© Ocean/Corbis CLIMATE CHANGE 2014 Mitigation of Climate Change Working Group III contribution to the IPCC Fifth Assessment Report Prof. Dr. Thomas Bruckner CLA „Energy Systems“, IPCC Working Group III The Presentation of the 5 th Assessment Report of the IPCC 4 December 2014, Beograd, Serbia

Working Group III contribution to the IPCC Fifth Assessment Report IPCC reports are the result of extensive work of many scientists from around the world. 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

Working Group III contribution to the IPCC Fifth Assessment Report Content: Framing Chapters Historic Emissions Transformation Pathways Sector Chapters Policy Chapters

Working Group III contribution to the IPCC Fifth Assessment Report Content: Framing Chapters Historic Emissions Transformation Pathways Sector Chapters Policy Chapters

Working Group III contribution to the IPCC Fifth Assessment Report Effective mitigation will not be achieved if individual agents advance their own interests independently. Existing and proposed international climate change cooperation arrangements vary in their focus and degree of centralization and coordination. Issues of equity, justice, and fairness arise with respect to mitigation and adaptation. Climate policy may be informed by a consideration of a diverse array of risks and uncertainties, some of which are difficult to measure, notably events that are of low probability but which would have a significant impact if they occur.

Working Group III contribution to the IPCC Fifth Assessment Report Content: Framing Chapters Historic Emissions Transformation Pathways Sector Chapters Policy Chapters

Working Group III contribution to the IPCC Fifth Assessment Report GHG emissions accelerate despite reduction efforts. Most emission growth is CO 2 from fossil fuel combustion. Figure SPM.1

Working Group III contribution to the IPCC Fifth Assessment Report Regional patterns of GHG emissions are shifting along with changes in the world economy. Figure TS.3

Working Group III contribution to the IPCC Fifth Assessment Report A growing share of CO 2 emissions from fossil fuel combustion and industrial processes in low and middle income countries has been released in the production of goods and services exported, notably from upper ‐ middle income countries to high income countries. Figure TS.5

Working Group III contribution to the IPCC Fifth Assessment Report GHG emissions rise with growth in GDP and population; long-standing trend of decarbonisation of energy reversed. Figure SPM.3

Working Group III contribution to the IPCC Fifth Assessment Report Due to an increase of both, energy demand and the share of coal in the global fuel mix, GHG emissions grew more rapidly between 2001 and 2010 than in the previous decade. Contribution of energy sources to global and regional primary energy use increments. Figure 7.2

Working Group III contribution to the IPCC Fifth Assessment Report Content: Framing Chapters Historic Emissions Transformation Pathways Sector Chapters Policy Chapters

Working Group III contribution to the IPCC Fifth Assessment Report „The 5 Reasons for Concern“ WG II SPM, Box 1

Working Group III contribution to the IPCC Fifth Assessment Report Without more mitigation, global mean surface temperature might increase by 3.7° to 4.8°C over the 21 st century. Based on Figure 6.7

Working Group III contribution to the IPCC Fifth Assessment Report Stabilization of atmospheric concentrations requires moving away from the baseline – regardless of the mitigation goal. Based on Figure 6.7

Working Group III contribution to the IPCC Fifth Assessment Report Content: Framing Chapters Historic Emissions Transformation Pathways Sector Chapters Policy Chapters

Working Group III contribution to the IPCC Fifth Assessment Report Mitigation requires changes throughout the economy. Efforts in one sector determine mitigation efforts in others. Figure SPM.7

Working Group III contribution to the IPCC Fifth Assessment Report 18 Based on Figure TS.17 Mitigation requires changes throughout the economy. Efforts in one sector determine mitigation efforts in others.

Working Group III contribution to the IPCC Fifth Assessment Report 19 Based on Figure TS.17 Mitigation requires changes throughout the economy. Efforts in one sector determine mitigation efforts in others.

