Polar bears defy extinction threat

According to new research, the numbers of the giant predator have grown by between 15 and 25 per cent over the last decade.

Some authorities on Arctic wildlife even claim that hunting, and not global warming, has been the real cause of the decrease in polar bear numbers in areas where the species is in decline.

A leading Canadian authority on polar bears, Mitch Taylor, said: "We’re seeing an increase in bears that’s really unprecedented, and in places where we’re seeing a decrease in the population it’s from hunting, not from climate change."

Mr Taylor estimates that during the past decade, the Canadian polar bear population has increased by 25 per cent - from 12,000 to 15,000 bears.

He even suggests that global warming could actually be good for the bears, and warns that the ever-increasing proximity of the animals to local communities could mean that a cull will be required sooner rather that later if bear numbers are to be kept under control.

In the northern territories, where temperatures have risen an average of four degrees since 1950, wildlife experts such as Mr Taylor say the bears have never been healthier or more plentiful.

The findings fly directly in the face of recent warnings from the scientific community on the demise of the species, with the Canadian World Wildlife Fund currently speculating that the last polar bear could vanish from the earth within 100 years.

The WWF website states: "By 2100, there may be no ice left in the Arctic in the summer. That means no polar bears. Global warming - caused by fossil fuels - is to blame."

The contradicting claims on the consequences of global warming are not confined to the Arctic, however.

The situation is mirrored on the opposite side of the world, where the extent of global warming and shifting ice in Antarctica is currently the subject of debate.

Scientists looking southward from the tip of South America, over steel-grey waters towards icy Antarctica, see only questions on the horizon about the fate of the planet.

Research carried out during a recent two-month exploratory mission to the South Pole has suggested that the West Antarctic ice shelf may be much thicker that at first thought - many hundreds of feet thicker in some parts - with the potential to raise water levels by around 15 feet worldwide if the shelf should gradually melt.

The hunt for data on ice movements around the South Pole has taken on fresh urgency after Antarctica’s "Larsen B," an ice shelf bigger than Luxembourg, collapsed into the Southern Ocean over the space of just 35 days in 2002.

And now that one mammoth Antarctic ice shelf has actually collapsed into the ocean, is it possible that another, even bigger one, might also crumble and slip into an ever-warming sea?

"People don’t have the answer to the question yet - what the probability is of that collapse, if any," said a scientist Gino Casassa, an authority in global warming based in Chile.

With the potential to raise ocean levels by around five metres worldwide should the ice melt, it is little wonder that glaciologists such as Mr Casassa view developments around the West Antarctic ice sheet with concern.

Should the ice eventually turn to water it would signal a slow-motion catastrophe for global coastlines - not instantly deadly like the tsunami in Asia - but more universal and more permanent. Although stressing that all the data secured from the recent two-month trip to the South Pole was still awaiting full analysis, Mr Casassa stressed that "the deeper the West Antarctic Ice Sheet, the greater the potential impact to sea level".

But scientists concede that much remains unknown about the links between ice, ocean and skies.

It still isn’t known, for example, how excess amounts of cold, fresh water from glaciers could affect the ocean current that circles Antarctica from west to east - a main driver of all the world’s ocean currents and therefore of global climate.