NEWS Back when the "internet" consisted of telegraph wires and morse code keys, a low-tech warning system was used to warn of dangerous gases in coal mines - a canary in a cage. If the bird stopped singing, miners knew to start heading for the exits. On a planet with no exits, however, glaciers are being described as a canary in awareness efforts to fight global warming, with the United Nations Environment Programme warning member countries to quickly agree to carbon limits. "There are many canaries emerging in the climate change coal mine," UNEP's executive director Achim Steiner said in a statement. "The glaciers are perhaps among those making the most noise and it is absolutely essential that everyone sits up and takes notice."