With Speed and Violence: Why Scientists Fear Tipping Points in Climate Change (7 page)

Svalbard has long been recognized as extremely sensitive to climate variations. In the early twentieth century, during a period of modest warming in much of the Northern Hemisphere, temperatures rose here by as much as 9°F-a figure probably not exceeded anywhere on the planet. In the 196os they fell again by almost as much, but the rise since has taken them back to the levels of the 192os, with no end in sight. Climatologists warn against seeing warming here as an unambiguous sign of man-made climate change. But Ny-Alesund does seem uniquely sensitive to nudges on the planetary thermostat. It is a place where climate feedbacks like melting sea ice and changes in winds and ocean currents work with special force. And who knows what the future will hold? Only about a hundred miles out to sea, Wadhams's last chimney may be living out its final days.

Svalbard is a place to watch like a hawk, and not just for changing climate. The ozone layer is on a hair trigger here, too. Many researchers expect a giant ozone hole to form over the Arctic one day soon, just as it did in the Antarctic twenty-five years ago. And so, on the roof of the Norwegian Polar Institute, the largest research station in Ny-Alesund, pride of place goes to a gleaming steel instrument with a grand embossed nameplate announcing that you are in the presence of Dr. Dobson's Ozone Spectrophotometer No. 8-Dobson Meter No. 8, for short. The British meteorologist Gordon Dobson, one of the earliest researchers into the ozone layer, built the first of his spectrophotometers in 1931, in a wooden hut near Oxford. His eighth, built in 1935, came north to Ny-Alesund and ever since has been pointing to the sky, measuring the ultraviolet radiation pouring through the atmosphere, and thus indirectly measuring the thickness of the ozone layer.

Dobson eventually produced 150 machines. They still form the core of the world's ozone-layer monitoring network. Their work was considered routine, even dull, until one of them discovered an ozone hole over Antarctica in the early r 98os. Now Dobson Meter No. 8 and its minder, research assistant Carl Petter Niesen, are looking into the skies above Ny-Alesund for a repeat here. The most northerly and among the oldest in continual service, the instrument needs a little help these days to keep going. It has a duvet and a small heater to keep it from seizing up in the winter cold. Uniquely here, it is not connected to a computer logger. Even in the depths of winter, Niesen goes up on the roof to write down its reading with a pencil in a large logbook. Not much science happens that way anymore, but the Dobson meter, with its idiosyncratic but continuous record for more than half a century, is irreplaceable.

Dobson Meter No. 8 hasn't spotted a full-blown hole in the ozone layer yet. But as the researchers have waited, they have discovered other strange things happening to the chemistry of the atmosphere. Svalbard, it turns out, is on the flight path of acid fogs from Siberia that get trapped in thin, pancakelike layers of air close to the ice and turn the clear, still air into a yellow haze. Sometimes it rains mercury here, as industrial pollution cruises north and suddenly, within a matter of minutes, precipitates onto the snow.

Pesticides, too, have arrived in prodigious quantities, apparently from the fields of Asia. They condense in the cold air and become absorbed in vegetation. They work their way up the food chain to fish and polar bears and birds. But the very highest concentrations occur in a lake on Bear Island, in the south of the Svalbard archipelago, beneath a huge auk colony. The chemicals that have become concentrated in the Arctic air, and then concentrated again in the Arctic food web, are concentrated one more time in the urine of the auks. What at first sight might seem to be just about the least polluted place on Earth turns out to be a toxic sump.

Ny-Alesund is the most northerly permanent settlement on Earth. And the summit of Mount Zeppelin, i,6oo feet above the settlement, is the top of the top of the world-the ultimate watchtower for the world's climate. I went to the summit in the world's most northerly cable car with Carl Petter Niesen, who was taking his daily journey to tend the huge array of instruments designed to sniff every molecule of passing Arctic air. Recently, he says, carbon dioxide levels in the air on Mount Zeppelin have increased more sharply than at other monitoring stations around the world. Some days he measures levels approaching 390 ppm-fully io ppm above the global average. There is always some scatter in the readings. But it seems, he says, as if fast-rising emissions from power plants and cars in China and India are traveling north on the winds with the mercury and the pesticides and the acid haze. Not for the first time, he has caught a whiff of the future here at the top of the world.

