Rising temperatures, retreating ice and less snow cover as a result of climate change means the Arctic as we know it could soon be a thing of the past, the researchers said yesterday.

Loss of habitat is leading to declining populations of polar bears, Pacific walruses, ringed and hooded seals, narwhals and ivory gulls, which all depend on the ice for ­hunting, breeding or avoiding predators.

Many young polar bear cubs are dying when the lairs under the snow in which they are born collapse in unusually early spring rains, while pollution may be affecting their ability to cope with changes to their habitat.

The bears are also suffering from a drop in the number of ringed seals, which they hunt and eat and whose pups have also been dying as a result of their under-snow lairs being washed out, melting or collapsing.

In Svalbard, birth rates of polar bears have declined, while numbers have fallen in Hudson Bay by more than a fifth in the past two decades and the number making their dens on pack ice in the Alaskan Beaufort Sea has halved.

Numbers of ivory gulls have fallen by 80% in the past two decades, according to a survey of their breeding colonies in Arctic Canada, as a result of the loss of the pack ice habitat they need.

And Pacific walruses have suffered from the impact of rising temperatures on the sea bottom where they forage for food, forcing adults to abandon their pups or become separated from them as they travel further in search of suitable feeding grounds.

Some species are being affected by northward movement of other animals, including the Arctic fox whose numbers are declining as red foxes move into its territory, the research published in the journal Science said.

Eric Post, who has led the team researching the impact of Arctic warming on wildlife, said: “Species on land and at sea are suffering adverse consequences of human behaviour at latitudes thousands of miles away.

“It seems no matter where you look – on the ground, in the air, or in the water – we’re seeing signs of rapid change.”

The associate professor of biology at Penn State University in the US added: “The Arctic as we know it may soon be a thing of the past.”

There have been some winners in the changes taking place in the Arctic, including more shrubs and trees, and reindeer which feed on them and whose populations have increased in Svalbard.

But caribou are declining in Greenland, where they have failed to alter their calving season to match the shift in the time of year when there is most plant growth to feed on, while hotter summers could also increase the number of insects and parasites affecting them.

This could harm the traditional ways of life of the Inuit people in the Arctic circle who hunt the caribou, the researchers said.

Warming in the Arctic has occurred at two or three times the rate of global average temperature rises over the past 150 years, while the minimum sea ice cover in the region has declined by 45,000 kilometres a year in recent decades.

The researchers said the Arctic was thought of as a simple ecosystem, but it was complex, with different species reacting in different ways – and even separate populations of the same species behaving differently to shifts in temperature.

With relatively few species in the Arctic, changes can have major effects on the ecosystem as a whole, and the team called for a series of studies across the region to monitor climate change and its impact on wildlife.