14 September 2005

Arctic Alaskan Shrubs Reveal Changing Climate

Researchers have found that warmer arctic temperatures are causing vegetation changes on Alaska's North Slope. According to the study, as shrubs increase in size and abundance, they impact the local heat balance. Because shrubs are dark, they absorb solar energy, rather than reflect it, like snow does. An increase in shrub size and abundance causes higher snowmelt rates, which in turn leads to slightly higher regional temperatures. The study also reports that the widespread transition from tundra to shrubland may release soil carbon into the atmosphere, which could have global ramifications. Although the researchers cite the need for continued monitoring, they suggest that increased shrub abundance is not only a result of warmer temperatures, but may in fact contribute to further arctic warming.

The study, "Changing snow and shrub conditions affect albedo with global implications," was published in the first issue of Journal of Geophysical Research - Biogeosciences, Volume 110.

NSIDC houses two of the data sets used in this study:

• Snow and Vegetation Measurements from Selected Sites Near Council, Alaska, USA, 2000-2002. Gathered from sites ranging from forest to tundra, these data characterize snow cover and snow-holding capacity of various vegetation types.
• A Half-Century of Change in Arctic Alaskan Shrubs: A Photographic-Based Assessment. Consisting of 193 pairs of photographs taken 50 years apart, the data set documents changing vegetation patterns that indicate warmer temperatures in northern Alaska.

The authors also acknowledged NSIDC scientist Drew Slater's help with fieldwork during this study.