On the role of the atlantic ocean in exacerbating indian heat waves

Summer heat waves over India have been increasing in frequency and severity during recent decades, and are responsible for thousands of deaths among those segments of the Indian population who lack basic adaptation resources. Despite its importance, our understanding of the causes of these heat waves is still limited and largely based on basic statistical analyses, rather than on physical processes. Here, using observations and climate model experiments we show that Indian heat waves during the 1961-2010 period were only weakly driven by Indian Ocean sea surface temperature (SST), but were instead strongly tied to SST in the Atlantic Ocean. The conditions in the Atlantic that drove these heat waves were exacerbated by greenhouse gas emissions rather than natural forcing, revealing the complex but prominent role played by anthropogenic forcing in the suffering faced by tens of millions of Indians over recent decades.