GHG emissions have grown faster in recent decades despite mitigation efforts. Most recent growth has occurred in emerging economies in Asia and Latin America. Without additional mitigation, global temperatures are projected to increase 3.7-4.8°C this century. While low climate stabilization at 2°C is possible, it requires significant policy efforts, investments, and international cooperation to rapidly transition energy systems to low-carbon technologies. Delaying mitigation will increase costs and limit options.

1. ©Ocean/Corbis
Dr. Shobhakar Dhakal
Associate Professor,
Asian Institute of Technology
Coordinating Lead Author, IPCC-WG III, AR5
Feasibility of 2⁰C world: Key
Findings from IPCC AR 5 WG III

2. 1 Summary for Policymakers
1 Technical Summary
16 Chapters
235 Authors
900 Reviewers
More than 2000 pages
Close to 10,000 references
More than 38,000 comments
IPCC reports are the result of extensive work of
many scientists from around the world
2Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

3. • GHG emission growth have accelerated despite ongoing
efforts
• There is a significant shift in emission structure in recent
decades regionally, along income groups, and sectors
• Climate change mitigation, if unabated, may result into 3.7-
4.8⁰C world
• While mitigation challenges exist, the low climate
stabilization (2⁰C) mitigation pathways are possible
• The costs to economy from low climate stabilization
scenarios would be nominal
• Delaying of mitigation would entail more costs and limit
options
• But such pathways needs significant efforts from policies and
institutions, investments and international cooperation
Summary Messages
3
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

4. GHG emissions growth between 2000 and 2010 has
been larger than in the previous three decades
4
Based on Figure 1.3
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

5. About half of cumulative anthropogenic CO2 emissions
between 1750 and 2010 occurred in the last 40 years
5
Based on Figure 5.3
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April
While historically most emission growth has occurred in industrialized countries, most of
the recent emission growth has been in emerging economies in Asia and Latin America

6. Regional patterns of GHG emissions are shifting
along with changes in the world economy
6
Based on Figure 1.6
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

7. Without additional mitigation, global mean surface
temperature is projected to increase by 3.7 to 4.8°C over
the 21st century
7
Based on WGII AR5 Figure 19.4
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

8. Stabilization of atmospheric concentrations requires moving
away from the baseline – regardless of the mitigation goal
8
Based on Figure 6.7
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

9. Stabilization of atmospheric concentrations requires moving
away from the baseline – regardless of the mitigation goal
9
~3°C
Based on Figure 6.7
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

10. Low climate mitigation scenario involves
substantial upscaling of low-carbon energy
10
• Rapid improvements of energy
efficiency
• A tripling to nearly a quadrupling of
the share of zero- and low-carbon
energy supply from renewables,
nuclear energy and fossil energy with
carbon dioxide capture and storage
(CCS), or bioenergy with CCS (BECCS)
by the year 2050
• 2° scenarios typically rely on the
availability and large-scale
deployment of carbon dioxide
removal technologies, but both are
uncertain
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

11. Delaying mitigation is estimated to increase the difficulty
and narrow the options for limiting warming to 2°C
11
„immediate action“
„delayed mitigation“
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

12. Delaying mitigation is estimated to increase the difficulty
and narrow the options for limiting warming to 2°C.
12
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

13. Delaying mitigation is estimated to increase the difficulty
and narrow the options for limiting warming to 2°C.
13
Based on Figures 6.32 and 7.16
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

14. Impacts of mitigation on GDP growth is nominal
(2⁰C climate stabilization)
2030 TimeCurrent
GDP
GDP without
mitigation
GDP with stringent
mitigation (reaching ≈
450 ppm CO2eq in
2100)
Loss in global
consumption
in 2030: 1.7%
(median)
Loss in
global
consumption
in 2050:
3.4%
(median)
Loss in global
consumption
in 2100: 4.8%
(median)
2050 2100
Estimates do not include the benefits of reduced climate change as well as co-
benefits and adverse side-effects of mitigation 14
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

15. Mitigation can result in large co-benefits for
human health and other societal goals
15
Based on Figures 6.33 and 12.23
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

