The net effective radiative forcing from ozone‐depleting substances and Its uncertainty

Western, L. M. ORCID: https://orcid.org/0000-0002-0043-711X, Shine, K. P. ORCID: https://orcid.org/0000-0003-2672-9978 and Collins, W. J. ORCID: https://orcid.org/0000-0002-7419-0850 (2026) The net effective radiative forcing from ozone‐depleting substances and Its uncertainty. Geophysical Research Letters, 53 (8). e2025GL119094. ISSN 0094-8276 doi: 10.1029/2025GL119094

Abstract/Summary

The direct effective radiative forcing (ERF) of long‐lived ozone‐depleting substances (ODS) is around 15%–20% of the pre‐industrial to present‐day ERF of CO2, but their net ERF, including indirect chemical adjustments, remains poorly constrained. We use an adapted simple climate model, trained on bulk indirect ODS forcing from complex climate models, to quantify uncertainty in net ERF over time and the net ERF across individual ODS. We find that the direct ODS ERF in 2019 of 0.35 (0.31,0.39) W m-2 net ERF of 0.11 (0.02,0.26) W m-2 is reduced to a when chemical adjustments are included. Most net ERF arises from CFC 12 and HCFC‐22 (0.18 W m-2), with chemical adjustments substantially reducing the net ERF of many other substances. Since the implementation of the Montreal Protocol, the total ODS net ERF has increased much less rapidly than the direct ERF.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/129520
Identification Number/DOI	10.1029/2025GL119094
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Geophysical Union
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