Relative roles of climate sensitivity and forcing in defining the ocean circulation response to climate change

Jeffery R. Scott, Andrei P. Sokolov, Peter H. Stone, Mort D. Webster

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The response of the ocean's meridional overturning circulation (MOC) to increased greenhouse gas forcing is examined using a coupled model of intermediate complexity, including a dynamic 3-D ocean subcomponent. Parameters are the increase in CO2 forcing (with stabilization after a specified time interval) and the model's climate sensitivity. In this model, the cessation of deep sinking in the north "Atlantic" (hereinafter, a "collapse"), as indicated by changes in the MOC, behaves like a simple bifurcation. The final surface air temperature (SAT) change, which is closely predicted by the product of the radiative forcing and the climate sensitivity, determines whether a collapse occurs. The initial transient response in SAT is largely a function of the forcing increase, with higher sensitivity runs exhibiting delayed behavior; accordingly, high CO2-low sensitivity scenarios can be assessed as a recovering or collapsing circulation shortly after stabilization, whereas low CO2-high sensitivity scenarios require several hundred additional years to make such a determination. We also systemically examine how the rate of forcing, for a given CO2 stabilization, affects the ocean response. In contrast with previous studies based on results using simpler ocean models, we find that except for a narrow range of marginally stable to marginally unstable scenarios, the forcing rate has little impact on whether the run collapses or recovers. In this narrow range, however, forcing increases on a time scale of slow ocean advective processes results in weaker declines in overturning strength and can permit a run to recover that would otherwise collapse.

Original languageEnglish (US)
Pages (from-to)441-454
Number of pages14
JournalClimate Dynamics
Volume30
Issue number5
DOIs
StatePublished - Apr 1 2008

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climate change
climate
ocean
stabilization
meridional circulation
surface temperature
air temperature
radiative forcing
bifurcation
climate modeling
greenhouse gas
ocean circulation
timescale
rate

All Science Journal Classification (ASJC) codes

  • Atmospheric Science

Cite this

Scott, Jeffery R. ; Sokolov, Andrei P. ; Stone, Peter H. ; Webster, Mort D. / Relative roles of climate sensitivity and forcing in defining the ocean circulation response to climate change. In: Climate Dynamics. 2008 ; Vol. 30, No. 5. pp. 441-454.
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Relative roles of climate sensitivity and forcing in defining the ocean circulation response to climate change. / Scott, Jeffery R.; Sokolov, Andrei P.; Stone, Peter H.; Webster, Mort D.

In: Climate Dynamics, Vol. 30, No. 5, 01.04.2008, p. 441-454.

Research output: Contribution to journalArticle

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