Relative Importance of Ocean Mass and Volume Changes to Global Sea Level Rise
Abstract
Sea level is an integrated indicator of climate variability, reflecting changes in the dynamic and thermodynamic in atmosphere, ocean and cryosphere. The rate of sea level rise and its causes is a topic of active debate. We examine the relationship between 50 year long records of global sea level (GSL) calculated from 1023 tide gauge stations and global ocean heat content (GOHC), glacier and ice sheet melting. The lack of consistent correlation between changes in GOHC and GSL during the period 1955-2003 argues against GOHC being the dominant factor in GSL as is often thought. We provide clear evidence of the substantial and increasing role in GSL from the eustatic component (47 per cent) compared with the contribution from increasing heat content (25 per cent), suggesting that the primary role is being played by the melting glaciers and ice sheets. There remains about 23 per cent of GSL rise unaccounted for by the best estimates of both eustatic and thermosteric effects. This fraction also exhibits large variability that is not readily associated with known causes of sea level variability. The most likely explanation of this unknown fraction is underestimated melting, climate- driven changes in terrestrial storage components and decadal time scale variability in global water cycle. This argues for a concerted effort to quantify changes in these reservoirs.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFM.G33B1243J
- Keywords:
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- 1616 Climate variability (1635;
- 3305;
- 3309;
- 4215;
- 4513);
- 1641 Sea level change (1222;
- 1225;
- 4556);
- 1827 Glaciology (0736;
- 0776;
- 1863);
- 4262 Ocean observing systems;
- 4556 Sea level: variations and mean (1222;
- 1225;
- 1641)