ENVIRONMENT: Wildlife Disrupted by Global Warming

By Suvendrini Kakuchi Reprint | | Print |

Suvendrini Kakuchi

KYOTO, Dec 4 1997 (IPS) - If doubts remain about how global warming is disrupting life on Earth, scientists say sceptics should take a good look at the many warning signals nature has been sending out.

In different parts of the world, trees’ leafing cycles are changing, migratory birds’ breeding and nesting patterns are shifting and extinction rates of some species may be climbing.

Clearly, scientists and environmentalists gathered here at negotiations for a world accord on climate change say, different wildlife populations around the world are already feeling the effects of global warming.

The emission of greenhouse gases, coming mostly from the burning of fossil fuel from industry and power plants, causes more heat than usual to be retained in the atmosphere. In turn, this acts as a suffocating atmospheric blanket that pushes up global temperatures.

In a report, the Britain-based Birdlife International said continued increases in the Earth’s temperature could also lead to a rise in competitor species, predators, parasites and diseases that would disrupt wildlife and ecology. Eventually, this could pose threats to human welfare, not least in the area of agriculture.

Experts say wildlife populations, from Arctic species to birds to marine mammals, are showing signs of behaviour changes linked to global warming.

Barnaby Briggs, climate policy officer with Birdlife International, cited an analysis of 211 years of data collected in Britain that show oak trees have been leafing earlier and earlier.

Other data show that of 65 bird species in the United Kingdom, 63 percent are breeding earlier. In terms of distribution changes, nine of 14 species of European butterflies studied have moved northward, he said.

In a report on climate change, the World Wildlife Fund (WWF) says the warming of the seas could cause damage to wildlife such as marine mammals, including whales. Warmer temperatures may also kill off coral reefs already threatened by pollution and misuse.

Likewise, it says wildlife populations, forests and plants were likely to move toward new areas where the weather would be better suited to them.

Signs of this effect have been monitored in Japan. Scientist Masayuki Kurechi, who has been studying the nesting patterns of the bean geese in Akita in northern Japan, reports that the brown, yellow-beaked birds have drastically changed migration patterns in the past five years.

Because of warmer weather and the melting of ice in Akita, the flocks of geese that normally appear there in October and December and reappear in March, are now coming earlier — in early September and then staying on till April.

Kurechi says the bean geese population of about 10,000 have not dwindled yet, but explains that changes in their migration patterns would reduce numbers in the long run.

“The temporary benefit, which is the warm weather, might disrupt their natural habitat, resulting in adverse effects in the long run,” Briggs added.

Scientists predict that many species will move northward as the Earth grows warmer.

In the United Kingdom, birds are arriving earlier and breeding earlier, resulting in a decline in populations. Over a 25-year period between 1971 and 1995, 31 percent of 65 bird species there were nesting earlier.

In Canada, studies indicate that the extinction rate of populations of Edith’s checkerspot butterfly in the far northern end of its range are also about two-and-a-half times higher at low elevations compared to populations above 8,000 feet.

Also, no fewer than 40 percent of the frog and toad species that previously inhabitated a 30-km study area in the Costa Rican cloudforests have become extinct during the 1990s.

Some of the clearest signs of the impact of climate change can be seen in the more remote, colder parts of the world, such as the Arctic and Antartic.

The WWF report says the caribou, a species of raindeer, may be among the most sensitive of the Arctic species to global change. There is evidence that earlier springs in the Arctic are forcing caribou herds to migrate a month earlier, in order to find food to survive and breed in the short northern summer.

A decline in the frequency of years with extensive heavy winter sea ice in the Antarctic, first noticeable in the 1940s, has been accompanied by a fall in the breeding numbers of the Adelie penguin.

In winter, penguins dive to catch food in cracks in the sea ice. When sea ice is reduced, the survival of adult and immature penguins tends to be poor. In summer, changing patterns of snow deposition and melt are leading to the accumulation of deep snow on the Adelie nesting sites, thus reducing breeding success.

Finally, the giant panda in China, one of the most well-known symbols of wildlife conservation, is already under threat of extinction as a result of habitat destruction and illegal poaching.

But recent computer modeling studies carried out by scientists from China and the WWF show that global warming would make panda’s situation worse, by altering the tenuous food ecology of its habitat.