A group of Mississippi residents has filed a class-action lawsuit against companies they say helped fuel the global warming that worsened the impact of Hurricane Katrina. The suit accuses the companies’ “operation of energy, fossil fuels, and chemical industries” as a factor in rising sea levels that “added to the ferocity of Hurricane Katrina.” The companies include the energy giants Shell, ExxonMobil, BP, Honeywell, American Electric Power and Chevron.