image: These are altimeter era sea level trends. view more
Credit: Image courtesy of John T. Fasullo
A study suggests that the spatial pattern of current trends in sea-level change are not mainly the result of natural variability and are likely to persist over the long term. Satellite altimetry data has provided detailed and accurate data on sea-level rise since 1993. However, the extent to which observed changes in sea level reflect natural climate variations and long-term trends driven by external forcings, such as aerosols or greenhouse gas emissions, remains unclear. To address this question, J.T. Fasullo and R.S. Nerem analyzed two large ensembles of 30-40 climate simulations, with each ensemble based on a single climate model. The authors calculated the forced response (FR) due to external factors by averaging all of the simulations in an ensemble together, thereby canceling out the effects of internal variability. In both ensembles, spatial patterns of change during the altimeter era (1993-2018) in each of the individual simulations in the ensemble correlated significantly with those due to the FR, much more so than in a control ensemble of unforced simulations. In addition, the altimeter-era FR was significantly correlated with that simulated for 2020-2045. The results suggest that a significant amount of the trends in sea level measured by altimetry is due to external forcing and that such trends are likely to persist over the coming decades, according to the authors.
Article #18-13233: "Altimeter-era emergence of the patterns of forced sea-level rise in climate models and implications for the future," by J.T. Fasullo and R.S. Nerem.
MEDIA CONTACT: J. T. Fasullo, National Center for Atmospheric Research, Boulder, CO; tel: 303-497-1712, 720-291-3500; e-mail: fasullo@ucar.edu; R. S. Nerem, University of Colorado Boulder, CO; tel: 303-492-6721, 303-641-0057; e-mail: nerem@colorado.edu
###
Journal
Proceedings of the National Academy of Sciences