Climate change disproportionately impacts the Arctic, where rising global temperatures wrought by the burning of fossil fuels have brought rapid, fundamental changes to places like Alaska. In a new study published in Global Change Biology, researchers conclude that 67,000 square miles of land in Alaska, 13 percent of the total land, have been affected over the past three decades.
The land has been impacted by what the study calls ‘directional change,’ in which a location has experienced fundamental change in its ecology from historic levels. For example, some areas have become greener and wetter and others have dried out as glaciers shrink and wildfires rage across the state. Even trees have shifted, with treelines moving farther north to adjust to a warming Arctic.
To study the drastic changes in Alaska, scientists at the U.S. Geological Survey used satellite and aerial imagery integrated with field data to create a mapping algorithm that assesses the level of change throughout the state. The study analyzed 540,000 square miles of land, noting the various kinds of changes in different Alaskan ecosystems. Near the tundra, the environment is becoming greener as trees and other plants spread beyond their traditional northern border. Meanwhile, interior forests are drying out, resulting in increased and more intense wildfires, which the researchers conclude is the greatest factor in Alaska’s ecological change. “What impressed me [was] how extensive and influential the fires were,” study co-author Bruce Wylie told Earther.
Climate change has also disrupted the state’s historic water patterns. Melting permafrost has led to depressions, allowing wetlands to form in unusual places. This has also exacerbated erosion along the coasts, which are being tested by an ever-shorter season of sea ice. The comprehensive study of these varied changes may be helpful as scientists and policymakers plan for Alaska’s future. “Now with this study we have spatially explicit interpretations of the changes on the land, with specific drivers identified and attributed to the changes,” NASA carbon cycle scientist Peter Griffith told Earther. However, there is still so much more to learn. The study’s results, limited by available technology and resources, do not tell the whole story.