UN IPCC Sixth Assessment Report Summary – Working Group III: Mitigation of Climate Change
The Intergovernmental Panel on Climate Change (IPCC) is the United Nations body for assessing the science related to climate change. The IPCC prepares comprehensive Assessment Reports about the state of scientific, technical and socio-economic knowledge on climate change, its impacts and future risks, and options for reducing the rate at which climate change is taking place. IPCC assessments and special reports are prepared by three Working Groups, each looking at a different aspect of the science related to climate change: Working Group I (The Physical Science Basis), Working Group II (Impacts, Adaptation and Vulnerability), and Working Group III (Mitigation of Climate Change). The IPCC is working on the Sixth Assessment Report(AR6) and the latest Working Group III (WG III) contribution was published on April 2022.
WG III focuses on climate change mitigation, assessing methods for reducing greenhouse gas emissions, and removing greenhouse gases from the atmosphere. Working Group III supports the IPCC’s solution-oriented approach but does not advocate any specific mitigation options. It takes both a near-term perspective relevant to decision-makers in government and the private sector and a long-term perspective that helps identify how high-level climate policy goals might be met. Working Group III addresses all aspects of mitigation including technical feasibility, cost and the enabling environments that would allow measures to be taken up.
The key insights from WG III contribution is elucidated in 4 sections:
- Recent development and current trends
- System transformation to limit global warming
- Linkages between mitigation, adaptation, and sustainable development
- Strengthening the response
The highlights from each section in the latest WG III contribution to AR6 is as follows:
- Recent development and current trends
o The average annual global greenhouse gas emissions were at their highest levels in human history between 2010-2019, but the rate of growth has slowed as compared to the previous decade.
o Net anthropogenic GHG emissions have increased since 2010 with increasing share attributed to urban areas and especially high emissions increases across industry, energy supply, transport, agriculture and buildings sectors that have offset the emission reductions due to improvements in energy intensity of GDP and carbon intensity of energy.
o Variations in regional, and national per capita emissions partly reflect different development stages, but they also vary widely at similar income levels.
o Tailored and comprehensive innovation policy packages have enabled cost reduction and supported global adoption of several low emission technologies, overcoming the distributional, environmental and social impacts potentially associated with global diffusion of low-emission technologies.
o Though there has been avoidance of emissions due to consistent expansion of policies and laws addressing mitigation especially with regards to investment in low-GHG technologies and investment, progress on the alignment of financial flows towards the goals of the Paris Agreement remains slow and tracked climate finance flows are distributed unevenly across regions and sectors.
o Based on the implementation of NDCs announced prior to COP26, it is likely that warming will exceed 1.5°C during the 21st century and limiting warming to below 2°C would then rely on a rapid acceleration of mitigation efforts after 2030.
o Projected cumulative future CO2 emissions over the lifetime of existing and currently planned fossil fuel infrastructure without additional abatement exceed the total cumulative net CO2 emissions in pathways that limit warming to 1.5°C.
- System transformation to limit global warming
o Global GHG emissions are projected to peak between 2020 and at the latest before 2025 in global modelled pathways that limit warming to 1.5°C and in those that limit warming to 2°C and assume immediate action.
o Without a strengthening of policies beyond those that are implemented by the end of 2020, GHG emissions are projected to rise beyond 2025, leading to a median global warming of 3.2 [2.2 to 3.5] °C by 2100.
o Global net zero CO2 emissions are reached in the early 2050s in modelled pathways that limit warming to 1.5°C, and around the early 2070s in modelled pathways that limit warming to 2°C.
o Deep GHG emissions reductions by 2030 and 2040, particularly reductions of methane emissions, lower peak warming, reduce the likelihood of overshooting warming limits and lead to less reliance on net negative CO2 emissions that reverse warming in the latter half of the century.
o All global modelled pathways that limit warming to 1.5°C, and those that limit warming to 2°C involve rapid and deep and, in most cases, immediate GHG emission reductions in all sectors such as:
§ transitioning from fossil fuels without CCS to very low- or zero-carbon energy sources, such as renewables or fossil fuels with CCS,
§ demand side measures and improving efficiency,
§ reducing non-CO2 emissions, and
§ deploying carbon dioxide removal (CDR) methods to counterbalance residual GHG emissions.
o Reducing GHG emissions across the full energy sector requires major transitions, including a substantial reduction in overall fossil fuel use, the deployment of low-emission energy sources, switching to alternative energy carriers, and energy efficiency and conservation.
o Net-zero CO2 emissions from the industrial sector will entail coordinated action throughout value chains to promote all mitigation options and will need to be enabled by the adoption of new production processes using low and zero GHG electricity, hydrogen, fuels, and carbon management.
o Urban areas can create opportunities to increase resource efficiency and significantly reduce GHG emissions through the systemic transition of infrastructure and urban form through low-emission development pathways towards net-zero emissions.
o In modelled global scenarios, existing buildings, if retrofitted, and buildings yet to be built, are projected to approach net zero GHG emissions in 2050 if policy packages, which combine ambitious sufficiency, efficiency, and renewable energy measures, are effectively implemented and barriers to decarbonisation are removed.
o Demand-side options and low-GHG emissions technologies can reduce transport sector emissions in developed countries and limit emissions growth in developing countries.
o AFOLU mitigation options, when sustainably implemented, can deliver large-scale GHG emission reductions and enhanced removals, but cannot fully compensate for delayed action in other sectors.
o Demand-side mitigation encompasses changes in infrastructure use, end-use technology adoption, and socio-cultural and behavioural change.
o The deployment of CDR to counterbalance hard-to-abate residual emissions is unavoidable if net zero CO2 or GHG emissions are to be achieved.
o Mitigation options costing USD100 tCO2-eq-1 or less could reduce global GHG emissions by at least half the 2019 level by 2030
- Linkages between mitigation, adaptation, and sustainable development
o Accelerated and equitable climate action in mitigating, and adapting to, climate change impacts is critical to sustainable development
o Coordinated cross-sectoral policies and planning can maximise synergies and avoid or reduce trade-offs between mitigation and adaptation
o Enhanced mitigation and broader action to shift development pathways towards sustainability will have distributional consequences within and between countries.
- Strengthening the response
o Barriers to feasibility would need to be reduced or removed, and enabling conditions strengthened to deploy mitigation options at scale.
o In all countries, mitigation efforts embedded within the wider development context can increase the pace, depth and breadth of emissions reductions.
o Climate governance, acting through laws, strategies and institutions, based on national circumstances, supports mitigation by providing frameworks through which diverse actors interact, and a basis for policy development and implementation.
o Regulatory and economic instruments could support deep emissions reductions and stimulate innovation if scaled up and applied more widely.
o Tracked financial flows fall short of the levels needed to achieve mitigation goals across all sectors and regions
§ Scaling up mitigation financial flows can be supported by clear policy choices and signals from governments and the international community.
§ Accelerated international financial cooperation is a critical enabler of low-GHG and just transitions, and can address inequities in access to finance and the costs of, and vulnerability to, the impacts of climate change.
o Partnerships, agreements, institutions and initiatives operating at the subglobal and sectoral levels and engaging multiple actors are emerging, with mixed levels of effectiveness.
Thus the report makes the case that the need is immediate for global concerted climate action that involves rapid and deep and immediate GHG emission reductions in all sectors, so as to limit global warming to manageable levels. The climate action shall be driven by tailored, comprehensive policy packages that fosters technological innovation and global partnership to leverage and scale up financial flows for mitigation.
