Heavy Australian rainfall put stop to sea level rise

Rainfall driven from the Indian and Pacific Oceans onto Australia in 2010 and 2011 was so heavy the world's ocean levels dropped measurably, researchers say. Unlike other continents, the soils and topography of Australia prevent almost all of its precipitation from running off into the ocean, they said. Research by the National Center for Atmospheric Research in Boulder, Colo., found three unusual atmospheric patterns came together over the Indian and Pacific oceans, creating the 2010-11 rainfall in Australia that temporarily halted a long-term trend of rising sea levels caused by higher temperatures and melting ice sheets. But those patterns have now returned to normal and more rain is falling over tropical oceans, causing sea levels to rise again. In fact, with Australia in a major drought, they are rising faster than before, researchers said. "It's a beautiful illustration of how complicated our climate system is," NCAR scientist John Fasullo said. "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." A rare combination of climate modes came together to drive such large amounts of rain over Australia that the continent, on average, received almost one foot of rain more than average in one of the wettest periods in Australia's recorded history, the researchers said. Because of the low-lying topography of Australia's vast Outback interior, most of the heavy rainfall remained inland rather than flowing into the oceans, they said. No other continent has this combination of atmospheric setup and topography," Fasullo said in an NCAR release Monday. "Only in Australia could the atmosphere carry such heavy tropical rains to such a large area, only to have those rains fail to make their way to the ocean."