August 1, 2012 View all news The GuardianSuzanne Goldenberg, US environment correspondentDrought, wildfires, hurricanes and heatwaves are becoming normal in America because of climate change, Congress was told on Wednesday in the first hearing on climate science in more than two years.In a predictably contentious hearing, the Senate's environment and public works committee heard from a lead scientist for the UN's climate body, the IPCC, on the growing evidence linking extreme weather and climate change."It is critical to understand that the link between climate change and the kinds of extremes that lead to disaster is clear," Christopher Field, a lead author of the IPCC report and director of global ecology at the Carnegie Institute for Science, said in testimony."There is no doubt that climate has changed," he went on. "There is also no doubt that a changing climate changes the risks of extremes, including extremes that can lead to disaster."Read more Categorised in: Climate Change