Net regional methane sink in high artic soils of northeast Greenland

TY - JOUR

T1 - Net regional methane sink in high artic soils of northeast Greenland

AU - Jørgensen, Christian Juncher

AU - Johansen, K. M. L.

AU - Westergaard-Nielsen, Andreas

AU - Elberling, Bo

N1 - CENPERM[2015]

PY - 2015/1/11

Y1 - 2015/1/11

N2 - Arctic tundra soils serve as potentially important but poorly understood sinks of atmospheric methane (CH4), a powerful greenhouse gas. Numerical simulations project a net increase in methane consumption in soils in high northern latitudes as a consequence of warming in the past few decades. Advances have been made in quantifying hotspots of methane emissions in Arctic wetlands, but the drivers, magnitude, timing and location of methane consumption rates in High Arctic ecosystems are unclear. Here, we present measurements of rates of methane consumption in different vegetation types within the Zackenberg Valley in northeast Greenland over a full growing season. Field measurements show methane uptake in all non-water-saturated landforms studied, with seasonal averages of-8.3 ± 3.7 μmol CH4 m-2 h-1 in dry tundra and-3.1 ± 1.6 μmol CH4 m-2 h-1 in moist tundra. The fluxes were sensitive to temperature, with methane uptake increasing with increasing temperatures. We extrapolate our measurements and published measurements from wetlands with the help of remote-sensing land-cover classification using nine Landsat scenes. We conclude that the ice-free area of northeast Greenland acts as a net sink of atmospheric methane, and suggest that this sink will probably be enhanced under future warmer climatic conditions.

AB - Arctic tundra soils serve as potentially important but poorly understood sinks of atmospheric methane (CH4), a powerful greenhouse gas. Numerical simulations project a net increase in methane consumption in soils in high northern latitudes as a consequence of warming in the past few decades. Advances have been made in quantifying hotspots of methane emissions in Arctic wetlands, but the drivers, magnitude, timing and location of methane consumption rates in High Arctic ecosystems are unclear. Here, we present measurements of rates of methane consumption in different vegetation types within the Zackenberg Valley in northeast Greenland over a full growing season. Field measurements show methane uptake in all non-water-saturated landforms studied, with seasonal averages of-8.3 ± 3.7 μmol CH4 m-2 h-1 in dry tundra and-3.1 ± 1.6 μmol CH4 m-2 h-1 in moist tundra. The fluxes were sensitive to temperature, with methane uptake increasing with increasing temperatures. We extrapolate our measurements and published measurements from wetlands with the help of remote-sensing land-cover classification using nine Landsat scenes. We conclude that the ice-free area of northeast Greenland acts as a net sink of atmospheric methane, and suggest that this sink will probably be enhanced under future warmer climatic conditions.

U2 - 10.1038/NGEO2305

DO - 10.1038/NGEO2305

M3 - Letter

SN - 1752-0894

VL - 8

SP - 20

EP - 23

JO - Nature Geoscience

JF - Nature Geoscience

ER -