A methane flux transect along the trans-Alaska pipeline haul road

This paper reports and analyzes methane flux measurements made during the summer of 1987 at 10 km intervals along a north-south direction from Prudhoe Bay to the Arctic Circle in Alaska. Mean CH4 flux from the arctic tundra was 52 mg/sq m/d while that from high-latitude taiga was 11 mg/sq m/d. Fluxes in mg/sq m/d for various plant communities were: wet tundra, 90; low brush-muskeg bog, 45; moist tundra, 31; freshwater ponds, 21; spruce forest, 4.6; and alpine tundra, 0.6. Annual CH4 emission from global tundra and taiga environments is estimated at 38 Tg and 15 Tg, respectively. This is about 46 percent of the wetland emission term of 10 percent of the global atmospheric input.