President Barack Obama said \"climate change is not a hoax\" Thursday and recommitted himself to reining in carbon pollution in a rebuttal of taunts from his Republican rival. Last week at the Republican convention in Tampa, Florida, White House hopeful Mitt Romney poked fun at the president in a barb suggesting that he prioritized environmental issues over acts to help hard-working Americans. \"President Obama promised to slow the rise of the oceans and heal the planet,\" the former Massachusetts governor said to applause and laughter from the party faithful. \"My promise is to help you and your family.\" There was no hint of amusement in Obama\'s response. \"My plan will continue to reduce the carbon pollution that is heating our planet, because climate change is not a hoax,\" he said, as he accepted his party\'s presidential nomination for the tight-fought election in November. \"More droughts and floods and wildfires are not a joke,\" he said. \"They are a threat to our children\'s future.\" Obama acknowledged in his annual State of the Union address in January that the deeply divided Congress would not approve comprehensive legislation to fight climate change. Legislation backed by Obama died in the US Senate in 2010 amid staunch opposition from Republicans, many of whom question scientists\' view that carbon emissions are behind rising temperatures. Obama has urged Congress to renew tax credits for clean energy, with incentives for wind power set to expire at the end of 2012, and called for an end to subsidies to already profitable oil companies.