25 February 2012 Glacier Retreat on Anvers Island

During the short time I’ve been at Palmer Station, I’ve heard several people mention the fact that the Western Antarctic Peninsula is one of the most rapidly warming areas on the planet. According to a recent New York Times article, the mean winter air temperature of the Western Antarctic Peninsula has risen 10.8 degrees Fahrenheit in the past half-century. Significant increases in water temperatures have also been observed. Because of these temperature increases, approximately 90% of the Antarctic Peninsula’s glaciers have retreated in the past 50 years, including the Marr GlacierA mass of ice that persists for many years and notably deforms and flows under the influence of gravity. here on Anvers Island. Scientists at Palmer Station map the edge of the Marr GlacierA mass of ice that persists for many years and notably deforms and flows under the influence of gravity. each year and have a precise record of how much it has retreated since 1963.

People who have spent multiple seasons here at Palmer Station, including the Amslers, often point out islands on which much more rock is exposed than in previous years because of glacial retreat. Increased air and water temperatures cause an increase in the frequency of glacial calving which I’ve described in other journals as sounding like a cannon being fired. Dr. McClintock told me that when he hears a glacier calving he thinks, “That is the sound of climate change.” I find that statement very powerful.

As glaciers melt, several changes occur to surrounding ecosystems. For example, the salinity of coastal water decreases which, in turn, affects the Antarctic phytoplankton community. Changes in the phytoplankton community are unfavorable for Antarctic krill, a shrimplike crustacean and keystone species of the Antarctic food web, which eat phytoplankton.

Krill are the major food source for penguins, whose populations in the area have also been impacted. In the past three decades, the Adélie penguin population on the peninsula has decreased, whereas the population of gentoo penguins has increased. This is attributed in part to the fact that Adelies rely on areas containing sea ice to breed, whereas gentoos can breed in ice-free areas.

The scientists and support staff who come to Palmer Station year after year love this part of the world and it’s easy for me to see why. The rate at which the peninsula is changing is alarming, but I take comfort in knowing there are scientists here who are working hard to document and understand the effects of rising temperatures on this region. Their work is so important.