Whales In Hot Water: Global Warming's Effect On World's Largest Creatures

Science Daily — Whales, dolphins and porpoises (cetaceans) are facing increasing threats from climate change, according to a new report published by WWF and the Whale and Dolphin Conservation Society.

Beluga whales rely on polar, icy waters for their habitat and food resources. (Credit: WWF-Canon / Kevin Schafer)

The report "Whales in hot water?" examines the impacts on cetaceans including:

• Changes in sea temperature
• Declining salinity because of the melting of ice and increased rainfall
• Sea level rise
• Loss of icy polar habitats
• Decline of krill populations in key areas. Krill is a tiny shrimp-like marine animal that is dependent on sea ice and is the main source of food for many of the great whales.

“Whales, dolphins and porpoises have some capacity to adapt to their changing environment,” said Mark Simmonds, International Director of Science at 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.”

Climate change impacts are currently greatest in the Arctic and the Antarctic. According to the report, cetaceans that rely on polar, icy waters for their habitat and food resources – such as belugas, narwhal, and bowhead whales – are likely to be dramatically affected by the reduction of sea ice cover.

As sea ice cover decreases there will be more human activities such as commercial shipping, oil, gas and mining exploration and development, and military activities in previously untouched areas of the Arctic.

“This will result in much greater risks from oil and chemical spills, worse acoustic disturbance and more collisions between whales and ships,” said the lead author of the report, Wendy Elliott, from WWF’s Global Species Program.

Other projected impacts of climate change listed in the report include: reduction of available habitat for several cetacean species unable to move into colder waters (e.g. river dolphins), the acidification of the oceans as they absorb growing quantities of CO₂, an increased susceptibility of cetaceans to diseases, and reduced reproductive success, body condition and survival rates.

Climate change could also be the nail in the coffin for the last 300 or so endangered North Atlantic right whales, as the survival of their calves has been directly related to the effects of climate variability on prey abundance.

WCDS and WWF are urging governments to cut CO₂ global emissions by at least 50 percent by the middle of this century. The latest report of the Intergovernmental Panel on Climate Change showed it was possible to stop global warming if the world’s emissions start to decline before 2015.

The two conservation organizations further call on the International Whaling Commission to facilitate research on future impacts of climate change on cetaceans, including supporting a special climate change workshop in the coming year, elaborate conservation and management plans in light of the climate change threat, and increase efforts and resources to fight other threats to cetaceans.

Note: This story has been adapted from a news release issued by World Wildlife Fund.