A significant reduction in summer monsoon rainfall has been observed in northern central India during the second half of the twentieth century, threatening water security and causing widespread socio-economic impacts. Here, using various observational data sets, we show that monsoon rainfall has increased in India at 1.34 mm d−1 decade−1 since 2002. This apparent revival of summer monsoon precipitation is closely associated with a favourable land–ocean temperature gradient, driven by a strong warming signature over the Indian subcontinent and slower rates of warming over the Indian Ocean.

A likely consequence of global warming will be the redistribution of Earth’s rain belts, affecting water availability for many of Earth’s inhabitants. We consider three ways in which planetary warming might influence the global distribution of precipitation. The first possibility is that rainfall in the tropics will increase and that the subtropics and mid-latitudes will become more arid. A second possibility is that Earth’s thermal equator, around which the planet’s rain belts and dry zones are organized, will migrate northward.