Monsoons affect more than half of the world’s population. It is therefore particularly important to research and understand how they react to global warming and rapid changes in Earth’s climate system

One of the key elements of this system is the Atlantic Meridional Overturning Circulation (AMOC), transporting large amounts of heat and salt northward in the upper layers of the Atlantic Ocean. Although its likelihood remains highly uncertain, a collapse of the AMOC in response to anthropogenic climate change would have catastrophic ecological and societal consequences. This is especially true in the vulnerable monsoon regions of the tropics. Yet, the precise effects of an AMOC collapse on the tropical monsoon systems remain unclear.

This is precisely the issue addressed in the recent research of M. Ben-Yami, P. Good, L. C. Jackson, M. Crucifix, A. Hu, O. Saenko, D. Swingedouw, and N. Boers, who looked into the impacts of AMOC collapse on the monsoon rainfall.

The research team took advantage of a climate model intercomparison project to provide a detailed and systematic analysis of the seasonal impacts of an AMOC collapse on the major tropical monsoon systems. The research showed a remarkable, previously unseen, agreement between four independent state-of-the-art climate models. Consistently across models, the results suggested major rearranging of all tropical monsoon systems in response to an AMOC collapse, with shorter wet and longer dry seasons for the West African Monsoon (WAM), the Indian Summer Monsoon (ISM) and the East Asian Summer Monsoon (EASM). Conversely, the models suggest the South American Monsoon (SAM) could experience increased rainfall in response to AMOC collapse.

Curious to learn more?

Access the recently published article in Open Access: M. Ben-Yami, P. Good, L. C. Jackson, M. Crucifix, A. Hu, O. Saenko, D. Swingedouw, N. Boers (2024), Impacts of AMOC Collapse on Monsoon Rainfall: A Multi-Model Comparison, Earth’s Future, Vol. 12, No. 9.