Siberia is melting. Vast tracts of Russian tundra, frozen for tens of thousands of years are starting to thaw. Many experts say the process is taking place so fast, they can only attribute it to the effects of global warming.
Western Siberia holds the world's largest frozen peat bog, an area bigger than Texas.
Snow covers this vast, flat expanse most of the year. But for several short months of summer, the wet marshes produce a riot of colors, with green and red mosses, white lichens, and bushes bearing blueberries and currants.
But this landscape is changing fast. Botanist Sergei Kirpotin says in the last three to four years, the underlying permafrost has begun to melt, increasing the size of shallow lakes dotting the land.
"You can see the bushes here at the edge of this lake recently sank under water," Kirpotin says. "The process is now taking place so quickly, it's producing effects we couldn't have seen just a short while ago."
Kirpotin says the perimeters of larger lakes have expanded by up to 50 yards in the past few years. This could be attributed to regional climate variation, but Kirpotkin says the scale of the changes are such that only man-made global warming can explain them.
Normally, patches of white lichen on higher ground reflect the sun's rays and help keep the ground cold. But as the dark lakes expand, more heat is absorbed, and more of the permafrost melts.
Kirpotin says this local warming process has probably become irreversible.
"As we predicted in the early 1990s, there's a critical barrier," he says. "Once global warming pushes the melting process past that line, it begins to perpetuate itself."
Kirpotin, who's been studying these bogs for 15 years, is raising alarm bells. He says Siberia is one of the best places to observe the effects of global warming because the harsh continental climate isn't moderated by the jet stream or other weather patterns. He says the smallest changes in global conditions can be seen here sooner than in most other places.
Other scientists are seeing worrying signs as well.
As botanist Evgenia Parshina collects plant samples in plastic bags, she says there's significant evidence of thawing.
"We can poke down into the permafrost up to 15 inches," she says. "That shows the melting goes pretty deep."
Kirpotin says one of the biggest environmental threats here is the release of greenhouse gases, carbon dioxide and methane that have been frozen and trapped in the permafrost for more than 10,000 years.
Many scientists believe that since methane is 20 times more damaging as a greenhouse gas than carbon dioxide, any release of the vast reserves frozen in Siberia could have its own damaging effects on the earth's temperature. Kirpotin says methane is bubbling up so violently in some of the lakes, it stops them from freezing even at the depth of winter.
"It's very difficult for experts to measure exactly how much concentrated methane is being released into the atmosphere. That means the process could be happening many times more quickly than we think."
But many Russian scientists are skeptical about Kirpotin's claim that human activity is causing global warming and thus Siberia's thawing.
At a conference of experts at the local headquarters of the giant Russian gas monopoly Gazprom, geologist Grigorii Zaichikov says the rise in temperature is part of a natural cyclical process.
"You can't just look at the earth's surface when talking about possible effects of global warming. You have to study both satellite images and geodynamics deep inside the earth to be able to come to any conclusion."
Still, no one disputes the growing evidence of warming temperatures. New flora and fauna are slowly moving north into the area, including animals like badgers usually seen much farther south.
The melting tundra is also having economic effects. The thawing surface is causing power and telephone poles to tilt, forcing the authorities to install concrete ties to stabilize them.
Kirpotin says such evidence shows something worrying is happening in Siberia. He's calling on the international scientific community to launch further investigations.