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Monday, June 18, 2007

Warnings From A Warming World: Spring Arriving in the Arctic Weeks Early

A team of Danish researchers have documented spring's rapid advance in the Arctic: regional ecoystems, species strained to adapt, at risk of extinction

[From BBC News:]

Ice in north-east Greenland is melting an average of 14.6 days earlier than in the mid-1990s, bringing forward the date plants flower and birds lay eggs.

The team warned that the observed changes could disrupt the region's ecosystems and food chain, affecting the long-term survival of some species.

The findings have been published in the journal Current Biology.

The scientists assessed how a range of species' behaviour was affected by the changing climate in Zackenberg, north-east Greenland, between 1996 and 2005.

Observation of 21 species - six plants, 12 arthropods and three birds - revealed that the organisms had brought forward their flowering, emergence or egg-laying in line with the earlier ice melt.

"We were particularly surprised to see the trends were so strong when considering that the entire summer is very short in the High Arctic - just three or four months from snowmelt to freeze-up," said co-author Toke Hoye, from the University of Aarhus.

"The real deciding factor is that each individual time series has a very close correlation, so it is not just that the average trend is very similar but each species is closely coupled (to the ice melt)."

Winner and losers

Dr Hoye suggested that the warming in the region, which was occurring at twice the rate of the global average, could affect the future stability of the region's ecosystem.

"There could be positive consequences in the short term, and potentially negative consequences in the long term.

"At first, this could be regarded as a positive result because it is extending the summer season, which is probably a factor in terms of organisms getting through their development.

"Over the long term, it is most likely to be the case that species from southern latitudes will be able to establish themselves (in the region) and increase competition for food."

Dr Hoye acknowledged that the 10-year period could be considered by some people as not long enough to reach these conclusions.

But he added the changes in behaviour had been observed in a large number of species, and that the findings were considered by independent reviewers who were satisfied by the consistency of the results.

"They had hoped for a longer time period, and we did too," he told BBC News.

"But until we have managed to gather another 10 years of data, it is relevant to make this point now."

He added that the findings, described as the first of their kind for the High Arctic, extended the global picture of changing behaviour among organisms.

In August, scientists from 17 nations examined 125,000 studies involving 561 species across Europe.

The researchers found a shift in the continent's seasons, with spring arriving an average of six to eight days earlier than it did 30 years ago.

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