Changes in precipitation over equatorial, tropical and subtropical South America under a collapsed Atlantic meridional overturning circulation

• Grant number: 23/04804-9
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: August 01, 2023
• Status: Discontinued
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Cristiano Mazur Chiessi
• Grantee: Luiza dos Santos Amancio
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 18/15123-4 - Past perspectives on tipping elements of the climate system: the Amazon Rainforest and the Atlantic Meridional Overturning Circulation (PPTEAM), AP.PFPMCG.JP2
• Associated scholarship(s): 24/01641-4 - Changes in precipitation over equatorial, tropical and subtropical South America under a collapsed Atlantic Meridional Overturning Circulation, BE.EP.DR

Abstract

Precipitation is arguably one of the main controlling factors of life on Earth. From foodproduction to water availability, changes in precipitation patterns can lead to social disruption and massive economic loss. Recent findings point to a possible human-driven collapse of the Atlantic Meridional Overturning Circulation. Knowing the effects of such a collapse on precipitation is crucial for decision-makers to build efficient adaptation strategies. Here wewill determine the consequences of a collapse in the Atlantic Meridional OverturningCirculation over South American precipitation. This is a strongly debated and timely subject:while some pieces of evidence point to a widespread increase in tropical South Americanprecipitation to the south of the equator during a collapsed circulation, others suggest that theincrease is restricted to specific parts of the continent. Thus, a comprehensive reconstructionof changes in precipitation during such extreme conditions is urgently needed to understandthe past and prepare for the future. The Atlantic Meridional Overturning Circulationcollapsed twice during the last 20,000 years. We will reconstruct South Americanprecipitation during these two events in unprecedented temporal and spatial resolution.Therefore, we will apply state-of-the-art precipitation proxies (i.e., hydrogen isotopes in leafwaxes, oxygen isotopes of surface seawater obtained via oxygen isotopes of foraminiferalcarbonate and alkenone-based sea surface temperatures) to a suite of marine sediment corescollected off eastern equatorial, tropical and subtropical South America. Our precipitationreconstruction will ultimately inform society about future changes in precipitation. (AU)