Last summer, NSHSS member Carsten Hansen, a senior at Lake Washington High School in Kirkland, Washington, researched climate change impacts in Denali National Park, Alaska. During his month-long project, he compared the change in permafrost (frozen subsoil) height from excessive melting to variations in the local ecosystem and found clear evidence of climate change.

Hansen was stationed in the Triple Lakes Wilderness, an area that offered him ample opportunity to observe impacts on spruce trees and beavers. Hansen found that the melting permafrost had caused several spruce trees to grow askew because their roots rested on soft, uneven soil. These trees lack the taproot that anchors most trees in place. Instead, they rely on a simple root system that can stand atop the frozen subsoil.

In order for it to be counted as evidence of a changing climate, the permafrost thawing had to be demonstrated in another dimension. Logically, the water from the melting subsoil would eventually seep into the nearby lakes. Hansen, therefore, studied a beaver family that had been subjected to the rising melt water. According to Denali park rangers, the beavers had been elevating their lodge for the past three years. To document their progress during his study, Hansen took photos of the lodge each day to compare at the end of the project. It was evident to him that the rangers were correct in their prediction--the beavers showed signs of being affected by a changing climate.

Hansen's study is a portent of some of the future climate impacts on lower latitude mountains. When sunlight hits the earth, its heat is first transported to the poles (a process known as global heat distribution). This leads to faster warming in places like Denali than it does in more populated parts of the world. If climate change continues, similar impacts as those currently seen in Alaska will become commonplace in lower latitude mountain ranges. These mountains do not necessarily have a high permafrost density, but many do support glaciers. As these glaciers melt at a faster-than-normal rate, animals in mountain and lowland lakes will experience consequences similar to those of the beavers in Alaska.

Hansen's study comes at an interesting time. The science linking greenhouse gas output with climate warming is more concrete than ever and the U.S. Congress recently forwarded a bill to President Bush that would begin to address American fossil fuel consumption. For more information about climate change visit: http://www.nrdc.org/globalwarming/.