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As part of the Â鶹Éç Wales Green Season, we recently featured a short film by Tom Rugg - a science teacher from Wales who is doing his bit to raise awareness about climate change and its effects on polar bear populations.

Tom has kindly written an exclusive blog for us about his thoughts on this subject:

"In late November 2008 I stood on the shores of Hudson Bay at Cape Churchill - a gathering point for the polar bears waiting to move out onto the sea ice.

In living memory Hudson Bay has reliably begun to freeze over from the first week in November.

At the end of November 2008 the Bay was still open water. This year, forecasts predict that Hudson Bay will not freeze over until mid-December.

While climate change is a misleading and emotive term (since the history of out planet is a history of a constantly changing climate), the patterns recognised have for the most part fallen into cyclical trends.

What is new about the phenomena we are witnessing now is the speed of the change and that it is contradictory to natural trends.

We can argue over the causes of climate change, but what we must acknowledge is that adding mind-boggling volumes of CO2 to the atmosphere can only make the whole situation worse - even if the methane released from thawing tundra seems a natural rather than man-made process.

The wholesale drowning of polar bears is not seriously predicted by anyone (though sightings of polar bears in open water more than 30 miles from land and the discovery of washed up polar bear corpses have increased in the past couple of years in the Beaufort Sea area).

But the more rapid decline in multi-year ice than any scientists predicted is of course going to lead to cases of increasingly desperate bears hunting on poor quality ice.

With the pack ice in recent years breaking up almost a month earlier than recorded in living memory, the impact on polar bears is painfully predictable.

The scientists and researchers I interviewed in Hudson Bay in 2008 were eminent in their fields.

Their data from the Beaufort Sea and Hudson Bay area confirmed a decline both in the number and condition of the polar bears they were studying over a 25 year period with a worrying increase in the mortality of 2 year-old bears who were foraging on the ice for the first time independent of their mothers.

Polar bears are an arctic icon and have become symbolic of our relationship with the biodiversity of the planet.Ìý

Current predictions indicate that we will lose a circumpolar Arctic species of polar bear (ursus maritimus) and be left with a fragmented population restricted to the surviving ice floes South West of Greenland.

Evidence does suggest that polar bears have been "absorbed" by brown bear populations in previous interglacials.

The species are closely related and polar bears appear to have "re-emerged" when conditions have become more favourable.

But these evolutionary processes take time...

Will we be content to have lost such a majestic species over such a large part of its present range in the hope that one day, in the eons beyond our own lifespan, it may reappear again?"

Tom Rugg