Tweet

Celine Guivarch

Mar 16 • 43 tweets • 14 min read

@IPCC_CH

So that you are not caught by surprise by the @IPCC_CH Synthesis Report next Monday, let’s get prepared looking at the conclusion from the reports it synthesizes.
Let’s talk about WGIII report today. #ClimateReport #AR6

The report is on mitigation of climate change, i.e. human intervention to reduce emissions or enhance the sinks of greenhouse gases.

The report synthesizes scientific knowledge on past emissions and future emission pathways, emission reduction options, climate change policies, their financing and the innovations they require.

Its report was published in April 2022.

Read it, or at least its summary: ipcc.ch/report/ar6/wg3/

Key points selected from the report headline statements:

Total net anthropogenic GHG emissions have continued to rise during the period 2010–2019, as have cumulative net CO2 emissions since 1850. Average annual GHG emissions during 2010-2019 were higher than in any previous decade, but the rate of growth slowed.

Regional contributions to global GHG emissions continue to differ widely. Variations in regional, and national per capita emissions partly reflect different development stages, but they also vary widely at similar income levels.

The 10% of households with the highest per capita emissions contribute a disproportionately large share of global household GHG emissions. At least 18 countries have sustained GHG emission reductions for longer than 10 years.

The unit costs of several low-emission technologies have fallen continuously since 2010. Innovation policy packages have enabled these cost reductions and supported global adoption.

Global GHG emissions in 2030 associated with the implementation of nationally determined contributions (NDCs) announced prior to COP26 would make it likely that warming will exceed 1.5°C during the 21st century.

Likely limiting warming to below 2°C would then rely on a rapid acceleration of mitigation efforts after 2030. Policies implemented by the end of 2020 are projected to result in higher global GHG emissions than those implied by NDCs.

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 (>50%) with no or limited overshoot.

They are approximately equal to total cumulative net CO2 emissions in pathways that limit warming to 2°C (>67%).

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 (>50%) with no or limited overshoot and in those that limit warming to 2°C (>67%) and assume immediate action.

Global net zero CO2 emissions are reached in the early 2050s in modelled pathways that limit warming to 1.5°C (>50%) with no or limited overshoot, and around the early 2070s in modelled pathways that limit warming to 2°C (>67%).

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.

The continued installation of unabated fossil fuel infrastructure will ‘lock-in’ GHG emissions.

Net-zero CO2 emissions from the industrial sector are challenging but possible. Reducing industry emissions will entail coordinated action throughout value chains to promote all mitigation options, ...

including demand management, energy and materials efficiency, circular material flows, as well as abatement technologies and transformational changes in production processes.

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.

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.

Demand-side options and low-GHG emissions technologies can reduce transport sector emissions in developed countries and limit emissions growth in developing countries

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.

In addition, sustainably sourced agricultural and forest products can be used instead of more GHG intensive products in other sectors.

Demand-side mitigation encompasses changes in infrastructure use, end-use technology adoption, and socio-cultural and behavioural change.

Demand-side measures and new ways of end-use service provision can reduce global GHG emissions in end use sectors by 40-70% by 2050 compared to baseline scenarios, while some regions and socioeconomic groups require additional energy and resources.

Demand side mitigation response options are consistent with improving basic wellbeing for all.

The deployment of Carbon Dioxide Removal to counterbalance hard-to-abate residual emissions is unavoidable if net zero CO2 or GHG emissions are to be achieved.

Mitigation options costing USD100 tCO2-eq-1 or less could reduce global GHG emissions by at least half the 2019 level by 2030

The global economic benefit of limiting warming to 2°C is reported to exceed the cost of mitigation in most of the assessed literature.

Enhanced mitigation and broader action to shift development pathways towards sustainability will have distributional consequences within and between countries.

Attention to equity and broad and meaningful participation of all relevant actors in decision-making at all scales can build social trust, and deepen and widen support for transformative changes.

Tracked financial flows fall short of the levels needed to achieve mitigation goals across all sectors and regions.

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

Climate governance is most effective when it integrates across multiple policy domains, helps realise synergies and minimize trade-offs, and connects national and sub-national policy-making levels.

Effective and equitable climate governance builds on engagement with civil society actors, political actors, businesses, youth, labour, media, Indigenous Peoples and local communities