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Does the recent freshening trend in the North Atlantic indicate a weakening thermohaline circulation?
Author(s) -
Wu Peili,
Wood Richard,
Stott Peter
Publication year - 2004
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2003gl018584
Subject(s) - thermohaline circulation , shutdown of thermohaline circulation , climatology , north atlantic deep water , oceanography , environmental science , ocean current , greenhouse gas , general circulation model , arctic , climate model , geology , climate change
It is widely expected that the thermohaline circulation of the ocean will slow down as greenhouse gas concentration in the atmosphere increases. This is partly due to an intensified hydrological cycle in a warmer climate. Is the recent observed freshening trend in the North Atlantic an indication of what has been expected? We report a similar freshening trend reproduced in an ensemble of four coupled model simulations with all major historical external (natural and anthropogenic) forcings. The modelled freshening trend originates from the Arctic Ocean where sea ice decrease and river runoffs increase with the same trend. Instead of weakening, we find an upward trend in the North Atlantic meridional overturning circulation.