose risks to drinking water quality even with conventional treatment, due to interacting

factors: increased temperature; increased sediment, nutrient, and pollutant loadings from heavy rainfall; increased concentration of pollutants

during droughts; and disruption of treatment facilities during floods (medium evidence, high agreement). Adaptive water management

techniques, including scenario planning, learning-based approaches, and flexible and low-regret solutions, can help create resilience to

uncertain hydrological changes and impacts due to climate change (limited evidence, high agreement).

Terrestrial and freshwater ecosystems

A large fraction of both terrestrial and freshwater species faces increased extinction risk under projected climate change during

and beyond the 21st century, especially as climate change interacts with other stressors, such as habitat modification, over-

4.2-3, 11.8, 19.5, 19.7, 26.5, Box CC-HS

3.4-5, 16.6, 17.2, 19.7, 20.3, 25.10, Tables 3-2, 8-3, and 8-6, Boxes 16-3 and 25-1

3.4-5, 26.3, Table 3-2, Box 25-8

SPM

xploitation, pollution, and invasive species (high confidence).

xtinction risk is increased under all RCP scenarios, with risk increasing

with both magnitude and rate of climate change. Many species will be unable to track suitable climates under mid- and high-range rates of

climate change (i.e., RCP4.5, 6.0, and 8.5) during the 21st century (medium confidence). Lower rates of change (i.e., RCP2.6) will pose fewer

problems. See Figure SPM.5. Some species will adapt to new climates. Those that cannot adapt sufficiently fast will decrease in abundance or

go extinct in part or all of their ranges. Management actions, such as maintenance of genetic diversity, assisted species migration and dispersal,

manipulation of disturbance regimes (e.g., fires, floods), and reduction of other stressors, can reduce, but not eliminate, risks of impacts to

terrestrial and freshwater ecosystems due to climate change, as well as increase the inherent capacity of ecosystems and their species to adapt

to a changing climate (high confidence).

Within this century, magnitudes and rates of climate change associated with medium- to high-emission scenarios (RCP4.5, 6.0,

and 8.5) pose high risk of abrupt and irreversible regional-scale change in the composition, structure, and function of terrestrial

and freshwater ecosystems, including wetlands (medium confidence).

Examples that could lead to substantial impact on climate are the

boreal-tundra Arctic system (medium confidence) and the Amazon forest (low confidence). Carbon stored in the terrestrial biosphere (e.g., in

peatlands, permafrost, and forests) is susceptible to loss to the atmosphere as a result of climate change, deforestation, and ecosystem

degradation (high confidence). Increased tree mortality and associated forest dieback is projected to occur in many regions over the 21st

century, due to increased temperatures and drought (medium confidence). Forest dieback poses risks for carbon storage, biodiversity, wood

production, water quality, amenity, and economic activity.

Trees

Herbaceous

plants

Split-hoofed

mammals

Carnivorous

mammals

Rodents

Primates

Plant-feeding

insects

Freshwater

mollusks

Maximum speed at which species can move (km per decade)

Lower

bound

Upper

bound

Median

100

RCP8.5 ﬂat areas

Average climate velocity

2050–2090

RCP6.0 ﬂat areas

RCP6.0 global average

RCP8.5 global average

RCP2.6 ﬂat areas and global average

RCP4.5 ﬂat areas

RCP4.5 global average

Figure SPM.5 | Maximum speeds at which species can move across landscapes (based on observations and models; vertical axis on left), compared with speeds at which

temperatures are projected to move across landscapes (climate velocities for temperature; vertical axis on right). Human interventions, such as transport or habitat fragmentation,

can greatly increase or decrease speeds of movement. White boxes with black bars indicate ranges and medians of maximum movement speeds for trees, plants, mammals,

plant-feeding insects (median not estimated), and freshwater mollusks. For RCP2.6, 4.5, 6.0, and 8.5 for 2050–2090, horizontal lines show climate velocity for the

global-land-area average and for large ﬂat regions. Species with maximum speeds below each line are expected to be unable to track warming in the absence of human

intervention. [Figure 4-5]

Summary for Policymakers

3.2, 3.4-6, 22.3, 23.9, 25.5, 26.3, Table 3-2, Table 23-3, Boxes 25-2, CC-RF, and CC-WE; WGI AR5 12.4

4.3-4, 25.6, 26.4, Box CC-RF

4.2-3, Figure 4-8, Boxes 4-2, 4-3, and 4-4

SPM

Summary for Policymakers

Change in maximum catch potential (2051–2060 compared to 2001–2010, SRES A1B)

> 100 %< –50 % –21 to –50 % –6 to –20 %

–1 to –5 %

20 to 49 %

50 to 100 %

5 to 19 %

0 to 4 %no data

Mollusk and crustacean ﬁsheries

(present-day annual catch rate

≥

0.005 tonnes km

-2

)

Cold-water

corals

Warm-water

corals

Change in pH (2081–2100 compared to 1986–2005, RCP8.5)

Positive effect

No effect

Negative effect

pCO

(μatm)

(A)

40 16 15 31

–

100

Mollusks

–2

37 4918

–

100

Crustaceans

–

Cold-water corals

7475

–

100

–2

Species (%)

26 9 15 23

100

–

–2

Warm-water corals

(B)

–

SPM

Coastal systems and low-lying areas

Due to sea level rise projected throughout the 21st century and beyond, coastal systems and low-lying areas will increasingly

experience adverse impacts such as submergence, coastal flooding, and coastal erosion (very high confidence). The population and

assets projected to be exposed to coastal risks as well as human pressures on coastal ecosystems will increase significantly in the coming

decades due to population growth, economic development, and urbanization (high confidence). The relative costs of coastal adaptation vary

strongly among and within regions and countries for the 21st century. Some low-lying developing countries and small island states are expected

to face very high impacts that, in some cases, could have associated damage and adaptation costs of several percentage points of GDP.

Marine systems

Due to projected climate change by the mid 21st century and beyond, global marine-species redistribution and marine-biodiversity

reduction in sensitive regions will challenge the sustained provision of fisheries productivity and other ecosystem services (high

confidence).

Spatial shifts of marine species due to projected warming will cause high-latitude invasions and high local-extinction rates in the

tropics and semi-enclosed seas (medium confidence). Species richness and fisheries catch potential are projected to increase, on average, at

mid and high latitudes (high confidence) and decrease at tropical latitudes (medium confidence). See Figure SPM.6A. The progressive expansion

of oxygen minimum zones and anoxic “dead zones” is projected to further constrain fish habitat. Open-ocean net primary production is

projected to redistribute and, by 2100, fall globally under all RCP scenarios. Climate change adds to the threats of over-fishing and other non-

climatic stressors, thus complicating marine management regimes (high confidence).

For medium- to high-emission scenarios (RCP4.5, 6.0, and 8.5), ocean acidification poses substantial risks to marine ecosystems,

especially polar ecosystems and coral reefs, associated with impacts on the physiology, behavior, and population dynamics of

individual species from phytoplankton to animals (medium to high confidence).

Highly calcified mollusks, echinoderms, and reef-building

corals are more sensitive than crustaceans (high confidence) and fishes (low confidence), with potentially detrimental consequences for fisheries

and livelihoods. See Figure SPM.6B. Ocean acidification acts together with other global changes (e.g., warming, decreasing oxygen levels) and

with local changes (e.g., pollution, eutrophication) (high confidence). Simultaneous drivers, such as warming and ocean acidification, can lead

to interactive, complex, and amplified impacts for species and ecosystems.

Food security and food production systems

For the major crops (wheat, rice, and maize) in tropical and temperate regions, climate change without adaptation is projected to

negatively impact production for local temperature increases of 2°C or more above late-20th-century levels, although individual

locations may benefit (medium confidence).

Projected impacts vary across crops and regions and adaptation scenarios, with about 10% of

projections for the period 2030–2049 showing yield gains of more than 10%, and about 10% of projections showing yield losses of more than

Figure SPM.6 | Climate change risks for ﬁsheries. (A) Projected global redistribution of maximum catch potential of ~1000 exploited ﬁsh and invertebrate species. Projections

compare the 10-year averages 2001–2010 and 2051–2060 using SRES A1B, without analysis of potential impacts of overﬁshing or ocean acidiﬁcation. (B) Marine mollusk and

crustacean ﬁsheries (present-day estimated annual catch rates ≥0.005 tonnes km

-2

) and known locations of cold- and warm-water corals, depicted on a global map showing the

rojected distribution of ocean acidiﬁcation under RCP8.5 (pH change from 1986–2005 to 2081–2100). [WGI AR5 Figure SPM.8] The bottom panel compares sensitivity to

ocean acidiﬁcation across mollusks, crustaceans, and corals, vulnerable animal phyla with socioeconomic relevance (e.g., for coastal protection and ﬁsheries). The number of

pecies analyzed across studies is given for each category of elevated CO

For 2100, RCP scenarios falling within each CO

partial pressure (pCO

)

category are as follows:

RCP4.5 for 500–650 μatm (approximately equivalent to ppm in the atmosphere), RCP6.0 for 651–850 μatm, and RCP8.5 for 851–1370 μatm. By 2150, RCP8.5 falls within the

1371–2900 μatm category. The control category corresponds to 380 μatm. [6.1, 6.3, 30.5, Figures 6-10 and 6-14; WGI AR5 Box SPM.1]

Summary for Policymakers

5.3-5, 8.2, 22.3, 24.4, 25.6, 26.3, 26.8, Table 26-1, Box 25-1

6.3-5, 7.4, 25.6, 28.3, 30.6-7, Boxes CC-MB and CC-PP

5.4, 6.3-5, 22.3, 25.6, 28.3, 30.5, Boxes CC-CR, CC-OA, and TS.7

SPM

Summary for Policymakers

25%, compared to the late 20th century. After 2050 the risk of more severe yield impacts increases and depends on the level of warming. See

Figure SPM.7. Climate change is projected to progressively increase inter-annual variability of crop yields in many regions. These projected

impacts will occur in the context of rapidly rising crop demand.

