Shobakar dhakal

© O

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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

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

2 Climate Change Mitigation 2014, WG3’s contribution to 5th Assessment Report of IPCC, 2014 April

• 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

GHG emissions growth between 2000 and 2010 has been larger than in the previous three decades

4

Based on Figure 1.3


About half of cumulative anthropogenic CO2 emissions between 1750 and 2010 occurred in the last 40 years

5

Based on Figure 5.3


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

Regional patterns of GHG emissions are shifting along with changes in the world economy

6

Based on Figure 1.6


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


Stabilization of atmospheric concentrations requires moving away from the baseline – regardless of the mitigation goal

8

Based on Figure 6.7


Stabilization of atmospheric concentrations requires moving away from the baseline – regardless of the mitigation goal

9

~3°C

Based on Figure 6.7


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


Delaying mitigation is estimated to increase the difficulty and narrow the options for limiting warming to 2°C

11

„immediate action“

„delayed mitigation“


Delaying mitigation is estimated to increase the difficulty and narrow the options for limiting warming to 2°C.

12


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


Impacts of mitigation on GDP growth is nominal

(2⁰C climate stabilization)

2030 Time Current

GDP

GDP without

mitigation

GDP with stringent

mitigation (reaching ≈

450 ppm CO2eq in

2100)

Loss in global consumption in 2030: 1.7% (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


Mitigation can result in large co-benefits for human health and other societal goals

15



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).


Baseline scenarios suggest rising GHG emissions in all sectors, except for CO2 emissions in the land‐use sector

17

Based on Figure TS.17


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


Interdependencies: Mitigation efforts in one sector determine efforts in others

19

Based on Figure TS.17 afforestation


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


Energy demand reductions can provide flexibility, hedge against risks, avoid lock-in and provide co-benefits.

21


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.


22

The wide-scale application of available best-practice low-GHG technologies could

lead to substantial emission reductions

IPCC WGIII 2014 Mitigation Report

23

Effective mitigation will not be achieved if individual agents advance their own

interests independently.

IPCC WGIII 2014 Mitigation Report

Substantial reductions in emissions would require large changes in investment patterns and appropriate policies.

24


• For comparison, global total annual investment in the energy system is presently about USD 1200 billion


There has been a considerable increase in national and sub-national mitigation policies since AR4.

25


• 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


Sector-specific policies have been more widely used than economy-wide policies.

26



Climate change mitigation is a global commons problem that requires international cooperation across scales.

27


• International cooperation on climate change has become more institutionally diverse over the past decade


Forms of international cooperation vary in their focus and degree of centralization and coordination.

28


Effective mitigation will not be achieved if individual agents advance their own interests independently.

29



• 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


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www.mitigation2014.org

Thank you [email protected]

http://www.mitigation2014.org/

Key characteristics of the scenarios collected and assessed for WGIII AR5

For all parameters, the 10th to 90th percentile of the scenarios is shown

GHG emissions rise with growth in GDP and population; long-standing trend of decarbonisation of energy reversed

33

Based on Figure 1.7

GHG emissions rise with growth in GDP and population; long-standing trend of decarbonisation of energy reversed

34

Based on Figure 1.7

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

35

Costs of many power supply technologies decreased substantially, some can already compete with conventional technologies.

36

Based on Figure 7.7

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

37

Private costs of reducing emissions in transport vary widely. Societal costs remain uncertain.

38

Based on Figure TS.21

Global costs rise with the ambition of the mitigation goal but impact to GDP is nominal

39

Based on Table SPM.2

2⁰C stabilization

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