IPCC１〜３作業部会報告の途中まとめ

Simon Evans @DrSimEvans

4/ There have been dramatic declines in cost of key techs solar (-85% 2010-2019), wind (-55%) & batteries (-85%) as well as rapidly increasing deployment Large-scale mitigation tech (not named in SPM but = nuclear, CCS) has seen "minimal cost reductions" and has "grown slowly" pic.twitter.com/ookX8FRDuk

Simon Evans @DrSimEvans

5/ Climate policies have worked (just not fast enough) – and only 53% of global GHGs are covered by "direct" laws focused on cutting emissions Climate finance flows are up 60% but remain below the $100bn by 2020 target pic.twitter.com/oZztzLejLz

Simon Evans @DrSimEvans

6/ Current climate policies and pledges are massively insufficient: If NDCs are followed to 2030, it is "likely" the world will pass 1.5C and there is no way to limit warming to 1.5C with "no or limited overshoot" It will also be harder to stay below 2C pic.twitter.com/jGGjsxMS3A

Simon Evans @DrSimEvans

7/ We already have enough high-carbon infrastructure to blow the budget for 1.5C Staying below 1.5C or 2C would mean early retirements, retrofits with CCS Cancelling new coal is a "major option" for aligning with the cheapest route to below 2C pic.twitter.com/Gu4VTViTvI

Simon Evans @DrSimEvans

8/ Global GHGs peak around 2020 & "before 2025 at latest" in pathways to 1.5C with no or limited overshoot; current policies imply ~3.2C For 1.5C: Global GHGs fall 43% below 2019 by 2030 & 84% by 2050; CO2 -48% by 2030 & to *net-zero* in "early 2050s"; CH4 -34% by 2030 pic.twitter.com/rpbERDv1hw

Simon Evans @DrSimEvans

9/ If the world cuts emissions quicker, then there is slightly more time before CO2 has to reach net-zero and we will be less reliant on CO2 removal (because of the carbon budget) pic.twitter.com/tnKeyV6gOa

Simon Evans @DrSimEvans

10/ There is a whole new way of categorising mitigation scenarios in AR6, from C1 (1.5C with no or limited overshoot) up to C8 (4C) There are also "illustrative mitigation pathways" showing different ways to limit warming (Watch out for another @CarbonBrief article on this) pic.twitter.com/4ndAZdLXWu

Simon Evans @DrSimEvans

11/ All modelled pathways to stay below 1.5C with no or limited overshoot involve "rapid and deep and in most cases immediate" cuts in "all sectors" Cutting energy demand (IMP-LD, IMP-SD, IMP-REN) reduces the need for large-scale CO2 removal (CDR) but some CDR is "unavoidable" pic.twitter.com/52uS9z8tvM

Simon Evans @DrSimEvans

12/ Cutting emissions "requires" a "substantial reduction in overall fossil fuel use", energy efficiency, low-emission energy sources (eg renewables) and alternative energy carriers (eg hydrogen) Renewables, EVs and efficiency would save money (blue bars on the chart) pic.twitter.com/Yo6Sz6Dcjp

Simon Evans @DrSimEvans

13/ For the first time, the IPCC has a chapter on demand-side mitigation including shifting diets, transport patterns and material efficiency These could cut end-use emissions 40-70% by 2050 vs baseline scenarios while improving well-being pic.twitter.com/nEvOtlFWV8

Simon Evans @DrSimEvans

14/ Climate adaptation and mitigation is "critical" to sustainable development; there are many synergies (+ on the chart) and though there are some potential trade offs (-), these can be minimised pic.twitter.com/PTLQ5fwITV

Simon Evans @DrSimEvans

15/ The economic benefits of limiting warming to 2C outweigh the costs "in most of the assessed literature" Looking only at the costs, mitigation for 2C would reduce annual global GDP growth by at most 0.14 percentage points (this excludes avoided damages, co-benefits etc) pic.twitter.com/nY5hzCSgdm