Attribution and projection of February extreme rainfall events in Southeast Africa
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Author(s)
Type
Journal Article
Abstract
Record-breaking extreme rainfall events, such as those observed in Southeast Africa (SEAF) in February 2023, underscore the urgent need to quantify anthropogenic impacts on extreme weather risks. This study presents an attribution and projection analysis of February extreme rainfall in SEAF by evaluating probabilistic risk changes across multiple Earth System Model (ESM) ensembles and numerical weather prediction (NWP) experiments. While NWP models reliably capture the magnitude and frequency of these extremes, ESMs generally exhibit a wet bias, necessitating the use of relative thresholds. Our attribution analysis reveals that greenhouse gas (GHG) forcing significantly increases the risk of extreme events (e.g. once-in-70-year and once-in-150-year events, comparable to the precipitation intensities of 2000 and 2023). However, this risk increase remains less certain under all-forcing simulations, as ESMs show substantial disagreement regarding aerosol (AER) influences. Future projections under various shared socioeconomic pathways indicate that a higher GHG emission exacerbates these risks, highlighting the critical importance of aggressive mitigation efforts. Furthermore, shifts in generalized extreme value (GEV) parameters demonstrate how forcing-driven climate changes may deform the risk probability distribution, with a higher emission of GHG potentially altering both the climatological mean and interannual variability of SEAF extreme rainfall. Our findings are supported by both ESM and NWP results (particularly short-lead forecasts), with the latter exhibiting lower uncertainty due to constraints on synoptic systems and internal oceanic variability. We conclude that GHG forcing likely elevates the risk of 2023-like extreme events in SEAF and discuss the remaining sources of uncertainty in these projections.
Date Issued
2026-09-25
Date Acceptance
2026-09-15
Citation
Environmental Research Letters, 2026, 21 (18)
ISSN
1748-9326
Publisher
IOP Publishing
Start Page
184038
End Page
184038
Journal / Book Title
Environmental Research Letters
Volume
21
Issue
18
Copyright Statement
© 2026 The Author(s). Published by IOP Publishing Ltd Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
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Publication Status
Published
Article Number
184038
Date Publish Online
2026-09-25