Arctic Tundra Undergoing Major Changes As it Warms, Studies Show

Several recent studies show that the rapid warming of Arctic tundra is leading to a host of sweeping changes, including more extensive fires, the growth of larger vegetation, more absorption of solar energy, melting permafrost, and substantially larger releases of carbon dioxide, methane, and other greenhouse gases. Taken together, the studies demonstrate that rising temperatures set in motion a vicious circle of more warming and higher releases of greenhouse gases. In Alaska, scientists studying a 2007 fire that burned nearly 400 square miles of the Brooks Range found that the burned tundra lost 40 to 120 grams of carbon per square meter, while pristine tundra absorbed 30 to 70 grams. Burned tundra also absorbed 71 percent more solar radiation than normal and caused permafrost to melt to a depth of several inches. A study in the Canadian Arctic has shown that tundra vegetation is becoming weedier, larger, and darker, significantly increasing the amount of absorbed sunlight and further boosting temperatures. The study also showed the warming tundra giving off unexpectedly high levels of methane and nitrous oxide. And in Scandinavia researchers found that by warming Arctic peatlands by nearly 2 degrees F over eight years, the tundra released an extra 60 percent CO2 in spring and 52 percent in summer, according to a study in the journal, Nature.