OS006-01
The causes of sea-level rise since 1900
Monday, 7 December 2020: 19:04
Virtual
Thomas Frederikse, NASA Jet Propulsion Laboratory, Pasadena, CA, United States, Felix W Landerer, JPL/NASA/Caltech, Pasadena, CA, United States, Lambert Caron, Jet Propulsion Laboratory, Pasadena, CA, United States, Surendra Adhikari, California Institute of Technology, Jet Propulsion Laboratory, Pasadena, CA, United States, David Parkes, University of Innsbruck, Innsbruck, Austria, Vincent Humphrey, ETH Swiss Federal Institute of Technology Zurich, Zurich, Switzerland, Sönke Dangendorf, Old Dominion University, Ocean, Earth & Atmospheric Sciences, Norfolk, VA, United States, Peter Hogarth, National Oceanography Center, Liverpool, United Kingdom, Laure Zanna, University of Oxford, Dept. of Physics, Oxford, United Kingdom, Lijing Cheng, Institute of Atmospheric Physics, International Center for Climate and Environment Sciences, Beijing, China and Yun-Hao Wu, Academia Sinica, Taipei, Taiwan
Abstract:
Since 1900, sea level has risen by about 1.5 mm/year, but this rate has varied considerably over time. The contributing factors to this rise and its temporal variations are still poorly understood. Here we present a probabilistic framework to reconstruct and budget global-mean and basin-scale sea-level changes with independent observations and their inherent uncertainties over 1900-2018.
We reconstruct sea-level changes from tide-gauge records combined with estimates of vertical land motion. The sum of thermal expansion, ice-mass loss and terrestrial water storage changes is consistent with the trends and multi-decadal variability in observed sea level on both global and basin scales.
Glacier-dominated cryospheric mass loss has caused twice as much sea-level rise as thermal expansion since 1900. Glacier and Greenland Ice Sheet mass loss explain the high rates in global sea-level rise during the 1940s, while a sharp increase in water impoundment by artificial reservoirs has been the dominant cause of lower-than-average rates during the 1970s. The acceleration in global sea level since the 1970s can be found in all ocean basins, and is caused by the combination of thermal expansion and increased Greenland mass loss.
This study reconciles the magnitude of observed global-mean sea-level rise since 1900 with estimates of underlying processes, and we show that the 20th-century sea-level budget is closed.
