The publication today of the 2021 FCCC NDCs reinforces the utter implausibility of CMIP/IPCC baseline scenarios (7.0, 8.5)
unfccc.int/sites/default/…
It also should mark the last time anyone cites Schwalm et al 2020 to defend RCP8.5/SSP5-8.5 as BAU (or even as plausible)
unfccc.int/sites/default/…
It also should mark the last time anyone cites Schwalm et al 2020 to defend RCP8.5/SSP5-8.5 as BAU (or even as plausible)
Absolutely huge news
UN FCCC expectations for 2030 GHG emissions
2016 INDCs = 62.0 Gt CO2-eq
2021 NDCs = 51.5 Gt CO2-eq
Net-zero is a massive challenge, of course, but compared to 5 years ago the world is now in a much better position that was expected
unfccc.int/sites/default/…
UN FCCC expectations for 2030 GHG emissions
2016 INDCs = 62.0 Gt CO2-eq
2021 NDCs = 51.5 Gt CO2-eq
Net-zero is a massive challenge, of course, but compared to 5 years ago the world is now in a much better position that was expected
unfccc.int/sites/default/…
IEA & FCCC now say CO2 & GHG emissions in coming decade(s) projected below RCP/SSP-4.5
Yet, president of US National Academies, lead author of 2018 US National Climate Assessment & former co-chair IPCC Working Group 2 all argue RCP8.5 is a proper BAU/reference scenario
Denial?
Yet, president of US National Academies, lead author of 2018 US National Climate Assessment & former co-chair IPCC Working Group 2 all argue RCP8.5 is a proper BAU/reference scenario
Denial?
Is the unanticipated progress on emissions since 2016 due to (a) originally flawed expectations now seen to be wrong or (b) greater progress in decarbonization than expected
Answer: surely some combination of (a) and (b), which will be an important focus of a rigorous evaluation
Answer: surely some combination of (a) and (b), which will be an important focus of a rigorous evaluation
Time to move from apocalyptic paralysis to a positive "let's do this"
An important part of that will be to reset science and policy discussions away from implausible scenarios & on those more plausible in short and long terms
To start, SSPs need to be retired and replaced ASAP
An important part of that will be to reset science and policy discussions away from implausible scenarios & on those more plausible in short and long terms
To start, SSPs need to be retired and replaced ASAP
This message won't be popular, given the huge momentum of apocalysm & the entrenched role of apocalyptic scenarios in climate discourse and throughout climate science
Expect pushback, mean Tweets, name calling etc
But climate policy is in a new place & that's good
/END
Expect pushback, mean Tweets, name calling etc
But climate policy is in a new place & that's good
/END
• • •
Missing some Tweet in this thread? You can try to
force a refresh
