Global warming affects all species

2002-03-28 11:47

Ed Cropley

London - From dying coral reefs to later autumns and endangered male painted turtles, global warming has started to affect plant and animal life across the planet, scientists said on Wednesday.

The world's mean temperature increased by around 0.6 degrees Celsius in the 20th century - most of the rise came in the last 30 years - and its impact is already being felt by flora and fauna from the equator to the poles.

Some species are doomed as they battle ever-rising temperatures in an increasingly crowded planet that offers fewer escape routes, according to scientists writing in the journal Nature.

"Temperature has increased by no more than 0.6 degrees and already the signs are very obvious," said geobotanist Gian-Reto Walther from the University of Hanover in Germany, who collated the research from across the branches of the natural sciences.

The study's conclusions highlight the seriousness of global climate change by showing parallel trends in plants, birds, animals and fish.

"This is a major concern," Walther said, adding extinction for some species was inevitable.

"The big difference between now and previous periods of climate change, like the Ice Age, is that seven billion people live on Earth now and many migration corridors for species are blocked," Walther said.

One of the most dramatic barometers of climate change has been the world's coral reefs, which have been devastated by 'coral bleaching' - a direct result of warmer ocean water.

In the worst case of mass bleaching, in 1998, an estimated 16 percent of the world's reef-building coral died, Nature said.

Meanwhile in Europe, trees are starting to show their autumn colour between 0.3 and 1.6 days later per decade, while some migrating birds are changing their travel plans.

Walther welcomed governments' gradual waking-up to the problems of climate change, widely recognised as the result of so-called greenhouse gases such as carbon dioxide, but said nobody had a clue where it would all end.

"It is good they are now talking about measures to try and keep at a certain level of emissions. Maybe this can slow the warming process, but so far there is no measurement of how it is slowing," Walther said.

Britain's Meteorological Office predicts global temperatures will rise between 1.4 degrees Celsius and nearly six degrees over the next century, depending on the success of greenhouse gas policies.

Even at the lower end of these estimates, the outlook is bleak for the male painted turtle.

"In painted turtles, offspring sex ratio is highly correlated with mean July temperature, and the production of male offspring would be potentially compromised even by modest (two to four degrees) temperature increases," Nature said.

- Reuters