Two scientists at the University of Virginia are repurposing an unlikely trove of historical data in their study of climate change: Cold War–era spy photographs.
U.S. and Soviet planes and satellites produced untold numbers of photographs of the rival superpowers. And while the U.S. was looking for Soviet military and nuclear activity, it ended up producing thousands of detailed photos of the Western Siberian tundra — photos that are now ideally suited for documenting the effects of climate change on the region.
University of Virginia Professor Howie Epstein and then–graduate student Gerald Frost decided to use the photos, taken between 1960 and 1984 and declassified after the end of the Cold War, to aid them in their study of the tundra and to identify specific effects of climate change on the remote region. (Old spy photos had also been used in the past to uncover previously unexamined archaeological sites in places like Iraq, Turkey, and Syria.)
“We are able to look at the exact same locations, in close detail, across several decades,” Epstein told UVA Today. Scientists know that much of the Arctic has been greening for decades, but the Siberian tundra had not been closely observed by satellites until relatively recently. So the spy photos provide crucial information that had previously been unavailable about what was occurring in Siberia in previous decades.
“We now know that a lot of greening has been going on there too, with tall shrubs and woody vegetation,” Epstein said. “The vegetation has been getting both taller and expanding in space and range.”
Looking closely at 11 distinct Siberian regions, Epstein and Frost were able to identify the expansion of certain flora — primarily tall shrubs like birch, willow, alder, and dwarf pine — over the course of half a century. Warming allows plants to move north, but when heat-absorbing shrubs replace heat-reflecting snow, they warm the regional climate even more. And though the scientists found greening was the trend over the course of the last several decades, they’ve also found that the tundra is browning for reasons not yet fully understand.
“The progression of growth may be reversing,” Epstein told UVA Today. “We’re not sure yet why, but it’s clear that vegetation dynamics are more complex across tundra than previously thought. We still have a lot of work to do to understand Arctic changes and how this affects and is affected by changes to the global climate.”