U.S. Students Experience Hands-on Science in Greenland

Joint Science Education Program brings high-school students to Arctic research sites

While most of the U.S. was battling record July heat, some U.S. students were seeing world-class research up-close in one of the world's coldest and most scientifically significant places: the tundra and ice sheet in Greenland.

The students--from the states of Alaska, Arizona, Colorado, Idaho, New York and Washington--were in Greenland as part of the Joint Science Education Program (JSEP), a cultural and scientific exchange between Denmark, Greenland and the United States, under the guidance of teachers from all three nations.

The three-week JSEP experience was divided into two parts: the Greenlandic-led Field School--which took place in and around Kangerlussuaq, Greenland--and Science Education Week, in which students visited Danish and U.S. research stations on the Greenland Ice Sheet. The National Science Foundation coordinates the Science Education Week experience.

In addition to being on the ground during a rare widespread melt of the ice sheet's surface, the students descended into a pit at NSF's Summit Camp to see how annual snows turn into layers of ice; used off-the-shelf scientific tools as part of an NSF-funded distance-learning pilot project with students in Idaho; worked with researchers measuring Arctic methane releases as groundwork for building a sensor for a possible future Mars probe; and visited the multi-year, Danish-led North Greenland Eemian (NEEM) Ice Drilling project, a paleoclimate research program, just as drilling came to an end.

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Cascade Lake, Southwestern Alaska

Cascade Lake in southwestern Alaska. The lake is fed by glaciers in the Ahklun Mountains. Glacier meltwater enters the lake on the left in this picture. The amount of sediment delivered to the lake can vary with the intensity of the summer melt season and is registered in sediment cores through changes in depositional rates and other indicators.

Sediment cores were taken as part of a study, supported primarily by the National Science Foundation (NSF), that indicates arctic temperatures suddenly increased during the last 50 years of the period from A.D. 1 to the year 2000. Because this warming occurred abruptly during the 20th century while atmospheric greenhouse gases were accumulating, these findings provide additional evidence that humans are influencing climate.

The study was led by Darrell Kaufman of Northern Arizona University. To learn more, see the NSF press release The Arctic Offers More Evidence of Human Influences on Climate Change. [NSF has supported climate change research in Alaska by Kaufman and his students since 1991. Recent awards include: "Holocene climatic variability in southern Alaska" (grant ATM 03-18341), "Accessing climate and lake monitoring equipment, southern Alaska" (grant EAR 08-20363), "Coupled glacial and lacustrine evidence for decadal- to millennial-scale variability in the climatologic Aleutian Low, southern Alaska" (grant EAR 08-23522), and "A synthesis of the last 2000 years of climatic variability from arctic lakes" (grant ARC 04-55043).]

(Date of Image: July 2004)

Credit: Darrell Kaufman, Northern Arizona University

Petermann Glacier

The Petermann Glacier grinds and slides toward the sea along the northwestern coast of Greenland, terminating in a giant floating ice tongue. Like other glaciers that end in the ocean, Petermann periodically calves icebergs. A massive iceberg, or ice island, broke off of the Petermann Glacier in 2010. Now, nearly two years later, another chunk of ice has broken free.

The Moderate Resolution Imaging Spectroradiometer, or MODIS, on NASA’s Aqua satellite observed the new iceberg calving and drifting downstream on July 16–17, 2012. Because Aqua is a polar-orbiting satellite, it makes multiple passes over the polar regions each day.

Image Credit: NASA

Glacier Sermeq Avangnardleq

The glacier Sermeq Avangnardleq, located about 35 kilometers northeast of the coastal town Ilulissat in west Greenland, has been flowing at an accelerated speed towards the ocean since 2000. In the last century and up to 1999, the glacier surface was smooth and used by the people of Ilulissat with their dog sledges to access the ice sheet. But in the last decade, surface air temperatures started to increase in summer and now, the glacier now moves with a speed of several miles per hour into the ocean, leaving its surface heavily crevassed and only accessible by helicopter. Climate and glacier studies have been carried out in this region since 1990 and have documented the rapid increase in ice flow during the warming climate.)

This picture was taken as part of the Greenland Climate Network (GC-Net), supported in part by a grant from the National Science Foundation (for logistic support; grant through Polar Resources; twin otter support for hours to maintain the Greenland climate network).

