60秒科学:Rain Zone Moving North（在线收听）

Rain Zone Moving North
An article in Nature Geoscience predicts that the rainiest area on Earth, the intertropical convergence zone, is moving steadily north. Christie Nicholson reports

[The following is an exact transcript of this podcast.]

If you’ve spoken to anyone in New York City—where Scientific American’s offices are—then you’ve heard about the rain, every day since mid-June.

Still, we’re not in the intertropical convergence zone, an area just north of the equator stretching across the Pacific that builds rain clouds 30,000 feet thick releasing as much as 13 feet of rain annually.

But the rainiest place on Earth might reach us, eventually. Researchers report in the journal Nature Geoscience the zone is moving north at a rate of nearly a mile per year.

It’s important because it supplies freshwater to a billion people in the tropics.
Researchers studied Washington Island in the Pacific that gets 10 feet of rain annually. Core samples revealed that it was desert-like only 400 years ago. A similar situation was found in Palau, now in the heart of the convergence zone. Also, the now arid Galapagos Islands had a very wet climate about 400 years ago.

Researchers predict that this zone will be more than 75 miles north of its current position as early as midcentury, having profound economic and cultural implications for those who currently depend upon it.

—Christie Nicholson