Monday, August 19, 2013

Does Increased Precipitation Stall Sea Level Rise?

When enough raindrops fall over land instead of the ocean, they begin to add up.

New research led by the National Center for Atmospheric Research (NCAR) shows that when three atmospheric patterns came together over the Indian and Pacific oceans, they drove so much precipitation over Australia in 2010 and 2011 that the world's ocean levels dropped measurably. Unlike other continents, the soils and topography of Australia prevent almost all of its precipitation from running off into the ocean.

The 2010-11 event temporarily halted a long-term trend of rising sea levels caused by higher temperatures and melting ice sheets.

Now that the atmospheric patterns have snapped back and more rain is falling over tropical oceans, the seas are rising again. In fact, with Australia in a major drought, they are rising faster than before.

"It's a beautiful illustration of how complicated our climate system is," says NCAR scientist John Fasullo, the lead author of the study. "The smallest continent in the world can affect sea level worldwide. Its influence is so strong that it can temporarily overcome the background trend of rising sea levels that we see with climate change."

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