BURLINGTON Senator Bernie Sanders announced recently that a new United Nations report makes the case, more forcefully then ever before, that reductions in greenhouse gases are needed to avert a global climate catastrophe. The scientists are now telling us the situation is worse than they previously thought. It is incumbent upon Congress to pass bold and aggressive legislation or the planet is going to suffer severe and irreversible harm, Sanders said of the latest report by the Intergovernmental Panel on Climate Change, the prestigious scientific panel that last month shared the Nobel Peace Prize with former vice president Al Gore. Sanders is the chief sponsor of the most far-reaching bill in Congress on global warming. He has worked to craft legislation that breaks a dependence on fossil fuels and invests in clean energy sources such as wind, solar and geothermal. The good news is that the technology is available. Whats lacking is the political will, said Sanders, a member of the Environment and Public Works Committee.