Hi all, This research runs counter to the models that suggest we may have ALREADY put enough CO2 in the atmosphere to produce 2C rise. And, as usual, the rising positive feedback, e.g. from carbon sink degradation and Arctic sea ice summer disappearance, is totally ignored. Thus their argument about time-independence falls down. Also the reduction of tropospheric sulphur aerosol, supported by environmentalists to clean up the atmosphere, threatens to further add to global warming.
Cheers, John http://www.guardian.co.uk/environment/2009/apr/30/temperature-rise-global-warming-fossil-fuels World already halfway to 2C rise, say scientists David Adam and Alok Jha The Guardian, Thursday 30 April 2009 Article history The world has already burned half the fossil fuels necessary to bring about a 2C rise in average global temperature, scientists reveal today. The experts say about half a trillion tonnes of carbon have been consumed since the industrial revolution. To prevent a 2C rise, they say, the total burned must be kept to below a trillion tonnes. On current rates, that figure will be reached in 40 years. The new research is released as a leading adviser to the government on climate policy said that Britain would "struggle" to meet its 2020 target to source 15% of its electricity from renewable sources. Jim Skea, research director of the UK Energy Research Centre (UKERC) and a member of the government's Advisory Committee on Climate Change, was speaking at the launch of a UKERC report that presents scenarios for how lifestyles and energy generation in Britain would have to change reach the 2050 climate targets. Myles Allen, a climate expert at Oxford University who led the new study on global carbon emissions, said: "Mother Nature doesn't care about dates. To avoid dangerous climate change we will have to limit the total amount of carbon we inject into the atmosphere, not just the emission rate in any given year." The scientists say their research could simplify political attempts to tackle global warming, which encompass a range of targets and timetables. Such proposals usually set future limits on the amount of carbon dioxide allowed to build up in the atmosphere, such as 450 parts per million, or as future emission rates, such as Britain's 's pledge to slash 80% of emissions by 2050. The new study in effect reframes such targets as an available budget - to avoid dangerous climate change of 2C the world can only burn another half a trillion tonnes of carbon. Writing in this week's Nature magazine, Allen and colleagues say a trillion tonnes of carbon burned would be likely to produce a warming of between 1.6C and 2.6C. Chris Huntingford of the NERC Centre for Ecology and Hydrology said: "Research often reveals new complexities, but this analysis could actually simplify matters for policymakers. The relationship between total emissions and future warming can be inferred largely from quantities we can observe, and is remarkably insensitive to the timing of future emissions." The key implication of the research, the scientists say, is that access to fossil fuels must somehow be rationed and eventually turned off, if the 2C target is to be met. "If country A burns it then country B can't," said Bill Hare, a climate expert with the Potsdam Institute in Germany. The research also highlights that continued high rates of fossil fuel use in the next decade will demand extraordinary cuts in emissions in future decades to hit the 2C target. Allen said: "If you use too much [carbon] this year, it doesn't mean the planet will come to an end. It means you have to work harder the next year." --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~----------~----~----~----~------~----~------~--~---
