Bog Breath: Sleeper Factor in Global Warming?

Article excerpt

The vast northern peatlands do a good job of storing carbon, but the stuff they burp up may be an even more noxious player in the greenhouse equation.

Call it a sign of the times. Twelve years ago, NASA asked researchers at the USDA Forest Service's North Central Forest Experiment Station in Minnesota if it could sample the air above their bogs and peatland forests. NASA was curious about the cocktail of gases that peatlands inhale and exhale as plants grow and decay. Something about these gases, the space agency believed, would help researchers understand the atmosphere on distant planets such as Mars.

In 1985, NASA returned to the Marcell Experimental Forest, even more eager to know about bog breath. This time the space agency didn't mention extraterrestrial air. It was far more concerned about the changing atmosphere on the third planet from the sun, the life-friendly one we call home.

A growing segment of the scientific community would now echo NASA's concern. Carbon dioxide, the renowned greenhouse gas released by burning fossil fuels, has increased 13 percent since 1959. Many scientists believe its heat-trapping qualities may be causing global temperatures to change. Those of us in the forestry community are well aware of the role forests play in the global-warming debate. We know that tropical rainforests, for instance, provide a sink for carbon (carbon dioxide is turned into plant bodies), which in turn helps regulate the earth's temperature.

But tropical forests are only one player in the carbon shell game. A potentially more influential player that gets a lot less press is peatlands. To many people, these mysterious quaking mats, dotted with carnivorous plants, elfin shrubs, and incredibly tough trees, are little more than an asterisk in the earth's roster of habitats. They are throwbacks to a time when wilderness was forbidden - the edge of the map that warned "serpents lie here." Despite our disinterest, peatlands have been faithfully breathing for thousands of years, helping to keep the earth's composition of gases as regular as a top. What that has meant for us is just now beginning to come clear, thanks in part to a group of Forest Service scientists whose careers revolve around bogs.

THE BOG-TROTTERS

"Most people don't realize how extensive northern peatlands are," says Dr. Elon "Sandy" Verry, lead scientist at North Central's Water Quality Research Project. "We're talking about 500 million hectares (one hectare equals 2.4 acres) of the globe, a wide band that stretches through Siberia, Alaska, Canada, and across the Scandinavian countries. Peatlands represent up to half of the land base in northern latitudes, and contain up to a third of all the soil carbon in the world. There's no doubt bogs will play a part in the greenhouse effect - the question is, will they alleviate or aggravate global warming? That's what we want to find out."

Sandy Verry doesn't fit the 1950s stereotype of the white-coated laboratory scientist. In a polo shirt and jeans, he reminds me of the slow-talking, canny ranchers I know in Montana. Like them, he has a quiet wit, an encyclopedic knowledge, and a way of explaining the world so that anyone leaning against the fence with him can understand.

The story he shares with me is the cutting edge of what is known about bog habitats, much of it discovered by him and his colleagues at the Marcell Experimental Forest. For 20-odd years, Verry has explored how peatlands relate to surrounding watersheds, and how activities like forestry might affect those relationships. His studies have recently been used to write Minnesota's Best Management Practices for forest harvest in wetlands. Now he's completing the picture by studying how peatlands in Marcell's Experimental Forest interact with the atmosphere. He is joined by scientists from around the world who are equally fascinated by earth's equilibriators. The picture emerging from their papers is a good news/bad news story. …