AbstractAs global temperatures rise, vegetation types will change, particularly in the northern high latitudes. Under a warming scenario, shrub and grasslands over the Arctic are expected to shift to boreal forests. This study compares the impact of such a change in Arctic vegetation type with that of CO2 doubling on the seasonality of Arctic warming. Even though vegetation is changed throughout the year, the effect of the surface albedo change is maximum in boreal summer when the incoming solar radiation is largest. Evapotranspiration changes are also maximized in the summer, when the photosynthesis rate is highest. As a result, when Arctic vegetation change is considered in addition to doubled CO2, Arctic amplification is maximized earlier in the annual cycle.