All aspects of food security are potentially affected by climate change, including food access, utilization, and price stability (high

confidence).

Redistribution of marine fisheries catch potential towards higher latitudes poses risk of reduced supplies, income, and employment

in tropical countries, with potential implications for food security (medium confidence). Global temperature increases of ~4°C or more above

late-20th-century levels, combined with increasing food demand, would pose large risks to food security globally and regionally (high

confidence). Risks to food security are generally greater in low-latitude areas.

Urban areas

Many global risks of climate change are concentrated in urban areas (medium confidence). Steps that build resilience and enable

sustainable development can accelerate successful climate-change adaptation globally.

Heat stress, extreme precipitation, inland and

coastal flooding, landslides, air pollution, drought, and water scarcity pose risks in urban areas for people, assets, economies, and ecosystems

(very high confidence). Risks are amplified for those lacking essential infrastructure and services or living in poor-quality housing and exposed

areas. Reducing basic service deficits, improving housing, and building resilient infrastructure systems could significantly reduce vulnerability

and exposure in urban areas. Urban adaptation benefits from effective multi-level urban risk governance, alignment of policies and incentives,

strengthened local government and community adaptation capacity, synergies with the private sector, and appropriate financing and

institutional development (medium confidence). Increased capacity, voice, and influence of low-income groups and vulnerable communities

and their partnerships with local governments also benefit adaptation.

Figure SPM.7 | Summary of projected changes in crop yields, due to climate change over the 21st century. The ﬁgure includes projections for different emission scenarios, for

tropical and temperate regions, and for adaptation and no-adaptation cases combined. Relatively few studies have considered impacts on cropping systems for scenarios where

global mean temperatures increase by 4

C or more. For ﬁve timeframes in the near term and long term, data (n=1090) are plotted in the 20-year period on the horizontal axis

that includes the midpoint of each future projection period. Changes in crop yields are relative to late-20th-century levels. Data for each timeframe sum to 100%. [Figure 7-5]

0 to –5%

–5 to –10%

–10 to –25%

–25 to –50%

–50 to –100%

0 to 5%

5 to 10%

10 to 25%

25 to 50%

50 to 100%

Range of yield change

increase

n yield

ecrease

n yield

Color Legend

Percentage of yield projections

2010–2029 2030–2049 2090–2109

100

2070–20892050–2069

7.4-5, 22.3, 24.4, 25.7, 26.5, Table 7-2, Figures 7-4, 7-5, 7-6, 7-7, and 7-8

6.3-5, 7.4-5, 9.3, 22.3, 24.4, 25.7, 26.5, Table 7-3, Figures 7-1, 7-4, and 7-7, Box 7-1

3.5, 8.2-4, 22.3, 24.4-5, 26.8, Table 8-2, Boxes 25-9 and CC-HS

SPM

Rural areas

Major future rural impacts are expected in the near term and beyond through impacts on water availability and supply, food

security, and agricultural incomes, including shifts in production areas of food and non-food crops across the world (high

confidence).

These impacts are expected to disproportionately affect the welfare of the poor in rural areas, such as female-headed households

and those with limited access to land, modern agricultural inputs, infrastructure, and education. Further adaptations for agriculture, water,

forestry, and biodiversity can occur through policies taking account of rural decision-making contexts. Trade reform and investment can improve

market access for small-scale farms (medium confidence).

Key economic sectors and services

For most economic sectors, the impacts of drivers such as changes in population, age structure, income, technology, relative prices,

lifestyle, regulation, and governance are projected to be large relative to the impacts of climate change (medium evidence, high

agreement).

Climate change is projected to reduce energy demand for heating and increase energy demand for cooling in the residential and

commercial sectors (robust evidence, high agreement). Climate change is projected to affect energy sources and technologies differently,

depending on resources (e.g., water flow, wind, insolation), technological processes (e.g., cooling), or locations (e.g., coastal regions, floodplains)

involved. More severe and/or frequent extreme weather events and/or hazard types are projected to increase losses and loss variability in

various regions and challenge insurance systems to offer affordable coverage while raising more risk-based capital, particularly in developing

countries. Large-scale public-private risk reduction initiatives and economic diversification are examples of adaptation actions.

Global economic impacts from climate change are difficult to estimate. Economic impact estimates completed over the past 20 years

vary in their coverage of subsets of economic sectors and depend on a large number of assumptions, many of which are disputable, and many

estimates do not account for catastrophic changes, tipping points, and many other factors.

With these recognized limitations, the incomplete

estimates of global annual economic losses for additional temperature increases of ~2°C are between 0.2 and 2.0% of income (±1 standard

deviation around the mean) (medium evidence, medium agreement). Losses are more likely than not to be greater, rather than smaller, than

this range (limited evidence, high agreement). Additionally, there are large differences between and within countries. Losses accelerate with

greater warming (limited evidence, high agreement), but few quantitative estimates have been completed for additional warming around 3°C

or above. Estimates of the incremental economic impact of emitting carbon dioxide lie between a few dollars and several hundreds of dollars

per tonne of carbon

(robust evidence, medium agreement). Estimates vary strongly with the assumed damage function and discount rate.

Human health

Until mid-century, projected climate change will impact human health mainly by exacerbating health problems that already exist

(very high confidence). Throughout the 21st century, climate change is expected to lead to increases in ill-health in many regions

and especially in developing countries with low income, as compared to a baseline without climate change (high confidence).

Examples include greater likelihood of injury, disease, and death due to more intense heat waves and fires (very high confidence); increased

likelihood of under-nutrition resulting from diminished food production in poor regions (high confidence); risks from lost work capacity and

reduced labor productivity in vulnerable populations; and increased risks from food- and water-borne diseases (very high confidence) and

Summary for Policymakers

9.3, 25.9, 26.8, 28.2, 28.4, Box 25-5

3.5, 10.2, 10.7, 10.10, 17.4-5, 25.7, 26.7-9, Box 25-7

Disaster loss estimates are lower-bound estimates because many impacts, such as loss of human lives, cultural heritage, and ecosystem services, are difficult to value and

monetize, and thus they are poorly reflected in estimates of losses. Impacts on the informal or undocumented economy as well as indirect economic effects can be very

important in some areas and sectors, but are generally not counted in reported estimates of losses. [SREX 4.5]

1 tonne of carbon = 3.667 tonne of CO

10.9

SPM

Summary for Policymakers

ector-borne diseases (medium confidence). Positive effects are expected to include modest reductions in cold-related mortality and morbidity

in some areas due to fewer cold extremes (low confidence), geographical shifts in food production (medium confidence), and reduced capacity

of vectors to transmit some diseases. But globally over the 21st century, the magnitude and severity of negative impacts are projected to

increasingly outweigh positive impacts (high confidence). The most effective vulnerability reduction measures for health in the near term are

programs that implement and improve basic public health measures such as provision of clean water and sanitation, secure essential health

care including vaccination and child health services, increase capacity for disaster preparedness and response, and alleviate poverty (very high

confidence). By 2100 for the high-emission scenario RCP8.5, the combination of high temperature and humidity in some areas for parts of the

year is projected to compromise normal human activities, including growing food or working outdoors (high confidence).

Human security

Climate change over the 21st century is projected to increase displacement of people (medium evidence, high agreement).

Displacement risk increases when populations that lack the resources for planned migration experience higher exposure to extreme weather

events, in both rural and urban areas, particularly in developing countries with low income. Expanding opportunities for mobility can reduce

vulnerability for such populations. Changes in migration patterns can be responses to both extreme weather events and longer-term climate

variability and change, and migration can also be an effective adaptation strategy. There is low confidence in quantitative projections of

changes in mobility, due to its complex, multi-causal nature.

Climate change can indirectly increase risks of violent conflicts in the form of civil war and inter-group violence by amplifying

well-documented drivers of these conflicts such as poverty and economic shocks (medium confidence).

Multiple lines of evidence

relate climate variability to these forms of conflict.

The impacts of climate change on the critical infrastructure and territorial integrity of many states are expected to influence

national security policies (medium evidence, medium agreement). For example, land inundation due to sea level rise poses risks to the

territorial integrity of small island states and states with extensive coastlines. Some transboundary impacts of climate change, such as changes

in sea ice, shared water resources, and pelagic fish stocks, have the potential to increase rivalry among states, but robust national and

intergovernmental institutions can enhance cooperation and manage many of these rivalries.

Livelihoods and poverty

Throughout the 21st century, climate-change impacts are projected to slow down economic growth, make poverty reduction

more difficult, further erode food security, and prolong existing and create new poverty traps, the latter particularly in urban

areas and emerging hotspots of hunger (medium confidence).

Climate-change impacts are expected to exacerbate poverty in most

developing countries and create new poverty pockets in countries with increasing inequality, in both developed and developing countries. In

urban and rural areas, wage-labor-dependent poor households that are net buyers of food are expected to be particularly affected due to food

price increases, including in regions with high food insecurity and high inequality (particularly in Africa), although the agricultural self-

employed could benefit. Insurance programs, social protection measures, and disaster risk management may enhance long-term livelihood

resilience among poor and marginalized people, if policies address poverty and multidimensional inequalities.

B-3. Regional Key Risks and Potential for Adaptation

Risks will vary through time across regions and populations, dependent on myriad factors including the extent of adaptation and mitigation. A

selection of key regional risks identified with medium to high confidence is presented in Assessment Box SPM.2. For extended summary of

regional risks and potential benefits, see Technical Summary Section B-3 and WGII AR5 Part B: Regional Aspects.

