Sightseers are about to get the cold shoulder in Antarctica under a new environmental protection plan proposed by the US.Countries signed up to the Antartic Treaty have agreed to limit the size of cruise ships and the number of tourists allowed to disembark. The changes still have to be ratified by the 28 countries signed up to the treaty. The news comes on the back of a major shift in Washington on the issue of greenhouse gases. For the first time, the US Environmental Protection Agency has said that man-made pollution is likely to be the cause of global warming and a danger to the public. Environmental groups are delighted. David Bookbinder at the Sierra Club said: “The importance is that the federal government will now begin setting limits for the first time on carbon dioxide and other greenhouse gas pollutants, something the Bush administration refused for eight years to do, as the problem grew worse and worse.” Opposition politicians have slammed the change as simply a move towards an energy tax. Observers in the US also say it could take years before regulations come into force and there are likely to be court challenges.