Arctic tundra ecosystems have experienced unprecedented change associated with climate change over recent decades. Across the Circum-Arctic, vegetation productivity and surface greenness have trended positively over the period of satellite observation. However, since 2011 these trends have slowed considerably, showing signs of browning in many regions. It is unclear what factors are driving this change and which regions/land cover will be most sensitive to future browning. We provide evidence linking decadal patterns in arctic greening/browning with regional climate change and local permafrost-driven landscape heterogeneity. We analyzed the spatial variability of decadal-scale trends in surface greenness across the Alaskan Arctic Coastal Plain (~60,000km²) using Landsat imagery (1999-2014), in combination with new 30m classifications of polygonal tundra and regional watersheds.
We found landscape heterogeneity and regional climate change to be the most important factors controlling historical greening/browning trends. Spatiotemporal analysis and model forecasting over the next decade suggests increased tundra greening/browning on the northeastern Beaufort coastal plains, and western Chukchi coast, respectively, with the magnitude of change tied to future climate.