16. Absence or limited availability of technology can
greatly influence mitigation costs
16
Based on Figure 6.24
• ‘Carbon capture and storage’ as well as
‘bioenergy’ strongly influence mitigation
costs
• Limits on nuclear, solar and wind influence
mitigation costs much less
2⁰C may not be achieved at all if mitigation is considerably delayed or key technologies
are limitedly availability, such as bioenergy, CCS, and their combination (BECCS).
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

17. Baseline scenarios suggest rising GHG emissions in all
sectors, except for CO2 emissions in the land‐use sector
17
Based on Figure TS.17
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

18. 450 ppm mitigation requires changes throughout the economy.
Systemic approaches are expected to be most effective
18
Based on Figure TS.17
BECCS
-ve emission
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

19. Interdependencies: Mitigation efforts in one
sector determine efforts in others
19
Based on Figure TS.17afforestation
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

20. Full decarbonization of energy supply is a key
requirement for limiting warming to 2°C
20
Based on Figure 7.11
There is a lot of flexibility for doing so
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

21. Energy demand reductions can provide flexibility, hedge against
risks, avoid lock-in and provide co-benefits.
21
Based on Figure 7.11
If we reduce energy demand
• The more flexibility in our choice of low carbon technologies;
• The better we can hedge against supply side risks;
• The smaller infrastructure lock-in will be; and
• The larger co-benefits will be.
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

22. 22
The wide-scale application of available
best-practice low-GHG technologies could
lead to substantial emission reductions
IPCC WGIII 2014 Mitigation
Report

23. 23
Effective mitigation will not be achieved if
individual agents advance their own
interests independently.
IPCC WGIII 2014 Mitigation
Report

24. Substantial reductions in emissions would require large
changes in investment patterns and appropriate policies.
24
Based on Figure 16.3
• For comparison, global total annual investment in the energy system is
presently about USD 1200 billion
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

25. There has been a considerable increase in national and sub-
national mitigation policies since AR4.
25
Based on Figures 15.1 and 13.3
• In 2012, 67% of global GHG emissions were subject to national legislation or strategies; 45% in 2007
• Yet, no substantial deviation in global emissions from the past trend
• Plans and strategies are in early stages of development and implementation in
countries
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

26. Sector-specific policies have been more widely used than
economy-wide policies.
26
Based on Figure 10.15
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

27. Climate change mitigation is a global commons problem that
requires international cooperation across scales.
27
Based on Figure 13.1
• International
cooperation on
climate change
has become
more
institutionally
diverse over
the past
decade
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

28. Forms of international cooperation vary in their focus and
degree of centralization and coordination.
28
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

29. Effective mitigation will not be achieved if individual agents
advance their own interests independently.
29
Based on Figure 13.2
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

30. • GHG emission growth have accelerated despite ongoing
efforts
• There is a significant shift in emission structure in recent
decades regionally, along income groups, and sectors
• Climate change mitigation, if unabated, may result into 3.7-
4.8⁰C world (which is undesirable)
• While mitigation challenges exist, the low climate
stabilization (2⁰C) mitigation pathways are possible
• But such pathways needs significant efforts from policies and
institutions, investments and international cooperation
• The costs to economy from low climate stabilization
scenarios are nominal
• Delaying of mitigation would entail more costs and limit
options
Summary Messages
30
Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

31. ©Ocean/Corbis
www.mitigation2014.org
Thank you
shobhakar@ait.ac.th

32. Key characteristics of the scenarios collected
and assessed for WGIII AR5
For all parameters, the 10th to 90th percentile of the scenarios is shown

33. GHG emissions rise with growth in GDP and population; long-
standing trend of decarbonisation of energy reversed
33
Based on Figure 1.7

34. GHG emissions rise with growth in GDP and population; long-
standing trend of decarbonisation of energy reversed
34
Based on Figure 1.7

35. Examples from power supply: Many technologies exist to reduce
GHG emissions, but do so to different degrees.
35

36. Costs of many power supply technologies decreased substantially,
some can already compete with conventional technologies.
36
Based on Figure 7.7

37. Example transport: several strategies exist to reduce emissions
from transportation.
37

38. Private costs of reducing emissions in transport vary widely.
Societal costs remain uncertain.
38
Based on Figure TS.21

39. Global costs rise with the ambition of the
mitigation goal but impact to GDP is nominal
39
Based on Table SPM.2
2⁰C stabilization