Dangerous new hot zones are spreading around the world
By Chris Mooney and John Muyskens
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A Washington Post analysis of multiple temperature data sets found numerous locations around the globe that have warmed by at least 2 degrees Celsius over the past century. That's a number that scientists and policymakers have identified as a red line if the planet is to avoid catastrophic and irreversible consequences. But in regions large and small, that point has already been reached.
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The percentage of the globe that has exceeded 2C varies depending on the time periods considered. Over the past five years, 8 to 11 percent of the globe crossed the threshold, The Post found, while over the past 10 years, the figures drop slightly to between 5 and 9 percent. Considering just the past five years increases the area by roughly 40 percent.
These hot spots are the scenes of a critical acceleration, places where geophysical processes are amplifying the general warming trend. They unveil which parts of the Earth will suffer the largest changes.
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Over the past five years, Earth has passed a significant threshold. The planet is now more than 1 degree Celsius warmer than it was in the mid- to late 1800s, before industrialization spread across the world.
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While the global data sets do not agree about what is happening to every stretch of the Earth, they show unmistakable patterns.
For instance, an intriguing group of ocean hot spots appears again and again. One cause? The tropics are expanding.
Straddling the equator, the tropics are already hot because they receive the most sunlight. As the sun hits the tropics, enormous columns of air rise skyward and then outward. But as greenhouse gases trap more heat, those columns of air are pushed farther toward the north and south poles.
Air that rises in the tropics falls back down over the middle latitudes. With a warming planet, though, the air is falling in different places.
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