Chapters
111
1
Introductory Chapter
Coordinating Lead Authors:
David G. Victor (USA), Dadi Zhou (China)
Lead Authors:
Essam Hassan Mohamed Ahmed (Egypt), Pradeep Kumar Dadhich (India), Jos Olivier
(Netherlands), H-Holger Rogner (Germany), Kamel Sheikho (Saudi Arabia), Mitsutsune Yamaguchi
(Japan)
Contributing Authors:
Giovanni Baiocchi (UK / Italy), Yacob Mulugetta (Ethiopia / UK), Linda Wong (USA)
Review Editors:
Arnulf Grübler (IIASA / Austria), Alick Muvundika (Zambia)
This chapter should be cited as:
Victor D. G., D. Zhou, E. H. M. Ahmed, P. K. Dadhich, J. G. J. Olivier, H-H. Rogner, K. Sheikho, and M. Yamaguchi, 2014: Intro-
ductory Chapter. In: Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth
Assessment Report of the Intergovernmental Panel on Climate Change [Edenhofer, O., R. Pichs-Madruga, Y. Sokona, E.
Farahani, S. Kadner, K. Seyboth, A. Adler, I. Baum, S. Brunner, P. Eickemeier, B. Kriemann, J. Savolainen, S. Schlömer, C. von
Stechow, T. Zwickel and J.C. Minx (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
112112
Introductory Chapter
1
Chapter 1
Contents
Executive Summary � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 113
1�1 Introduction � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 114
1�2 Main messages and changes from previous assessment � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 115
1�2�1 Sustainable development
� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 115
1�2�2 The world macroeconomic situation
� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 116
1�2�3 The availability, cost and performance of energy systems
� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 118
1�2�4 International institutions and agreements
� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 120
1�2�5 Understanding the roles of emissions other than fossil fuel CO
2
� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 122
1�2�6 Emissions trajectories and implications for Article 2
� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 124
1�3 Historical, current and future trends � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 125
1�3�1 Review of four decades of greenhouse gas emissions
� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 125
1�3�2 Perspectives on mitigation
� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 129
1�3�3 Scale of the future mitigation challenge
� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 134
1�4 Mitigation challenges and strategies � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 137
1�4�1 Reconciling priorities and achieving sustainable development
� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 137
1�4�2 Uncertainty and risk management
� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 137
1�4�3 Encouraging international collective action
� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 139
1�4�4 Promoting investment and technological change
� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 139
1�4�5 Rising attention to adaptation
� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 140
1�5 Roadmap for WG III report � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 140
1�6 Frequently Asked Questions � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 141
References � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 143
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Introductory Chapter
1
Chapter 1
Executive Summary
Since the first Intergovernmental Panel on Climate Change (IPCC)
assessment report (FAR) (IPCC, 1990a), the quantity and depth of sci-
entific research on climate change mitigation has grown enormously.
In tandem with scholarship on this issue, the last two decades have
seen relatively active efforts around the world to design and adopt
policies that control (‘mitigate’) the emissions of pollutants that affect
the climate. The effects of those emissions are felt globally; mitigation
thus involves managing the global commons and requires a measure
of international coordination among nations. But the actual policies
that lead to mitigation arise at the local and national levels as well
as internationally. Those policies have included, among others, market-
based approaches such as emission trading systems along with regula-
tion and voluntary initiatives; they encompass many diverse economic
development strategies that countries have adopted with the goal of
promoting human welfare and jobs while also achieving other goals
such as mitigating emissions of climate pollutants. These policies also
include other efforts to address market failures, such as public invest-
ments in research and development (R&D) needed to increase the pub-
lic good of knowledge about new less emission-intensive technologies
and practices. International diplomacy leading to agreements such
as the United Nations Framework Convention on Climate Change
(UNFCCC) and the Kyoto Protocol as well as various complementary
initiatives such as the commitments pledged at the Copenhagen and
Cancun Conferences of the Parties has played a substantial role in
focusing attention on mitigation of greenhouse gases (GHGs).
The field of scientific research in this area has evolved in parallel with
actual policy experience allowing, in theory, insights from each domain
to inform the other. Since the 4th assessment report (AR4) of IPCC
(2007a; b) there have been numerous important developments in both
the science and practical policy experience related to mitigation. There
is growing insight into how climate change mitigation policies inter-
act with other important social goals from the local to the national
and international levels. There is also growing practical experience
and scholarly research concerning a wide array of policy instruments.
Scholars have developed much more sophisticated information on how
public opinion influences the design and stringency of climate change
mitigation policies.
Meanwhile, events in the world have had a large impact on how scien-
tific researchers have seen the scale of the mitigation challenge and its
practical policy outcomes. For example, a worldwide economic reces-
sion beginning around 2008 has affected patterns of emissions and
investment in the world economy and in many countries has affected
political priorities on matters related to climate change mitigation.
The present chapter identifies six conclusions. Where appropriate, we
indicate not only the major findings but also our confidence in the
finding and the level of supporting evidence. (For an overview of the
language on agreement and confidence see Mastrandrea etal. (2011).
First, since AR4, annual global GHG emissions have continued
to grow and reached 49�5 billion tonnes (giga tonnes or Gt) of
carbon dioxide equivalents (CO
2
eq) in the year 2010, higher
than any level prior to that date, with an uncertainty estimate
at ± 10 % for the 90 % confidence interval On a per-capita basis,
emissions from industrialized countries that are listed in AnnexI of the
UNFCCC are on average 2.5 times of those from developing countries.
