Study: Tropical rain band is shifting north

Warming suspected; freshwater shortages for some Pacific isles likely

Earth’s most prominent rain band, near the equator, has been moving north at an average rate of almost a mile a year for three centuries, likely because of a warming world, scientists say.

The band supplies fresh water to almost a billion people and affects climate elsewhere.

If the migration continues, some Pacific islands near the equator that today enjoy abundant rainfall may be starved of freshwater by midcentury or sooner, researchers report in the July issue of the journal Nature Geoscience.

“We’re talking about the most prominent rainfall feature on the planet, one that many people depend on as the source of their freshwater because there is no groundwater to speak of where they live,” said Julian Sachs, associate professor of oceanography at the University of Washington and lead author of the paper. “In addition many other people who live in the tropics but farther afield from the Pacific could be affected because this band of rain shapes atmospheric circulation patterns throughout the world.”

MSNBC