World View of Global Warming

Pushing the Boundaries of Life: Alaska

At the United States’ northern extremity, Barrow, Alaska, scientists are monitoring the exchange of tundra gases daily, in real time. Tundra radiation and gas flux are very intense when the ground is free of snow and plants are growing rapidly. The heat waves rippling in this photo are symbolic of the invisible flow of carbon dioxide and methane being measured by the equipment in the background. But there were visible changes too: Snow melted from the tundra a month earlier in 2002 than in previous years.

Dr. Walt Oechel and his associates from the Global Change Research Group at San Diego State University measure tundra radiation, temperature and the flux of carbon dioxide. They are the only ones in the world posting real time changes. During the past 30-35 years, Oechel has seen the moist tundra change from an important sink of greenhouse gases -- taking up and storing carbon dioxide in plant material -- to a time in the early 1980’s when the tundra was a source equal to 8% of human emissions. Now his readings show the area around Barrow is a source of emissions at night and a slightly larger sink during the day when plants are active. He suspects the tundra is changing or adapting in some way.

Dr. Yoshinobu Harazono, from an agro-environmental insititute in Tsukuba Japan, maintains a tower from which real-time levels of methane are sampled. Methane output, which is from decompostion and from the roots of active plants, is also increasing, probably due to the lengthening snow-free growing period in the arctic.

Plots in the Barrow area have been studied for more than 30 years, in part to discover if vegetation is changing due to climate warming. This location was documented in 1973 as a wet tundra, but has visibly changed to more dry-site vegetation.

Many of these sites are investigated by Dr. Craig Tweedie, a Research Fellow from The University of Queensland, Australia, working with teams from the Arctic Ecology Lab at Michigan State University. Dr. Tweedie provided the photograph on the left.

Early onset of spring is more than just a weather statistic.  It impacts natives who must travel over the ice, limits the depth of seasonal permafrost re-freezing, extends the amount of time for greenhouse gas interactions by tundra plants, and is slowly changing the timing of when forage plants are available to caribou and other grazing animals.  In 2003 the early thaw forced great changes in the route of the Iditarod dogsled race.          As winter gets shorter in the Alaskan Arctic, even the oil industry has been forced to make note of it.  Most oil exploration and some drilling is completed in the winter when the hard frozen tundra resists most damage from the heavy equipment, and when ice roads can be made. One official response is a new study by the State of Alaska and federal Dept. of Energy:  "...  During the past three decades...the number of days between the opening and closing of the tundra for exploration activity has declined from over two hundred days in 1970, to only one hundred-three days in 2002.... This trend appears consistent with findings of general warming in the Alaska arctic associated with global climate change."  (from DOE grant 38391, March 2003)

In a feat of persistent observations matching the work of Dr. Bill Fraser in Antarctica, Dr. George Divoky has documented the climate-mediated rise and decline of a colony of black guillemots on a barrier island in the Arctic Ocean. The birds normally nest in cliff cavities, but in the 1970’s a few were attracted to left over crates and barrels at a former Navy station on Cooper Island. Successful nesting was made possible by the slow retreat of Arctic sea ice from around the island, according to Divoky’s observations, and more than 225 pairs nested on Cooper in the late 1990’s. But the ice has continued to move away from the island and with it the prime prey of the guillemots, Arctic cod. The seabird colony has declined to fewer than 150 nests.

During the summer of 2002, Divoky and his small crew of assistants had to leave Cooper Island a little early when polar bears kept foraging across the low and barren island. The large number of bears on land in the Barrow area this year is symbolic of the problem created for bears by the retreat and breakup of Arctic Ocean near shore ice.