Samples that Schuur brought back from Siberia to his laboratory in Gainesville contained carbon that dated back tens of thousands of years as organic material became trapped in the soil.
Further examination revealed that the carbon from the Siberia samples was released very rapidly as the soil thawed.
"If these rates are sustained in the long term, as field observations suggest, then most carbon in recently thawed (permafrost) will be released within a century -- a striking contrast to the preservation of carbon for tens of thousands of years when frozen in permafrost," the scientists conclude in their Science paper.
It's easy to find examples of changes that are already taking place.
The Mendenhall Glacier, just a short drive from my home in Juneau, Alaska, is one of the premier tourist attractions in the state. It is a spectacular river of ice that extends up a vast valley carved by the glacier as it gorged its way down through the rocky cliffs that tower above.
When I first saw it as a young Coast Guard officer on duty in Alaska, I was awed. I'm still awed today. But the Mendenhall is rapidly becoming a shadow of its former self. It is melting and receding at a rate of several hundred feet a year.
Just a few years ago, scientists thought the 500-square-mile ice field that feeds the glacier would soon start to get colder, part of an anticipated natural cycle.
But the Mendenhall, like nearly every other glacier in Alaska, is disappearing. Just 200 years ago, the toe of the glacier was where the Juneau airport is today. Now it's several miles -- that's miles -- back into the spruce-covered hills.
Living in Alaska, I find it's sometimes kind of nice to think that the planet is growing warmer. But there's a price to be paid. And the loss of the Mendenhall Glacier pales in the face of horrendous storms, starvation and inundation of coastlines that are sure to come.
Don't think of it in terms of centuries, or even decades. It's happening now.