To learn more about the CG-Net, visit the project's website. [This picture was taken at 69 de 21' 43.70" N, 50 deg 18' 11.01" W; Glacier Sermeq Avangnardleq, 35 km NE of Ilulissat, western slope of the Greenland ice sheet. Picture taken from helicopter 25 meters above the surface using a Nikon 700, 1/1600, f8.8, ISO 200.]

(Date of Image: August 2009)

Credit: Konrad Steffen, CIRES/University of Colorado

Analysis of Speed of Greenland Glaciers Gives New Insight for Rising Sea Level

Researchers determine that although glaciers continue to increase in velocity, the rate at which they can dump ice into the ocean is limited

Changes in the speed that ice travels in more than 200 outlet glaciers indicates that Greenland's contribution to rising sea level in the 21st century could be significantly less than the upper limits some scientists thought possible.

The finding comes from a paper funded by the National Science Foundation (NSF) and NASA and published in today's journal Science.

While the study indicates that a melting Greenland's contributions to rising sea levels could be less than expected, researchers concede that more work needs to be done before any definitive trend can be identified.

Studies like this one are designed to examine more closely and in greater detail what is actually happening with the ice sheets, often using newer and more precise tools and thereby better defining the parameters that scientists use to make predictions, such as the upper limits of sea-level rise.

"This study provides more evidence that the rate at which these glaciers can dump ice into the ocean is indeed limited," said Ian Howat, assistant professor of Earth sciences and member of the Byrd Polar Research Center at Ohio State University, a co-author on the paper. "What remains to be seen is how long the acceleration will continue--but it appears that our worst-case scenarios aren't likely."

The fate of the Earth's ice sheets and their potential contributions to sea-level rise as the globe warms are among the major scientific uncertainties cited in the Fourth Assessment of the Intergovernmental Panel on Climate Change (IPCC). This is in part because the Greenland and Antarctic ice sheets have historically been, and in large measure continue to be, relatively sparsely monitored, as compared to other parts of the globe.

The faster the glaciers move, the more ice and melt water they release into the ocean.

In previous studies, scientists trying to understand the contribution of melting ice to rising sea level in a warming world considered a scenario in which the Greenland glaciers would either double or increase by as much as ten-fold their velocity between 2000 and 2010 and then stabilize at the higher speed.

This new study shows Greenland ice would likely move at the lower rate--a doubling of its speed--and contribute about four inches to rising sea level by 2100. The previous studies used the higher speed and estimated the glaciers would contribute nearly 19 inches by the end of this century.

In the new study, the scientists extracted a decade-long record of changes in Greenland outlet glaciers by producing velocity maps using data from the Canadian Space Agency's Radarsat-1 satellite, Germany's TerraSar-X satellite and Japan's Advanced Land Observation Satellite. They started with the winter of 2000-01 and then repeated the process for each winter from 2005-06 through 2010-11 and found that the outlet glaciers had not increased in velocity as much as had been speculated.

"So far, on average we're seeing about a 30 percent speedup in 10 years [of Greenland glaciers, which gives new insight for rising sea level]," said Twila Moon, a University of Washington doctoral student in Earth and space sciences and lead author of the paper documenting the observations.

"This study is a great example of the power of high-resolution data sets in both space and time, and the importance of looking carefully at as much data as possible in helping make the best predictions we can of future changes", said Henrietta Edmonds, program director for Arctic Natural Sciences in NSF's Office of Polar Programs.

The scientists saw no clear indication in the new research that the glaciers will stop gaining speed during the rest of the century, and so by 2100 they could reach or exceed the scenario in which they contribute four inches to sea level rise.

The record showed a complex pattern of behavior. Nearly all of Greenland's largest glaciers that end on land move at top speeds of 30 to 325 feet a year, and their changes in speed are small because they are already moving slowly. Glaciers that terminate in fjord ice shelves move at 1,000 feet to a mile a year, but didn't gain speed appreciably during the decade.

In the East, Southeast and Northwest areas of Greenland, glaciers that end in the ocean can travel seven miles or more in a year. Their changes in speed varied (some even slowed), but on average the speeds increased by 28 percent in the Northwest and 32 percent in the Southeast during the decade.

Moon said she was drawn to the research from a desire to take the large store of data available from the satellites and put it into a usable form to understand what is happening to Greenland's ice. "We don't have a really good handle on it and we need to have that if we're going to understand the effects of climate change," she said.  "We are going to need to continue to look at all of the ice sheet to see how it's changing, and we are going to need to continue to work on some tough details to understand how individual glaciers change."