SPM

Key risk Adaptation issues & prospects

Climatic

drivers

Risk & potential for

adaptation

Timeframe

Africa

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Very

low

Very

high

Medium

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Very

low

Very

high

Medium

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Very

low

Very

high

Medium

Carbon dioxide

fertilization

Damaging

cyclone

Ocean

acidiﬁcation

Precipitation

Climate-related drivers of impacts

Warming

trend

Extreme

precipitation

Extreme

temperature

Sea

level

Level of risk & potential for adaptation

otential for additional adaptation

to reduce risk

Risk level with

current adaptation

Risk level with

high adaptation

Drying

trend

Snow

cover

Compounded stress on water resources facing

signiﬁcant strain from overexploitation and

degradation at present and increased demand in the

future, with drought stress exacerbated in

drought-prone regions of Africa (high conﬁdence)

[22.3-4]

• Reducing non-climate stressors on water resources

• Strengthening institutional capacities for demand management,

groundwater assessment, integrated water-wastewater planning,

and integrated land and water governance

• Sustainable urban development

Reduced crop productivity associated with heat and

drought stress, with strong adverse effects on

regional, national, and household livelihood and food

security, also given increased pest and disease

damage and ﬂood impacts on food system

infrastructure (high conﬁdence)

[22.3-4]

• Technological adaptation responses (e.g., stress-tolerant crop

varieties, irrigation, enhanced observation systems)

• Enhancing smallholder access to credit and other critical production

resources; Diversifying livelihoods

• Strengthening institutions at local, national, and regional levels to

support agriculture (including early warning systems) and

gender-oriented policy

• Agronomic adaptation responses (e.g., agroforestry, conservation

agriculture)

Changes in the incidence and geographic range of

vector- and water-borne diseases due to changes in

the mean and variability of temperature and

precipitation, particularly along the edges of their

distribution (medium conﬁdence)

[22.3]

• Achieving development goals, particularly improved access to safe

water and improved sanitation, and enhancement of public health

functions such as surveillance

• Vulnerability mapping and early warning systems

• Coordination across sectors

• Sustainable urban development

Continued next page

Assessment Box SPM.2 Table 1 | Key regional risks from climate change and the potential for reducing risks through adaptation and mitigation. Each key risk is characterized as

very low to very high for three timeframes: the present, near term (here, assessed over 2030–2040), and longer term (here, assessed over 2080–2100). In the near term,

projected levels of global mean temperature increase do not diverge substantially for different emission scenarios. For the longer term, risk levels are presented for two scenarios

of global mean temperature increase (2°C and 4°C above preindustrial levels). These scenarios illustrate the potential for mitigation and adaptation to reduce the risks related to

climate change. Climate-related drivers of impacts are indicated by icons.

Summary for Policymakers

8.2, 11.3-8, 19.3, 22.3, 25.8, 26.6, Figure 25-5, Box CC-HS

9.3, 12.4, 19.4, 22.3, 25.9

12.5, 13.2, 19.4

12.5-6, 23.9, 25.9

8.1, 8.3-4, 9.3, 10.9, 13.2-4, 22.3, 26.8

Assessment Box SPM.2 | Regional Key Risks

The accompanying Assessment Box SPM.2 Table 1 highlights several representative key risks for each region. Key risks have been

identiﬁed based on assessment of the relevant scientiﬁc, technical, and socioeconomic literature detailed in supporting chapter sections.

Identiﬁcation of key risks was based on expert judgment using the following speciﬁc criteria: large magnitude, high probability, or

irreversibility of impacts; timing of impacts; persistent vulnerability or exposure contributing to risks; or limited potential to reduce risks

through adaptation or mitigation.

For each key risk, risk levels were assessed for three timeframes. For the present, risk levels were estimated for current adaptation and

a hypothetical highly adapted state, identifying where current adaptation deﬁcits exist. For two future timeframes, risk levels were

estimated for a continuation of current adaptation and for a highly adapted state, representing the potential for and limits to adaptation.

The risk levels integrate probability and consequence over the widest possible range of potential outcomes, based on available literature.

These potential outcomes result from the interaction of climate-related hazards, vulnerability, and exposure. Each risk level reﬂects total

risk from climatic and non-climatic factors. Key risks and risk levels vary across regions and over time, given differing socioeconomic

development pathways, vulnerability and exposure to hazards, adaptive capacity, and risk perceptions. Risk levels are not necessarily

comparable, especially across regions, because the assessment considers potential impacts and adaptation in different physical,

biological, and human systems across diverse contexts. This assessment of risks acknowledges the importance of differences in values

and objectives in interpretation of the assessed risk levels.

SPM

Summary for Policymakers

Continued next page

Key risk Adaptation issues & prospects

Climatic

drivers

Risk & potential for

adaptation

Timeframe

Europe

ear term

(

2030–2040)

resent

ong term

(

2080–2100)

°C

4°C

Very

low

Very

high

Medium

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Very

ery

high

edium

ear term

(

2030–2040)

resent

ong term

(2080–2100)

2°C

4°C

ery

low

ery

high

Medium

ncreased economic losses and people affected by

ﬂ

ooding in river basins and coasts, driven by

increasing urbanization, increasing sea levels,

coastal erosion, and peak river discharges

(

high conﬁdence)

[

23.2-3, 23.7]

daptation can prevent most of the projected damages (high

onﬁdence).

• Signiﬁcant experience in hard ﬂood-protection technologies and

increasing experience with restoring wetlands

•

High costs for increasing ﬂood protection

•

Potential barriers to implementation: demand for land in Europe

and environmental and landscape concerns

Increased water restrictions. Signiﬁcant reduction in

ater availability from river abstraction and from

groundwater resources, combined with increased

water demand (e.g., for irrigation, energy and industry,

omestic use) and with reduced water drainage and

runoff as a result of increased evaporative demand,

particularly in southern Europe (high conﬁdence)

[23.4, 23.7]

• Proven adaptation potential from adoption of more water-efﬁcient

echnologies and of water-saving strategies (e.g., for irrigation, crop

species, land cover, industries, domestic use)

• Implementation of best practices and governance instruments in

iver basin management plans and integrated water management

Increased economic losses and people affected by

xtreme heat events: impacts on health and

well-being, labor productivity, crop production, air

quality, and increasing risk of wildﬁres in southern

urope and in Russian boreal region

(medium conﬁdence)

[23.3-7, Table 23-1]

• Implementation of warning systems

•

Adaptation of dwellings and workplaces and of transport and

nergy infrastructure

• Reductions in emissions to improve air quality

•

Improved wildﬁre management

•

Development of insurance products against weather-related yield

variations

Key risk Adaptation issues & prospects

Climatic

drivers

Risk & potential for

adaptation

Timeframe

Asia

Near term

(2030–2040)

Present

Long term

(2080–2100)

°C

4°C

Very

low

Very

high

Medium

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Very

low

Very

igh

Medium

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Very

low

Very

high

Medium

Increased riverine, coastal, and urban

ﬂooding leading to widespread damage

to infrastructure, livelihoods, and

settlements in Asia (medium conﬁdence)

[24.4]

• Exposure reduction via structural and non-structural measures, effective

land-use planning, and selective relocation

• Reduction in the vulnerability of lifeline infrastructure and services (e.g., water,

energy, waste management, food, biomass, mobility, local ecosystems,

telecommunications)

• Construction of monitoring and early warning systems; Measures to identify

exposed areas, assist vulnerable areas and households, and diversify livelihoods

• Economic diversiﬁcation

Increased risk of heat-related mortality

(high conﬁdence)

[24.4]

• Heat health warning systems

• Urban planning to reduce heat islands; Improvement of the built environment;

Development of sustainable cities

• New work practices to avoid heat stress among outdoor workers

Increased risk of drought-related water

and food shortage causing malnutrition

(high conﬁdence)

[24.4]

• Disaster preparedness including early-warning systems and local coping

strategies

• Adaptive/integrated water resource management

• Water infrastructure and reservoir development

• Diversiﬁcation of water sources including water re-use

• More efﬁcient use of water (e.g., improved agricultural practices, irrigation

management, and resilient agriculture)

Assessment Box SPM.2 Table 1 (continued)

SPM

ontinued next page

Key risk Adaptation issues & prospects

Climatic

rivers

Risk & potential for

daptation

Timeframe

Australasia

ear term

(2030–2040)

Present

Long term

(

2080–2100)

°C

4°C

Very

igh

Medium

Near term

(

2030–2040)

Present

ong term

(

2080–2100)

°C

4°C

Very

low

ery

igh

Medium

Near term

(2030–2040)

resent

Long term

(

2080–2100)

°C

4°C

Very

low

ery

high

Medium

igniﬁcant change in community

composition and structure of coral reef

systems in Australia (high conﬁdence)

[

25.6, 30.5, Boxes CC-CR and CC-OA]

•

Ability of corals to adapt naturally appears limited and insufﬁcient to offset the

detrimental effects of rising temperatures and acidiﬁcation.

• Other options are mostly limited to reducing other stresses (water quality,

ourism, ﬁshing) and early warning systems; direct interventions such as assisted

olonization and shading have been proposed but remain untested at scale.

ncreased frequency and intensity of ﬂood

damage to infrastructure and settlements

in Australia and New Zealand

(high conﬁdence)

[Table 25-1, Boxes 25-8 and 25-9]

•

Signiﬁcant adaptation deﬁcit in some regions to current ﬂood risk.

• Effective adaptation includes land-use controls and relocation as well as

protection and accommodation of increased risk to ensure ﬂexibility.

ncreasing risks to coastal infrastructure

nd low-lying ecosystems in Australia and

New Zealand, with widespread damage

towards the upper end of projected

ea-level-rise ranges (high conﬁdence)

[25.6, 25.10, Box 25-1]

•

Adaptation deﬁcit in some locations to current coastal erosion and ﬂood risk.

uccessive building and protection cycles constrain ﬂexible responses.

• Effective adaptation includes land-use controls and ultimately relocation as well

s protection and accommodation.

