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Arctic Expedition Gleans Clues to Warming

Think scientific research is boring? Try sleeping in an unheated tent perched on a lonely hunk of ice in the Arctic Ocean for six straight weeks, equipped with a noisemaker in case of polar bear attacks, in temperatures that hover around  minus 46 degrees Fahrenheit (minus 43 Celsius).
/ Source: OurAmazingPlanet

Think scientific research is boring? Try sleeping in an unheated tent perched on a lonely hunk of ice in the Arctic Ocean for six straight weeks, equipped with a noisemaker in case of polar bear attacks, in temperatures that hover around  minus 46 degrees Fahrenheit (minus 43 Celsius).

Nearly a dozen scientists braved such hardships of polar living earlier this year as part of the Catlin Arctic Survey, aimed atgathering data that may help solve the enduring puzzle of increasing Arctic ice melt.

"It was incredibly cold, but I wouldn't be there if I didn't enjoy it," said Victoria Hill, a research assistant professor at Old Dominion University in Virginia. "I go because I’m curious, and that makes it fun," Hill said, "because you never know what you're going to find."

Hill studies colored dissolved organic material, or CDOM (pronounced SEE-dahm), a material produced when plants die and break down, which appears in oceans around the world. Dead algae is a significant source of CDOM.

CDOM sucks up sunlight — particularly blue and UV light, the sun's most powerful rays — and warms ocean waters.

Hill said that CDOM may be one of the mechanisms that govern ice melt in the Arctic, and she set out to measure how much CDOM was in the local ice and in ocean water down to about 600 feet (200 meters), taking samples every two days during the six-week trip.

Not nice for ice

The Arctic is undergoing dramatic changes. Satellite records show the average extent of Arctic sea ice has dropped by about 12 percent per decade since 1979, when satellites first began monitoring the ice.

"That's pretty big," said Mark Serreze, director of the National Snow and Ice Data Center at the University of Colorado. "It's amazing how we're seeing the Arctic transform before our eyes."

And although certain factors do account for a good chunk of the ice loss — increasing greenhouse gases and natural climate variability are two big factors, Serreze said — scientists still can't get climate models to accurately reflect the marked decline in Arctic ice.

"The observed rate of loss seems to be larger than what our models are telling us we should be seeing," Serreze told OurAmazingPlanet.

Climate models are a bit like a movie that scientists can run backward and forward through time. To make sure models tell the correct story, scientists plug in a host of factors and conditions, turn them on in reverse, and see if the models recreate what actually happened.

"If they can simulate past climate, that gives us more confidence they're going to be simulating future conditions as well," Serreze said.

Because the climate model "movies" of Arctic ice melt keep turning out wrong, showing there should be more ice than there actually is, there must be some missing characters. That's where CDOM comes in.

See what?

Hill said she expected to find more CDOM in the water and the ice than she initially did. When she first arrived at the camp in March, she says there was almost no CDOM in the water, and very little in the ice.

"But as our time at the camp progressed, and there was more and more sunlight, I started to see more," Hill said, which likely indicates the increase was driven by the growth — and subsequent death — of algae that live deep in sea ice. (The tiny plants need sunlight to bloom.)

The end of the trip cut short Hill's data-collecting, yet she says she has a good idea of what would have happened.

"If we'd stayed longer, what we would have seen is the CDOM in the ice going out into the water, and as the ice broke apart and the water was exposed to sunlight, that would have caused heating," Hill said.

However, Hill said, how big a role CDOM plays in that heating is still a mystery. "Does it account for 50 percent of the heating, 70 percent, 10 percent?" she said. "Nobody has been able to measure that and tease it out."

To that end, Hill wants to set up a buoy that, unlike a human, would be able to stay in the Arctic for months at a time. Equipped with the correct sensors, the buoy would be able to send back data on water temperature and how much CDOM is in the water — and would also provide a picture of how CDOM levels change seasonally.

Hill said that if funding comes through, she hopes to have the buoy in the Arctic in 2013.

Unhappy ending?

Jinlun Zhang, a scientist who focuses on Arctic climate models, said CDOM could be a key player in ice melt, "but right now we don't have a lot of the data." Zhang, principle oceanographer at the Applied Physics Laboratory at the University of Washington's Polar Science Center, said "more data would definitely be helpful, that's for sure."

And although Zhang said it's important to refine models and gain a better understanding of the myriad forces at play in Earth's far north, Arctic sea ice appears to be on a doomed path.

"I think it's very likely that by around 2030 or 2040 the Arctic summer will be ice-free," Zhang said.

Research has shown that a feedback model is driving ice melt in Arctic, meaning that as more and more open water is exposed to sunlight, more heat is absorbed into the water, which then melts more ice, and exposes more water. So understanding CDOM's role in that melting may help improve forecasts of what the future holds. And although forecasts of impending ice-free summers persist, Hill maintains that understanding precisely why and how melt is happening is of utmost importance.

"Once we understand the system properly," Hill said, "and we're able to take that understanding and make a good model of how the world works, then I think we have a much better chance of taking care of the world properly."

Reach Andrea Mustain at Follow her on Twitter @AndreaMustain.