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Scientists Unlock Record of Ecosystem Changes Frozen in World's Glaciers

New clues about how Earth's remote ecosystems have been influenced by the industrial revolution have been uncovered. Until now they were locked away, frozen in the ice of glaciers.

So say scientist Aron Stubbins of the Skidaway Institute of Oceanography and colleagues.

They published results of their study in the March, 2012, issue of the journal Nature Geoscience. It shows that everything flows downhill, eventually.

The research was funded by the National Science Foundation (NSF).

The key to the process is carbon-containing dissolved organic matter (DOM) in glacial ice.

Glaciers provide large amounts of carbon to downstream ecosystems. Many scientists believe the source of this carbon lies in ancient forests and peatlands overrun by the glaciers.

However, Stubbins and others think the carbon comes mainly from modern biomass and fossil fuel burning that makes its way onto the glaciers' surfaces.

Once deposited by snow and rain, the DOM moves with the glacier and is eventually delivered downstream where it provides food for microorganisms at the base of the aquatic food web.

"In warmer ecosystems like in the temperate or tropical zones, once this atmospheric organic material makes landfall it is quickly consumed by plants, animals and microbial populations," says Stubbins. "But in cold glacier environments, these carbon 'signals' are preserved."

Remote regions often are perceived as pristine and devoid of human influence.

But glaciers show us that nowhere goes untouched, Stubbins says. Burning fuels has effects on ecosystems far removed from industrial activity.

"Because deposition of combustion products is a global phenomenon, all ecosystems may be receiving this 'subsidy,'" says Matt Kane, program director in NSF's Division of Environmental Biology, which funded the study along with NSF's Divisions of Ocean and Earth Sciences.

"Some aquatic systems previously thought to be pristine have, in fact, been affected by human activities for a century or more."

Glacier ecosystems cover ten percent of the Earth, yet how carbon moves through these ecosystems isn't completely understood.

"More knowledge of glacier biogeochemistry is a priority, as glacier environments are among the most sensitive to climate warming and the effects of industrial pollution," says Stubbins.

Globally, glacier ice loss is accelerating, driven in part by deposits of carbon in the form of soot or "black carbon," which darken glacier surfaces and increase their absorption of light and heat.

Biomass and fossil fuel burning by people around the globe are the major sources of black carbon.

Stubbins and colleagues have conducted much of their research at the Mendenhall Glacier near Juneau, Alaska.

Mendenhall and other glaciers that end their journey in the Gulf of Alaska receive large amounts of rain and snow. This precipitation acts to strip the atmosphere of organic materials, then dumps them on the glaciers.

Consequently, these glaciers are among the most sensitive to global emissions of soot.

The researchers' findings also reveal that the ocean may have changed over past centuries as a result of this process.

The microbes that form the bottom of the food web are sensitive to changes in the quantity and quality of carbon entering the marine system.

The scientists found that the organic matter in glacier outflows stems largely from human activities. This means that the supply of glacial carbon to the coastal waters of the Gulf of Alaska is a modern, post-industrial phenomenon.

"When we look at marine food webs today, we may be seeing a picture that is significantly different from what existed before the late 18th century," says Stubbins.

"It's unknown how this man-made carbon has influenced the coastal food webs of Alaska, for example, and the fisheries they support."

A warming climate will increase the outflow of the glaciers and the accompanying input of dissolved organic material into the coastal ocean.

The effects will be most clear in glacially-dominated coastal regions, such as those off the Gulf of Alaska, Greenland and Patagonia. These areas have the highest rate of glacier ice loss.

"It's not known to what extent organic material deposition has changed, and will continue to alter, glacially-dominated coastal ecosystems or the open ocean," says Stubbins.

"But glaciers will continue to provide a valuable and unique window into the role this deposition of organic material plays in a rapidly-changing environment."

Stubbins' collaborators on the project include Eran Hood and Andrew Vermilyea of the University of Alaska Southeast; Peter Raymond and David Butman of Yale University; George Aiken, Robert Striegl and Paul Schuster of the U.S. Geological Survey; Rachel Sleighter, Hussain Abdulla and Patrick Hatcher of Old Dominion University; Peter Hernes of the University of California-Davis; Durelle Scott of Virginia Polytechnic Institute and State University; and Robert Spencer of the Woods Hole Research Center.

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