Limiting global warming to 1.5°C will reduce the exposure of hundreds of millions of South Asian people to lethal heat events by half, in turn preventing economy-destabilizing drops in labour productivity, says a new study by an international climate science institute. 

In a report just published in Geophysical Research Letters, Climate Analytics researchers flagged that, “based on a middle-of-the-road population growth projection scenario, people in Bangladesh, India, and Pakistan will experience 774 million exposures (measured in ‘person-days’) to potentially deadly heat stress events by 2050 if warming rises to 2°C above pre-industrial levels.” Should governments make good on their Paris pledge to limit warming to 1.5°C, the report adds, “human exposures would nearly halve to 423 million.”

The consequences of our current 1°C of warming are already deadly, notes lead author Fahad Saeed. “In 2015, 3,500 people in Pakistan lost their lives during the world’s fifth-deadliest heat wave.”

The economic effects of warming have been—and will continue to be—severe, as well. Once warming reaches 2°C, the South Asia region “could expect 7.89 billion exposures” above the relatively safe threshold of 32°C by 2050, the scientists discovered—an effect that will greatly hinder people’s ability to work, especially outside. Reining in global warming to 1.5°C would reduce that figure to 5.01 billion exposures and help avoid some of the plunge in labour productivity.

The study adds that adaptive capacity in the region will depend on a compounding mix of “regional demographic and socioeconomic factors, such as high population density, population growth and poverty.” That makes precise forecasting difficult.

“The precise number of people who will be exposed to such extreme heat waves is uncertain because we can’t foresee how populations will grow, and it’s very possible that people may migrate to avoid these deadly conditions,” said report co-author Carl-Friedrich Schleussner.

But the time for action is now, he added, especially for South Asia, where “the climate of the future is already here,” along with its effects. 

“This research shows it’s in the best interest of Bangladesh, India, and Pakistan to ensure that warming is limited to 1.5°C,” Schleussner said. Those countries’ “continued investment in new coal power plants is incompatible with the urgent need for global decarbonization.”