Global Warming

Alaska's Excelsior Glacier Is Being Replaced by a Lake 5 Times the Size of Central Park

Seventy years ago, Alaska's Excelsior Glacier stretched its cold fingers from a vast plain in the state's southern edge nearly all the way to the North Pacific Ocean. Now, the glacier is separated from the sea by a meltwater lake more than five times the size of New York City's Central Park.

In a recent blog post on the American Geophysical Union (AGU) website, glaciologist Mauri Pelto of Nichols College in Massachusetts shows how that relatively new lake — now called Big Johnstone Lake — has more than doubled in size over the last 24 years as rising global temperatures force Excelsior Glacier into a hasty retreat. The glacier has lost about 30% of its length in just 24 years.

Even if no more calving ice makes its way into Big Johnston Lake, the glacier will continue to retreat, but probably at a slower pace than the rapid melting observed over the last 25 years. A similar fate has already befallen many neighboring glaciers in Alaska and British Columbia, Pelto wrote, providing yet more examples of how climate change is rapidly redrawing the map of our world.