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Here we analyzed a time series of 21‐yr satellite data for three bioclimate subzones in northern Alaska and confirmed a long‐term trend of increase in vegetation greenness for the Alaskan tundra that has been detected globally for the northern latitudes. There was a 16.9% (±5.6%) increase in peak vegetation greenness across the region that corresponded to simultaneous increases in temperatures. We also examined the changes for four specific vegetation types using an 11‐yr finer resolution (1‐km) satellite data and found that the temporal changes in peak and time‐integrated greenness were greatest in areas of moist nonacidic tundra. These changes in greenness between 1981 and 2001 correspond approximately to a 171 g/m² (±81 g/m²) increases in aboveground plant biomass for Alaskan tundra. This remotely sensed interpretation is conducted in the absence of long‐term biomass records in the region.