Climate Watchers Place Own Big Bet On Alaska's Thaw

Submitted by Charles Frost on Wed, 03/12/2008 - 19:22.

Climate Watchers Place Own Big Bet On Alaska's Thaw
March 7, 2008; Page B1

Every winter since 1917, people in Nenana, a village 55 miles southwest of Fairbanks, have wagered on the exact moment that the ice breaks up on the nearby Tanana River. For the 450 townsfolk, the annual Alaska ice lottery, called the Nenana Ice Classic, is a financial lifeline that offers some their year's only employment. Winners last year shared a jackpot of $303,272.

But for many geophysicists, the contest itself is something more valuable than any monetary prize.

The Ice Classic has given them a rare, reliable climate history that has documented to the minute the onset of the annual thaw as it shifted across 91 years. By this measure, spring comes to central Alaska 10 days earlier than in 1960, said geophysicist Martin Jeffries at the University of Alaska, Fairbanks -- and that trend is accelerating. "The Nenana Ice Classic is a pretty good proxy for climate change in the 20th century," Dr. Jeffries said.

The local ice lottery is further evidence of a long warming trend affecting lakes and rivers throughout the Northern Hemisphere, reported by University of Wisconsin researchers who analyzed newspaper archives, transport ledgers and religious records dating back to the 16th century. Seventeen lakes in Europe, Asia and the U.S. with records going back 150 years are thawing, on average, 13 days earlier now than when first recorded, said Wisconsin lake scientist Barbara Benson.

Associated Press
Volunteers help lift the Nenana tripod on the Tanana River as part of the Nenana Ice Classic.

In Nenana, climatology is folk art. There are no laser altimeters, seismometers or strain gauges to monitor the ice flow. Instead, there is a 26-foot-high pyramid of painted spruce logs anchored in the crust of river ice. When the ice breaks up, the contraption collapses. A trip wire triggers a siren and stops a clock on shore.

"This data didn't come from a long-term planned scientific monitoring scheme. This was a home-grown effort by people to pay attention to what was going on in the world," said Duke University ecologist Raphael Sagarin, who analyzed the lottery records. "It speaks to a larger issue in climate-change science."

By happenstance, the snowbound surveyors who founded the event in 1917 set up a system that today can help researchers begin to understand the interplay of climate, land-use changes, solar cycles, ocean currents and fluctuating levels of greenhouse gases, such as carbon dioxide and methane. The natural variations of weather can mask long-term trends, especially in regions where records are sparse.

Lately, the world weather has been especially perplexing, influenced by the cold ocean temperatures of a La Niña current in the equatorial Pacific.


Between 1846 and 1995, lake and river ice around the northern hemisphere froze progressively later and thawed incrementally earlier, providing historical evidence of a world-wide long-term warming trend, researchers at the University of Wisconsin's Center for Limnology discovered.
In Science, the scientists reported that later freezes and earlier thaws translate into air temperatures increasing at about 1.2°C per 100 years. In the journal Oceanography and Limnology they analyzed 65 lakes and rivers in the Great Lakes region and determined that the thawing trend has accelerated in recent years.
Lakes in New England thaw more than a week earlier now than in 1850, the U.S. Geological Survey reported. Between 1850 and 2000, lake ice thawed 9 days earlier in northern and mountainous areas of New England and by 16 days in more southerly locations. The researchers catalogued ice-out dates for 29 New England lakes. In Alaska, the Nenana Ice Classic makes an annual lottery of the spring thaw, offering people the chance to bet of the precise time the winter ice on the Tenana River breaks up.

For Earth's land areas, 2007 was the warmest year on record. This year, record cold is more the norm. Global land-surface temperatures so far are below the 20th-century mean for the first time since 1982, according to the National Climatic Data Center. Last month in China, snowstorms stranded millions of people, while in Mumbai, officials reported the coldest day in 46 years.

Yet, England basked in its fourth-warmest January since 1914, the British Met Office reported. The crocus and narcissus at the U.K.'s Royal Botanical Gardens at Kew flowered a week earlier than last year -- 11 days ahead of their average for the decade and weeks ahead of their pattern in the 1980s. In Prague, New Year's Day was the warmest since 1775.

"It is difficult to judge the significance of what we are seeing this year," said Kew researcher Sandra Bell. "Is it a glitch or is it the beginning of something more sinister and alarming?"

Seeking the order underlying so much variation, scientists have combed generations of farm records, maple-sugaring notes, bird-watchers' logs, botanical files, museum indexes and religious documents. Assembling a mosaic of incremental shifts, researchers believe they detect the effects of rising temperatures on seasonal rhythms touching on hundreds of species.

"The year-to-year variation confuses people," said University of Wisconsin freshwater-ice expert John Magnuson. "Over the long-term -- 150 years -- the trend is unmistakable."

After studying notes kept by amateur pond-watchers, for instance, scientists at the U.S. Geological Survey concluded that lakes in the New England highlands now thaw almost two weeks earlier than in 1850, a sign of a warming climate.

This spring, the behavior of Nenana's frozen river is anyone's guess. Last Sunday, lottery workers were out on the ice -- already 41 inches thick -- setting up the spruce pyramid, anticipating a breakup in late April or May. They celebrated the construction with fireworks, sled-dog races and a fur-hat contest.

Over the decades, the river ice has confounded predictions. Some players have bet based on computer analysis of past temperatures and ice thickness; others have looked to sunspot activity.

None of them have won.

"Sometimes I use birthdays and sometimes I pull numbers out of a hat," said lottery manager Cherrie Forness. "We almost won one year. It was a second away from our minute. But a second away doesn't count."

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