The UK should take active steps to prepare for dangerous climate change of perhaps 4C according to one of the government’s chief scientific advisers. In policy areas such as flood protection, agriculture and coastal erosion Professor Bob Watson said the country should plan for the effects of a 4C global average rise on pre-industrial levels. The EU is committed to limiting emissions globally so that temperatures do not rise more than 2C.
According to the government’s 2006 Stern review on the economics of climate change, between 7 million and 300 million more people would be affected by coastal flooding each year, there would be a 30-50% reduction in water availability in Southern Africa and the Mediterranean, agricultural yields would decline 15 to 35% in Africa and 20 to 50% of animal and plant species would face extinction.
Watson’s plea to prepare for the worst was backed up by the government’s former chief scientific adviser, Sir David King. He said that even with a comprehensive global deal to keep carbon dioxide levels in the atmosphere at below 450 parts per million there is a 50% probability that temperatures would exceed 2C and a 20% probability they would exceed 3.5C.
One big unknown is the stage at which dangerous tipping points would be reached that lead to further warming – for example the release of methane hydrate deposits in the Arctic. “My own feeling is that if we get to a 4 degree rise it is quite possible that we would begin to see a runaway increase,” said King. Other experts were concerned that Watson’s comments might be seen as defeatist and an admission that emissions reductions were impossible to achieve.
“At 4 degrees we are basically into a different climate regime,” said Prof Neil Adger, an expert on adaptation to climate change at the Tyndall Centre for Climate Change Research in Norwich. “I think that is a dangerous mindset to be in. Thinking through the implications of 4 degrees of warming shows that the impacts are so significant that the only real adaptation strategy is to avoid that at all cost because of the pain and suffering that is going to cost. “There is no science on how we are going to adapt to 4 degrees warming. It is actually pretty alarming,” he added.
– from www.guardian.co.uk