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Very

low

Very

igh

Medium

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Very

low

Very

high

Medium

Heat-related human mortality

(high conﬁdence)

[26.6, 26.8]

• Residential air conditioning (A/C) can effectively reduce risk. However,

availability and usage of A/C is highly variable and is subject to complete loss

during power failures. Vulnerable populations include athletes and outdoor

workers for whom A/C is not available.

• Community- and household-scale adaptations have the potential to reduce

exposure to heat extremes via family support, early heat warning systems,

cooling centers, greening, and high-albedo surfaces.

Urban ﬂoods in riverine and coastal areas,

inducing property and infrastructure

damage; supply chain, ecosystem, and

social system disruption; public health

impacts; and water quality impairment, due

to sea level rise, extreme precipitation, and

cyclones (high conﬁdence)

[26.2-4, 26.8]

• Implementing management of urban drainage is expensive and disruptive to

urban areas.

• Low-regret strategies with co-beneﬁts include less impervious surfaces leading

to more groundwater recharge, green infrastructure, and rooftop gardens.

• Sea level rise increases water elevations in coastal outfalls, which impedes

drainage. In many cases, older rainfall design standards are being used that need

to be updated to reﬂect current climate conditions.

• Conservation of wetlands, including mangroves, and land-use planning

strategies can reduce the intensity of ﬂood events.

Key risk Adaptation issues & prospects

Climatic

drivers

Risk & potential for

adaptation

Timeframe

North America

Near term

(2030–2040)

Present

Long term

(2080–2100)

°C

4°C

Very

low

Very

high

Medium

Wildﬁre-induced loss of ecosystem

integrity, property loss, human morbidity,

and mortality as a result of increased

drying trend and temperature trend

(high conﬁdence)

[26.4, 26.8, Box 26-2]

• Some ecosystems are more ﬁre-adapted than others. Forest managers and

municipal planners are increasingly incorporating ﬁre protection measures (e.g.,

prescribed burning, introduction of resilient vegetation). Institutional capacity to

support ecosystem adaptation is limited.

• Adaptation of human settlements is constrained by rapid private property

development in high-risk areas and by limited household-level adaptive capacity.

• Agroforestry can be an effective strategy for reduction of slash and burn

practices in Mexico.

Assessment Box SPM.2 Table 1 (continued)

Summary for Policymakers

SPM

Summary for Policymakers

Continued next page

ot available

not available

Key risk Adaptation issues & prospects

Climatic

drivers

Risk & potential for

adaptation

Timeframe

Central and South America

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Very

low

ery

high

edium

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Very

low

ery

high

Medium

Water availability in semi-arid and

glacier-melt-dependent regions and Central

America; ﬂooding and landslides in urban

and rural areas due to extreme precipitation

(high conﬁdence)

[27.3]

• Integrated water resource management

• Urban and rural ﬂood management (including infrastructure), early warning

systems, better weather and runoff forecasts, and infectious disease control

Decreased food production and food quality

(medium conﬁdence)

[27.3]

• Development of new crop varieties more adapted to climate change

(temperature and drought)

•

Offsetting of human and animal health impacts of reduced food quality

• Offsetting of economic impacts of land-use change

• Strengthening traditional indigenous knowledge systems and practices

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Very

low

Very

high

Medium

Spread of vector-borne diseases in altitude

and latitude (high conﬁdence)

[27.3]

• Development of early warning systems for disease control and mitigation

based on climatic and other relevant inputs. Many factors augment

vulnerability.

•

Establishing programs to extend basic public health services

Very

low

Very

high

Medium

Key risk Adaptation issues & prospects

Climatic

drivers

Risk & potential for

adaptation

Timeframe

Small Islands

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Very

low

Very

high

Medium

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Very

low

Very

high

Medium

Key risk Adaptation issues & prospects

Climatic

drivers

Risk & potential for

adaptation

Timeframe

Polar Regions

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Very

low

ery

high

edium

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

ery

low

Very

igh

Medium

Loss of livelihoods, coastal settlements,

infrastructure, ecosystem services, and

economic stability (high conﬁdence)

[29.6, 29.8, Figure 29-4]

• Signiﬁcant potential exists for adaptation in islands, but additional external

resources and technologies will enhance response.

• Maintenance and enhancement of ecosystem functions and services and of

water and food security

• Efﬁcacy of traditional community coping strategies is expected to be

substantially reduced in the future.

The interaction of rising global mean sea level

in the 21st century with high-water-level

events will threaten low-lying coastal areas

(high conﬁdence)

[29.4, Table 29-1; WGI AR5 13.5, Table 13.5]

• High ratio of coastal area to land mass will make adaptation a signiﬁcant

ﬁnancial and resource challenge for islands.

• Adaptation options include maintenance and restoration of coastal landforms

and ecosystems, improved management of soils and freshwater resources, and

appropriate building codes and settlement patterns.

Risks for freshwater and terrestrial ecosystems

(high conﬁdence) and marine ecosystems

(medium conﬁdence), due to changes in ice,

snow cover, permafrost, and freshwater/ocean

conditions, affecting species´ habitat quality,

ranges, phenology, and productivity, as well as

dependent economies

[28.2-4]

• Improved understanding through scientiﬁc and indigenous knowledge,

producing more effective solutions and/or technological innovations

• Enhanced monitoring, regulation, and warning systems that achieve safe and

sustainable use of ecosystem resources

• Hunting or ﬁshing for different species, if possible, and diversifying income

sources

Risks for the health and well-being of Arctic

residents, resulting from injuries and illness

from the changing physical environment,

food insecurity, lack of reliable and safe

drinking water, and damage to

infrastructure, including infrastructure in

permafrost regions (high conﬁdence)

[28.2-4]

• Co-production of more robust solutions that combine science and technology

with indigenous knowledge

• Enhanced observation, monitoring, and warning systems

• Improved communications, education, and training

• Shifting resource bases, land use, and/or settlement areas

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Unprecedented challenges for northern

communities due to complex inter-linkages

between climate-related hazards and societal

factors, particularly if rate of change is faster

than social systems can adapt

(high conﬁdence)

[28.2-4]

• Co-production of more robust solutions that combine science and

technology with indigenous knowledge

• Enhanced observation, monitoring, and warning systems

• Improved communications, education, and training

• Adaptive co-management responses developed through the settlement of

land claims

ssessment Box SPM.2 Table 1 (continued)

SPM

ey risk

daptation issues & prospects

Climatic

rivers

Risk & potential for

daptation

imeframe

The Ocean

Near term

(2030–2040)

resent

ong term

(2080–2100)

2°C

4°C

Very

low

Very

igh

Medium

ear term

(2030–2040)

resent

Long term

(2080–2100)

2°C

4°C

Very

igh

Medium

Near term

(2030–2040)

Present

Long term

(2080–2100)

2°C

4°C

Very

ery

igh

Medium

Distributional shift in ﬁsh and invertebrate

pecies, and decrease in ﬁsheries catch

potential at low latitudes, e.g., in equatorial

upwelling and coastal boundary systems and

sub-tropical gyres (high conﬁdence)

[

6.3, 30.5-6, Tables 6-6 and 30-3, Box

CC-MB]

• Evolutionary adaptation potential of ﬁsh and invertebrate species to warming

is limited as indicated by their changes in distribution to maintain temperatures.

• Human adaptation options: Large-scale translocation of industrial ﬁshing

activities following the regional decreases (low latitude) vs. possibly transient

increases (high latitude) in catch potential; Flexible management that can react

to variability and change; Improvement of ﬁsh resilience to thermal stress by

reducing other stressors such as pollution and eutrophication; Expansion of

sustainable aquaculture and the development of alternative livelihoods in some

egions.

educed biodiversity, ﬁsheries abundance,

and coastal protection by coral reefs due to

heat-induced mass coral bleaching and

ortality increases, exacerbated by ocean

acidiﬁcation, e.g., in coastal boundary systems

nd sub-tropical gyres (high conﬁdence)

[5.4, 6.4, 30.3, 30.5-6, Tables 6-6 and 30-3,

Box CC-CR]

•

Evidence of rapid evolution by corals is very limited. Some corals may migrate

to higher latitudes, but entire reef systems are not expected to be able to track

the high rates of temperature shifts.

• Human adaptation options are limited to reducing other stresses, mainly by

enhancing water quality, and limiting pressures from tourism and ﬁshing. These

ptions will delay human impacts of climate change by a few decades, but their

efﬁcacy will be severely reduced as thermal stress increases.

Coastal inundation and habitat loss due to

sea level rise, extreme events, changes in

precipitation, and reduced ecological

resilience, e.g., in coastal boundary systems

and sub-tropical gyres

(medium to high conﬁdence)

[5.5, 30.5-6, Tables 6-6 and 30-3, Box

CC-CR]

• Human adaptation options are limited to reducing other stresses, mainly by

reducing pollution and limiting pressures from tourism, ﬁshing, physical

destruction, and unsustainable aquaculture.

• Reducing deforestation and increasing reforestation of river catchments and

coastal areas to retain sediments and nutrients

• Increased mangrove, coral reef, and seagrass protection, and restoration to

rotect numerous ecosystem goods and services such as coastal protection,

tourist value, and ﬁsh habitat

Assessment Box SPM.2 Table 1 (continued)

C: MANAGING FUTURE RISKS AND BUILDING RESILIENCE

Managing the risks of climate change involves adaptation and mitigation decisions with implications for future generations, economies, and

environments. This section evaluates adaptation as a means to build resilience and to adjust to climate-change impacts. It also considers limits

to adaptation, climate-resilient pathways, and the role of transformation. See Figure SPM.8 for an overview of responses for addressing risk

related to climate change.

C-1. Principles for Effective Adaptation

Adaptation is place- and context-specific, with no single approach for reducing risks appropriate across all settings (high

confidence). Effective risk reduction and adaptation strategies consider the dynamics of vulnerability and exposure and their linkages with

socioeconomic processes, sustainable development, and climate change. Specific examples of responses to climate change are presented in

Table SPM.1.

