PASADENA (CBSLA.com) — Climate change has slowed - at least temporarily - the rate of rising sea levels, NASA researchers said Thursday.
A new study by scientists at NASA's Jet Propulsion Laboratory in Pasadena and the University of California, Irvine, shows that while ice sheets and glaciers continue to melt, changes in weather and climate over the past decade have caused Earth's continents to soak up and store an extra 3 trillion tons of water in soils, lakes and underground aquifers, temporarily slowing the rate of sea level rise by about 20 percent.
The study - which was published in the Feb. 12 issue of the journal Science - was the first time scientists were able to identify and quantify how climate-driven increases of liquid water storage on land have affected the rate of sea level rise.
Globally, the water gains were equal to the volume of Lake Huron, the world's seventh largest lake, according to the study.
Each year, a large amount of water evaporates from the ocean, falls over land as rain or snow, and returns to the ocean through runoff and river flows, in what is commonly known as the global hydrologic, or water, cycle.
While scientists have long known that small changes in the hydrologic cycle could change the rate of sea level rise, they did not know how large the "land storage effect" would be because there were no instruments that could accurately measure global changes in liquid water on land, according to the study's lead author J.T. Reager of JPL.
"We always assumed that people's increased reliance on groundwater for irrigation and consumption was resulting in a net transfer of water from the land to the ocean," said Reager, who began work on the study as a UCI graduate student. "What we didn't realize until now is that over the past decade, changes in the global water cycle more than offset the losses that occurred from groundwater pumping, causing the land to act like a sponge -- at least temporarily."
The new data is expected to be "critical" for future long-term projections of sea level rise, Reager added.
Following the 2002 launch of NASA's Gravity Recovery and Climate Experiment (GRACE) twin satellites, scientists were able to detect changes in Earth's gravitational pull resulting from regional changes in the amount of water across Earth's surface by measuring the distance between the two GRACE satellites.
The study's findings appeared to contradict several major studies conducted in recent years on sea level rise, including a 2015 study that found the current sea level rise rate - which started in 1990 - is 2.5 times faster than it was from 1900 to 1990.
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