 Radio Script 2001
Alaska Getting Shrubbier STORY: The photographs nearly ended up in the landfill—some 3,000 images of Alaska's North Slope, taken by scientists in the 1940s who were looking for signs of oil beneath the tundra. Kenneth Tape is a research technician at the University of Alaska Fairbanks. TAPE: "These photographs were taken out of the side door of an airplane flying low to the ground, so you can imagine what they look like. They're not typical aerial photographs from above. Rather you're looking at the landscape from about 400 yards off the ground." By chance, Mathew Sturm, a scientist with the U.S. Army's Cold Regions Research and Engineering Laboratory in Fairbanks, Alaska, heard about the photographs while doing a study on shrub growth in the Arctic. STURM: "Somewhere along the way someone mentioned these mythical photos. We heard about them but couldn't seem to find them. Eventually, I located a guy in Anchorage, at the United States Geological Survey. He was going to get rid of them. I wasn't sure if they were what we were looking for. I said send me two or three, and when they came,they were a bonanza. They were magnificent." Soon, Sturm's contact at the United States Geological Survey was sending him boxes full of high-resolution photographs of the Arctic tundra's grasses, tussocks and shrubs. Each photograph is 18 inches across by nine inches high. STURM: "They photographed virtually every creek and drainage you can imagine from the Canning River west to practically the west coast, generally within 100 miles of the Arctic coast. They photographed a vast stretch of territory, several hundred miles wide and more than a couple of hundred miles north to south."
Tape, Sturm and colleague Charles Racine poured over the photographs and selected 66 of the most visible images. After they figured out exactly where the photographs were taken, Kenneth Tape says they set out to take new photographs of the sites. TAPE: "It's a pretty painstaking process, because you're up there in a helicopter with a GPS. You give the GPS coordinates to the pilot, but the helicopter is drifting around and you're trying to get just the right angle." But it was apparently worth the effort because what they found is some of the best evidence of climate change yet discovered in Alaska. Mathew Sturm says the photos reveal a dramatic increase in the extent of dwarf birch, alder, and willow shrubs on the Arctic tundra. Their findings appear in this week's issue of the international science journal, Nature. STURM: "What we're seeing is that individual shrubs are getting bigger, patches of shrubs that existed 50 years ago are now denser, thicker, and with more shrubs. And areas where there weren't shrubs 50 years ago now have new shrubs that have colonized and taken over. The exciting part is that we're seeing this over a wide area, several hundred miles in extent. It's rare we have a chance to get a measurement that has that kind of geographic distribution to it." Sturm says evidence of moderate to significant shrub growth showed up in more than half of the sites they visited. At the remaining sites, they noted no decrease in shrub abundance or density. He says the cause is most likely a warming of the Arctic's climate. STURM: "This is completely consistent with the models we have since we know that Arctic Alaska has been warming. This is the response we would have expected." Sturm says it's easy to see the changes when a photo from the 1940s is placed next to a photo of the same location today. STURM: "It's easily grasped by anybody. These are before and after photos from areas that are not impacted by man. It's a pristine area, and you can see large and dramatic changes. I think most people looking at that say it really is changing. That's the beauty of it. It's a clean example that goes into the pile of evidence that things are changing apparently in response to climate warming." Not surprisingly, the researchers are pleased their work has garnered international attention. But Sturm says they can't take all the credit. STURM: "In some ways the real winners were the guys who took those photos 50 years ago. Without those, we wouldn't have gotten anywhere." Sturm says the last time Alaska experienced a rapid growth in shrubs was about 8,000 years ago. He says the next step in their research is to determine the exact role played by climate warming in the changing Arctic landscape. OUTRO: This is Arctic Science Journeys Radio, a production of the Alaska Sea Grant Program and the University of Alaska Fairbanks. I'm Doug Schneider. Audio version and related Web sites Thanks to the following individuals for help preparing this script:
Mathew Sturm, Geophysicist
Kenneth Tape, Research Technician Arctic Science Journeys is a radio service highlighting science, culture, and the environment of the circumpolar north. Produced by the Alaska Sea Grant College Program and the University of Alaska Fairbanks.
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Listen to story on RealAudio Photos: Related Web sites Nature science journal U.S. Army Cold Regions Research and Engineering Laboratory,Fort Wainwright, Alaska Shrub census shows Alaskan Arctic losing its cool (CNN) Alaska Shows Signs of Warming (ABC) How Does Climate Change Influence Alaska's Vegetation? Insights from the Fossil Record (USGS) |