Adaptation planning and implementation can be enhanced through complementary actions across levels, from individuals to

governments (high confidence).

National governments can coordinate adaptation efforts of local and subnational governments, for example

by protecting vulnerable groups, by supporting economic diversification, and by providing information, policy and legal frameworks, and

financial support (robust evidence, high agreement). Local government and the private sector are increasingly recognized as critical to progress

in adaptation, given their roles in scaling up adaptation of communities, households, and civil society and in managing risk information and

financing (medium evidence, high agreement).

A first step towards adaptation to future climate change is reducing vulnerability and exposure to present climate variability

(high confidence). Strategies include actions with co-benefits for other objectives.

Available strategies and actions can increase

resilience across a range of possible future climates while helping to improve human health, livelihoods, social and economic well-being, and

Summary for Policymakers

2.1, 8.3-4, 13.1, 13.3-4, 15.2-3, 15.5, 16.2-3, 16.5, 17.2, 17.4, 19.6, 21.3, 22.4, 26.8-9, 29.6, 29.8

2.1-4, 3.6, 5.5, 8.3-4, 9.3-4, 14.2, 15.2-3, 15.5, 16.2-5, 17.2-3, 22.4, 24.4, 25.4, 26.8-9, 30.7, Tables 21-1, 21-5, & 21-6, Box 16-2

environmental quality. See Table SPM.1. Integration of adaptation into planning and decision making can promote synergies with development

and disaster risk reduction.

Adaptation planning and implementation at all levels of governance are contingent on societal values, objectives, and risk

perceptions (high confidence). Recognition of diverse interests, circumstances, social-cultural contexts, and expectations can

benefit decision-making processes.

Indigenous, local, and traditional knowledge systems and practices, including indigenous peoples’

holistic view of community and environment, are a major resource for adapting to climate change, but these have not been used consistently in

existing adaptation efforts. Integrating such forms of knowledge with existing practices increases the effectiveness of adaptation.

Decision support is most effective when it is sensitive to context and the diversity of decision types, decision processes, and

constituencies (robust evidence, high agreement). Organizations bridging science and decision making, including climate services, play

an important role in the communication, transfer, and development of climate-related knowledge, including translation, engagement, and

knowledge exchange (medium evidence, high agreement).

Existing and emerging economic instruments can foster adaptation by providing incentives for anticipating and reducing impacts

(medium confidence).

Instruments include public-private finance partnerships, loans, payments for environmental services, improved resource

pricing, charges and subsidies, norms and regulations, and risk sharing and transfer mechanisms. Risk financing mechanisms in the public and

private sector, such as insurance and risk pools, can contribute to increasing resilience, but without attention to major design challenges, they

can also provide disincentives, cause market failure, and decrease equity. Governments often play key roles as regulators, providers, or insurers

of last resort.

Constraints can interact to impede adaptation planning and implementation (high confidence). Common constraints on

implementation arise from the following: limited financial and human resources; limited integration or coordination of governance; uncertainties

SPM

Summary for Policymakers

EMISSIONS

and Land-use Change

azards

Anthropogenic

Climate Change

Socioeconomic

Pathways

Adaptation and

Mitigation

Actions

Governance

MPACTS

Natural

Variability

OCIOECONOMIC

ROCESSES

CLIMATE

ocioeconomic Pathways

daptation & Interactions

ith Mitigation

Governance

•

iverse values & objectives

[

A-3]

•

limate-resilient pathways

[C-2]

•

ransformation

[C-2]

•

ecision making under

uncertainty

[A-3]

•

earning, monitoring, & ﬂexibility

[A-2, A-3, C-1]

•

oordination across scales

[A-2, C-1]

•

Incremental & transformational

adaptation

[A-2, A-3, C-2]

•

Co-beneﬁts, synergies, &

radeoffs

[A-2, C-1, C-2]

•

ontext-speciﬁc adaptation

[C-1]

•

omplementary actions

[C-1]

•

imits to adaptation

[C-2]

Exposure

ulnerability

ISK

ulnerability & Exposure

isk

• Vulnerability & exposure

reduction

[

C-1]

• Low-regrets strategies &

actions [

C-1]

•

Addressing multidimensional

inequalities

[

A-1, C-1]

•

Risk assessment

[

•

Iterative risk management

[A-3]

•

Risk perception

[

A-3, C-1]

nthropogenic

Climate Change

•

Mitigation [WGIII AR5]

Figure SPM.8 | The solution space. Core concepts of the WGII AR5, illustrating overlapping entry points and approaches, as well as key considerations, in managing risks related

to climate change, as assessed in this report and presented throughout this SPM. Bracketed references indicate sections of this summary with corresponding assessment ﬁndings.

3.6, 8.3, 9.4, 14.3, 15.2-3, 17.2, 20.4, 20.6, 22.4, 24.4-5, 25.4, 25.10, 27.3-5, 29.6, Boxes 25-2 and 25-6

2.2-4, 9.4, 12.3, 13.2, 15.2, 16.2-4, 16.7, 17.2-3, 21.3, 22.4, 24.4, 24.6, 25.4, 25.8, 26.9, 28.2, 28.4, Table 15-1, Box 25-7

2.1-4, 8.4, 14.4, 16.2-3, 16.5, 21.2-3, 21.5, 22.4, Box 9-4

10.7, 10.9, 13.3, 17.4-5, Box 25-7

SPM

Overlapping

Approaches

Category Examples Chapter Reference(s)

Human

development

Improved access to education, nutrition, health facilities, energy, safe housing & settlement structures,

social support structures; Reduced gender inequality & marginalization in other forms.

.3, 9.3, 13.1-3, 14.2-3, 22.4

Poverty alleviation

mproved access to & control of local resources; Land tenure; Disaster risk reduction; Social safety nets

& social protection; Insurance schemes.

8.3-4, 9.3, 13.1-3

Livelihood security

ncome, asset, & livelihood diversiﬁ cation; Improved infrastructure; Access to technology & decision-

making fora; Increased decision-making power; Changed cropping, livestock, & aquaculture practices;

eliance on social networks.

.5, 9.4, 13.1-3, 22.3-4, 23.4, 26.5,

27.3, 29.6, Table SM24-7

Disaster risk

management

Early warning systems; Hazard & vulnerability mapping; Diversifying water resources; Improved

drainage; Flood & cyclone shelters; Building codes & practices; Storm & wastewater management;

ransport & road infrastructure improvements.

.2-4, 11.7, 14.3, 15.4, 22.4, 24.4,

26.6, 28.4, Box 25-1, Table 3-3

Ecosystem

management

Maintaining wetlands & urban green spaces; Coastal afforestation; Watershed & reservoir

anagement; Reduction of other stressors on ecosystems & of habitat fragmentation; Maintenance

of genetic diversity; Manipulation of disturbance regimes; Community-based natural resource

anagement.

.3-4, 8.3, 22.4, Table 3-3, Boxes 4-3,

8-2, 15-1, 25-8, 25-9, & CC-EA

Spatial or land-use

planning

Provisioning of adequate housing, infrastructure, & services; Managing development in ﬂ ood prone &

other high risk areas; Urban planning & upgrading programs; Land zoning laws; Easements; Protected

reas.

4.4, 8.1-4, 22.4, 23.7-8, 27.3, Box 25-8

Structural/physical

Engineered & built-environment options: Sea walls & coastal protection structures; Flood levees;

ater storage; Improved drainage; Flood & cyclone shelters; Building codes & practices; Storm &

wastewater management; Transport & road infrastructure improvements; Floating houses; Power plant

electricity grid adjustments.

3.5-6, 5.5, 8.2-3, 10.2, 11.7, 23.3,

24.4, 25.7, 26.3, 26.8, Boxes 15-1,

5-1, 25-2, & 25-8

Technological options: New crop & animal varieties; Indigenous, traditional, & local knowledge,

technologies, & methods; Efﬁ cient irrigation; Water-saving technologies; Desalinization; Conservation

agriculture; Food storage & preservation facilities; Hazard & vulnerability mapping & monitoring; Early

warning systems; Building insulation; Mechanical & passive cooling; Technology development, transfer,

& diffusion.

7.5, 8.3, 9.4, 10.3, 15.4, 22.4, 24.4,

6.3, 26.5, 27.3, 28.2, 28.4, 29.6-7,

Boxes 20-5 & 25-2, Tables 3-3 & 15-1

Ecosystem-based options: Ecological restoration; Soil conservation; Afforestation & reforestation;

Mangrove conservation & replanting; Green infrastructure (e.g., shade trees, green roofs);

Controlling overﬁ shing; Fisheries co-management; Assisted species migration & dispersal; Ecological

corridors; Seed banks, gene banks, & other ex situ conservation; Community-based natural resource

management.

4.4, 5.5, 6.4, 8.3, 9.4, 11.7, 15.4, 22.4,

23.6-7, 24.4, 25.6, 27.3, 28.2, 29.7,

30.6, Boxes 15-1, 22-2, 25-9, 26-2,

& CC-EA

Services: Social safety nets & social protection; Food banks & distribution of food surplus; Municipal

services including water & sanitation; Vaccination programs; Essential public health services; Enhanced

emergency medical services.

3.5-6, 8.3, 9.3, 11.7, 11.9, 22.4, 29.6,

Box 13-2

Institutional

Economic options: Financial incentives; Insurance; Catastrophe bonds; Payments for ecosystem

services; Pricing water to encourage universal provision and careful use; Microﬁ nance; Disaster

contingency funds; Cash transfers; Public-private partnerships.

8.3-4, 9.4, 10.7, 11.7, 13.3, 15.4, 17.5,

22.4, 26.7, 27.6, 29.6, Box 25-7

Laws & regulations: Land zoning laws; Building standards & practices; Easements; Water regulations

& agreements; Laws to support disaster risk reduction; Laws to encourage insurance purchasing;

Deﬁ ned property rights & land tenure security; Protected areas; Fishing quotas; Patent pools &

technology transfer.

