Warming Oceans Put More Stress on Whales
GLAND, Switzerland, May 21, 2007 (ENS) – Climate change is making life more difficult for whales, dolphins and porpoises that must adapt to shrinking sea ice and decline in their prey species, according to a new study released by conservationists ahead of next week's annual meeting of the International Whaling Commission.
Climate change impacts are greatest in the Arctic and the Antarctic, and the report finds cetaceans such as belugas, narwhals, and bowhead whales that rely on icy polar waters for habitat and food are likely to suffer most from the reduction in sea ice.
"Whales, dolphins and porpoises have some capacity to adapt to their changing environment," said Mark Simmonds, international director of science at the Whale and Dolphin Conservation Society, WCDS. "But the climate is now changing at such a fast pace that it is unclear to what extent whales and dolphins will be able to adjust, and we believe many populations to be very vulnerable to predicted changes."
Accelerating climate change adds to disturbances from other human activities, such as chemical and noise pollution, collisions with ships, and entanglement in fishing nets, which kills some 1,000 cetaceans every day, the conservation groups report.
The Arctic could be seasonally free of sea ice as early as the year 2020, according to a report issued in April by the National Center for Atmospheric Research and the University of Colorado's National Snow and Ice Data Center.
As sea ice shrinks, there will be more human activities, such as commercial shipping, oil, gas and mining exploration and development as well as military activities, in previously untouched areas of the Arctic, the conservation groups warn.
"This will result in much greater risks from oil and chemical spills, worse acoustic disturbance and more collisions between whales and ships," said the report's lead author Wendy Elliott, from WWF’s Global Species Programme.
Other projected impacts of climate change listed in the report include the reduction of available habitat for several cetacean species, such as river dolphins, that are unable to move into colder waters.
Cetacean survival is also threatened by the acidification of the oceans as they absorb growing quantities of carbon dioxide, an increased susceptibility of whales, dolphins and porpoises to diseases, and reduced reproductive success, body condition and survival rates, the report finds.
In the Antarctic, sea ice is decreasing in several areas, resulting in massive declines in krill which spend the winter under the ice.
In January 2006, a 30 year study published by an international team of scientists showed that El Nino ocean warming events affect the availability of krill in the Southern Ocean. This in turn affects the number of calves produced by southern right whales in the South Atlantic, as ENS reported at the time.
Southern right whales, Eubalaena australis, migrate from the South Atlantic to the Southern Ocean to feed. Following an El Niño event, changes in sea temperatures affect the availability of krill, which is the main diet of these whales.
Keith Reid from British Antarctic Survey said in January 2006, "These results help us to understand processes in three connected oceans and are crucial to predicting the consequences of climate change on the whales."
The conservation groups warn that the cumulative impact of climate change on other human induced impacts on cetaceans, such as pollution, bycatch and overfishing, means that reducing all threats to cetaceans is now essential for their long-term survival.
The two conservation organizations are urging governments to cut global emissions of carbon dioxide by at least 50 percent by the middle of this century.
They point to the latest report of the Intergovernmental Panel on Climate Change which showed may be possible to limit global warming if the world’s greenhouse gas emissions start to decline before 2015.
The two organizations are calling on the International Whaling Commission, IWC, to facilitate research on future impacts of climate change on cetaceans, including by supporting a special climate change workshop in the coming year.
They are urging the International Whaling Commission to detail cetacean conservation and management plans in view of the climate change threat, and in addition to increase efforts and resources to fight all the other threats to cetaceans.
The Commission is already beginning to consider the impacts of the warming climate on whales, dolphins and porpoises.
At an IWC Symposium on the State of the Conservation of Whales in the 21st Century that took place April 12 and 13 April at UN Headquarters in New York, delegates discussed whether the IWC is sufficiently robust to cover the full range of threats that whales face, such as climate change.
While the 69 delegates from around the world, met specifically to explore policies for resolving the current impasse over commercial and scientific whaling at the International Whaling Commission, their discussion extended into options for dealing with the effects of climate change on cetacean survival.
"Other participants were less convinced and some argued that there are also moral and ethical considerations that should be taken into account," Palmer wrote in his summary of the Symposium's deliberations.
The Palmer report as well as the conservationists' report "Whales in hot water?" will be available to the delegates from 75 IWC member nations when they convene on May 28 in Anchorage, Alaska.