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A more productive, but different, ocean after mitigation
Author(s) -
John Jasmin G.,
Stock Charles A.,
Dunne John P.
Publication year - 2015
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 - 10.1002/2015gl066160
Subject(s) - primary production , environmental science , phytoplankton , effects of global warming on oceans , sea surface temperature , lag , ecosystem , climatology , global warming , climate change , atmospheric sciences , overshoot (microwave communication) , marine ecosystem , oceanography , geology , ecology , nutrient , computer network , engineering , computer science , electrical engineering , biology
Reversibility studies suggest a lagged recovery of global mean sea surface temperatures after mitigation, raising the question of whether a similar lag is likely for marine net primary production (NPP). Here we assess NPP reversibility with a mitigation scenario in which projected Representative Concentration Pathway (RCP) 8.5 forcings are applied out to 2100 and then reversed over the course of the following century in a fully coupled carbon‐climate Earth System Model. In contrast to the temperature lag, we find a rapid increase in global mean NPP, including an overshoot to values above contemporary means. The enhanced NPP arises from a transient imbalance between the cooling surface ocean and continued warming in subsurface waters, which weakens upper ocean density gradients, resulting in deeper mixing and enhanced surface nitrate. We also find a marine ecosystem regime shift as persistent silicate depletion results in increased prevalence of large, non‐diatom phytoplankton.