4.4, 8.3, 9.3, 10.5, 10.7, 15.2, 15.4,

17.5, 22.4, 23.4, 23.7, 24.4, 25.4, 26.3,

27.3, 30.6, Table 25-2, Box CC-CR

National & government policies & programs: National & regional adaptation plans including

mainstreaming; Sub-national & local adaptation plans; Economic diversiﬁ cation; Urban upgrading

programs; Municipal water management programs; Disaster planning & preparedness; Integrated

water resource management; Integrated coastal zone management; Ecosystem-based management;

Community-based adaptation.

2.4, 3.6, 4.4, 5.5, 6.4, 7.5, 8.3, 11.7,

15.2-5, 22.4, 23.7, 25.4, 25.8, 26.8-9,

27.3-4, 29.6, Boxes 25-1, 25-2, & 25-9,

Tables 9-2 & 17-1

Social

Educational options: Awareness raising & integrating into education; Gender equity in education;

Extension services; Sharing indigenous, traditional, & local knowledge; Participatory action research &

social learning; Knowledge-sharing & learning platforms.

8.3-4, 9.4, 11.7, 12.3, 15.2-4, 22.4,

25.4, 28.4, 29.6, Tables 15-1 & 25-2

Informational options: Hazard & vulnerability mapping; Early warning & response systems;

Systematic monitoring & remote sensing; Climate services; Use of indigenous climate observations;

Participatory scenario development; Integrated assessments.

2.4, 5.5, 8.3-4, 9.4, 11.7, 15.2-4, 22.4,

23.5, 24.4, 25.8, 26.6, 26.8, 27.3, 28.2,

28.5, 30.6, Table 25-2, Box 26-3

Behavioral options: Household preparation & evacuation planning; Migration; Soil & water

conservation; Storm drain clearance; Livelihood diversiﬁ cation; Changed cropping, livestock, &

aquaculture practices; Reliance on social networks.

5.5, 7.5, 9.4, 12.4, 22.3-4, 23.4, 23.7,

25.7, 26.5, 27.3, 29.6, Table SM24-7,

Box 25-5

Spheres of change

Practical: Social & technical innovations, behavioral shifts, or institutional & managerial changes that

produce substantial shifts in outcomes.

8.3, 17.3, 20.5, Box 25-5

Political: Political, social, cultural, & ecological decisions & actions consistent with reducing

vulnerability & risk & supporting adaptation, mitigation, & sustainable development.

14.2-3, 20.5, 25.4, 30.7, Table 14-1

Personal: Individual & collective assumptions, beliefs, values, & worldviews inﬂ uencing climate-change

responses.

14.2-3, 20.5, 25.4, Table 14-1

Vulnerability & Exposure Reduction

through development, planning, & practices including many low-regrets measures

Adaptation

including incremental & transformational adjustments

Transformation

Table SPM.1 | Approaches for managing the risks of climate change. These approaches should be considered overlapping rather than discrete, and they are often pursued

simultaneously. Mitigation is considered essential for managing the risks of climate change. It is not addressed in this table as mitigation is the focus of WGIII AR5. Examples are

presented in no speciﬁ c order and can be relevant to more than one category. [14.2-3, Table 14-1]

Summary for Policymakers

SPM

Summary for Policymakers

bout projected impacts; different perceptions of risks; competing values; absence of key adaptation leaders and advocates; and limited tools

to monitor adaptation effectiveness. Another constraint includes insufficient research, monitoring, and observation and the finance to maintain

them. Underestimating the complexity of adaptation as a social process can create unrealistic expectations about achieving intended adaptation

outcomes.

Poor planning, overemphasizing short-term outcomes, or failing to sufficiently anticipate consequences can result in maladaptation

(medium evidence, high agreement).

Maladaptation can increase the vulnerability or exposure of the target group in the future, or the

vulnerability of other people, places, or sectors. Some near-term responses to increasing risks related to climate change may also limit future

choices. For example, enhanced protection of exposed assets can lock in dependence on further protection measures.

Limited evidence indicates a gap between global adaptation needs and the funds available for adaptation (medium confidence).

There is a need for a better assessment of global adaptation costs, funding, and investment. Studies estimating the global cost of adaptation

are characterized by shortcomings in data, methods, and coverage (high confidence).

Significant co-benefits, synergies, and trade-offs exist between mitigation and adaptation and among different adaptation

responses; interactions occur both within and across regions (very high confidence). Increasing efforts to mitigate and adapt to climate

change imply an increasing complexity of interactions, particularly at the intersections among water, energy, land use, and biodiversity, but

tools to understand and manage these interactions remain limited. Examples of actions with co-benefits include (i) improved energy efficiency

and cleaner energy sources, leading to reduced emissions of health-damaging climate-altering air pollutants; (ii) reduced energy and water

consumption in urban areas through greening cities and recycling water; (iii) sustainable agriculture and forestry; and (iv) protection of

ecosystems for carbon storage and other ecosystem services.

C-2. Climate-resilient Pathways and Transformation

Climate-resilient pathways are sustainable-development trajectories that combine adaptation and mitigation to reduce climate change and its

impacts. They include iterative processes to ensure that effective risk management can be implemented and sustained. See Figure SPM.9.

Prospects for climate-resilient pathways for sustainable development are related fundamentally to what the world accomplishes

with climate-change mitigation (high confidence). Since mitigation reduces the rate as well as the magnitude of warming, it also

increases the time available for adaptation to a particular level of climate change, potentially by several decades. Delaying mitigation actions

may reduce options for climate-resilient pathways in the future.

Greater rates and magnitude of climate change increase the likelihood of exceeding adaptation limits (high confidence). Limits to

adaptation occur when adaptive actions to avoid intolerable risks for an actor’s objectives or for the needs of a system are not possible or are

not currently available. Value-based judgments of what constitutes an intolerable risk may differ. Limits to adaptation emerge from the

interaction among climate change and biophysical and/or socioeconomic constraints. Opportunities to take advantage of positive synergies

between adaptation and mitigation may decrease with time, particularly if limits to adaptation are exceeded. In some parts of the world,

insufficient responses to emerging impacts are already eroding the basis for sustainable development.

3.6, 4.4, 5.5, 8.4, 9.4, 13.2-3, 14.2, 14.5, 15.2-3, 15.5, 16.2-3, 16.5, 17.2-3, 22.4, 23.7, 24.5, 25.4, 25.10, 26.8-9, 30.6, Table 16-3, Boxes 16-1 and 16-3

5.5, 8.4, 14.6, 15.5, 16.3, 17.2-3, 20.2, 22.4, 24.4, 25.10, 26.8, Table 14-4, Box 25-1

14.2, 17.4, Tables 17-2 and 17-3

2.4-5, 3.7, 4.2, 4.4, 5.4-5, 8.4, 9.3, 11.9, 13.3, 17.2, 19.3-4, 20.2-5, 21.4, 22.6, 23.8, 24.6, 25.6-7, 25.9, 26.8-9, 27.3, 29.6-8, Boxes 25-2, 25-9, 25-10, 30.6-7, CC-WE,

and CC-RF

2.5, 20.3-4

1.1, 19.7, 20.2-3, 20.6, Figure 1-5

1.1, 11.8, 13.4, 16.2-7, 17.2, 20.2-3, 20.5-6, 25.10, 26.5, Boxes 16-1, 16-3, and 16-4

SPM

ransformations in economic, social, technological, and political decisions and actions can enable climate-resilient pathways (high

confidence).

Specific examples are presented in Table SPM.1. Strategies and actions can be pursued now that will move towards climate-

resilient pathways for sustainable development, while at the same time helping to improve livelihoods, social and economic well-being, and

responsible environmental management. At the national level, transformation is considered most effective when it reflects a country’s own

visions and approaches to achieving sustainable development in accordance with its national circumstances and priorities. Transformations to

sustainability are considered to benefit from iterative learning, deliberative processes, and innovation.

Low risk High resilience

(D) Decision points

(E) Climate-resilient pathways

Low resilience High risk

(B) Opportunity space

(F) Pathways that lower resilience

Resilience space

Multiple stressors

including

climate change

(A) Our world

Social stressors

Biophysical stressors

Figure SPM.9 | Opportunity space and climate-resilient pathways. (A) Our world [Sections A-1 and B-1] is threatened by multiple stressors that impinge on resilience from many directions,

represented here simply as biophysical and social stressors. Stressors include climate change, climate variability, land-use change, degradation of ecosystems, poverty and inequality, and

cultural factors. (B) Opportunity space [Sections A-2, A-3, B-2, C-1, and C-2] refers to decision points and pathways that lead to a range of (C) possible futures [Sections C and B-3] with

differing levels of resilience and risk. (D) Decision points result in actions or failures-to-act throughout the opportunity space, and together they constitute the process of managing or failing

to manage risks related to climate change. (E) Climate-resilient pathways (in green) within the opportunity space lead to a more resilient world through adaptive learning, increasing scientiﬁc

knowledge, effective adaptation and mitigation measures, and other choices that reduce risks. (F) Pathways that lower resilience (in red) can involve insufﬁcient mitigation, maladaptation,

failure to learn and use knowledge, and other actions that lower resilience; and they can be irreversible in terms of possible futures.

