Atmospheric methane lifetime during the Last Glacial Maximum was reduced owing to dust-mediated chlorine chemistry
Atmospheric methane (CH 4 ) plays a central role in Earth’s climate, yet the drivers of its decline during the high-dust conditions of glacial periods, such as the Last Glacial Maximum (LGM), remain uncertain. Previous explanations imply source-driven changes, assuming an atmospheric lifetime comparable to that of present day. Recent work shows that interactions between mineral dust and sea salt aerosols produce CH 4 -removing chlorine radicals. In this work, we show that during the LGM, CH 4 lifetime shortened to 7.8 years, 20% lower than that of present day. Chlorine contributed ~15% of global CH 4 loss, fourfold that of present day. Our results reproduce ice core CH 4 isotopic evidence, demonstrating that stronger-than-assumed atmospheric sinks can explain CH 4 variability without invoking substantial source changes, highlighting the overlooked role of chlorine chemistry in the glacial CH 4 budget.
Authors
- Nicolás J. Cosentino (ORCID: https://orcid.org/0000-0001-9023-2726)
- Juan Pablo Corella (ORCID: https://orcid.org/0000-0001-5127-9011)
- Rafael P. Fernández (ORCID: https://orcid.org/0000-0002-4114-5500)
- Samuel Albani (ORCID: https://orcid.org/0000-0001-9736-5134)
- Carlos A. Cuevas (ORCID: https://orcid.org/0000-0002-9251-5460)
- Alfonso Saiz‐Lopez (ORCID: https://orcid.org/0000-0002-0060-1581)
- Jennifer Campos Ayala
- N. M. Mahowald (ORCID: https://orcid.org/0000-0002-2873-997X)
- Markus Grimmer (ORCID: https://orcid.org/0000-0001-8750-0582)
- Michaela Mühl (ORCID: https://orcid.org/0000-0001-9128-1052)
- Andrea Spolaor (ORCID: https://orcid.org/0000-0001-8635-9193)
- J. H. M. M. Schmitt (ORCID: https://orcid.org/0000-0003-4695-3029)
- Julián Villamayor (ORCID: https://orcid.org/0000-0002-8844-7389)
- Daphne Meidan (ORCID: https://orcid.org/0000-0001-7746-4979)
- Hubertus Fischer (ORCID: https://orcid.org/0000-0002-2787-4221)
Institutions
- Institut polytechnique de Grenoble (FR)
- University of Bern (CH)
- Centre National de la Recherche Scientifique (FR)
- Oeschger Centre for Climate Change Research (CH)
- Consejo Nacional de Investigaciones Científicas y Técnicas (AR)
- Cornell University (US)
- Instituto Interdisciplinario de Ciencias Básicas (AR)
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (FR)
- Museo Nacional de Ciencias Naturales (ES)
- Institut des Géosciences de l'Environnement (FR)
- Institute of Astronomy and Space Physics (AR)
- Instituto Franco-Argentino sobre Estudios de Clima y sus Impactos (AR)
- National Research Council (IT)
- Institut de Recherche pour le Développement (FR)
- University of Milano-Bicocca (IT)
- Université Grenoble Alpes (FR)
Publication Details
- Journal
- Science
- Published
- 2026-09-17
- DOI
- https://doi.org/10.1126/science.aec4071
- Primary Topic
- Atmospheric chemistry and aerosols
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Association du Syndrome de Lowe
- Svensk Njurmedicinsk Förening
- Deutsches Museum