The Mysteriously Low Death Toll of the Heat Waves in India and Pakistan
First, the official death count is an undercount.
This was the interpretation offered to me by Dr. Friederike Otto, of World Weather Attribution, in May; by Kathy Baughman-McLeod, director of the Atlantic Council’s Arsht-Rockefeller Resilience Center, in June; and by Avikal Somvanshi, of India’s Center for Science and the Environment, in July. In fact, it was the first thing mentioned by everyone I spoke to, in India and Pakistan and elsewhere, when discussing the toll of the heat wave.
Heat is something of an epistemological and epidemiological challenge to doctors and coroners, even in places most conscientious about data collection. That’s because few deaths even under the most extreme temperature conditions present obviously as heat stress; mostly, fatalities accrue when underlying conditions are exacerbated or made worse by the additional strain.
Aditya Valiathan Pillai, an associate fellow at India’s Center for Policy Research, went to emergency rooms “just to see if the fact that nothing was popping up in the media about people dying was true or whether it was sort of a mortality whitewash, the way we saw with Covid,” he said. “And universally, I went to government hospitals and they said, we did see a steady uptake in the number of people showing up, but very few deaths. Then again, all of them raised their hands and said, we don’t really actually know how to count a heat death. And so we’re not entirely sure.”
A full accounting of the toll of any heat wave requires “excess mortality data” — overall accounting of how many people died in a given period above a baseline average — but compiling that can take months, wherever the extreme event hits. Without it, Baughman-McLeod said, “we don’t know how many, because we don’t count properly. The data collection isn’t there — whether in India or in the U.S.”
For his part, Somvanshi estimates that the ultimate toll of these heat waves will be “at least twice than what is officially reported. But based on the available information, it will most probably be much more than twice.” A simple doubling of data still yields a relatively low estimate; getting even to the 2015 toll in India would require something like a 20-fold adjustment. To get to the mortality levels of the European heat waves, a much larger adjustment still.
Second, for mortality, humidity matters enormously.
“Humid heat is more dangerous to human health and well-being than dry heat,” Somvanshi said. Through much of the heat wave, the temperatures were alarmingly high but humidity relatively low — making those truly concerning wet-bulb readings relatively rare and brief, even through the oppressively hot spring.