Summary for Policymakers

1.1, 2.1, 2.5, 8.4, 14.1, 14.3, 16.2-7, 20.5, 22.4, 25.4, 25.10, Figure 1-5, Boxes 16-1, 16-4, and TS.8

SPM

Summary for Policymakers

SUPPLEMENTARY MATERIAL

Continued next page

Africa

Snow & Ice,

Rivers & Lakes,

Floods & Drought

•

etreat of tropical highland glaciers in East Africa ( high conﬁ dence, major contribution from climate change)

• Reduced discharge in West African rivers ( low conﬁ dence, major contribution from climate change)

•

ake surface warming and water column stratiﬁ cation increases in the Great Lakes and Lake Kariba ( high conﬁ dence, major contribution from climate change)

•

ncreased soil moisture drought in the Sahel since 1970, partially wetter conditions since 1990 ( medium conﬁ dence, major contribution from climate change)

[22.2-3, Tables 18-5, 18-6, and 22-3]

Terrestrial

Ecosystems

•

ree density decreases in western Sahel and semi-arid Morocco, beyond changes due to land use ( medium conﬁ dence, major contribution from climate change)

• Range shifts of several southern plants and animals, beyond changes due to land use ( medium conﬁ dence, major contribution from climate change)

•

ncreases in wildﬁ res on Mt. Kilimanjaro ( low conﬁ dence, major contribution from climate change)

[22.3, Tables 18-7 and 22-3]

Coastal Erosion

& Marine

Ecosystems

•

ecline in coral reefs in tropical African waters, beyond decline due to human impacts ( high conﬁ dence, major contribution from climate change)

[Table 18-8]

Food Production

& Livelihoods

• Adaptive responses to changing rainfall by South African farmers, beyond changes due to economic conditions ( very low conﬁ dence, major contribution from climate

change)

•

ecline in fruit-bearing trees in Sahel ( low conﬁ dence, major contribution from climate change)

• Malaria increases in Kenyan highlands, beyond changes due to vaccination, drug resistance, demography, and livelihoods ( low conﬁ dence, minor contribution from

limate change)

• Reduced ﬁ sheries productivity of Great Lakes and Lake Kariba, beyond changes due to ﬁ sheries management and land use ( low conﬁ dence, minor contribution from

limate change)

[7.2, 11.5, 13.2, 22.3, Table 18-9]

Europe

Snow & Ice,

Rivers & Lakes,

Floods & Drought

• Retreat of Alpine, Scandinavian, and Icelandic glaciers ( high conﬁ dence, major contribution from climate change)

• Increase in rock slope failures in western Alps ( medium conﬁ dence, major contribution from climate change)

• Changed occurrence of extreme river discharges and ﬂ oods ( very low conﬁ dence, minor contribution from climate change)

[18.3, 23.2-3, Tables 18-5 and 18-6; WGI AR5 4.3]

Terrestrial

Ecosystems

• Earlier greening, leaf emergence, and fruiting in temperate and boreal trees ( high conﬁ dence, major contribution from climate change)

• Increased colonization of alien plant species in Europe, beyond a baseline of some invasion ( medium conﬁ dence, major contribution from climate change)

• Earlier arrival of migratory birds in Europe since 1970 ( medium conﬁ dence, major contribution from climate change)

• Upward shift in tree-line in Europe, beyond changes due to land use ( low conﬁ dence, major contribution from climate change)

• Increasing burnt forest areas during recent decades in Portugal and Greece, beyond some increase due to land use ( high conﬁ dence, major contribution from climate

change)

[4.3, 18.3, Tables 18-7 and 23-6]

Coastal Erosion

& Marine

Ecosystems

• Northward distributional shifts of zooplankton, ﬁ shes, seabirds, and benthic invertebrates in northeast Atlantic ( high conﬁ dence, major contribution from climate

change)

• Northward and depth shift in distribution of many ﬁ sh species across European seas ( medium conﬁ dence, major contribution from climate change)

• Plankton phenology changes in northeast Atlantic ( medium conﬁ dence, major contribution from climate change)

• Spread of warm water species into the Mediterranean, beyond changes due to invasive species and human impacts ( medium conﬁ dence, major contribution from

climate change)

[6.3, 23.6, 30.5, Tables 6-2 and 18-8, Boxes 6-1 and CC-MB]

Food Production

& Livelihoods

• Shift from cold-related mortality to heat-related mortality in England and Wales, beyond changes due to exposure and health care ( low conﬁ dence, major contribution

from climate change)

• Impacts on livelihoods of Sámi people in northern Europe, beyond effects of economic and sociopolitical changes ( medium conﬁ dence, major contribution from

climate change)

• Stagnation of wheat yields in some countries in recent decades, despite improved technology ( medium conﬁ dence, minor contribution from climate change)

• Positive yield impacts for some crops mainly in northern Europe, beyond increase due to improved technology ( medium conﬁ dence, minor contribution from climate

change)

• Spread of bluetongue virus in sheep and of ticks across parts of Europe ( medium conﬁ dence, minor contribution from climate change)

[18.4, 23.4-5, Table 18-9, Figure 7-2]

Table SPM.A1 | Observed impacts attributed to climate change reported in the scientiﬁ c literature since the AR4. These impacts have been attributed to climate change with

very low, low, medium, or high conﬁ dence, with the relative contribution of climate change to the observed change indicated (major or minor), for natural and human systems

across eight major world regions over the past several decades. [Tables 18-5, 18-6, 18-7, 18-8, and 18-9] Absence from the table of additional impacts attributed to climate

change does not imply that such impacts have not occurred.

SPM

Continued next page

sia

now & Ice,

ivers & Lakes,

Floods & Drought

•

ermafrost degradation in Siberia, Central Asia, and Tibetan Plateau ( high conﬁ dence, major contribution from climate change)

• Shrinking mountain glaciers across most of Asia ( medium conﬁ dence, major contribution from climate change)

• Changed water availability in many Chinese rivers, beyond changes due to land use ( low conﬁ dence, minor contribution from climate change)

• Increased ﬂ ow in several rivers due to shrinking glaciers ( high conﬁ dence, major contribution from climate change)

• Earlier timing of maximum spring ﬂ ood in Russian rivers ( medium conﬁ dence, major contribution from climate change)

•

educed soil moisture in north-central and northeast China (1950 – 2006) ( medium conﬁ dence, major contribution from climate change)

• Surface water degradation in parts of Asia, beyond changes due to land use ( medium conﬁ dence, minor contribution from climate change)

[24.3-4, 28.2, Tables 18-5, 18-6, and SM24-4, Box 3-1; WGI AR5 4.3, 10.5]

Terrestrial

Ecosystems

• Changes in plant phenology and growth in many parts of Asia (earlier greening), particularly in the north and east ( medium conﬁ dence, major contribution from

limate change)

• Distribution shifts of many plant and animal species upwards in elevation or polewards, particularly in the north of Asia ( medium conﬁ dence, major contribution from

climate change)

• Invasion of Siberian larch forests by pine and spruce during recent decades ( low conﬁ dence, major contribution from climate change)

• Advance of shrubs into the Siberian tundra ( high conﬁ dence, major contribution from climate change)

[

4.3, 24.4, 28.2, Table 18-7, Figure 4-4]

Coastal Erosion

& Marine

cosystems

• Decline in coral reefs in tropical Asian waters, beyond decline due to human impacts ( high conﬁ dence, major contribution from climate change)

• Northward range extension of corals in the East China Sea and western Paciﬁ c, and of a predatory ﬁ sh in the Sea of Japan ( medium conﬁ dence, major contribution

from climate change)

• Shift from sardines to anchovies in the western North Paciﬁ c, beyond ﬂ uctuations due to ﬁ sheries ( low conﬁ dence, major contribution from climate change)

• Increased coastal erosion in Arctic Asia ( low conﬁ dence, major contribution from climate change)

[6.3, 24.4, 30.5, Tables 6-2 and 18-8]

Food Production

& Livelihoods

•

mpacts on livelihoods of indigenous groups in Arctic Russia, beyond economic and sociopolitical changes ( low conﬁ dence, major contribution from climate change)

• Negative impacts on aggregate wheat yields in South Asia, beyond increase due to improved technology ( medium conﬁ dence, minor contribution from climate change)

• Negative impacts on aggregate wheat and maize yields in China, beyond increase due to improved technology ( low conﬁ dence, minor contribution from climate change)

• Increases in a water-borne disease in Israel ( low conﬁ dence, minor contribution from climate change)

[7.2, 13.2, 18.4, 28.2, Tables 18-4 and 18-9, Figure 7-2]

Australasia

Snow & Ice,

Rivers & Lakes,

Floods & Drought

• Signiﬁ cant decline in late-season snow depth at 3 of 4 alpine sites in Australia (1957– 2002) ( medium conﬁ dence, major contribution from climate change)

• Substantial reduction in ice and glacier ice volume in New Zealand ( medium conﬁ dence, major contribution from climate change)

• Intensiﬁ cation of hydrological drought due to regional warming in southeast Australia ( low conﬁ dence, minor contribution from climate change)

• Reduced inﬂ ow in river systems in southwestern Australia (since the mid-1970s) ( high conﬁ dence, major contribution from climate change)

[25.5, Tables 18-5, 18-6, and 25-1; WGI AR5 4.3]

Terrestrial

Ecosystems

• Changes in genetics, growth, distribution, and phenology of many species, in particular birds, butterﬂ ies, and plants in Australia, beyond ﬂ uctuations due to variable

local climates, land use, pollution, and invasive species ( high conﬁ dence, major contribution from climate change)

• Expansion of some wetlands and contraction of adjacent woodlands in southeast Australia ( low conﬁ dence, major contribution from climate change)

• Expansion of monsoon rainforest at expense of savannah and grasslands in northern Australia ( medium conﬁ dence, major contribution from climate change)

• Migration of glass eels advanced by several weeks in Waikato River, New Zealand ( low conﬁ dence, major contribution from climate change)

[Tables 18-7 and 25-3]

Coastal Erosion

& Marine

Ecosystems

• Southward shifts in the distribution of marine species near Australia, beyond changes due to short-term environmental ﬂ uctuations, ﬁ shing, and pollution ( medium

conﬁ dence, major contribution from climate change)

• Change in timing of migration of seabirds in Australia ( low conﬁ dence, major contribution from climate change)

• Increased coral bleaching in Great Barrier Reef and western Australian reefs, beyond effects from pollution and physical disturbance ( high conﬁ dence, major

contribution from climate change)

