Global warming has been called, with good reason, the biggest environmental challenge the world has ever faced and the bad news about the impacts of climate change just keeps piling up. Summer arctic sea ice is disappearing faster than even the most pessimistic scientists ever predicted, villages in Alaska are tumbling into the sea, the beloved polar bear is at risk of extinction and Adelie penguin populations on the Antarctic Peninsula have been declining as temperatures there have risen an average of 6 degrees Celsius in the winter.
The losses are mounting, but is there good news for some? Anyone who has read Andrew Revkin’s series of stories about the land rush in the Arctic knows that some oil and shipping interests will benefit from an opening of the fabled Northwest passage across the Arctic Ocean. (However, these short-term gains will inevitably lead to long-term losses by the rest of the human and natural world as NCAR’s Michael Glantz so eloquently writes about in his blog Fragile Ecologies).
But did you know that residents of Greenland can now enjoy locally grown potatoes and brocolli? And that in the Ross Sea region of Antarctica, Adelie penguin populations are actually increasing, unlike the penguins of the Antarctic peninsula? That was the subject of a recent talk at the Exploratorium by David Ainley, a biologist who has been studying the intrepid Adelie penguin for nearly thirty years and reports on his research in the Penguin Science website.
The story, David says, is more complex than the view that a warming earth melts ice and destroys the habitat for all animals that live on or near frozen sea or ground. In reality, global warming does more than melt ice and heat up the air, it also changes wind patterns which can affect the extent and movement of floating sea ice. For Adelies, which nest on bare rock near the coast, increasing winds push sea ice farther offshore and give the penguins access to ocean feeding grounds without having to walk across kilometers of ice. That makes them better able to feed their chicks, increases reproductive success and has meant a steadily rising population of Adelie penguins in Eastern Antarctica. At the same time, this loss of sea ice threatens the Emperor Penguin, the heroes of “March of the Penguin” and “Happy Feet.” These large birds need a stable platform of sea ice to lay their eggs and hatch chicks. They do this in winter, rather than summer, and the caretakers do not return to sea while they are raising chicks, as the Adelie penguins do. Emperor penguins are vulnerable to shifting sea ice and have suffered population declines as much as 50% as increasing winds have destabilized their breeding habitat and swept chicks and eggs out to sea. The very bad news for Emperor Penguins is that climate models are forecasting even stronger winds in a warming Antarctica, making them climate losers.