Working Group III contribution to the IPCC Fifth Assessment Report 20 Based on Figure TS.17 If negative emissions are not achieved in the energy sector (via BECCS) they have to occur due to land-use change

Working Group III contribution to the IPCC Fifth Assessment Report 1 st Pillar: final energy demand reduction (energy efficiency improvements)

Working Group III contribution to the IPCC Fifth Assessment Report 2 nd Pillar: upscaling of low-carbon technologies: renewable energy, carbon capture and sequestration (CCS), and/or nuclear energy Figure SPM.4

Working Group III contribution to the IPCC Fifth Assessment Report Limited availability of technologies increases costs, but does not necessarily exclude ambitious goals (e.g. 2°C) Figure TS.13

Working Group III contribution to the IPCC Fifth Assessment Report Decarbonizing electricity generation is a key component of cost-effective mitigation strategies. The share of low carbon power generation exceeds 80 % in most low CO 2 concentration stabilization scenarios in Share of low-carbon energy in total primary energy, electricity and liquid supply sectors for the year IPCC, AR5, WG III, Figure 7.14

Working Group III contribution to the IPCC Fifth Assessment Report In cost-effective 2°C mitigation strategies, emission levels in 2030 tend to be lower than today Cost-effective mitigation 50 GtCO 2 e Delayed mitigation Figure SPM.5

Working Group III contribution to the IPCC Fifth Assessment Report Delayed mitigation significantly increases the challenge to reach low concentration targets Sweden and Figure SPM.5

Working Group III contribution to the IPCC Fifth Assessment Report Current Cancun Pledges imply increased mitigation challenges for reaching 2°C Figure SPM.5

Working Group III contribution to the IPCC Fifth Assessment Report Estimates for mitigation costs vary widely. Reaching 450ppm CO 2 eq entails consumption losses of 1.7% (1%-4%) by 2030, 3.4% (2% to 6%) by 2050 and 4.8% (3%-11%) by 2100 relative to baseline (which grows between 300% to 900% over the course of the century). This is equivalent to a reduction in consumption growth over the 21 st century by about 0.06 ( ) percentage points a year (relative to annualized consumption growth that is between 1.6% and 3% per year). Cost estimates exlude benefits of mitigation (reduced impacts from climate change). They also exclude other benefits (e.g. improvements for local air quality). Cost estimates are based on a series of assumptions.

Working Group III contribution to the IPCC Fifth Assessment Report Mitigation can result in large co-benefits for human health and other societal goals. Figure TS.14 Figure 12.23

Working Group III contribution to the IPCC Fifth Assessment Report Substantial reductions in emissions would require large changes in investment patterns. Figure SPM.9

Working Group III contribution to the IPCC Fifth Assessment Report Content: Framing Chapters Historic Emissions Transformation Pathways Sector Chapters Policy Chapters

Working Group III contribution to the IPCC Fifth Assessment Report The number and coverage of climate policies have increased substantially since AR4 National Climate legislation and strategies in 2007 and 2012

Working Group III contribution to the IPCC Fifth Assessment Report Since AR4, there has been an increased focus on policies designed to integrate multiple objectives, increase co-benefits and reduce adverse side-effects. Economic Instruments:  Taxes, Charges, and Subsidy Removal  Emissions Trading Regulatory Approaches Information Policies Government Provision of Public Goods and Services and Procurement Voluntary Actions Technology Policy and R&D Policy

Working Group III contribution to the IPCC Fifth Assessment Report Key messages on mitigation policies: Sector-specific policies have been more widely used than economy-wide policies. Regulatory approaches and information measures are widely used, and are often environmentally effective. Since AR4, cap and trade systems for GHGs have been established in a number of countries and regions. In some countries, tax-based policies specifically aimed at reducing GHG emissions–alongside technology and other policies–have helped to weaken the link between GHG emissions and GDP. The reduction of subsidies for GHG-related activities in various sectors can achieve emission reductions, depending on the social and economic context.

Working Group III contribution to the IPCC Fifth Assessment Report The number and coverage of climate policies have increased substantially since AR4

Working Group III contribution to the IPCC Fifth Assessment Report Economic instruments have been established in a number of countries and regions. Cap and trade systems for greenhouse gases are being established in a growing number of countries and regions  Although economic theory suggests that market ‐ based policies are generally more cost ‐ effective, political economy considerations often make those policies harder to achieve than sectoral policies.  The environmental effect of cap-and-trade systems has so far been limited because caps have either been loose or have not yet been binding. Carbon taxes have been implemented in some countries and - alongside technology and other policies - have contributed to decoupling of emissions from gross domestic product (GDP)  Differentiation by sector, which is quite common, reduces cost ‐ effectiveness.

