Changes to population-based emergence of climate change from CMIP5 to CMIP6

Douglas, H. C. ORCID: https://orcid.org/0000-0002-5411-7656, Harrington, L. J. ORCID: https://orcid.org/0000-0002-1699-6119, Joshi, M., Hawkins, E. ORCID: https://orcid.org/0000-0001-9477-3677, Revell, L. E. and Frame, D. J. (2023) Changes to population-based emergence of climate change from CMIP5 to CMIP6. Environmental Research Letters, 18 (1). 014013. ISSN 1748-9326 doi: 10.1088/1748-9326/aca91e

Abstract/Summary

The Coupled Model Intercomparison Project Phase 6 (CMIP6) model ensemble projects climate change emerging soonest and most strongly at low latitudes, regardless of the emissions pathway taken. In terms of signal-to-noise (S/N) ratios of average annual temperatures, these models project earlier and stronger emergence under the Shared Socio-economic Pathways (SSPs) than the previous generation did under corresponding Representative Concentration Pathways (RCPs). Spatial patterns of emergence also change between generations of models; under a high emissions scenario, mid-century S/N is lower than previous studies indicated in Central Africa, South Asia, and parts of South America, West Africa, East Asia, and Western Europe, but higher in most other populated areas. We show that these global and regional changes are caused by a combination of higher effective climate sensitivity (ECS) in the CMIP6 ensemble, as well as changes to emissions pathways, component-wise effective radiative forcing (ERF), and region-scale climate responses between model generations. We also present the first population-weighted calculation of climate change emergence for the CMIP6 ensemble, quantifying the number of people exposed to increasing degrees of abnormal temperatures now and into the future. Our results confirm the expected inequity of climate change-related impacts in the decades between now and the 2050 target for net-zero emissions held by many countries. These findings underscore the importance of concurrent investments in both mitigation and adaptation.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/109337
Identification Number/DOI	10.1088/1748-9326/aca91e
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > NCAS Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	IOP Science
Download/View statistics	View download statistics for this item