With Speed and Violence: Why Scientists Fear Tipping Points in Climate Change (13 page)

"We had never seen anything like it, and had not expected it," he said. Huge areas of frozen peat bog were suddenly melting. The former soft, spongy surface of lichens and moss was turning into a landscape of lakes that stretched unbroken for hundreds of miles. He described it as an "ecological landslide that is probably irreversible and is undoubtedly connected to climate warming." Most of the lakes had formed, he said, since his previous visit, three years before. There was clearly a huge danger that the melting peatland would begin to generate methane.

I had come across Russian scientists before who had been left out in the tundra too long with their crackpot theories. But Kirpotin did not fit that category. He had only recently been appointed vice-rector of his university. And the more I checked it, the more likely his story seemed. Larry Smith, of the University of California at Los Angeles, told me that the western Siberian peat bog was warming faster than almost any other place on the planet. Every year, he said, the spring melt was starting earlier and the rainfall was increasing, making the whole landscape wetter.

Others were finding big methane emissions in the region. Katey Walter, of the University of Alaska in Fairbanks, had told a meeting of the U.S. Arctic Research Consortium just a few weeks before about "hot spots" of methane releases from lakes in eastern Siberia that were "unlike anything that has been observed before." Peat on the bottom of lakes was converting to methane and bubbling to the surface so fast that it kept the lakes from freezing over in winter. And Euan Nisbet, of London's Royal Holloway College, who oversees a big international methane-monitoring program that includes Siberia, said his estimate was that methane releases from the western Siberian peat bog were up to ioo,ooo tons a day, which meant a warming effect on the planet greater than that of all the U.S.'s man-made emissions. "This huge methane flux depends on temperature," he said. "If peatlands become wetter with warming and permafrost degradation, methane release from peatlands to the atmosphere will dramatically increase."

So I wrote up Kirpotin's story for New Scientist magazine, emphasizing the methane angle. It went around the world. The London Guardian reproduced much of it the day after the story was released, under the frontpage banner headline "Warming hits `tipping point.'" In Dr. Strangelove, one nuclear device dropped on Siberia unleashed a thousand more. Here, in the real world of melting Arctic permafrost, one degree of global warming could unleash enough methane to raise temperatures several more degrees.

I had visited western Siberia a few years before, traveling with Western forest and oil-industry scientists to Noyabr'sk, a large oil town on the south side of the great peat bog. On a series of helicopter rides, I had seen thousands of square miles of still-intact swamp sitting on top of permafrost. The landscape was terribly scarred by human activity: divided into fragments by oil pipelines, roads, pylons, and seismic-survey routes; smeared with spilled oil; littered with abandoned drums, pipes, cables, and the remains of old gulags and half-built railways; and shrouded in black smoke from gas flares. The reindeer had fled, and the bears had been hunted almost to extinction. But the peat bog and the permafrost had survived. The helicopter landed frequently, and we jumped out without so much as getting our feet wet on the spongy surface.

No longer. On my way to meet Kirpotin's colleagues at their research station at Pangody, on the Arctic Circle, I flew for two hours over a vast bog that was seemingly going into solution. In place of the green carpet of moss and lichen, as Kirpotin had told me, numberless lakes stretched to the horizon. From the air, they did not look like lakes that form naturally in depressions in the landscape. They were generally circular, looking more like flooded potholes in a road. The lakes had formed individually from small breaches in the permafrost. Wherever ice turned to water, a small pond formed. Then surrounding lumps of frozen peat would slump into the water, and the pond would grow in an ever-widening circle, until mile after mile of frozen bog had melted into a mass of lakes.

"Western scientists cannot imagine the scale of the melting," Kirpotin told me. But I could see it beneath me as I flew east. It seemed to me that a positive feedback was at work, much as in the accelerated melting of Arctic sea ice. The new melted surface, darker than the old frozen surface, absorbed more heat and caused more warming. Kirpotin agreed. There seemed to be a "critical threshold" beyond which "the process of warming would be essentially and suddenly changed," he said. "Some kind of trigger hook mechanism would come into play, and the process of permafrost degradation would start to stimulate itself and to urge itself onwards." His imperfect English somehow made the events he was describing sound even more awful. "The problem concerned does not have only a scientific character: it has passed to the plane of world politics. If mankind does not want to face serious social and economic losses from global warming, it is necessary to take urgent measures. Obviously we have less and less time to act."

