There is no doubt that CO2 emissions cause global warming. Since the early 1800, scientists have found that greenhouse gases in the atmosphere trap heat. That is why Professor Johan Rockstrom stated that by 2020, we need to bend the global curve of emissions. Then, by 2030, we are required to cut emissions in the world by half. "That is the way to land Earth on a safe trajectory for the future in ten years," he said as the Potsdam Institute for Climate Impact Research director at Davos.