FOX -- Research on permafrost today is distributed across the entire Arctic, from the forest floor in Interior Alaska to the seabed off the Siberian coast. Scientists probe the frozen ground with electric waves, measuring rods and other tools, monitoring changes in thickness and the rate of carbon release.
But the best way to learn about permafrost's basic qualities -- the way it looks, feels, and smells -- is a visit to the Permafrost Tunnel Research Facility near Fairbanks.
On a summer day, the first sensation upon entering the tunnel is the steep drop in temperature. A vent circulates air a few degrees below freezing in an attempt to keep conditions in the tunnel as constant as possible.
Then comes an intense stench, reminiscent of something rotting. That's the smell of decomposing plant matter deposited in the silt and gravel of the tunnel walls thousands of years ago. Evidently, the frigid air blasting out of the special air-conditioning system cannot prevent the work of microbes breaking down all that organic matter.
Slowly, the lights lining the tunnel's ceiling brighten, revealing the decaying roots of ancient plants dangling from above. The first 50 feet of the tunnel feature fossilized remains of mammoths and saber-toothed tigers, who roamed the area in the middle of the last ice age, preserved in the permafrost. In the further reaches of the tunnel where no mammal bones are found, the tunnel walls are dominated by dramatic ice formations.
"(The facility) seems exotic to people," said Matthew Sturm, who recently ended his 27-year tenure with the Army Corps of Engineers that runs the site. "Permafrost is just a word until people go into the tunnel."
The story of the permafrost tunnel goes back to a time in U.S. history when science knew very little about the characteristics and behavior of the frozen ground that underlies up to a quarter of the northern hemisphere.
After World War II, the U.S. Army became concerned about its budget, as the Pentagon shifted funding to the Navy and Air Force, branches that seemed more relevant to the future of warfare.
In an effort to hold onto research money amid the post-war cuts, the Army made case that the United States must be ready to face the Soviet Union in the Arctic, and that the Army Corp of Engineers was prepared to lead the way on cold regions research.
Funds were allocated, and in the winter of 1963, Army engineers began excavating a shaft into the side of a squat hill in former gold-mining country, 16 miles north of Fairbanks. Over the next three years, they dug a 120-yard long tunnel that can fit two pickup trucks side by side at its widest.
The excavation revealed a cross-section of soil that's been frozen for thousands of years, and launched a laboratory for the study of permafrost. A severe lack of knowledge about modern construction in frozen environments had plagued engineers since as early as 1943, when permafrost underneath sections of the new Alaska highway thawed, causing the road to collapse.
During the Cold War, the Army was concerned with building underground and moving troops through Alaska in the event of a Soviet invasion across the Bering Strait, said Kevin Bjella, the facility's chief scientist.
"We didn't know exactly where the Russians were based," he said. "The north wasn't mapped yet. We were afraid. Russia was supposedly at our doorstep."
Alaska never became a theater of war, but investment in the tunnel certainly generated a hefty return.
Bjella credits his facility with contributing to at least 110 scientific studies in at least half a dozen fields, from mining to paleontology to microbiology. In one of the more exotic examples, NASA used the tunnel's frozen terrain to help design sensors for landing a probe on Mars ahead of a 1999 launch. (Unfortunately, the Mars Polar Lander's engine malfunctioned and the mission ended in failure.)
Sturm, Bjella's predecessor, said that the tunnel is not the only place in Alaska where people have dug into permafrost. He pointed to various mine shafts excavated over the years. But those tunnels are not as useful to science. "The rarity is being able to sample (from the permafrost) in a controlled environment." he said.
A few years ago, work on a new tunnel adjacent to the old one began. The new excavation is taller and wider, but less of a jackpot for bone remains. Aside from a few chips from a bison horn and a mummified shrew not much was discovered.
"They got very lucky with the old tunnel," Sturm said.
Read more: Scientists in Alaska race to understand thawing permafrost
Alaska Dispatch Publishing