Researcher tests ties of greenhouse gas to climate (2/21/09)

Science with flare

December 21, 2009 

EDITOR'S NOTE: This profile of UAF professor Katey Walter Anthony first appeared in the Los Angeles Times on Feb. 20. More recently, Anthony was one of two Alaskans named Adventurers of the Year by National Geographic Adventure magazine, which is asking readers to vote for their favorite. A story on that and the other Alaskan named an Adventurer of the Year is Lt. Col. Marc Hoffmeister of Fort Richardson.

BERING LAND BRIDGE NATIONAL PRESERVE -- Four miles south of the Arctic Circle, the morning sky is streaked with apricot. Frozen rivers split the tundra of the Seward Peninsula, coiling into vast lakes. And on a silent, wind-whipped pond, a lone figure, sweating and panting, shovels snow off the ice.

The young woman with curly reddish hair stops, scribbles data, snaps a photo, grabs a heavy metal pick and stabs at white orbs in the thick black ice.

"Every time I see bubbles, I have the same feeling," says Katey Walter Anthony, a UAF research professor. "They are amazing and beautiful."

Beautiful, yes. But ominous. When her pick breaks through the surface, the orbs burst with a low gurgle, spewing methane, a potent greenhouse gas that could accelerate the pace of climate change across the globe.

International experts are alarmed. "Methane release due to thawing permafrost in the Arctic is a global warming wild card," warned a 2008 report by the United Nations Environment Programme. Large amounts entering the atmosphere, it concluded, could lead to "abrupt changes in the climate that would likely be irreversible."

Methane (CH4) has at least 20 times the heat-trapping effect of an equivalent amount of carbon dioxide (CO2). As warmer air thaws Arctic soils, as much as 55 billion metric tons of methane could be released from beneath Siberian lakes alone, according to Anthony's research. That would amount to 10 times the amount currently in the atmosphere.

At 32, Anthony, an aquatic ecologist, is a rising star among the thousands of scientists who are struggling to map, measure and predict climate change. According to one of her studies, methane emissions from Arctic lakes were a major contributor to a period of global warming more than 11,000 years ago.

"It happened on a large scale in the past, and it could happen on a large scale in the future," says Anthony, who refers to potential methane emissions as "a time bomb."

GAS FLARE STUNT

Methane levels in the atmosphere have tripled since preindustrial times. Human activities, including rice cultivation, cattle raising and coal mining, account for about 70 percent of releases, according to recent studies. Natural sources, from tropical wetlands to termites, make up the rest. But those estimates had not incorporated the bubbles Anthony was probing on an autumn morning on the Seward Peninsula.

That gurgling gas could change the entire model for predicting global warming. And lakes are not the only methane source: Newly discovered seeps -- places where methane leaks to the surface -- from the shallow waters of Siberia's vast continental shelf may also upset previous assumptions.

Anthony's work "has gotten a lot of attention," said John Walsh, chief scientist of the International Arctic Research Center in Fairbanks. "She found direct evidence of methane releases in high-latitude lakes. That was not fully realized before."

In a field where the science often seems opaque, Anthony's research has a flashy side. She enjoys igniting methane seeps with a cigarette lighter, leaping away as the gas flares as high as 20 feet.

"It's fun," she says. "And it is informative."

Videos of the stunts have swept through the Internet, rare visual evidence of possible danger ahead. Al Gore played a clip of her lighting a methane seep at a Senate hearing.

The complex science of Arctic methane is only beginning to be understood. In the desolate wilderness of the Bering Land Bridge National Preserve, a sense of urgency is palpable among Anthony and three fellow researchers, hunkered down in neon-orange tents.

An occasional helicopter ferries supplies from Nome, the closest town, soaring over scattered herds of caribou. A red fox scampers through the brush. Across a snowfield, bear tracks recede into the distance, a reminder that field science isn't for sissies.

"Can you shoot a gun?" Anthony asks a visitor as she heads out to one of 20 lakes she is surveying. When the answer is noncommittal, she hands over a can of bear spray.

TRANSFORMING PERMAFROST

Nowhere is the evidence of a heating planet more dramatic than in the polar regions. Over the last 50 years, the Arctic has warmed twice as fast as the rest of the globe.

Even as melting glaciers and sea ice have captured most headlines, growing concern is focused on the transformation of permafrost -- soils that are frozen year-round.

Today, 20 percent of Earth's land surface is locked up in a deep freeze. But scientists predict that air temperature in the Arctic is likely to rise as much as 10.8 degrees Fahrenheit by the end of the century, boosting the emission of carbon compounds from soils.

