Researchers with the Climate Impact Lab found in a recent study that heat-related mortality will expand dramatically in the coming decades and in the world’s poorest and hottest places, exacerbating inequality. They projected that higher temperatures will lead to a staggering 150,000 added deaths per year in Pakistan by 2040 — unless the country can grow substantially more wealthy and better adapt to frequent bouts of extreme heat. The rising death rate, 50 per 100,000, is higher than that of nearly all other countries, barring some of the least developed parts of Africa and the Middle East. It is more than twice the number estimated for neighboring India, which has more financial resources to shield its population from the worst climate impacts. “The way the rich countries are going to respond is by spending more to protect ourselves, and in many parts of the world those opportunities don’t exist,” said Michael Greenstone, a University of Chicago economist and the study’s co-author.