For those who still doubt:
By Clive Cookson in Chicago
Published: February 16 2009
The world is warming far more quickly than scientists forecast just two years ago when the Intergovernmental Panel on Climate Change published its last reports, according to a series of assessments presented over the weekend.
Chris Field of Stanford University, a senior member of the IPCC, told the annual meeting of the American Association for the Advancement of Science that the unexpectedly rapid increase in the burning of fossil fuels, especially coal, since 2000 would have dire consequences because of “feedback loops” in the global climate.
“We are looking now at a future climate that’s beyond anything we’ve considered seriously in climate model simulations,” Prof Field said.
The IPCC’s fourth assessment in 2007 concluded that the average global temperature would increase by between 1.1°C and 6.4°C by 2100, depending how much carbon dioxide and other greenhouse gases were released into the atmosphere over the coming decades. Prof Field said that seriously underestimated the potential severity of global warming, based on the new evidence.
Prof Field warned that there were early signs of melting in the Arctic tundra and increased fires in tropical forests – over and above deliberate deforestation – that could add billions of tonnes of carbon dioxide to the atmosphere.
“There is a real risk that human-caused climate change will accelerate the release of carbon dioxide from forest and tundra ecosystems, which have been storing a lot of carbon for thousands of years,” Prof Field said.
“We don’t want to cross a critical threshold where this massive release of carbon starts to run on autopilot.”
Al Gore, the former US vice-president turned climate change campaigner, responded with a passionate plea to an audience of 1,600 scientists, urging them to become more politically active in the fight against global warming.
“Scientists can no longer in good conscience accept this division between the work you do and the civilisation in which you live. This is a historic struggle.”
Mr Gore focused particularly on the accelerating loss of Arctic ice and the global increase in coal burning.
However there was optimism at the AAAS meeting – based on the professed determination of the new US administration to promote effective action, both in its domestic energy policies and in taking a lead in international climate change negotiations.
James McCarthy, a climate change expert at Harvard University and this year’s AAAS president, said: “The scientific talent President [Barack] Obama has recruited is of extraordinary calibre. He could not have found anyone better to look after energy and the environment.”
Copyright The Financial Times Limited 2009