Opinion: India's Heatwaves Are Testing The Limits Of Human Survival

New Delhi feels like it is on fire. The heat comes off the road in blistering waves, and the water that flows from the cold tap is too hot to touch. Daytime temperatures have hit 44 degrees Celsius (111 Fahrenheit) and often do not fall below 30 in the night. A giant landfill on the outskirts of the capital spontaneously combusted a week ago, and the 17-story high dump that contains millions of tons of garbage continues to smolder, worsening the city's already dangerously polluted air.

Daily power outages driven by a surge in demand for electricity have resulted in blackouts as long as eight hours in some parts of India, while coal stocks the fuel that accounts for 70% of the country's electricity generation are running low, prompting warnings of a fresh power crisis. The northern wheat crop is scorched. It was the the hottest March in 122 years. Spring just didn't happen, and those extreme temperatures continued into April and May (though they are predicted to ease this week). Still, it's not until June that the monsoon is expected to arrive and provide any kind of relief.

What's most alarming about this heatwave is that it's not so much a one-time ordeal as a taste of things to come as the effects of global warming push India and its neighbors to levels where the climate is a core threat to human health.

The most worrying weather measurement is not the heat typically reported in forecasts but the wet-bulb temperature, which combines heat and humidity to indicate how much evaporation can be absorbed into the air. At wet-bulb temperatures above 35 degrees Celsius, we become unable to reduce our temperature via sweating and will suffer potentially fatal heatstroke after only a few hours, even with shade and water. Similar effects can result for those working outdoors when wet bulb temperatures exceed 32 degrees, and measures as low as 28 degrees caused tens of thousands of deaths in the European and Russian heatwaves of 2003 and 2010.