Warming 'threatens third of habitats'

Pressure on species like tigers will increase even more

By environment correspondent Alex Kirby

The environment campaign group WWF says global warming could cause fundamental changes to a third of the world's plant and animal habitats.

By the year 2100, WWF says, the changing climate may have driven some species to extinction.

It says areas in high northern latitudes are likely to be worst affected, losing up to 70% of their habitat.

And coastal and island species will be at risk from a combination of warming oceans, sea-level rise, and changes in the areas where they can survive.

WWF says conditions today, in a world of six billion people and widespread industrial societies, are very different from 13,000 years ago, the last time the climate warmed as quickly as it is predicted to heat up this century.

"At that time the whole of human society probably numbered in the tens of millions, and all were hunter-gatherers. Farming and cities did not yet exist."

Effects widespread

In a report, Global Warming and Terrestrial Biodiversity Decline, WWF says northern Russia, Scandinavia and Canada are likely to be among the areas hardest hit.

Orang-utans will find their range reduced

It believes other parts of northern Europe, some of Asia, and some parts of Latin America could lose nearly half their available habitats.

One of the report's authors, Adam Markham, said: "As global warming accelerates, plants and animals will come under increasing pressure to migrate to find suitable habitat.

"Some will just not be able to move fast enough. In some places, plants would need to be able to move ten times faster than they did during the last ice age merely to survive.

"It is likely that global warming will mean extinction for some plants and animals."

WWF says species at greatest risk are those that are rare or that live in isolated or fragmented habitats. Examples include

• a rare Ethiopian baboon
• the Monarch butterfly at its Mexican wintering grounds
• Australia's mountain pygmy possum.

Cautious estimate

In the US, most of the northern spruce and fir forest of New England and New York state could be lost, it says.

The report's predictions are based on an estimate that atmospheric concentrations of carbon dioxide (CO2), the main global warming gas caused by human activities, will double from pre-industrial levels by 2100.

But WWF says some projections suggest a tripling of CO2 levels by the end of the century on present trends.

Caribou and other Arctic animals face stress

Already, it says, birds like the great tit in Scotland and the Mexican jay in Arizona are beginning to breed earlier in the year, and butterflies are moving their ranges northwards throughout Europe.

Many Arctic mammals are starting to feel the effects of reduced sea ice and the warming tundra.

Pests, by contrast, will often benefit. An entomologist with the US Forestry Service in Alaska, Ed Holsten, told WWF: "Insects being cold-blooded, they can complete their life cycle twice as fast when it gets warmer.

"In the last ten years we've had an almost exponential increase in temperature, and the bark beetle that normally has a two-year life cycle many years now goes through its life cycle in one year."

Decision time

Governments are due to take final decisions on rules for operating the 1997 Kyoto Protocol on climate change at the UN climate summit in the Netherlands in November.

Some researchers still doubt that human activities are inducing rapid climate change. They highlight the inconsistencies between the temperature records taken at the Earth's surface, which show rapid warming over the last century, and data produced by satellite and balloon studies.