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  • Counter :
  • 694
  • Date :
  • 6/19/2007

Global Warming Brings Spring


Plants and animals in upper Greenland have adapted their lifecycles to the arrival of the Arctic spring several weeks earlier than a decade ago .

In a study that underscored the impact of global warming on the northern polar region, researchers discovered that plant, insect and bird life native to the High Arctic had made dramatic seasonal cycle adjustments to the region's earlier snowmelt in the space of just 10 years.

In some cases, flowers are emerging from buds and chicks are hatching a full 30 days sooner than they did in the mid-1990s in response to sharply increased temperatures burning off the winter's snow layer.

Birds such as the Sanderling and the Ruddy Turnstone had moved their springtime rituals forward by an average of two weeks by 2005, compared to 1996.

"Our study confirms what many people already think, that the seasons are changing and it is not just one or two warm years but a strong trend seen over a decade," said Toke Hoye, a researcher with the National Environmental Research Institute at the University of Aarhus in Denmark.

The trend can be traced to the region's earlier spring snowmelt, which occurs about a fortnight earlier than it did a decade ago.

This should serve as an early warning system to the rest of the planet of the scale and pace of climate-related change, the researchers said.

And while not unexpected, the rate of change is surprising, even in light of the fact that Arctic temperatures are increasing at twice the global average.

Similar studies have noted much more modest changes with respect to plants in Europe (an advancement of 2.5 days per decade) and globally (5.1 days per decade).

"We were particularly surprised to see that the trends were so strong when considering that the entire summer is very short in the High Arctic -- with just three to four months from snowmelt to freeze up at our Zackenberg study site in northeast Greenland," said Hoye, a co-author of the study.

The Danish and US researchers also noted considerable variation in the response to climate change even within species, with much stronger shifts in plants and animals living in areas where the snow melts later in the year.

That variation could lead to particular problems by disrupting the complex web of species' interactions that are crucial to successful reproduction in the highly seasonal environment, Hoye said.

The wildlife that makes its home in the icy northern Arctic wasteland is unlikely to sustain this rate of change because of evolutionary constraints, but the region's shrinking sea ice is expected to keep pushing temperatures higher, the study said.

The study is published in the June 19th issue of Current Biology and is based on a 10-year analysis of six plant species, 12 insect species and three bird species in a 19 square kilometers (4,700 acres) area near Zackenberg.

A satellite view shows the Eastern coast of Greenland in 2002. A study says earlier ice melt could disrupt the area's ecosystems.


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