Glob. Change Biol. http://doi.org/fz3xc2 (2012)

Reliable estimates of the level of global warming in response to a given level of anthropogenic forcing are, in part, dependant on quantifying climate feedbacks. One such potential feedback is the release of carbon dioxide and methane from northern ecosystems, which has the potential to strongly accentuate climate warming. Despite the importance of this mechanism, there remain large uncertainties in the carbon-source strength of tundra ecosystems in relation to environmental variables.

To improve quantitative understanding of these processes over a full growing season, Torbern Tagesson, from the Department of Physical Geography and Ecosystem Analysis, Lund University, Sweden, and co-workers measured the exchange of methane and carbon dioxide in a high-Arctic wet tundra ecosystem in northeastern Greenland.

They found that the wetland acted as a carbon source during the warmer and wetter part of the measurement period in 2008 and as a carbon sink for the colder and drier period during 2009. In addition to improving quantification of carbon exchange, these measurements support the idea that wet tundra ecosystems may be expected to play a more significant role in the climate in the future, as temperature and precipitation are predicted to increase in the high Arctic.