For comparison: Global sea level is rising at about 2.1 millimeters per year, or a little over one-sixteenth of an inch.

Seasons: Winter, Spring, Summer, Fall

Sources: Overeem, I et al. “Sea ice loss enhances wave action at the Arctic coast.” Geophysical Research Letters 38 (2011): L17503 and National Snow and Ice Data Center: Arctic Sea Ice News and Analysis. Accessed Online 28 January 2011 <http://nsidc.org/arcticseaicenews/> and Francis, OP et al. “Ocean wave conditions in the Chukchi Sea from satellite and in situ observations.” Geophysical Research Letters 38 (2011): L24610.

For at least the past two million years, Earth has moved between interglacial phases, like the past 10,000 years when ice cover was confined to the polar regions, and glacial phases, when large ice sheets extend into the midlatitudes. The most common reason cited for these shifts are changes in the nature of Earth’s orbital properties:

• Eccentricity: The Earth does not orbit in a perfect circle, but instead has a perihelion, a point in the year when the Earth is closest to the Sun, and an aphelion, a point in the year when the Earth is farthest away. The greater the difference between Earth’s orbit and a perfect circle, the more eccentric the orbit is.
• Obliquity: Today, Earth’s axis is tilted at 23.44 degrees, but it moves between 21.5 and 24.5 degrees on periods of about 41,000 years.
• Precession: Where the Earth is in its seasonal cycle when it is at its orbital perihelion and aphelion affects the length and intensity of the seasons. This cycle moves in a period of about 20,000 years and its effects on Earth’s climate are more extreme during periods when eccentricity is more extreme.

Together, these cycles push Earth into and out of glacial states. For example, when Earth’s axial tilt is close to 24.5 degrees and the eccentricity and precessional cycles put Earth closest to the sun during the Northern Hemisphere summer, the summer becomes much more intense and glaciers will shrink. These warm summers also stimulate greater tree growth at Northern Hemisphere high latitudes, which leads to more absorption of sunlight at the Earth’s surface and warmer temperatures, reinforcing the warming trend.

Seasons: Winter, Spring, Summer, Fall

Source: Huybers, P. “Combined obliquity and precession pacing of late Pleistocene deglaciations.” Nature 480 (2011): 229-232.

Seasons: Winter, Spring, Summer, Fall

Source: Kinnard, C et al. “Reconstructed changes in Arctic sea ice over the past 1,450 years.” Nature 479 (2011): 509-512.

For comparison: The sudden 5,300,000 cubic feet per second surge of freshwater is almost ten times the average flow of the Mississippi River at Baton Rouge, Louisiana, and slightly less than half of the record flow for that location.

Seasons: Winter, Spring, Summer, Fall

Source: Sionneau, T et al. “Provenance of freshwater pulses in the Gulf of Mexico during the last deglaciation.” Quaternary Research 74 (2010): 235-245 and Tarasov, L and Peltier, WR. “A calibrated deglacial drainage chronology for the North American continent: evidence of an Arctic trigger for the Younger Dryas.” Quaternary Science Reviews 25 (2006): 659-688.

The Arctic, where the temperature rise has been twice the global average, has born some of the most visible impacts of the last 40 years of warming. Melting permafrost on land and melting sea ice in the water, the release of methane that had formerly been locked frozen in the tundra, a retreating Greenland Ice Sheet and melting glaciers, the movement of trees into zones formerly too cold to support trees, and the movement of more temperate marine species into the Arctic Ocean have all been observed. Another impact is the degradation of silt ocean cliffs, particularly those along Alaska’s Beaufort and Chuckchi Seas. Local residents, many of whom are descendants of people who lived in the same region thousands of years ago, have houses and other important structures on these cliffs. These cliffs also support infrastructure that is part of the National Petroleum Reserve – Alaska. These silt cliffs have always been subject to erosion from wave action, but have for the most part been immune to complete collapse. This began to change as waters sufficiently warm to melt the ice that holds them together began to appear over the past 40 years, and as the sea ice began to retreat to minimums unprecedented in modern history. Between 1979 and 2009 the number of open water days along the coast (days without ice masses protecting the cliffs from waves) increased from an average of 45 to 95 days, allowing more storms and high-wave events to bring warm, ice melting waters to the cliffs. The average coastal erosion rate of 28.5 feet during the 1980s and 1990s increased to 45 feet per year during the 2000s.

Seasons: Summer, Fall

Source: Overeem, I et al. “Sea ice loss enhances wave action at the Arctic coast.” Geophysical Research Letters 38 (2011): L17503.