FAULT LINES IN THE ICE

6

NINETY DEGREES NORTH

Why melting knows no bounds in the far North

"Has anybody in history ever got to 9o° north, to be greeted by water and not ice?" That was the question posed by a group of scientists after returning from a cruise to the North Pole in August 2000. Sailing north from Svalbard on one of the world's most powerful icebreakers, the Yamal, the researchers found very little ice to break. And when they got to their polar destination, they were amazed to find not pack ice but a mile-wide expanse of clear blue water.

The story went around the world. For some, it revived the tales of ancient mariners, who said that beyond the Arctic ice there was an open ocean, and beyond that a mystical land, an Atlantis of the North. The proprietors of the Yamal were quick to cash in, offering summer cruises to "the land beyond the pole." But for the less romantically inclined, the story of the ice-free North Pole ignited panic about Arctic melting. By chance, the scientists on board the Yamal had included James McCarthy, a Harvard oceanographer on summer vacation from chairing an IPCC working group on the impacts of climate change. He didn't want to be alarmist, he said on his return. The Arctic ice sheet is made up of shifting plates, so there are bound to be gaps. But there were more and more gaps. So the unexpected discovery was "a dramatic punctuation to a more remarkable journey, in which the ice was everywhere thin and intermittent, with large areas of open water."

The whole Arctic was remarkably ice-free that summer. And that included the Holy Grail of generations of Arctic explorers, the Northwest Passage. The search for a route from the Atlantic to the Pacific and the riches of the Orient excited early explorers almost as much as El Dorado. But it was a deadly pursuit. The ice swallowed up hundreds of them, most notably Sir John Franklin, whose 1845 expedition disappeared with all 128 hands. But in 2000, a Canadian ship made the journey through the Northwest Passage without touching ice. Its skipper, Ken Burton, said: "There were some bergs, but we saw nothing to cause any anxiety."

Inuit whalers the previous June told glaciologists meeting in Alaska that the ice had been disappearing for some years. "Last year it stayed over the horizon the whole summer; we had to go thirty miles just to hunt seals," said Eugene Brower, of the Barrow Whaling Captain's Association. Recently declassified data from U.S. and British military submarines had revealed that the Arctic ice in late summer was on average 40 percent thinner in the 199os than in the 195os. And NASA satellites, which had been photographing the ice for a quarter century, offered the most incontrovertible evidence. Their analyst-in-chief is Ted Scambos, of the National Snow and Ice Data Center, in Boulder, Colorado, a wannabe astronaut who turned to exploring the polar regions as a second best. He reports annually on how the retreat of ice is turning into a rout. In 2005, just 2 million square miles of ice were left in mid-September, the usual date of minimum ice cover. That was 20 percent less than in 1978.

The Arctic is a place without half measures. There is no mid point between water and ice. Melting and freezing are, in the jargon of the systems scientists, threshold processes. Melting takes a lot of solar energy, but once it is complete, the sun is free to warm the water left behind. And, because it is so much darker, that water is also far better at absorbing the solar energy and using it to heat the ambient air. "This makes the whole ice sheet extremely dynamic," says Seymour Laxon, a climate physicist at University College London. "The concept of a slowly dwindling ice pack in response to global warming is just not right. The process is very dynamic, and it depends entirely on temperature each summer."

"Feedbacks in the system are starting to take hold," Scambos says. The winter refreeze is less complete every year; the spring melt is starting ever earlier-seventeen days earlier than usual in 2005. "With all that dark, open water, you start to see an increase in Arctic Ocean heat storage." The Arctic "is becoming a profoundly different place." Most glaciologists agree with Scambos that the root cause of the great melt is Arctic air tempera tures that have risen by about 3 to 5"F in the past thirty years-several times the global average. Global warming, it seems, is being amplified here. This is partly because the feedbacks of melting ice create extra local warming. And partly, too, because of a long warm phase in a climatic variable called the Arctic Oscillation, which brings warm winds farther north into the Arctic. The Arctic Oscillation is a natural phenomenon, but there is growing evidence that it is being accentuated by global warming, as we shall see in Chapter 37.

