http://www.eurekalert.org/pub_releases/2007-12/su-srs120507.php
Stanford researchers say climate change will significantly increase
impending bird extinctions
Public release date: 5-Dec-2007
Where do you go when you've reached the top of a mountain and you can't
go back down?
It's a question increasingly relevant to plants and animals, as their
habitats slowly shift to higher elevations, driven by rising
temperatures worldwide. The answer, unfortunately, is you can't go
anywhere. Habitats shrink to the vanishing point, and species go
extinct.
That scenario is likely to be played out repeatedly and at an
accelerating rate as the world continues to warm, Stanford researchers
say.
By 2100, climate change could cause up to 30 percent of land-bird
species to go extinct worldwide, if the worst-case scenario comes to
pass. Land birds constitute the vast majority of all bird species.
''Of the land-bird species predicted to go extinct, 79 percent of them
are not currently considered threatened with extinction, but many will
be if we cannot stop climate change,'' said Cagan Sekercioglu, a senior
research scientist at Stanford and the lead author of a paper detailing
the research, which is scheduled to be published online this week in
Conservation Biology.
The study is one of the first analyses of extinction rates to
incorporate the most recent climate change scenarios set forth earlier
this year in the reports of the Intergovernmental Panel on Climate
Change (IPCC), which shared the Nobel Peace Price with Al Gore.
The researchers modeled changes to the elevational limits of the ranges
of more than 8,400 species of land birds using 60 scenarios. The
scenarios consisted of various combinations of surface warming
projections from the 2007 IPCC report, habitat loss estimates from the
2005 Millennium Ecosystem Assessment (an evaluation of the planet's
ecosystems by 1,360 experts around the world), and several
possibilities of shifts in elevational range limits.
The worst-case scenario of 6.4 degrees Celsius surface warming combined
with extensive habitat loss produced the estimate of 30 percent of land
bird species going extinct by 2100. Increasing habitat loss exacerbates
the effects of climate change because organisms seeking more suitable
conditions will be less likely to find intact habitats. Even with an
intermediate 2.8 C warming, 400 to 550 land-bird extinctions are
expected.
''Vegetational shift is the key issue here,'' Sekercioglu said. ''Birds
will follow the shift in habitat.''
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