I was defeated in my efforts to see these processes in the Siberian bogs at first hand. Landing at Novy Urengoi with all the necessary paperwork, I was nonetheless refused admission. "You need a special invitation from an organization in the city," a fearsome policewoman at the airport told me as she confiscated my passport and put it in a safe. This was a company town. I later discovered that the mayor, a gas-company nominee, had won approval from Moscow some months earlier for special rules to keep out unwanted foreigners. Novy Urengoi was one of Russia's few surviving closed cities.

It was also rather disorganized. Unsupervised, I wandered into town anyhow, and looked around one of the most desolate and inhospitable places I have ever been to. No wonder its name means "godforsaken place" in the language of the local reindeer herders. I briefly met with the scientists I had come halfway across the world to see, before being rounded up and driven back to the airport by a spook wearing a double-breasted suit and a smile like Vladimir Putin's. He seemed to think I was a terrorist, and the fact that I was meeting scientists investigating the tundra only made him more suspicious. I can at any rate say I have been thrown out of Siberia.

Back home, concern has grown about the role of methane in stoking the fires of global warming. In early 2006, a dramatic study suggested that all plants, not just those in bogs, are manufacturing methane-something never previously considered by scientists. That led to headlines about trees causing global warming, which seemed a bit hard on them. If they do make methane, they also absorb carbon dioxide. And since trees have been around for millions of years, and there are probably fewer of them now than for the majority of that time, any role for them in recent warming seems unlikely. They are simply part of the natural flux of chemicals into and out of the atmosphere. Though if evidence emerged that they were emitting more methane than before, as a result of warming, that would be a big worry. And that is precisely what seems to be happening with peat bogs in the Arctic permafrost.

There is a critical line around the edge of the Arctic that marks the zone of maximum impact from global warming. It is a front line of climate change, marking the melting-point isotherm, where the average yearround temperature is 32°F, the melting point of ice. To the north of this line lie ice and snow, frozen soil and Arctic tundra. To the south lie rivers and lakes and fertile soils where trees grow. The line runs through the heart of Siberia and Alaska-where huge blocks of frozen soil, stable for thousands of years, are now melting-and across Canada, skirting the southern shore of Hudson Bay, through the southern tip of Greenland, and over northern Scandinavia.

Having failed to visit Kirpotin's field station to see the melting of the Siberian bogs close up, I went instead to northern Sweden to visit what is almost certainly the longest continually monitored Arctic peat bog in the world. In 1903, scientists took over buildings erected near Abisko during the construction of a railway to take iron ore from the Swedish mine of Kiruna to the Norwegian port of Narvik. They have been out there ever since, through the midnight sun and the long dark winters, measuring temperatures and dating when the ice came and went on Tornetrask, an adjacent lake; plotting movements of the tree line; examining the bog ecosystems; reconstructing past climates from the growth rings of logs in the lake, and investigating the cosmic forces behind the area's spectacular northern lights.

So they are on solid ground when they say it is getting dramatically warmer here. The lake freezes a month later than it did only a couple of decades ago-in January rather than mid-December. It used to stay frozen till late May, but several times in recent years an early breakup has forced the cancellation of the annual ice-fishing festival on the lake in early May. The average annual temperature here over the past century has been 30.7"F, but in recent years it has sometimes crept above 32"

Just east of Abisko is the Stordalen mire. This is not a large bog, but it is old, and probably the best-monitored bog in the best-monitored Arctic region in the world. It has withstood numerous periods of natural climate change during the past 5,000 years. But suddenly it seems doomed. For here, as Kirpotin has found across the western Siberian wetland, the evidence of what happens to a bog that finds itself straddling the meltingpoint isotherm is obvious at every step. Apart from scientists, the bog's main visitors are birdwatchers. A couple of years ago, the local authorities built a network of duckboards for them. But already the boards are capsizing, because the mounds of permafrost on which they were built are melting and slumping into newly emerging ponds of water.

