Original URL: http://www.theregister.co.uk/2006/08/15/planet_heating_risks/

Planet heating: how bad is bad?

A round up of models and a range of risks

By Lucy Sherriff

Posted in Science, 15th August 2006 11:03 GMT

Climatologists at the University of Bristol are warning that a hotter planet will mean more damage to fragile ecosystems, and a higher risk of natural disasters such as forest fires, floods and droughts.

Drawing on data from more than 50 models of the Earth's climate, the researchers were able to make predictions about how the planet would be affected by varying degrees of warming over the next two hundred years, the BBC reports.

They were also able to assess how effective various reductions on carbon emissions would be at tackling the changes predicted, and concluded that even if emissions were cut now, some places would still face serious damage as a result of rising global temperatures.

The researchers identified three scenarios predicted by the models: a temperature rise of less than two degrees C, of between two and three degrees C and of over three degrees C.

For each, they made predictions about the amount of environmental damage the planet is likely to sustain, and found that the risks increase sharply with the temperature.

Rises of over three degrees C were found to cause existing carbon sinks, places which are overall consuming more CO2 than they produce, to go into reverse, releasing their stored carbon into the atmosphere.

They also identified the areas most at risk of deforestation, including eastern China, Canada and the Amazon. Western Africa, southern Europe and eastern states in the USA, meanwhile, were most at risk of losing their fresh water supplies, and experiencing drought.

The research team, headed by Dr. Marko Scholze, said that the work was important because it considered a variety of models.

He told the BBC: "The United Nations says we should limit greenhouse gas emissions so we do not have dangerous climate change. So the question is 'what is dangerous climate change?'.

"In this paper we define the level we think is dangerous and see how likely it will come true."

He said that because the work considered a variety of models, he hoped it would answer some of the critics of the predictions made by climate models.

Richard Betts, manager of Climate Impacts at the Met Office's Hadley Centre, added that the research was useful because it showed how much the various models agreed and disagreed. ®