How does rising atmospheric CO2 affect marine organisms?

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Are Climate Models Up to the Challenge Required of Them?
Vaughan, D.G., Marshall, G.J., Connolley, W.M., King, J.C. and Mulvaney, R.  2001.  Devil in the detail.  Science 293: 1777-1779.

What was done
The authors, all of whom are with the UK's British Antarctic Survey, analyze some interesting aspects of regional climate change that come to bear upon the issue of whether current global circulation models are good enough to make reliable climate forecasts upon which individual nations can confidently depend to make rational decisions about the future.  In doing so, they focus on one of three places where there has been significant warming over the past half-century or so -- the Antarctic Peninsula and Bellingshausen Sea -- about which they are particularly knowledgeable.

What was learned
Although directly-measured air temperatures at the South Pole have cooled since 1958, they have warmed on the Antarctic Peninsula.  In addition, three of four ice cores there also show a rise in temperature over the last half-century.  What is more, the authors note that "rapid regional warming has led to the loss of seven ice shelves during the past 50 years."  On the other hand, sediment cores reveal that from 6000 to 1900 years ago, the Prince Gustav Channel ice shelf -- which collapsed in 1995 -- "was absent and climate was as warm as it has been recently."

What it means
Although the authors refer to the Antarctic Peninsula warming of the last 50 years as "exceptional" within the context of the past 500 -- and possibly 1900 -- years, it is clear that the region's present temperature status is anything but exceptional within the context of the last 6000 years, in that for 68% of this longer period the climate there was "as warm as it has been recently."  Hence, Vaughan et al. are right on target when they say "it may be tempting to cite anthropogenic greenhouse gases as the culprit, but to do so without offering a mechanism is superficial."

In an attempt to overcome this superficiality, the authors suggest three possible reasons for the warming of the past half-century, one of which is a variant of the standard global warming theory.  However, they say that "because we cannot distinguish between these widely differing mechanisms, we have no basis for predicting future changes."  Honestly acknowledging current climate model deficiencies, they go on to say that "we do not yet have tools to predict potentially socially significant regional climate changes in the next 100 years," noting that "for national adaptation planning to be properly targeted, we must achieve competency in predicting regional climate changes."

We agree.