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?
OSLO, Norway — 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.
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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 skeptical 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.
ROBINS IN ARCTIC
However, U.N. data show that the warmest year since records began in the 1860s was 1998, followed by 2002, 2003 and 2004. Most scientists link the rise in temperatures to human emissions of carbon dioxide from burning fossil fuels, rather than natural change.
The panel that advises the United Nations says that rising temperatures may drive thousands of species to extinction and cause more storms, floods and deserts while raising sea levels, perhaps by 3 feet by 2100.
Inuit peoples have noted southerly species of wildlife reaching the Arctic in summertime in recent years, including robins, hornets and barn owls.
Anecdotal evidence from further south is piling up.
Two yellow, green and brown bee-eater birds, usually found in southern Europe, have nested in a hedge in southern England -- the fourth time a bee-eater nest has been found in Britain.
"It looks as if it's linked to climate change," John Lanchbery, head of climate policy at Britain's Royal Society for the Protection of Birds, said of a general shift northwards of birds in Europe.
Growing seasons have extended and seas have become warmer, he said.
However, some examples are misleading.
In the Piedmont region of northern Italy this summer, residents were surprised by swarms of locusts, suspecting they had flown over from Africa.
Insect experts said they were an Italian species and did not migrate over long distances. Still, an exceptionally hot summer in 2003 has meant more parched ground, ideal conditions for the pests to lay their eggs.
"Global warming could also be a reason," said Vincenzo Girolami, an entomologist at Padua University. If there were more hotter, drier summers, there were likely to be more swarms of locusts in Italy, he said.
HEADACHE FOR RANGERS
In the United States, birds such as the Cape May warbler and Blackburnian warbler are moving north into Canada, causing a headache for forest rangers.
If the birds leave, spruce forests in the United States could be vulnerable to attacks by spruce budworm caterpillars, normally eaten by the birds. If the caterpillars are left to thrive they will eat, and dry out, the trees.
"The trees could be more stressed which could lead to more fires," said Terry Root, a professor at Stanford University in the United States. "We could really have a difficult situation."
In Costa Rica's Monteverde cloud forest, toucans, with their brightly-colored, banana-shaped bills, are threatening another species, the spectacular green quetzal, by moving to higher altitudes where the quetzals nest, she said.
(Additional reporting by Timothy Gardner in New York, Robin Pomeroy in Rome and Ed Stoddard in Johannesburg)
Source: Reuters
