Heat death

Relying on carbon capture globally could require large-scale scrubbing plantations nearly everywhere on Earth — the planet transformed into something like an air-recycling plant orbiting the sun, an industrial satellite tracing a parabola through the solar system.

Cities only magnify the problem of high temperature. Asphalt and concrete and everything else that makes a city dense, including human flesh, absorb ambient heat, essentially storing it for a time like a slow-release poison pill the concrete and asphalt of cities absorb so much heat during the day that when it is released, at night, it can raise the local temperature as much as 22 degrees Fahrenheit, turning what could be bearably hot days into deadly ones — as in the Chicago heat wave of 1995, which killed 739 people, the direct-heat effects compounded by broken public health infrastructure. That commonly cited figure only reflects immediate deaths; of the many thousands more who visited hospitals during the heat wave, almost half died within the year. Others merely suffered permanent brain damage. Scientists call this the “heat island” effect — each city its own enclosed space, and hotter the more crowded it is.

Climate change won’t likely slow that pattern by much, but it will make the great migrations it reflects more perilous, with many millions of the world’s ambitious flooding into cities whose calendars are dotted with days of deadly heat, gathering in those new megalopolises like moths to a flame.

By 2050, 255,000 are expected to die globally from direct heat effects. Already, as many as 1 billion are at risk for heat stress worldwide, and a third of the world’s population is subject to deadly heat waves at least twenty days each year.

Heat death is among the cruelest punishments to a human body, just as painful and disorienting as hypothermia. First comes “heat exhaustion,” mostly a mark of dehydration: profuse sweating, nausea, headache. After a certain point, though, water won’t help, your core temperature rising as your body sends blood outward to the skin, hoping desperately to cool it down. The skin often reddens; internal organs begin to fail. Eventually you could stop sweating. The brain, too, stops working properly, and sometimes, after a period of agitation and combativeness, the episode is punctuated with a lethal heart attack. “When it comes to extreme heat”, Langewiesche has written, “you can no more escape the conditions than you can shed your skin”.