Scientists to outline threat of melting permafrost

Impact of changes likely to be ‘substantial’

The threat posed by the thawing Arctic permafrost will for the first time be predicted when the next international climate change report is published later this month. The impact is likely to be "substantial", according to a scientist in the UK Met Office who has contributed to the report.

The difficulties of being able to predict changes, for example, in the Arctic permafrost, ice sheet melting and ocean warming were discussed yesterday in Newcastle on the closing day of the British Science Festival. This is done using computers and predictive models.

Advanced new computer models were coming into play every year along with more powerful computers, said Dr Vicky Pope, who has held a number of senior posts in the Met Office, including head of its climate change research centre.

For the first time the latest models will offer predictions describing what will happen when the millions of square miles of permafrost, permanently frozen ground in the far north, begins to thaw. Almost a quarter of all exposed land in the northern hemisphere is rock-hard permafrost and it locks up millions of tonnes of carbon dioxide and methane, two powerful greenhouse gases.

Studies have already shown that these gases are released when permafrost thaws. Melting could cause a feedback loop where more warming melts more frozen ground to release more carbon and methane to cause more warming.

The research at the Met Office looked at a variety of scenarios, trying to assess what would happen, say, if greenhouse gas emissions reached higher levels and what types of extreme events might follow, Dr Pope said. This included scenarios such as more tree loss in the rainforest, but no predictions were available for the permafrost scenarios until now, she said.

"What we have been able to do is estimate how much permafrost will melt," she said. The Met Office permafrost data has already been fed into the fifth Assessment Report of the Intergovernmental Panel on Climate Change, set for publication in two weeks.

Other independent research groups have also run their own permafrost assessments and all will be included in the assessment report, she said. The report needed independent groups to get a better spread of data and results, and this also led to greater competition between them.

She was prohibited from giving specific information from the report before publication but did comment on it. "The change could be quite substantial but I can't quote any figures," she said.