Parts of the treeless Arctic tundra have become greener as rising temperatures stimulate plant growth.

Low-resolution satellite imagery and some observations made on the ground have suggested that the Arctic tundra, an often-frozen landscape dotted with hardy small plants, has become greener since the 1980s. Now, Logan Berner at Northern Arizona University in Flagstaff and his colleagues have analysed high-resolution images from the Landsat Earth-observing satellites.

The team found that between 1985 and 2016, 37% of the Arctic tundra, including parts of western Eurasia and North America, grew substantially greener. And since the turn of the century, the highest latitudes have experienced the most intense greening.

Temperature records show that the Arctic air and soil grew warmer in summer, on average, over the study period. However, most areas did not become greener. And about 5% of the area studied became browner rather than greener.

Changes in Arctic vegetation affect how carbon cycles through the soil and atmosphere, how wildlife and people make use of the landscape, and how vulnerable the tundra is to wildfires.