JPL Study Shows Acceleration of Sea Level's Rise

Published : Thursday, April 19, 2018 | 5:17 PM

Global sea level rise is accelerating incrementally over time rather than increasing at a steady rate, as previously thought, according to a new study based on 25 years of NASA and European satellite data. Credit: NASA's Goddard Space Flight Center/Kathryn Mersmann

The rate of global sea level rise has been accelerating in recent decades, according to a study based on 25 years of NASA and European satellite data, according to JPL scientists.

This acceleration, driven mainly by increased ice melting in Greenland and Antarctica, has the potential to double the total sea level rise projected by 2100, according to lead author Steve Nerem, a professor of Aerospace Engineering Sciences at the University of Colorado Boulder, a fellow at Colorado’s Cooperative Institute for Research in Environmental Sciences, and a member of NASA’s Sea Level Change team.

If the rate of ocean rise continues to change at the pace predicted, sea level will rise 26 inches by 2100. That’s enough to cause significant problems for coastal cities, according to the assessment by Nerem and his colleagues. The team, driven to understand and better predict Earth’s response to a warming world, published the work in February in the journal “Proceedings of the National Academy of Sciences.”

“This is almost certainly a conservative estimate,” Nerem said. “Our extrapolation assumes that sea level continues to change in the future as it has over the last 25 years. Given the large changes we are seeing in the ice sheets today, that’s not likely.”

The rate of sea level rise in the satellite era has climbed from about 0.1 inch per year in the 1990s to about 0.13 inches per year today, NASA said.

Higher concentrations of greenhouse gases in Earth’s atmosphere increase the temperature of air and water, which causes sea level to rise in two ways—warm water expanding, and melting land ice flowing into the ocean.

The “thermal expansion” of the ocean has contributed about half of the 2.8 inches of global mean sea level rise seen over the last 25 years, Nerem said. Melting land ice also significantly increases sea level across the globe.

In 2018, NASA will launch two new satellite missions critical to improving future sea level projections—the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, a partnership with GeoForschungsZentrum (GFZ) in Germany, will continue measurements of the mass of the Greenland and Antarctic ice sheets. While the Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) will make precise observations of the elevation of ice sheets and glaciers.








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