However, since AR4, total emissions from countries not listed in AnnexI
have overtaken total emissions from the AnnexI industrialized coun-
tries (see glossary for AnnexI countries). Treating the 27 members of
the EU as a single country, about ten large countries from the indus-
trialized and developing worlds account for 70 % of world emissions.
(robust evidence, high agreement) [Section 1.3]. The dominant driving
forces for anthropogenic emissions include population, the structure
of the economy, income and income distribution, policy, patterns of
consumption, investment decisions, individual and societal behaviour,
the state of technology, availability of energy resources, and land-use
change. In nearly all countries it is very likely that the main short-term
driver of changes in the level of emissions is the overall state of the
economy. In some countries there is also a significant role for climate
policies focused on controlling emissions. (medium evidence, medium
agreement) [1.3]
Second, national governments are addressing climate change in
the context of other national priorities, such as energy security
and alleviation of poverty� In nearly all countries the most impor-
tant driving forces for climate policy are not solely the concern about
climate change. (medium evidence, medium agreement) [1.2 and 1.4].
Studies on policy implementation show that improvements to cli-
mate policy programs need to engage these broader national priori-
ties. Despite the variety of existing policy efforts and the existence of
the UNFCCC and the Kyoto Protocol, GHG emissions have grown at
about twice the rate in the recent decade (2000 2010) than any other
decade since 1970. (robust evidence, high agreement) [1.3.1]
Third, the current trajectory of global annual and cumulative
emissions of GHGs is inconsistent with widely discussed goals
of limiting global warming at 1�5 to 2 degrees Celsius above
the pre-industrial level (medium evidence, medium agreement).
[1.2.1.6 and 1.3.3] The ability to link research on mitigation of emis-
sions to actual climate outcomes, such as average temperature, has
not substantially changed since AR4 due to a large number of uncer-
tainties in scientific understanding of the physical sensitivity of the
climate to the build-up of GHGs discussed in Working Group I of the
IPCC (WGI). Those physical uncertainties are multiplied by the many
socioeconomic uncertainties that affect how societies would respond
to emission control policies (low evidence, high agreement). Acknowl-
edging these uncertainties, mitigating emissions along a pathway that
would be cost-effective and consistent with likely avoiding warming
of more than 2 degrees implies that nearly all governments promptly
engage in international cooperation, adopt stringent national and
international emission control policies, and deploy rapidly a wide array
of low- and zero-emission technologies. Modelling studies that adopt
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Introductory Chapter
1
Chapter 1
assumptions that are less ideal for example, with international coop-
eration that emerges slowly or only restricted availability of some tech-
nologies show that achieving this 2 degree goal is much more costly
and requires deployments of technology that are substantially more
aggressive than the least-cost strategies (robust evidence, medium
agreement) [1.3.3]. The assumptions needed to have a likely chance of
limiting warming to 2 degrees are very difficult to satisfy in real world
conditions (medium evidence; low agreement). The tenor of modelling
research since AR4 suggests that the goal of stabilizing warming at 1.5
degrees Celsius is so challenging to achieve that relatively few model-
ling studies have even examined it in requisite detail (low evidence,
medium agreement) [1.3.3].
Fourth, deep cuts in emissions will require a diverse portfolio
of policies, institutions, and technologies as well as changes in
human behaviour and consumption patterns (high evidence; high
agreement). There are many different development trajectories capable
of substantially mitigating emissions; the ability to meet those trajec-
tories will be constrained if particular technologies are removed from
consideration. It is virtually certain that the most appropriate policies
will vary by sector and country, suggesting the need for flexibility
rather than a singular set of policy tools. In most countries the actors
that are relevant to controlling emissions aren’t just national govern-
ments. Many diverse actors participate in climate policy from the local
to the global levels including a wide array of nongovernmental orga-
nizations representing different environmental, social, business and
other interests. (robust evidence, medium agreement) [1.4]
Fifth, policies to mitigate emissions are extremely complex and
arise in the context of many different forms of uncertainty�
While there has been much public attention to uncertainties in the
underlying science of climate change a topic addressed in detail in
the WGI and II reports profound uncertainties arise in the socioeco-
nomic factors addressed here in WGIII. Those uncertainties include the
development and deployment of technologies, prices for major primary
energy sources, average rates of economic growth and the distribu-
tion of benefits and costs within societies, emission patterns, and a
wide array of institutional factors such as whether and how countries
cooperate effectively at the international level. In general, these uncer-
tainties and complexities multiply those already identified in climate
science by WGI and WGII. The pervasive complexities and uncertainties
suggest that there is a need to emphasize policy strategies that are
robust over many criteria, adaptive to new information, and able to
respond to unexpected events. (medium evidence, medium agreement)
[1.2].
Sixth, there are many important knowledge gaps that additional
research could address This report points to at least two of
them� First is that the scholarship has developed increasingly sophisti-
cated techniques for assessing risks, but so far those risk management
techniques have not spread into widespread use in actual mitigation
strategies. Risk management requires drawing attention to the interac-
tions between mitigation and other kinds of policy responses such as
adaptation to climate change; they require more sophisticated under-