Tropical response to ocean circulation slowdown raises future drought risk

• 成果类型: Article
• 署名作者: Dinezio, Pedro N.; Shanahan, Timothy M.; Sun, Tianyi; Sun, Chijun; Wu, Xian; Lawman, Allison; Lea, David; Kageyama, Masa; Merkel, Ute; Prange, Matthias; Otto-Bliesner, Bette; Zhang, Xu
• 署名单位: University of Colorado System; University of Colorado Boulder; University of Texas System; University of Texas Austin; Environmental Defense Fund; University of California System; University of California Davis; University of Texas System; University of Texas Dallas; Colorado College; University of California System; University of California Santa Barbara; Universite Paris Saclay; University of Bremen; National Center Atmospheric Research (NCAR) - USA; UK Research & Innovation (UKRI); Natural Environment Research Council (NERC); NERC British Antarctic Survey
• 刊物名称: Nature
• ISSN/ISSBN: 0028-1497
• DOI: 10.1038/s41586-025-09319-x
• 发表日期: 2025-08-21
• 关键词: last glacial maximum; meridional overturning circulation; CLIMATE-CHANGE; atlantic climate; northwest africa; indian monsoon; asian monsoon; ice-sheet; temperatures; simulations

摘要

Projections of tropical rainfall under global warming remain highly uncertain1,2, largely because of an unclear climate response to a potential weakening of the Atlantic meridional overturning circulation (AMOC)3. Although an AMOC slowdown can substantially alter tropical rainfall patterns4, 5, 6, 7-8, the physical mechanisms linking high-latitude changes to tropical hydroclimate are poorly understood11. Here we demonstrate that an AMOC slowdown drives widespread shifts in tropical rainfall through the propagation of high-latitude cooling into the tropical North Atlantic. We identify and validate this mechanism using climate model simulations and palaeoclimate records from Heinrich Stadial 1 (HS1)-a past period marked by pronounced AMOC weakening9,10. In models, prevailing easterly and westerly winds communicate the climate signal to the Pacific Ocean and Indian Ocean through the transport of cold air generated over the tropical and subtropical North Atlantic. Air-sea interactions transmit the response across the Pacific Ocean and Indian Ocean, altering rainfall patterns as far as Indonesia, the tropical Andes and northern Australia. A similar teleconnection emerges under global warming scenarios, producing a consistent multi-model pattern of tropical hydroclimatic change. These palaeo-validated projections show widespread drying across Mesoamerica, the Amazon and West Africa, highlighting an elevated risk of severe drought for vulnerable human and ecological systems.