How does rising atmospheric CO2 affect marine organisms?

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Greenland's Outlet Glaciers
Reference
Nick, F.M., Vieli, A., Howat, I.M. and Joughin, I. 2009. Large-scale changes in Greenland outlet glacier dynamics triggered at the terminus. Nature Geoscience 2: 10.1038/NGEO394.

Background
The authors write that "the recent marked retreat, thinning and acceleration of most of Greenland's outlet glaciers south of 70°N has increased concerns over Greenland's contribution to future sea level rise," because, as they continue, "these dynamic changes seem to be parallel to the warming trend in Greenland."

What was done
Nick et al. developed "a numerical ice-flow model that reproduces the observed marked changes in Helheim Glacier," which they describe as "one of Greenland's largest outlet glaciers," after which they used the model to study the glacier's dynamics and determine what they might imply about the future mass balance of the Greenland Ice Sheet and subsequent global sea levels.

What was learned
The four researchers say their model simulations show that "ice acceleration, thinning and retreat begin at the calving terminus and then propagate upstream through dynamic coupling along the glacier." What is more, they find that "these changes are unlikely to be caused by basal lubrication through surface melt propagating to the glacier bed," which phenomenon is often cited by climate alarmists as a cause of great concern with respect to its impact on sea level.

What it means
Nick et al. conclude that "tidewater outlet glaciers adjust extremely rapidly to changing boundary conditions at the calving terminus," and that their results thus imply that "the recent rates of mass loss in Greenland's outlet glaciers are transient and should not be extrapolated into the future [our italics]." And if this advice is followed, the scary sea-level scenarios concocted by Gore and Hansen fail to materialize.

Reviewed 1 April 2009