India's surprising 'warming hole': How irrigation and pollution may be temporarily shielding it from global heat

India presents a surprising exception to the global warming trend, exhibiting a significantly slower rise in average temperature compared to the rest of the planet. While the world has warmed by approximately 1.4 degrees Celsius since 1980, India's average temperature has increased by less than 0.9 degrees Celsius since the early 20th century. This phenomenon, dubbed a "warming hole" by some researchers, makes India stand out on climate maps, appearing as a cooler region amidst surrounding areas experiencing substantial temperature increases.

Scientists are exploring several theories to explain this anomaly. One prominent hypothesis centers on the extensive use of water for agricultural irrigation, particularly for rice and wheat crops in northern India. Since the 1960s, farmers have pumped vast amounts of groundwater, especially during dry periods. This water evaporates, leading to a cooling effect on the land surface and increasing atmospheric humidity. Researchers suggest that increased evaporation and humidity can suppress temperature rises, a phenomenon also observed in agricultural regions of the United States.

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You can see much reduced warming or even no warming over India during this period.

Another significant factor under consideration is air pollution. Particulate matter from traffic, industry, and other activities can reflect solar radiation before it reaches the Earth's surface. Paradoxically, this pollution may offer a temporary shield against even higher temperatures. Similar effects have been noted in China after significant reductions in aerosol emissions. Scientists believe the combination of irrigation and pollution in India could be responsible for a substantial part of the temperature difference observed compared to surrounding regions.

Despite these protective mechanisms, researchers caution that India's situation is precarious. The very factors that may be temporarily mitigating warming could also lead to a temporary acceleration of warming if pollution levels decrease. Furthermore, the country has experienced extreme heat events, with temperatures reaching 52 degrees Celsius in 2024 and official reports of at least 84 heatstroke deaths. Scientists warn that if these phenomena shift, India could face catastrophic climate scenarios.

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The idea is that if you spread more water on the ground, you get more evaporation, you increase the humidity in the air, and you suppress temperature increases.