[permaculture] BBC NEWS | Science/Nature | 'More disasters' for warmer world
Lawrence F. London, Jr.
lfl at intrex.net
Mon Aug 14 22:14:51 EDT 2006
Last Updated: Monday, 14 August 2006, 22:02 GMT 23:02 UK
'More disasters' for warmer world
File image of a forest fire (Image: AP)
A warmer world could make wildfires more frequent, research shows
Rising temperatures will increase the risk of forest fires, droughts and flooding over the next two centuries, UK
climate scientists have warned.
Even if harmful emissions were cut now, many parts of the world would face a greater risk of natural disasters, a team
from Bristol University said.
The projections are based on data from more than 50 climate models looking at the impact of greenhouse gas emissions.
The study appears in the Proceedings of the National Academy of Sciences.
The researchers gathered results from 52 computer simulations to calculate the risks from climate-induced changes to the
world's key ecosystems.
They then grouped the results according to the amount of global warming: less than 2C (3.6F); 2-3C (3.6F-5.4F); and more
than 3C (5.4F).
For each of the temperature ranges, the team assessed the probability of changes in forest cover, the frequency of
wildfires and changes to freshwater supplies over the next 200 years.
'Dangerous climate change'
Marko Scholze, from the University of Bristol's Department of Earth Sciences, and the paper's lead author, said the
findings revealed a direct link between rises in global temperature and damage to ecosystems.
"We show the steeply increasing risks, and increasingly large areas affected, associated with higher warming levels," he
told BBC News.
"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."
Richard Betts, manager of Climate Impacts at the Met Office's Hadley Centre, welcomed the findings.
"This makes an important new contribution to the debate on the effects of climate change," he said.
"We already knew that we cannot rely on just one model, as different models give different answers.
Sandbags protecting a river bank (Getty Images)
We do have to make decisions on climate change now so if we wait for the perfect model we will be too late
Dr Richard Betts, Hadley Centre
"This work helps us go beyond that vague statement, as it shows how much the models agree on particular levels of impact
and how much they disagree."
He said the research was an important first step towards quantifying the risks of damaging impacts associated with
particular levels of global warming.
The findings showed areas that would experience the worst forest loss would include Eurasia, eastern China, Canada and
Areas of western Africa, southern Europe and eastern US states were at most risk from dwindling freshwater supplies and
droughts as a result of rising temperatures.
The data also showed that any temperature increase of more than 3C (5.4F) could result in land "carbon sinks" releasing
their stored carbon into the atmosphere, exacerbating the problem of global warming.
Dr Scholze hoped the collated data would answer some of the concerns among more sceptical members of the scientific
community who questioned the accuracy of climatic modelling.
"That is exactly why we did this study," he said. "We used as many models as we could and did not rely on any one study.
"We looked at 52 simulations and the probabilities of dangerous climate change these models showed."
Dr Betts agreed: "Of course it is risky to make these projections when models are continuously being changed, but we do
have to make decisions on climate change now so if we wait for the perfect model we will be too late.
"The models give the best encapsulation of current understanding of the climate system, and are the only way of
assessing physically plausible futures."
Dr Scholze said he hoped the findings would be used in debates on dangerous climate change and the measures needed to
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