Antarctica‘s ice would raise sea levels around the globe by 4 to 9 meters.Floods would cover low­lying regions and turn coastal cities like New York and New Orleans into real life underwater world. Scientists first predicted in the 1970s that heat trapped in the Earth's atmosphere could cause a polar meltdown.Many people now believe that human activities are turning up the heat.When we burn fossil fuels like coal and oil，we add carbon dioxide (CO2) gas to the Earth's atmosphere.Cutting down trees also makes CO2 levels rise