There is another driver for the melting, again probably connected to global warming. Warmer air above the ice is being accompanied by warmer waters beneath. Weeks before Scambos published his 2005 report, Igor Polyakov, of the International Arctic Research Center, in Fairbanks, Alaska, reported on an "immense pulse of warm water" that he had been tracking since it entered the Arctic in 1999. It had burst through the Fram Strait, a narrow "throat" of deep water between Greenland and Svalbard that connects the Greenland Sea and the Atlantic to the Arctic Ocean. And since then, it had been slowly working its way around the shallow continental shelves that encircle the Arctic Ocean. One day in February 2004, the pulse reached a buoy in the Laptev Sea north of Siberia. A thermometer strapped to the buoy recorded a jump in water temperature of half a degree within a few hours. The warm water stayed, the rise proved permanent, and the Laptev Sea rapidly became ice-free. "It was as if the planet became warmer in a single day," Polyakov told one journalist.

Pulses of warm water passing through the Fram Strait may be a regular feature of the Arctic. They were known to the Norwegian explorer and oceanographer Fridtjof Nansen, who a century ago used a specially strengthened ship called the Fram to float with the ice and monitor currents in the Arctic. But as the Atlantic itself becomes warmer, the pulses appear to become bigger, and their impact on the Arctic is growing. One theory is that some of the water that once disappeared down the chimneys in the Greenland Sea now comes farther north into the Arctic.

"The Arctic Ocean is in transition toward a new, warmer state," says Polyakov. And most glaciologists working in the Arctic agree. Writing in the journal of the American Geophysical Union, Eos, in late 2005, a group of twenty-one of them began in almost apocalyptic terms: "The Arctic sys tem is moving to a new state that falls outside the envelope of glacialinterglacial fluctuations that prevailed during recent Earth history." Soon the Arctic would be ice-free in summer, "a state not witnessed for at least a million years," they said. "The change appears to be driven largely by global warming, and there seem to be few, if any, processes within the Arctic system that are capable of altering the trajectory towards this 'superinterglacial' state."

What would the world be like with an ice-free Arctic? Oil and mineral companies and shipping magnates long for the day when they can prospect at will, build new cities, and navigate their vessels in all seasons from Baffin Island to Svalbard and Greenland and Siberia. But it would be a world without polar bears and ice-dwelling seals, a world with no place for the Inuit way of life. And the influence of such a change would spread around the world. Without the reflective shield of ice, the whole world would warm several more degrees; ocean and air currents driven by temperature differences between the poles and the tropics would falter; on land, methane and other gases would break out of the melting permafrost, raising temperatures further; and as the ice caps on land melted, sea levels would rise so high that much of the world's population would have to move or drown. If the Arctic is especially sensitive to climate change, the whole planet is especially sensitive to changes in the Arctic.

7

ON THE SLIPPERY SLOPE

Greenland is slumping into the ocean

We are on "a slippery slope to hell." That is not the kind of language you expect to read in a learned scientific paper by one of the top climate scientists in the U.S., who is, moreover, the director of one of NASA's main science divisions, the Goddard Institute for Space Studies, in New York. Not even in a picture caption. But Jim Hansen, President George W. Bush's top in-house climate modeler, though personally modest and unassuming, calls it as he sees it.

I've followed Hansen's work for a long time. He began his career investigating the greenhouse effect on Venus, and was principal investigator for the Pioneer space probe to that planet in the 1970s. But he soon switched to planet Earth. He was the first person to get global warming onto the world's front pages, during the long, hot U.S. summer of 1988. Half the states in the country were on drought alert, and the mighty Mississippi had all but dried up. The Dust Bowl, it seemed to many, was returning. Hansen picked that moment to turn up at a hearing of the Senate's Energy and Natural Resources Committee in Washington and tell the sweating senators: "It is time to stop waffling so much. We should say that the evidence is pretty strong that the greenhouse effect is here." He didn't quite say that greenhouse gases were causing the drought across the country-a claim that would have been hard to substantiate. But everybody assumed he had.