Thaw contest shows warming trend

The Associated Press

ANCHORAGE, Alaska — For 84 years, winter-weary Alaskans have amused themselves every spring by placing bets on when the ice on the Tanana River will break up. Now those years of data have helped climate researchers conclude that spring is arriving earlier.

The study by Stanford University scientists in Friday’s issue of the journal Science relied on records from the Nenana Ice Classic, an annual guessing game held in the community 230 miles north of Anchorage.

The contest was started in 1917 by engineers building a railroad bridge over the Tanana. Because ice halted construction, the idle engineers bided their time by placing bets on when the ice would break up.

Now a wooden tripod is placed on the ice and is hooked up to a clock onshore. Those who come closest to guessing the exact time and date when the ice breaks and the tripod moves downriver share a jackpot that has grown to more than $300,000 in recent years.

Breakup on the river is seen as the unofficial start of spring in Alaska, and contest organizers have carefully recorded the date and time of its arrival every year.

Stanford marine biologist Raphael Sagarin learned of the contest while doing research in Alaska last year and realized the possibilities.

"I immediately thought this might be a great record of climate change. It turns out to be really good, accurate data," said Sagarin, who co-wrote the study with Stanford biology professor Fiorenza Micheli.

The researchers analyzed contest records and discovered that, on average, the Tanana River breakup is occurring 5.5 days earlier in recent years than it did in 1917. The findings are in line with historic temperature data from Nenana and Fairbanks, about 40 miles away.

The study did not address what might be behind the change

For centuries, hobbyists have collected data on the world around them — from the arrival of the first bird in spring to the first frost in autumn. The branch of science that looks at the annual timing of natural events is known as phenology.

Until recent years, scientists have dismissed such nontraditional data gathered by amateurs.

"Now scientists are taking a second look at phenology and giving it some respect," Sagarin said.

On the Net: www.sciencemag.org