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Climate change models may underestimate extinctions
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Author:  Wayne Stollings [ Mon Jan 09, 2012 7:58 pm ]
Post subject:  Climate change models may underestimate extinctions

http://www.eurekalert.org/pub_releases/ ... 122811.php

Predictions of the loss of animal and plant diversity around the world are common under models of future climate change. But a new study shows that because these climate models don't account for species competition and movement, they could grossly underestimate future extinctions.

"We have really sophisticated meteorological models for predicting climate change," says ecologist Mark Urban, the study's lead author. "But in real life, animals move around, they compete, they parasitize each other and they eat each other. The majority of our predictions don't include these important interactions."

Author:  Wayne Stollings [ Mon Jan 09, 2012 7:58 pm ]
Post subject:  Re: Climate change models may underestimate extinctions

http://rspb.royalsocietypublishing.org/ ... hort?rss=1


Most climate change predictions omit species interactions and interspecific variation in dispersal. Here, we develop a model of multiple competing species along a warming climatic gradient that includes temperature-dependent competition, differences in niche breadth and interspecific differences in dispersal ability. Competition and dispersal differences decreased diversity and produced so-called ‘no-analogue’ communities, defined as a novel combination of species that does not currently co-occur. Climate change altered community richness the most when species had narrow niches, when mean community-wide dispersal rates were low and when species differed in dispersal abilities. With high interspecific dispersal variance, the best dispersers tracked climate change, out-competed slower dispersers and caused their extinction. Overall, competition slowed the advance of colonists into newly suitable habitats, creating lags in climate tracking. We predict that climate change will most threaten communities of species that have narrow niches (e.g. tropics), vary in dispersal (most communities) and compete strongly. Current forecasts probably underestimate climate change impacts on biodiversity by neglecting competition and dispersal differences.

Author:  Johhny Electriglide [ Tue Jan 10, 2012 12:48 pm ]
Post subject:  Re: Climate change models may underestimate extinctions

A good prediction I read 6 years ago, said that Anthropocene Thermal Max will kill off 87% of all species within 500 years. I suppose playing with models has led to predictions of 80% and others to 90%. Then there is the runaway greenhouse if all fossil fuel is burned, and a planet devoid of life.
I think the population crash of humans will preclude burning all the fossil fuels. The worse than PETM conditions (when there was a ~30% or more ELE), will most likely take place because people will not lower their fossil fuel and other burning enough before they have a 90-95% die off. The survivors will still burn fossil fuel, but not enough to cause a runaway greenhouse effect.
I have seen some ridiculous models where they are oblivious to the tipping points of Arctic ice loss albedo effects and tundra methane releases becoming self-sustaining. The tipping points are already in process of being breached with a 1*C average rise. Even with total stopping of HGHGs today, another .4*C is in the system and will probably take us past the tipping points. The minimum predictions of +2*C, and others higher to some sort of stabilization, are mere fantasies. +2*C and the methane turnover reaction will take place ten times faster than PETM, and higher temperature with more CH4 sequestered now than 55 million years ago. (Hanson, "Storms of My Grandchildren").

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