On Wed, Jan 28, 2009 at 07:55:09PM +1000, L&L Knight wrote:
> http://news.bbc.co.uk/2/hi/science/nature/7851276.stm
> Based on predictions of sea ice extent from climate change models, the
> penguins are likely to see their numbers plummet by 95% by 2100.
There is a big gap between the research and the news report.
The PNAS paper models the fate of one Emperor colony which is notable
because there is long-term demographic data. Previous work has suggested
sea ice extent has major impacts on this colony.
But Antarctic sea ice extent is poorly handled by climate models and
projections of its future differ wildly. In other words we have little
happen to sea ice in coming decades. The authors handle this by modelling
the colony's fate for each of the regional sea ice projections produced
by a set of 10 climate models - and given their demographic assumptions
the future for the colony looks grim in every case.
But what is not highlighted is one of the climate models projects little
regional change in sea ice over the next century and their modelling
still shows a major penguin decline. They project the colony at major
risk of extinction without any change from current conditions.
The reason seems to be that this colony has been in decline since about
1970 perhaps due to a change in the local sea ice conditions - there
isn't good data about sea ice going back that far. Anyway this colony
seems to be in trouble without any future climate change, perhaps doomed
for entirely natural reasons. So I'm not sure this paper illuminates
much the future of Emperors generally.
Andrew
Paper here:
http://www.pnas.org/content/early/2009/01/26/0806638106.abstract
Previous work here:
http://www.nature.com/nature/journal/v411/n6834/full/411183a0.html
And info about modelling antarctic climate here:
http://www.agu.org/pubs/crossref/2007/2007GL031648.shtml
Andrew
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