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Nature 415, 863 - 869 (2002); doi:10.1038/415863a
The role of the thermohaline circulation in abrupt climate change
PETER U. CLARK*, NICKLAS G. PISIAS, THOMAS F. STOCKER & ANDREW J.
* Department of Geosciences, Oregon State University, Corvallis,
Oregon 97331, USA College of Oceanic and Atmospheric Sciences,
Oregon State University, Corvallis, Oregon 97331, USA Climate and
Environmental Physics, University of Bern, Physics Institute,
Sidlerstrasse 5, 3012 Bern, Switzerland § School of Earth and Ocean
Sciences, University of Victoria, PO Box 3055, Victoria, British
Columbia V8W 3P6, Canada
Correspondence and requests for materials should be addressed to
P.U.C. (e-mail: clarkp@...).
"The possibility of a reduced Atlantic thermohaline circulation in
response to increases in greenhouse-gas concentrations has been
demonstrated in a number of simulations with general circulation
models of the coupled oceanatmosphere system. But it remains
difficult to assess the likelihood of future changes in the
thermohaline circulation, mainly owing to poorly constrained model
parameterizations and uncertainties in the response of the climate
system to greenhouse warming. Analyses of past abrupt climate changes
help to solve these problems. Data and models both suggest that
abrupt climate change during the last glaciation originated through
changes in the Atlantic thermohaline circulation in response to small
changes in the hydrological cycle. Atmospheric and oceanic responses
to these changes were then transmitted globally through a number of
feedbacks. The palaeoclimate data and the model results also indicate
that the stability of the thermohaline circulation depends on the
mean climate state. "
Confusions here are as follows:
1. Hydrology changes not just fresh water capping but biological
input and hence conductivity.
2. Warmer oceans are more conductive.
3. Forcings come from cirrus down, not thermohaline up,
thermodyanamically. The cirrus forcing is very strong this way. For
instance, the 1997-8 El Nino ended in May 1998 with SSTs dropping
almost 10 degrees F. in ONE MONTH. This is all cirrus/fair weather
driven. The huge differences between IR lost to space in fair weather
and trapped by clouds is well enough to force SSTs from the top down.
Efforts to make the SSTs move from bottom up, with inputs from the
hydrology, only take advantage of the correlations to the real causal
4. These are chaos idiots looking at a modulated and highly tuned
biological system, not a chaotic one for which they seek another
There are more points but this is enough to set their pants on fire.