Wildlife moves to stay cool in a warmer world

By Alister Doyle, Environment Correspondent OSLO, Aug 8 (Reuters) -
Salmon swim north into Arctic seas, locusts plague northern Italy and two heat-loving bee-eater birds nest in a hedge in Britain. Signs of global warming fed by greenhouse gases produced by human activity, or just summertime oddities? In the United States, some warblers are flying north to Canada. In Costa Rica, toucans are moving higher up into the mountains, apparently because of rising temperatures. In July, a Norwegian man fishing in a fjord had a shock when he landed a John Dory, a fish more usually found in temperate waters off southern Europe or Africa. "There's a long list of migratory species ending up further north. It's certainly a sign of warmer temperatures," said Steve Sawyer, climate policy director at the Greenpeace environmental group. He said salmon had been swimming through the Bering Strait between Alaska and Russia into the Chukchi Sea, apparently because the frigid water had warmed up. Such shifts could have vast long-term implications for farmers and fishing fleets. However, some experts are sceptical that unusual sightings of everything from bears to butterflies support theories that temperatures are rising because of a build-up of heat-trapping gases emitted by cars, factories and power plants. "If you want to measure temperatures, you use a thermometer, not a bird," said Fred Singer, who heads the U.S. Science and Environmental Policy Project. "Birds have all sorts of reasons for moving north, south, sideways or whatever." Singer says people and creatures have adapted to unexplained changes in temperature, linked to natural variation, throughout history. Some species simply move in unexpected directions or unwittingly stow away on trucks, planes or ships.