• Changed coral disease patterns at Great Barrier Reef, beyond effects from pollution ( medium conﬁ dence, major contribution from climate change)

[6.3, 25.6, Tables 18-8 and 25-3]

Food Production

& Livelihoods

• Advanced timing of wine-grape maturation in recent decades, beyond advance due to improved management ( medium conﬁ dence, major contribution from climate

change)

• Shift in winter vs. summer human mortality in Australia, beyond changes due to exposure and health care ( low conﬁ dence, major contribution from climate change)

• Relocation or diversiﬁ cation of agricultural activities in Australia, beyond changes due to policy, markets, and short-term climate variability ( low conﬁ dence, minor

contribution from climate change)

[11.4, 18.4, 25.7-8, Tables 18-9 and 25-3, Box 25-5]

North America

Snow & Ice,

Rivers & Lakes,

Floods & Drought

• Shrinkage of glaciers across western and northern North America ( high conﬁ dence, major contribution from climate change)

• Decreasing amount of water in spring snowpack in western North America (1960 – 2002) ( high conﬁ dence, major contribution from climate change)

• Shift to earlier peak ﬂ ow in snow dominated rivers in western North America ( high conﬁ dence, major contribution from climate change)

• Increased runoff in the midwestern and northeastern US ( medium conﬁ dence, minor contribution from climate change)

[Tables 18-5 and 18-6; WGI AR5 2.6, 4.3]

Terrestrial

Ecosystems

• Phenology changes and species distribution shifts upward in elevation and northward across multiple taxa ( medium conﬁ dence, major contribution from climate change)

• Increased wildﬁ re frequency in subarctic conifer forests and tundra ( medium conﬁ dence, major contribution from climate change)

• Regional increases in tree mortality and insect infestations in forests ( low conﬁ dence, minor contribution from climate change)

• Increase in wildﬁ re activity, ﬁ re frequency and duration, and burnt area in forests of the western US and boreal forests in Canada, beyond changes due to land use

and ﬁ re management ( medium conﬁ dence, minor contribution from climate change)

[26.4, 28.2, Table 18-7, Box 26-2]

Coastal Erosion

& Marine

Ecosystems

• Northward distributional shifts of northwest Atlantic ﬁ sh species ( high conﬁ dence, major contribution from climate change)

• Changes in musselbeds along the west coast of US ( high conﬁ dence, major contribution from climate change)

• Changed migration and survival of salmon in northeast Paciﬁ c ( high conﬁ dence, major contribution from climate change)

• Increased coastal erosion in Alaska and Canada ( medium conﬁ dence, major contribution from climate change)

[18.3, 30.5, Tables 6-2 and 18-8]

Food Production

& Livelihoods

• Impacts on livelihoods of indigenous groups in the Canadian Arctic, beyond effects of economic and sociopolitical changes ( medium conﬁ dence, major contribution

from climate change)

[18.4, 28.2, Tables 18-4 and 18-9]

able SPM.A1 (continued)

Summary for Policymakers

SPM

Summary for Policymakers

Central and South America

Snow & Ice,

Rivers & Lakes,

Floods & Drought

•

hrinkage of Andean glaciers ( high conﬁ dence, major contribution from climate change)

•

hanges in extreme ﬂ ows in Amazon River ( medium conﬁ dence, major contribution from climate change)

• Changing discharge patterns in rivers in the western Andes ( medium conﬁ dence, major contribution from climate change)

•

ncreased streamﬂ ow in sub-basins of the La Plata River, beyond increase due to land-use change ( high conﬁ dence, major contribution from climate change)

[27.3, Tables 18-5, 18-6, and 27-3; WGI AR5 4.3]

Terrestrial

Ecosystems

•

ncreased tree mortality and forest ﬁ re in the Amazon ( low conﬁ dence, minor contribution from climate change)

• Rainforest degradation and recession in the Amazon, beyond reference trends in deforestation and land degradation ( low conﬁ dence, minor contribution from climate

hange)

[

4.3, 18.3, 27.2-3, Table 18-7]

Coastal Erosion

& Marine

Ecosystems

• Increased coral bleaching in western Caribbean, beyond effects from pollution and physical disturbance ( high conﬁ dence, major contribution from climate change)

•

angrove degradation on north coast of South America, beyond degradation due to pollution and land use ( low conﬁ dence, minor contribution from climate change)

[27.3, Table 18-8]

Food Production

& Livelihoods

• More vulnerable livelihood trajectories for indigenous Aymara farmers in Bolivia due to water shortage, beyond effects of increasing social and economic stress

(

medium conﬁ dence, major contribution from climate change)

• Increase in agricultural yields and expansion of agricultural areas in southeastern South America, beyond increase due to improved technology ( medium conﬁ dence,

major contribution from climate change)

[

13.1, 27.3, Table 18-9]

Polar Regions

Snow & Ice,

Rivers & Lakes,

Floods & Drought

• Decreasing Arctic sea ice cover in summer ( high conﬁ dence, major contribution from climate change)

• Reduction in ice volume in Arctic glaciers ( high conﬁ dence, major contribution from climate change)

•

ecreasing snow cover extent across the Arctic ( medium conﬁ dence, major contribution from climate change)

• Widespread permafrost degradation, especially in the southern Arctic ( high conﬁ dence, major contribution from climate change)

•

ce mass loss along coastal Antarctica ( medium conﬁ dence, major contribution from climate change)

• Increased river discharge for large circumpolar rivers (1997–2007) ( low conﬁ dence, major contribution from climate change)

• Increased winter minimum river ﬂ ow in most of the Arctic ( medium conﬁ dence, major contribution from climate change)

•

ncreased lake water temperatures 1985–2009 and prolonged ice-free seasons ( medium conﬁ dence, major contribution from climate change)

• Disappearance of thermokarst lakes due to permafrost degradation in the low Arctic. New lakes created in areas of formerly frozen peat ( high conﬁ dence, major

contribution from climate change)

[28.2, Tables 18-5 and 18-6; WGI AR5 4.2-4, 4.6, 10.5]

Terrestrial

Ecosystems

• Increased shrub cover in tundra in North America and Eurasia ( high conﬁ dence, major contribution from climate change)

• Advance of Arctic tree-line in latitude and altitude ( medium conﬁ dence, major contribution from climate change)

• Changed breeding area and population size of subarctic birds, due to snowbed reduction and/or tundra shrub encroachment ( medium conﬁ dence, major contribution

from climate change)

• Loss of snow-bed ecosystems and tussock tundra ( high conﬁ dence, major contribution from climate change)

• Impacts on tundra animals from increased ice layers in snow pack, following rain-on-snow events ( medium conﬁ dence, major contribution from climate change)

• Increased plant species ranges in the West Antarctic Peninsula and nearby islands over the past 50 years ( high conﬁ dence, major contribution from climate change)

• Increased phytoplankton productivity in Signy Island lake waters ( high conﬁ dence, major contribution from climate change)

[28.2, Table 18-7]

Coastal Erosion

& Marine

Ecosystems

• Increased coastal erosion across Arctic ( medium conﬁ dence, major contribution from climate change)

• Negative effects on non-migratory Arctic species ( high conﬁ dence, major contribution from climate change)

• Decreased reproductive success in Arctic seabirds ( medium conﬁ dence, major contribution from climate change)

• Decline in Southern Ocean seals and seabirds ( medium conﬁ dence, major contribution from climate change)

• Reduced thickness of foraminiferal shells in southern oceans, due to ocean acidiﬁ cation ( medium conﬁ dence, major contribution from climate change)

• Reduced krill density in Scotia Sea ( medium conﬁ dence, major contribution from climate change)

[6.3, 18.3, 28.2-3, Table 18-8]

Food Production

& Livelihoods

• Impact on livelihoods of Arctic indigenous peoples, beyond effects of economic and sociopolitical changes ( medium conﬁ dence, major contribution from climate

change)

• Increased shipping trafﬁ c across the Bering Strait ( medium conﬁ dence, major contribution from climate change)

[18.4, 28.2, Tables 18-4 and 18-9, Figure 28-4]

Small Islands

Snow & Ice,

Rivers & Lakes,

Floods & Drought

• Increased water scarcity in Jamaica, beyond increase due to water use ( very low conﬁ dence, minor contribution from climate change)

[Table 18-6]

Terrestrial

Ecosystems

• Tropical bird population changes in Mauritius ( medium conﬁ dence, major contribution from climate change)

• Decline of an endemic plant in Hawai’i ( medium conﬁ dence, major contribution from climate change)

• Upward trend in tree-lines and associated fauna on high-elevation islands ( low conﬁ dence, minor contribution from climate change)

[29.3, Table 18-7]

Coastal Erosion

& Marine

Ecosystems

• Increased coral bleaching near many tropical small islands, beyond effects of degradation due to ﬁ shing and pollution ( high conﬁ dence, major contribution from

climate change)

• Degradation of mangroves, wetlands, and seagrass around small islands, beyond degradation due to other disturbances ( very low conﬁ dence, minor contribution from

climate change)

• Increased ﬂ ooding and erosion, beyond erosion due to human activities, natural erosion, and accretion ( low conﬁ dence, minor contribution from climate change)

• Degradation of groundwater and freshwater ecosystems due to saline intrusion, beyond degradation due to pollution and groundwater pumping ( low conﬁ dence,

minor contribution from climate change)

[29.3, Table 18-8]

Food Production

& Livelihoods

• Increased degradation of coastal ﬁ sheries due to direct effects and effects of increased coral reef bleaching, beyond degradation due to overﬁ shing and pollution ( low

conﬁ dence, minor contribution from climate change)

[18.3-4, 29.3, 30.6, Table 18-9, Box CC-CR]

Table SPM.A1 (continued)

WORKING GROUP II CONTRIBUTION TO THE

FIFTH ASSESSMENT REPORT OF THE

INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE

WG II

I N T E RG OV E R N M E N TA L PA N E L O N climate change