The glaciers that make the peaks of the Western United States white year round are located almost exclusively within National Forests and National Parks. In addition to providing scenery and tourist attractions, these glaciers partially melt during the summer months, feeding streams and rivers that bring waters to cities and farms in the West. In fact, most of the West’s water comes from mountain snowpack or glaciers. As long as the glaciers accumulate enough snow during the wet and cold winter months to offset the summer melt, they persist. When temperatures warm however, as they have over the past century, summertime melt exceeds winter freeze, and the glaciers shrink in size. Warmer temperatures over the past century have resulted in melting glaciers across the National Parks and Forests of the West:

• North Cascades National Park has 40 percent less glacial mass than it did in 1850, and Lewis Glacier disappeared in 1990. Streamflow in the watershed fed by Lewis subsequently declined by 40 percent.
• In Alaska’s Glacier Bay National Park, Muir Glacier, one of the Park’s best recognized, is a mile shorter and 600 feet thinner than it was in 1980.
• The glaciers of Glacier National Park have been some of the hardest hit in the West: Today, about 27 percent of the area of Glacier National Park that was covered by glaciers in 1850 is still covered. The number of glaciers has been cut from 150 to 37.
• In the past 110 years, the seven largest of Mt. Hood’s eleven glaciers in Oregon’s Mt. Hood National Forest have each lost more than 30 percent of their masses. Sandy Glacier, which faces downtown Portland, has retreated by 60 percent during this period.

Sources: “Most Alaskan Glaciers Retreating, Thinning, and Stagnating, Says Major USGS Report: Press Release.” U.S.G.S. Newsroom. 2008. U.S. Department of the Interior, U.S. Geological Survey: Office of Communication. 6 October 2008 < http://www.usgs.gov/newsroom/article.asp?ID=2033> and United States. National Park Service. Climate Monitoring in Glacier Bay National Park and Preserve: Capturing Climate Change Indicators. 2007 Annual Report. Washington, GPO, 2007. Accessed Online 3 November 2008 and Sources: United States Geologic Survey. “Fifty-Year Record of Glacier Change Reveals Shifting Climate in the Pacific Northwest and Alaska, USA.” 6 July 2009. Accessed Online 7 August 2009 and The National Park Service. “North Cascades National Park Complex: Glacial Monitoring Program.” Accessed Online 10 July 2007 and Global Glacier Retreat Project. Nichols College. Accessed Online 5 July 2007 and Jackson, K.M. and Fountain, A.G. “Spatial and morphological change on Eliot Glacier, Mount Hood, Oregon, USA.” Annals of Glaciology 22 (2007): 222-226 and Fagre, DB. “Adapting to the Reality of Climate Change at Glacier National Park, Montana, USA.” Proceedings I Conferencia Cambio Climático 2005.

For comparison: 200 gigatons is equivalent in volume to 550,000 Empire State Buildings, 38 Lake Okeechobees and 11 Great Salt Lakes.

Seasons: Winter, Spring, Summer, Fall

Source: Mernild, SH et al. “Increasing mass loss from Greenland’s Mittivakkat Gletscher.” The Cryosphere 5 (2011): 341-348.

The last interglacial period (LIG), which ran from about 130,000 to 120,000 years ago, was a particularly warm interglacial period with global temperatures about 3.6 degrees warmer than today. Sea levels during the LIG were about 23 feet higher than current Holocene (the last 10,000 years) levels, despite global sea surface temperatures not being much warmer than today (perhaps 1.3 degrees Fahrenheit warmer). This lack of a major water temperature difference implies that only a small fraction – about a foot or two – of the 23-foot sea level rise was due to thermal expansion of the ocean waters, which happens as the ocean collects heat and the water molecules become more energetic. For comparison, about one-third of the eight-inch sea level rise experienced during the 20th century was due to thermal expansion; melting of mountain glaciers and the Greenland and Antarctic ice sheets accounted for the rest. In addition to thermal expansion, estimates of sea level rise sources during the LIG suggest that less than one-third was from Greenland and mountain glaciers, and at least two thirds was from the Antarctic Ice Sheet. This implies that the stability of the Antarctic Ice Sheet may be particularly sensitive to temperature rises.

Source: McKay, NP et al. “The role of ocean thermal expansion in Last Interglacial sea level rise.” Geophysical Research Letters 38 (2011): L14605.  

The 2007 September Arctic sea ice minimum extent was the smallest on record. This ice has been in a declining trend since 2002, with warmer temperatures favoring melt and prevailing winds favoring ice transport out of the Fram Strait between Greenland and Scandinavia. There has been a slight recovery in ice levels since 2008, although the multiyear ice extent in March 2011 was lower than it was in any year prior to spring 2008, following the fall 2007 record minimum. The measurement of multiyear ice, or ice that has survived at least one melt season, is important for assessing the robustness of the Arctic sea ice, which has traditionally been a permanent, not seasonal, feature of the North Pole. Between 1980 and 2011, the percent of multiyear sea ice present in March declined by 33 percent, while the percentage of multiyear ice at the September minimum declined by 50 percent. In March 2011, only about 45 percent of the ice present in the Arctic was multiyear ice, compared with 75 percent in 1980. Additionally, in March 1980, about 50 percent of the ice cover was particularly old ice (older than five years), whereas by this March that number had declined to 10 percent. The last four years have seen a marked decline in the survival rate of multiyear ice, which is now at 74 percent, compared to the 1980 to 2006 period when the survival rate was 90 percent.

