By Environment Correspondent Alex Kirby (BBC News- Aug 99)

A Greenpeace expedition to the Arctic says it has found new evidence to show that climate change appears to be affecting the region's wildlife.

The expedition, which ended on 31 July, says young walruses seem to be especially hard hit. Researchers from ten countries sailed along the edge of the ice pack in the Chukchi Sea, between Alaska and Russia.

Travelling on the Greenpeace icebreaker Arctic Sunrise, they counted and assessed the age of groups of walrus.

Juveniles struggling

They also kept an eye out for polar bears and for black guillemots, birds which depend on the ice. The head of the research team, Dr Brendan Kelly, of the University of Alaska, said: "Preliminary results indicate that the walrus population isn't doing so well".

"Although we saw more calves than last year, the last several years have seen low juvenile survival rates, clearly indicating that this is a population in decline.

"We don't have enough data to say how rapid a decline it is.

"But the early signs of climate change such as the retreat of the sea ice and the changes in the food supply do not bode well for the walrus."

The team surveyed almost 5,000 animals in the three weeks the expedition lasted.

In that time, the researchers say, the ice in the Chukchi Sea melted very rapidly, in some places retreating nearly 300 miles.

A change of prey

In contrast, the sea ice had been heavy during the spring. The researchers say the Arctic is warming three to five times more quickly than the rest of the earth.

They saw one polar bear attack an adult male walrus on the ice - an event they say is very rare. This is because bears are usually about half the size and weight of a mature walrus, and seldom prey on them. Creatures that live in the Arctic have adapted to life there, and even if they can adapt over time to new conditions, a rapid change in the amount of ice could be critical.

When the ice retreats, its edge is over much deeper water, and walruses may find it very hard to dive to the bottom to feed.

They are an important part of the diet of indigenous people on the shores of the Bering and Chukchi Seas.

Bears are also being forced to range further to find food.

This is the second year that Greenpeace has voiced its concerns about Arctic walruses. It is not alone in believing that global warming is at least partly responsible.

There are fears that the melting of the ice could actually accelerate warming.

This is because open water warms the atmosphere more than the icepack does - so the less ice there is, the more the atmosphere warms.

Debate over causes

But some scientists believe what is happening in the Chukchi Sea may be the result of local conditions, not global changes.

In 1998, they say, the ice was at a record low north of Alaska.

But on the other side of the Pole, north of Russia, it was unusually heavy.

Last April, British and US scientists reported unexpectedly large losses of ice in the Antarctic.