We measured COs^-1 which corresponds to a growing season estimate of 0.04 to 0.16 g CH₄ m^-2. We find that this moss tundra emits about 60 gCO₂-equivalents m^-2 yr^-1 of which CH₄ is responsible for 7%. Air temperature, soil moisture and greenness index contributed significantly to explain the variation in ecosystem respiration (R_eco) while active layer depth, soil moisture and greenness index best explained CH₄ emissions. Estimate of temperature sensitivity of R_eco and gross primary productivity showed that a modest increase in air temperature of 1 degree did not significantly change the NEE during the growing season but that the annual NEE would be even more positive adding another 8.5 gC m^-2 to the atmosphere. We tentatively suggest that the warming of the Arctic that has already taken place is partly responsible for the fact that the moist moss tundra now is a source of CO₂ to the atmosphere.