The upper 3 meters (about 10 feet) of permafrost store 1.7 trillion metric tons of carbon, more than double the amount in the atmosphere today, according to a recent study in the journal Bioscience.

"We are seeing thawing down to 5 meters," says geophysicist Vladimir Romanovsky of UAF. "A third to a half of permafrost is already within a degree to a degree and a half (Celsius) of thawing."

If only 1 percent of permafrost carbon were to be released each year, that could double the globe's current annual carbon emissions, Romanovsky notes. "We are at a tipping point for positive feedback," he warns, referring to a process where warming spurs emissions, which in turn generates more heat.

Anthony's work is crucial, according to Romanovsky and others, because global warming hinges partly on the ratio of how much carbon is released as CO2 versus how much as methane, a molecule that contains both carbon and hydrogen.

Although a far more potent greenhouse gas than carbon dioxide, methane breaks down quicker. When it does, it oxidizes into a carbon dioxide molecule, which can last more than a century in the atmosphere.

Out on the lake, Anthony explains: When organic matter (dead plants and animals) rots in the ground, it gives off carbon dioxide. Much of the organic material of thawed permafrost is expected to release carbon dioxide.

But as ice inside permafrost melts, small sinkholes open in the ground and fill with water, joining together to form millions of ponds and lakes. Organic matter slips from eroding shorelines to lake bottoms, where microbes feed on it. Because lake bottoms are oxygen-free, the microbes generate methane in addition to carbon dioxide -- as in the burping La Brea tar pits.

"These lakes are getting bigger -- in some places by a meter a year," Anthony says, scooping out slush from the hole she has punched through 6 inches of ice. Into the seep, she inserts a plastic umbrellalike contraption fitted with a bottle to collect gas and a suspended brick to hold it straight.

GRUELING FIELD WORK

Before Anthony perfected the methane trap, when she was a graduate student in Siberia, she would swim in near-freezing water, dodging leeches and muskrats. Once she caught pneumonia. Another time, her hair caught on fire as she ignited a methane seep.

On the Seward Peninsula trip, she hikes up to 8 miles a day from lake to lake. Her hip is black and blue from a fall through the ice.

"Methane is hard work," she says with a smile.

At each seep, Anthony places a small red flag so her colleagues can find the bubbles. Lawrence Plug, a geophysicist from Dalhousie University in Halifax, Nova Scotia; Guido Grosse, a German geologist; and Benjamin Jones, a U.S. Geological Survey researcher, help shovel off the ice in straight-line paths, take notes on the size of each bubble group, record the location with global positioning system devices and measure the depth of the lakes.

Over the next two years, the researchers, funded by the National Science Foundation and NASA, will move between Siberia and Alaska, drilling permafrost cores, mapping seeps and analyzing data to produce a model of how methane from Arctic lakes might affect Earth's climate.

"By figuring out how quickly permafrost thawed in the past, we can test our models to predict how fast it could thaw in the next 100 years," says Plug, who will make the complex calculations. "If the temperature warms a couple of degrees Celsius, the lakes could expand at two or three times their current rate."

SPREADING THE WORD

Elsewhere, scientists cast a wary eye toward clouds of methane bubbles in the waters of the Siberian continental shelf. Those emissions, possibly from subsurface permafrost, are harder to measure than lake emissions.

Walsh, at the International Arctic Research Center, emphasizes the "huge range of uncertainty" as to how much climate change methane emissions could trigger: "The potential is there for large releases. But there is also a risk of alarmism."

To many Alaskans, it is hardly news that permafrost is thawing. Across the state, houses have been collapsing and trees tipping over. Researchers estimate that repairing affected schools, roads and bridges will cost billions over the next two decades.

But the global implications have yet to sink in.

Out on the wild frontier of climate research, far from the legislatures and the diplomatic gatherings where climate policy is debated, Anthony and her colleagues focus on what they call "ground truthing."

And beyond that laborious data-gathering, Anthony has a mission: To spread the word about what is happening. At the beginning of her field trip, she stops in Nome and leads a group of fifth-graders out to poke holes in the ice of a nearby lake and light methane flares.

She talks to them about people who live in faraway cities, driving automobiles and working in industries that emit carbon dioxide. And how that causes warming that is felt in the Arctic. And why, even though there are so few people in Alaska, the ice around them is melting.

"That's what we're studying," she explains. "It's all related."


Reprinted with permission of the Los Angeles Times.

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