Wildlife Changes Seen with Global Warming 9/11/09
| Marilyn Sigman, Alaska SeaGrant/MAP
Tags: Walrus, Salmon, Gray Whale, Polar Bear, Ringed Seal, Climate change, Changing Arctic Sea Ice, Arctic Ocean, Arctic Ecosystems, Alaska Marine Ecosystems,
By Jessica Berman
Scientists carrying out studies of wildlife in the Arctic say global warming is causing dramatic changes in animal and plant life, threatening some species with extinction. The report is a compilation of studies of Arctic ecosystems by an international team of scientists who have been collaborating during the fourth International Polar Year, which ended in 2008. Eric Post, a professor of biology at Penn State University and leader of the study team, says previous research has focused on the non-living or abiotic effects of global warming on the Arctic, including the melting of sea ice and subsequent rises in seawater levels.
But Post says this is the first comprehensive report investigating the sweeping impacts of climate change on ecosystems and living creatures in the north polar region. "Fresh water systems, terrestrial systems, resident species, migratory species, birds, mammals, plants, pretty much everything. It seems like wherever you look in the Arctic right now, things are changing quite rapidly," he said.
The report, published in the September 11, 2009 Science journal, summarizes impacts on marine life related in the study to the 1 degree C. temperature rise over the 150-year weather record in the study as follows:
- Sea ice cover has shrunk by a staggering 45,000 kilometers a year over the past 20 to 30 years, causing a rapid decline in the gulls, walruses, seals, horned narwhal whales and polar bears which rely upon it.
- Polar bears and ringed seals both give birth in lairs or caves under the snow and can lose many newborn pups when the lairs collapse. Polar bear cubs are dying when the lairs under the snow in which they are born collapse in unusually early spring rain, while pollution may be affecting their ability to cope with changes to their habitat. In Svalbard, birthrates of polar bears have declined, while numbers have fallen in Hudson Bay by more than a fifth in the past two decades and the number making their dens on pack ice in the Alaskan Beaufort Sea has halved.
- Ivory gulls have seen their numbers fall by 80 per cent in two decades, according to a survey of their breeding colonies in Arctic Canada, as a result of the loss of the pack-ice habitat they need.
- Pacific walruses have suffered from the impact of rising temperatures on the sea bottom, where they forage for food, forcing adults to abandon their pups or become separated from them as they travel further in search of suitable feeding grounds.
- Some species, including sockeye salmon, pink-footed goose, and grey whale are benefiting from the warmer Arctic climate or adapting well to it.