Thursday, February 11, 2016

Downpours Over Land Have Slowed Sea Level Rise

By John Upton
Feb. 11, 2016

Vast volumes of water falling as rain and snow have stayed on land in recent years, slowing the rise of the seas, new research has revealed.

Water is constantly evaporating from oceans and moving to land, where it’s stored fleetingly in lakes, snowpacks, soil and tree canopies, before flowing back again.

The land “has been taking up water,” said NASA Jet Propulsion Laboratory scientist John Reager, who led the study published Thursday in Science. “That’s been slowing the rate of sea level rise.”

The effect may have been temporary, and it has not been enough to protect coastal residents from profound shoreline changes triggered by global warming.

The new study relied on NASA gravity data from 2002 to 2014 to track the changes in the amount of water stored on land. The finding excluded water stored in glaciers, which continued to decline as warming temperatures caused them to melt.

Because of global warming, high tides are lapping an average of 8 inches higher than they were in the 1800s, causing routine flooding along the East and Gulf coasts. Several feet or more of additional sea level rise is anticipated this century, threatening roads, pipelines, buildings and residents around the world.


Scientists aren’t sure whether the pattern they discovered is part of a longer-term trend linked to climate change and increasing storminess, or part of a shorter-term cycle linked to natural variations in the weather.

But many suspect it’s part of a cycle, which may mean seas will rise even more quickly than anticipated in the years ahead.

“We think it could even reverse and go in the other direction,” Reager said. “It could be an accelerator for sea level rise.”

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