Arriving rather spectacularly aboard a helicopter hired to remove some equipment from the site, I found a dry hummock on which to talk to Torben Christensen, a Danish biochemist who heads the research effort here. "The bog is changing very fast," he said. Below our feet, the permafrost was still as deep as 30 feet, but a step away it was gone. We examined a crack in the peat, where another chunk was preparing to slide into the water. "Of all the places in the world, it is right here on the melting-point isotherm, on the edge of the permafrost, that you'd expect to see climate change in action," Christensen said. "And that is exactly what we are seeing. Of course, they are seeing it on a much bigger scale in the Siberian bogs, but here we are measuring everything."

Out on the mire, Christensen has some of the most sophisticated equipment in the world for measuring gas emissions in the air. In one area, individual bog plants grow inside transparent plastic boxes whose lids open and shut automatically as monitoring equipment captures and measures the flux of gases between plant and atmosphere. Pride of place goes to an eddy-correlation tower. This logs every tiny wind movement in the ambient air, vertical as well as horizontal, and uses a laser to measure passing molecules of methane and other gases. Combining the two sets of data, the tower can produce a constant and extremely accurate readout of the flux of methane coming off the mire.

There is a regular loss of methane from the bog now, says Christensen. Some of the gas seeps out of the boggy soil, some bubbles up through the pond water, and some is brought to the surface by plants. The figures sound small: an average of 0.0002 ounces of methane is released per 1o square feet of mire per hour. But scaled up, this packs a greenhouse punch. Combining the flux data with satellite images that show the changing vegetation on the Stordalen mire, Christensen estimates that in the past thirty years, methane emissions have risen by 30 percent and increased this small bog's contribution to global warming by 50 percent.

There is nothing unusual about Stordalen. It was not chosen to give dramatic results. Monitoring began back when researchers were intent only on tracking what they believed to be unchanging processes. Other local mires are faring far worse as the melting-point isotherm moves north. Out in the nearby birch forest, the Katterjokk bog has gone in just five years from being an area largely underlain by permafrost to being an icefree zone. Rather, Stordalen looks to be typical of bogs across northern Scandinavia and right round the melting-point isotherm. Individually they are only a pinprick on climate change, but taken together they threaten an eruption.

Back in the warmth of the Abisko library, Christensen found a study showing that half the bog permafrost in the north of Finland has disappeared since 1975. The rest will be gone by 2030. Christensen himself has coordinated a study of methane emissions from peatlands at sites right around the Arctic, using temporarily deployed equipment for measuring gas fluxes. North of the melting-point isotherm, the study shows little change. Little methane bubbles out of the tundra in northeastern Greenland, for instance, where the average temperature is still around 14°F. But, he says, "as temperatures rise, methane emissions grow exponentially." The highest emissions are in western Siberia and Alaska, where big temperature rises are taking place.

What is happening out on these Arctic mires is, at one level, quite subtle. On many of them, temperatures remain cold enough to limit the decomposition of vegetable matter, and so carbon is still accumulating as it has done ever since the bogs began to form, at the end of the last ice age. But the decomposition rates are rising. And critically, because the melting permafrost is making the bogs ever wetter, more and more of the carbon is released not as carbon dioxide but as methane. That dramatically changes the climate effect of the bogs. Methane being such a powerful greenhouse gas, the warming influence of its release overwhelms the cooling influence of continued absorption of carbon dioxide. Thus "mires are generally still a sink for carbon, while at the same time being a cause of global warming," Christensen says. "This can be a hard point for people to grasp, but it is absolutely crucial for what is happening right around the Arctic."

There are still so few good data that it is hard to say for sure how much the Arctic peat bogs are contributing to global warming today. Current emissions of methane are probably still below 50 million tons a year. But that is still the warming equivalent of more than a billion tons of carbon dioxide. And with lakes forming everywhere, and climate models predict ing that 9o percent of the Arctic permafrost will have melted to a depth of at least three yards by 2012, there is "alarming potential for positive feedback to climate from methane," says Christensen.