What the models project—and who gets hit hardest
A new analysis by World Weather Attribution and Climate Central projects that by 2100 the average place on Earth will experience 57 more “superhot” days annually—defined as days hotter than 90% of comparable dates in 1991–2020. Without policies like the 2015 Paris Agreement, the study says that number would have been roughly double. The burden is uneven. Small island states and tropical countries face the biggest increases in extreme heat even though they emit little. Panama, for instance, is projected to see more than four months of additional superhot days. In contrast, high emitters like the U.S., China and India see smaller increases on average, though their large populations mean many more people are exposed. Researchers stress that health risks rise well before heat records are broken—heat illness, dehydration and power grid failures track with longer spells of high wet-bulb conditions.

Adaptation buys time—but mitigation sets the ceiling
The study’s core message is twofold: adaptation can save lives now, but only emissions cuts decide how livable the century becomes. Cities are testing heat action plans—cool roofs, shaded transit stops, and targeted alerts for outdoor workers. Utilities are adding peak capacity and demand-response programs to avoid blackouts, while employers revisit rest-break rules. Yet adaptation costs climb as the baseline warms. The authors argue that locking in cleaner power, electrified cooling, and efficient buildings can limit how often communities cross dangerous thresholds. They also caution that the projections are based on climate models that, while robust, still carry uncertainty—local geography, urban design and socioeconomic factors change outcomes on the ground. The bottom line: the world has already avoided the worst-case path, but a future with dozens of extra scorching days each year still demands faster action.