Today’s wet, temperate areas near the equator will someday be arid thanks to a tropical rain band that has been moving north at an average rate of almost a mile a year for three centuries – probably because of global warming, according to scientists. And ‘someday’ isn’t centuries away: it’s as soon as 2050 for some Pacific Islands.
New research suggests that we need merely look toward the Galapagos Islands as evidence of where this has already happened. The dry, freshwater-starved island had a wet climate four centuries ago.
From MSNBC:
“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.”
The authors analyzed natural records of rainfall (including microbes and chemical ratios) left in annual layers of lake and lagoon sediments from four Pacific islands at or near the equator.
Washington Island, about 5 degrees north of the equator, is now at the southern edge of the intertropical convergence zone and receives nearly 10 feet of rain a year. But during the Little Ice Age it was arid. A similar arid past was found for Palau, which lies about 7 degrees north of the equator and in the heart of the modern convergence zone.
In contrast, the researchers present evidence that the Galapagos Islands, today an arid place on the equator in the Eastern Pacific, had a wet climate during the Little Ice Age.
Once again, the time to act was yesterday – at this point, we need to start preparing for some of the consequences of global warming as well as taking action to keep it from getting worse.
Link [MSNBC]
Photo credit: Flickr user sly06
