Inventories of emissions and removals of greenhouse gases will be used under the United Nations Framework Convention on Climate Change and under the Kyoto protocol to demonstrate compliance with obligations. During the negotiation process of the Kyoto protocol it has been a concern that uptake of carbon in forest sinks can be difficult to verify. The reason for high uncertainties are high temporal and spatial variability, and lack of representative estimation parameters. Additional uncertainties will be a consequence of definitions made in the Kyoto protocol reporting. In the Nordic countries, the national forest inventories will be very useful to estimate changes in carbon stocks. The main uncertainty lies in the conversion from changes in tradable timber to changes in total carbon biomass. The uncertainties in the emissions of the non-CO2 greenhouse gases and emissions and removals of carbon from forest soils are particularly high. On the other hand, the removals reported under the Kyoto protocol will only be a fraction of the total uptake, and are not expected to constitute a high share of the total inventory. It is also expected that the Nordic countries will be able to implement a high tier methodology. As a consequence total uncertainties may not be extremely high.