Forests play an important role in the global carbon cycle as carbon sinks of terrestrial ecosystem. Human activities such as deforestation and forest degradation have a considerable impact on the ability of forests to sequester and store carbon. Pressure to convert and degrade forests continues to be high in developing countries such as Kenya, resulting in substantial emissions of carbon dioxide (CO2). This research focuses on distinguishing emissions due to deforestation from the forest degradation in Kenya over the period 2003-2014, and to better understand the deforestation drivers. The main outcome of this study is that degradation is responsible for the 60% (-15.1 Mt) of the total change on biomass carbon with a rate of -2% of stock loss per year, while the main deforestation driver is pasture. The dominant role of degradation as source of carbon emissions sets important new light on land cover dynamics in Kenya and indicates the need for further research on the human activities leading to degradation to define specific and effective lines of interventions.