Satellite Images Depict Transformation of Siberian Tundra

A pair of satellite images taken four decades apart shows the shifting ecological landscape of the Siberian Arctic, where warming temperatures have enabled a swath of thick shrubs to thrive in once-open tundra. The photos, posted by the NASA Earth Observatory, show the fundamental shift that occurred in a lake-covered region near Russia’s Yennisey River between 1966 and 2009. In the 1966 image — a declassified spy satellite photo — the region between lakes is visibly open tundra. By 2009, thick shrubs had colonized the entire area, a shift that scientists say has triggered a cascade of ecological changes, including the loss of plant diversity and a more difficult landscape for deer and caribou to forage. Whether the spread of the shrubs will accelerate or slow the melting of the region’s permafrost — an outcome that could have global impacts if large amounts of methane are released — depends on the balance of two competing effects: Shrubs provide shade in summer, keeping permafrost cooler, but they also trap snow and warmth in winter, raising the temperature of permafrost.