Atmospheric methane levels increased over geological formations in Northern Siberia following a heat wave in 2020, suggesting that permafrost thaw releases methane from reservoirs.
Image credit: Wikimedia Commons.
Edited by Robert E. Dickinson, University of California, Los Angeles, CA, and approved July 16, 2020 (received for review April 17, 2020)
Abstract
Climate simulation-based scenarios are routinely used to characterize a range of plausible climate futures. Despite some recent progress on bending the emissions curve, RCP8.5, the most aggressive scenario in assumed fossil fuel use for global climate models, will continue to serve as a useful tool for quantifying physical climate risk, especially over near- to midterm policy-relevant time horizons. Not only are the emissions consistent with RCP8.5 in close agreement with historical total cumulative CO2 emissions (within 1%), but RCP8.5 is also the best match out to midcentury under current and stated policies with still highly plausible levels of CO2 emissions in 2100.
Footnotes
- ↵1To whom correspondence may be addressed. Email: cschwalm{at}whrc.org.
Author contributions: C.R.S., S.G., and P.B.D. designed research; C.R.S. performed research; C.R.S. analyzed data; and C.R.S., with contributions from S.G. and P.B.D. wrote the paper.
The authors declare no competing interest.
Data Availability.
All data used for analysis are publicly available from refs. 6 and 9 as well as from RCP Database Version 2.0.5 (https://tntcat.iiasa.ac.at/RcpDb/).
- Copyright © 2020 the Author(s). Published by PNAS.
This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND).
RCP8.5 tracks cumulative CO2 emissions
Article Classifications
- Physical Sciences
- Environmental Sciences
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