Polar Bears pushed to the edge

A new report on the state of the Arctic tundra makes for depressing reading for the future of all biodiversity in the region, writes DICK AHLSTROMScience Editor

A TIME IS fast approaching when the only polar bears on the planet will be living in zoos. A rapid loss of sea ice due to global warming may soon leave this iconic animal unable to live in a changed world.

And the bear is just one of many species being threatened by warming in the Arctic. The vast frozen tundra is melting, giving way to encroaching shrubs and trees. Reindeer and caribou may not be able to cope with the changes. A new report on Arctic biodiversity will be presented today at a meeting in Copenhagen of ministers from Arctic Council countries, those nations whose borders touch the Arctic.

It illustrates the startling pace of change in the Arctic, says Tom Barry who heads a working group for the report, Arctic Biodiversity Trends 2010: selected indicators of change.

“This is a preliminary report. It gives an indication of what is happening in advance of a full assessment to be released in 2013,” explains the Cork man and University College Cork graduate who now lives in Akureyri in northern Iceland with his wife and family.

The document is published by the Conservation of Arctic Flora and Fauna (Caff) Working Group under the Arctic Council. Work on the report started in 2007 and it is fitting that it is ready for release now, during the international year on biodiversity. It makes for decidedly depressing reading however as it shows that things are not as they used to be in the polar north. It looks at different habitats, tundra, marine and fresh water environments and at the species that occupy these areas.

Hundreds of researchers are involved, pulling together information from a variety of sources and assembling it using a single methodology, he says. The goal is to produce baseline data that can be used to monitor change. “This is synthesising existing information and standardising it into a form where we can see what is happening with, for example, the tree line or a particular sea bird,” says Barry. “There is a big focus on using traditional indigenous knowledge as well.”

There has been a lot of research done in the Arctic but little integration or coordination for data handling. This new approach means that research done in Canada or Russia will be interpreted in the same way by all participants whether they be in Greenland, the US or Scandinavia. This preliminary report already shows the rapid pace of change, he says. Some 25,000 polar bears exist in 19 sub-populations, but only one group appears to be increasing in number.

Three of the sub-populations are stable, while eight more are in decline. And a lack of data means that the status of the remaining seven groups is unknown.

These animals are “fundamentally dependent” on the use of sea ice as a platform for seal hunting, travelling, mating and breeding, says the Caff report.

“Continued climate change will increase the vulnerability and risk to the welfare of all polar bears, and population and habitat modelling have projected substantial future declines in the distribution and abundance of polar bears,” the body says.

Massive ecosystem change is also taking place on land. The vast frozen tundra is rapidly disappearing, with a 20 per cent loss in tundra since 1980, the report states. As the land mass gradually warms, permafrost melts and shrubs and trees begin to spread northward. Repeat aerial photographic studies backed up by ground and satellite monitoring have shown increased shrub cover in northern Alaska and the Mackenzie Delta region of Canada, the report outlines.

Trees have also begun to advance north, as already documented in locations across Alaska and Canada where white spruce forests have taken over from tundra. The report cites one model that says tree lines will have moved 500km north by 2100, wiping out more than half the tundra habitat.

Caribou and reindeer will be amongst those species put under pressure by this change. Their numbers have declined by about a third since a peak in the 1990s and the report suggests that climate change was “a critical determinant behind recent declines”.

They are also struggling due to human activity and industrial development, including road and powerplant projects. Better road access also opens up wilderness areas to recreational activities.

Guillemots adapted to Arctic conditions may also suffer, the report says. It highlights a decline in most regional populations over the past 30 years and predicts a continued fall in the long-term as sea ice disappears and water temperatures increase.

dahlstrom@irishtimes.com

Twitter: @dickahlstrom