Working Group III contribution to the IPCC Fifth Assessment Report Economic instruments have been established in a number of countries and regions. Fuel taxes are often originally put in place for objectives such as revenue – they are not necessarily designed for the purpose of climate change mitigation  In Europe, where fuel taxes are highest, they have contributed to reductions in carbon emissions from the transport sector of roughly 50% for this group of countries. Reduction of subsidies to fossil energy can result in significant emission reductions at negative social cost  The short ‐ run response to higher fuel prices is often small, but long ‐ run price elasticities are quite high, or roughly ‐ 0.6 to ‐ 0.8. This means that in the long run, 10% higher fuel prices correlate with 7% reduction in fuel use and emissions.

Working Group III contribution to the IPCC Fifth Assessment Report Sector-specific policies have been more widely used than economy-wide policies. Sector ‐ specific policies may also be needed to overcome sectoral market failures that price policies do not address For example, building codes can require publicly funded energy efficient investments where private investments would otherwise not exist. Regulatory approaches and information measures are widely used, and are often environmentally effective, though debate remains on the extent of their environmental impacts and cost effectiveness Since AR4 there has been continued investigation into the ‘rebound’ effects that arise when higher efficiency leads to lower energy prices and greater consumption There is general agreement that such rebound effects exist, but there is low agreement in the literature on the magnitude.

Working Group III contribution to the IPCC Fifth Assessment Report Adding a mitigation policy to another may not necessarily enhance mitigation. For instance, if a cap and trade system has a sufficiently stringent cap, then other policies such as renewable subsidies have no further impact on total emissions (although they may affect costs and possibly the viability of more stringent future targets) If the cap is loose relative to other policies, it becomes ineffective. This is an example of a negative interaction between policy instruments. Since other policies cannot be ‘added on’ to a cap ‐ and ‐ trade system, if it is to meet any particular target, a sufficiently low cap is necessary A carbon tax, on the other hand, can have an additive environmental effect to policies such as subsidies to renewables

Working Group III contribution to the IPCC Fifth Assessment Report There is a distinct role for technology policy as a complement to other mitigation policies Properly implemented technology policies reduce the cost of achieving a given environmental target Technology policy will be most effective when technology ‐ push policies (e.g.,publicly funded research and development (R&D)) and demand ‐ pull policies (e.g., governmental procurement programmes or performance regulations) are used in a complementary fashion. While technology ‐ push and demand ‐ pull policies are necessary, they are unlikely to be sufficient without complementary framework conditions For instance, if a cap and trade system has a sufficiently stringent cap, then other policies such as renewable subsidies have no further impact on total emissions (although they may affect costs and possibly the viability of more stringent future targets ).

Working Group III contribution to the IPCC Fifth Assessment Report Existing and proposed international climate agreements vary in the degree to which their authority is centralized Strong multilateral agreements (such as the Kyoto Protocol targets) Harmonized national policies (such as the Copenhagen/Cancún pledges) Decentralized but coordinated national policies (such as planned linkages of national and sub-national emissions trading schemes)

© Ocean/Corbis CLIMATE CHANGE 2014 Mitigation of Climate Change Working Group III contribution to the IPCC Fifth Assessment Report

Working Group III contribution to the IPCC Fifth Assessment Report From climate change risks to GHG emissions Figure AR5,SYR SPM 10

Working Group III contribution to the IPCC Fifth Assessment Report Climate change is a global commons problem that implies the need for international cooperation. SRREN, Figure 1.7

Working Group III contribution to the IPCC Fifth Assessment Report National per ‐ capita GHG emissions are highly variable within and between income groups. Figure TS.4

Working Group III contribution to the IPCC Fifth Assessment Report Low CO 2 concentration stabilization scenarios require a fundamental transformation of the energy supply system Influence of energy demand on the deployment of energy supply technologies for stringent mitigation scenarios (430–530 ppm CO 2eq ) in 2050.

Working Group III contribution to the IPCC Fifth Assessment Report Life Cycle Greenhouse Gas Emissions (1) Fig. 7.6 Natural gas: higher emissions than previously assumed

Working Group III contribution to the IPCC Fifth Assessment Report Life Cycle Greenhouse Gas Emissions (2) Fig. 7.6 Solar, wind, ocean, nuclear: <50 g CO 2 e/kWh

Working Group III contribution to the IPCC Fifth Assessment Report Fig. 7.7 Fig. TS19

Working Group III contribution to the IPCC Fifth Assessment Report

Coal’s high emissions leading to particulate matter exposure Coal technologies even with state-of-art emissions control have high emissions of particulate and of pollutants forming fine particulates in the atmosphere (SO 2, NO x, NH 3 ) Fig. 7.8

Working Group III contribution to the IPCC Fifth Assessment Report

List of references to support Table 7.3