Glacier lake puts global warming on the map
The Boston Globe, July 16, 2002
MACUGNAGA, Italy - The people of this Alpine resort village long ago learned to cope with the floods that sometimes accompany the melting snow in the spring. But nothing prepared them for the catastrophic flood threat they now face - a glacier rapidly melting from unusually warm temperatures.
For the past two weeks, as many as 300 officials and volunteers have been struggling under a state of emergency to prevent a gigantic glacier-fed lake from breaking through the giant ice wall that confines it. If they fail, a devastating wall of water, carrying chunks of glacier and mountainside, would crash down this verdant valley.
Known technically as a ''glacier lake outburst flood,'' or GLOF, it's an event previously seen only in the Himalayas where the slopes of the mountains are steeper. But scientists say the threat is both real, and a warning of things to come if the global-warming trend continues.
''It's a dangerous situation because the border of the lake is ice, which isn't stable,'' said Claudia Smiraglia, a professor of physical geography at Milan University. ''The glacier is always in motion.''
In the event that the water escapes, the 650 residents of Macugnaga (pronounced maa-COON-yaga) - and as many as 7,000 vacationers, depending on the time of year - would have approximately 40 minutes to gather their belongings and get to higher ground before the wave of water and mountain wipes out much, if not all, of the manmade structures, according to Luka Spoletini, a spokesman for the Italian government's Department of Civil Protection.
For now, the water level is down and the village is out of imminent danger, though it has more to do with natural seepage than the emergency efforts being organized by the civil protection department. But people aren't out of danger yet - and the state of emergency has not been lifted.
The potential problem began to appear in March when the Belvedere glacier began surging forward, creating an icy basin at 7,500 feet. Tons of melting snow and ice rushed into the basin in June as temperatures reached a scorching 86 degrees Fahrenheit at the top of the mountain that overlooks Belvedere - Mount Rose, Europe's second-highest Alpine peak.
''Last month was very hot,'' said Macugnaga Mayor Teresio Valessia.
Scientists aren't exactly sure of the mechanism that causes glacial surges, but one theory suggests that, as the glacier melts, water accumulates underneath, gradually cutting through the glacier's base and sending it lurching down the mountain. As Belvedere advanced, a relatively small pool of water, dubbed Lake Ephemeral, collected at the bottom.
Since then, the lake has grown to nearly a quarter of a mile in area as both the unusually warm air and the water beneath and around the glacier melt the ice.
''Observing glacial lakes so high is a global-warming effect,'' said Luca Mercalli, director of Societa Meterologica Italiana in Turin. Mercalli, working with officials at the National Council of Research, first saw the lake's appearance.
The crisis in Macugnaga brings home the human dimension of the global-warming threat in northerly climates and at high altitudes. Sure, the world's glaciers have collectively been retreating at an accelerating pace, and part of the far north is several degrees warmer than a century ago; but, until now, there has been relatively little direct harm to people beyond some houses in Alaska that have become uninhabitable as the permafrost beneath them melted.
Climate change researchers, however, say it was only a matter of time before the warming temperatures at northern high altitudes took a toll. While the entire planet's average temperature has increased by more than 1 degree Fahrenheit in the last century, temperatures in places such as parts of Alaska have risen by nearly 5 degrees.
''This is not a surprise,'' said James Hansen, director of NASA's Goddard Institute for Space Studies during a telephone interview from his office in New York City.
As early as 1988, when Hansen first brought the issue of global warming to wide public attention through his testimony before a Senate committee, Hansen had predicted that, by 2000, ordinary people would begin to notice the effects of global warming.
But what to do about global warming remains highly controversial. The Bush administration has rejected the international Kyoto Protocol, which committed developed nations to reduce emissions of carbon dioxide and other so-called greenhouse gases that trap heat in the atmosphere. Top Bush officials say it may take years for the administration to come up with an alternative strategy, bringing accusations from environmentalists that Bush is delaying action on measures that might hurt the oil or coal industries.
The emergency operation on Mount Rose almost certainly will save the village. But saving lives requires risking lives. So far, no one has been hurt, but this is risky business.
Helicopters ferrying materials 3 miles up this narrow Alpine valley are relatively safe. The real danger is to those working on the lake. The water temperature is 33 degrees, according to Spoletini of the government's civil protection department. Anyone who falls in has maybe 30 seconds to get out. Even the rescue crews, standing by at the lake, can only stay in for three minutes with their wetsuits on.
For the past two weeks, the drone of helicopters has echoed through this normally tranquil valley. From shortly after sunrise until evening, the choppers, flying just above the treetops, are carrying people and equipment 3 miles back and forth from the village's operating base to the lake. Down on the ground, a variety of military and fire trucks have been rumbling through narrow streets more suited for VW Beetles.
So far, one pump, powered by a generator, is pushing 300 liters of glacial lake water per second through a temporary piping system that is feeding a mountain river. But a generator is only a viable short-term source of energy - and this is a long-term problem.
The lake is 185 feet deep and 60 hectares (nearly a quarter of a mile square), with 3 million cubic meters of water. Pumping it dry is nearly impossible. For one thing, the more the water level drops, the harder the pump has to work to get the water out.
Two more pumps are on the lake and ready to start, but they require more energy than the 61/2-ton generator can supply. So electric wires are being strung into no man's land at the lake.
Once the lake is connected to the electrical grid and the 10-feet-in-diameter piping system is assembled, the three pumps will be put into action, with a goal of lowering the lake about 33 feet.
Experts believe it will be safe at that depth. The lake will surely freeze in the winter but it is virtually assured of melting again in the spring. And as the Earth continues to warm, glacier ice will refill the lake. So, pumps and on-site monitors will be needed indefinitely.
This story ran on page C1 of the Boston Globe on 7/16/2002.