"This is a victory for the polar bear, and all wildlife threatened by global warming" Kassie Siegel, Centre for Biological Diversity. It is the first time the US has made a direct link between global warming and the threat to a species. President George W. Bush has steadfastly refused to back mandatory controls of emissions of carbon dioxide - believed the main gas behind global warming. There are 20,000 to 25,000 polar bears across the globe, about 4,700 of them in the US state of Alaska.