Carbon cycling and trace gas emissions from high latitude ecosystems has over the last decade received increasing attention due to the dramatic climate change experienced and predicted by GCM scenarios for the region, and the effect that such changes may have on the carbon stored in the arctic soils. Our knowledge about the exchanges of CO2 and other trace gas fluxes in the arctic region has been constrained by the limited availability of measurements during the long winter season. For that reason only a small number of sites have been able to produce annual budgets of C exchange and the driving processes behind winter time exchange of CO2 are not fully understood. Here we present two very different examples of CO2 exchange from shoulder seasons in the Arctic. In an example from NE Greenland, eddy covariance measurements show that the snow cover has a significant effect on the release of CO2 during spring. The other example, from a study during late autumn and winter from high arctic Svalbard we found that episodical emissions of CO2 accounted for a significant part of the total CO2 emission form the site. The emission pattern could be associated with temperature variations at the site and show high emission rates the freeze-in periods, whereas shorter periods with temperatures above freezing point resulted in lower emission rates. In We interpret this as emission of CO2 is being decoupled from the biological production during the freeze-in period and is primarily linked to pressure build up in the soil.