At present it is not very likely that a warmer climate will lead to a sudden large release of methane in the North-eastern Siberian tundra, unless permafrost melt will accelerate. This resulted from research on greenhouse gas exchange in the by Frans-Jan Parmentier. He will defend his PhD thesis on 30 May 2011.

Uptake and emission

Gas flux measurements in 2007, 2008 and 2009 in the Northeastern Siberian tundra show that during the growing season more greenhouse gas is taken up than is emitted by the soil and vegetation. Furthermore, Parmentier concluded that warmer seasons lead to a higher uptake of CO₂ through photosynthesis, but that more CO₂ was emitted from respiration by soil bacteria as well. These opposed processes meant that the net uptake of CO₂ did not change much during summer. On the other hand, warmer circumstances do lead to a higher activity of methane producing bacteria. This leads to higher methane emissions which are not compensated for by an increase in the uptake of CO₂. However, in the near future it is unlikely that warmer climates at the studied site will increase methane emissions so much that the system will switch from a sink to a source of greenhouse gases unless permafrost melt accelerates.

Global warming

Methane is the second most important greenhouse gas and 25 times stronger than CO₂, the most important greenhouse gas. The exchange of these gases in the may change dramatically when global temperatures rise, since the arctic climate warms two to three times faster than the rest of the world.

Carbon storage

Because of the cold climate in this area, plant remains decay very slowly in the soil and this has led to the build-up of large amounts of carbon in the soil through time. This carbon can be released as a greenhouse gas when soil bacteria slowly convert the stored carbon into methane.

More information: Frans-Jan Parmentier, frans-jan.parmentier@falw.vu.nl.