The Heat You Can't Outrun

In 1975, the global landscape of emissions looked very different. The United States and Western Europe remained among the highest emitters, even as the ongoing oil crisis slowed industrial growth. Despite this, the regions facing the hottest wet-bulb temperatures in the future are not the top emitters. Instead, countries like Bangladesh, India, and parts of Southeast Asia lead future extreme-temperature risk. These areas emitted relatively little in 1975, yet were projected to face the most dangerous heat-humidity levels. The imbalance between responsibility and vulnerability is already clear at this early point in the timeline.

By 1980, the oil crisis had ended, and global energy demand accelerated again. Fossil fuel use rebounded quickly, especially in rapidly industrializing economies. Yet the pattern remains: the nations emitting the most, such as the U.S., USSR, and Western Europe, are not the ones projected to experience the highest wet-bulb extremes in 2030. Instead, much hotter future temperatures will strike tropical, densely populated regions like India, Myanmar, and coastal West Africa. The gap between northern emitters and equatorial heat exposure continues to widen.

In 1990, emissions surged alongside globalization and expanding manufacturing. China’s rise was beginning, while the U.S. remained the single largest emitter. Yet future wet-bulb extremes in 2040 still cluster around South Asia, the Middle East, and equatorial Africa. Countries like Pakistan and the UAE, which were smaller emitters at the time, are projected to face some of the world's highest heat-humidity stress. Emissions and exposure continue to diverge.

By 2005, China had overtaken the U.S. as the world’s largest emitter. Energy use was skyrocketing across Asia, while global transportation and industrial expansion drove emissions to record levels. Still, the hottest projected wet-bulb temperatures in 2055 remain concentrated in tropical climates. Heat-saturated regions are already close to physiological limits. High-emitting nations with cooler climates continue to shape the warming experienced elsewhere.

In 2010, global emissions kept rising even as renewables began scaling. China, the U.S., and the EU dominated fossil fuel output. But the highest wet-bulb temperatures expected in 2060 concentrate in regions like South Asia and the Persian Gulf, areas already under severe heat strain. These regions contribute less carbon per capita, but face the harshest weather and temperature patterns.

By 2020, brief dips in emissions caused by the pandemic gave way to a rapid rebound. Global totals remain near all-time highs. Meanwhile, the regions projected to have the most dangerous wet-bulb levels in 2070 are densely populated and vulnerable. Even today, Pakistan, India, Bangladesh, and the Gulf states see heat-humidity extremes more severe than high-emitting northern nations. The mismatch between who drives warming and who suffers from it remains clear.