Climate change brings early spring in the Arctic

By Steve Connor, Science Editor
Published: 19 June 2007
The Independent

The Arctic spring is coming two weeks ahead of time compared to a decade ago, with birds, butterflies, flowers and small animals all appearing earlier in the year as a result of climate change.

A study of a range of animals and plants living in the high Arctic has revealed that many of them are responding to the earlier spring by flowering or laying their eggs significantly ahead of their normal times of the year.

On average, the breeding and flowering seasons in the Arctic have shifted by 14.5 days but some species of mosquitoes have begun laying their eggs 30 days earlier than in the mid 1990s, Toke Hoye, of the University of Copenhagen in Denmark, said.

"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 trend seen over a decade," Dr Hoye said. "This is the most extensive study of its kind in the Arctic in terms of the number and variety of species and the replication of the observations."

The findings, published in the journal Current Biology, show the shift in the spring season has been greater in the Arctic than elsewhere in the world. Previous studies have shown that plants in Europe are flowering 2.5 days earlier than a decade ago, whereas globally animal and plants are appearing 5.1 days earlier each decade.

The study investigated the time of year when insects, butterflies, spiders and birds began laying eggs or emerging from their winter hibernation. They also looked at the time of first flowering of Arctic plants.

Dr Hoye said the movements in the season of six species of plants, 12 species of arthropods and three bird species must be tied to the earlier times of the year when the snow melts in the Zackenberg region of north-east Greenland, where the study was carried out.

"It's an indication that for the plants, arthropods and birds there's a change in their shared physical environment that results in a change in their behaviour," he said. "That must be when the snow melts.

"We know that the snow is melting about two weeks earlier than it did a decade ago in this part of the Arctic. Given the wide selection of species we studied in each group, we can see no other explanation for the shift in their behaviour," he said.

"We were particularly surprised to see that the trends were so strong 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 study site."

Records of global temperatures show that the polar regions, and especially the Arctic, are experiencing some of the largest increase in average temperatures.

Dr Hoye warned that the change in timing of emergence, egg-laying and flowering could disturb local food webs with some animals appearing ahead or behind of others on which they rely for food.