Seasons: Summer

Source: Maslanik, J et al. “Distribution and trends in Arctic sea ice age through spring 2011.” Geophysical Research Letters 38 (2011): L13502.

For comparison: 92 gigatons is about the same weight as 250,000 Empire State Buildings.

Seasons: Spring, Summer, Fall

Source: Gardner, AS et al. “Sharply increased mass loss from glaciers and ice caps in the Canadian Arctic Archipelago.” Nature 473 (2011): 357-360.

For Comparison: When sea levels were 23 feet higher, South Florida was likely under water, as was Louisiana’s Bayou. Cities like Baltimore, parts of Washington, DC, Boston, the Norfolk/Hampton Roads area and the Outer Banks were likely submerged as well. The Jutland Peninsula in Denmark was probably cut off from mainland Europe and enough of Scandinavia would have been submerged to allow the Baltic Sea to join the Arctic Ocean.

Seasons: Winter, Spring, Summer, Fall

Sources: Denton, GH et al. “The Last Glacial Termination.” Science 328 (2010): 1652-1655 and Kopp, RE et al. “Probabilistic assessment of sea level during the last interglacial stage.” Nature 462 (2009): 863-868.

For Comparison: 1670 Petagrams is about the same mass as 18 million Nimitz Class Aircraft Carriers or 300,000 Great Pyramids at Giza.

Seasons: Winter, Spring, Summer, Fall

Sources: Schuur, EAG et al. “The effect of permafrost thaw on old carbon release and net carbon exchange from tundra. Nature 459 (2009): 556-559 and Schuur, EAG et al. “Effects of Experimental Warming of the Deep Soil and Permafrost on Ecosystem Carbon Balance in Alaskan Tundra.” American Geophysical Union Fall Meeting 2009, abstract #U44A-03 and Tarnocai, C et al. “Soil organic carbon pools in the northern circumpolar permafrost region.” Global Biogeochemical Cycles 23 (2009): GB2023.

The eruption of Iceland’s Laki volcano from June 8, 1783 to February 1784 had widespread and devastating consequences the world over. The event was one of the biggest natural disasters in British history, with sulfuric acid gas fumes killing over 23,000 Britons. The gas plume initially caused heat waves in Europe before spreading around the globe and cooling the rest of the Northern Hemisphere. Both France and Japan experienced crop failures and famines that year, and Alaskan tree ring records tell of a remarkably cold summer in North America. The Inuit remember it as “the summer that did not come.” The following winter was remarkably cold as well, with Europe being around 3.6 degrees Fahrenheit below normal and eastern North America having temperatures 8.6 degrees Fahrenheit below the 225 year mean. Early Americans skated on the harbor ice of Charleston, South Carolina, the Mississippi River was frozen at its delta, ice floes floated through the Gulf of Mexico and the Chesapeake Bay had its longest freeze-over on record. But was this severely cold winter caused by Laki’s eruption? According to tree ring proxy records used to reconstruct conditions in the tropical Pacific Ocean and North Atlantic over the centuries before instrumental data, at least part of the winter’s severity was due to a strong El Niño in the tropical Pacific and a strongly negative North Atlantic Oscillation (NAO). The strong El Niño event shifted storm tracks to the south, bringing frequent winter storms to the southern United States, while the strongly negative NAO allowed frigid Arctic air masses to easily sweep southward into the mid-latitudes. The coincidence of these conditions, as a result of serendipitous sea surface temperature variability, is similar to what happened during the 2009-2010 winter, which brought record cold to parts of the United States.

Seasons: Winter, Spring, Summer, Fall

Source: D’Arrigo R, et al. “The anomalous winter of 1783-1784: Was the Lake eruption or an analog of the 2009-2010 winter to blame?” Geophysical Research Letters 38 (2011): L05706.

Boreal (Northern Hemisphere) spring is here. Even in the high northern latitudes, temperatures are beginning to warm and plants are beginning to come out of dormancy and photosynthesize, using the Sun’s energy to turn water and atmospheric carbon dioxide into sugar and grow. Snow cover may seem like a relic of winter, but snow also effectively reflects sunlight off the ground. In the boreal forests of the Northern Hemisphere, snow still covers much of the forest floor. Gaps in the tree canopy allow sunlight to hit snow on the ground, which reflects sunlight back towards the trees above. The amount of energy the trees receive from this reflection can even exceed the amount of energy they get from the initial downward wave of sunlight! It is likely that this reflection gives the trees a boost of energy, giving them the kick they need to “wake-up” and photosynthesize. This boost may be diminishing in importance as the duration of Northern Hemisphere snow cover has been shrinking at a rate of 5.5 days per decade over the past 40 years. Most of this decline in snow cover duration is due to melting in the late winter and early spring period.

Seasons: Spring

Sources: Choi, G et al. “Changing Northern Hemisphere Snow Season.” Journal of Climate 23 (2010): 5305-5310 and Pinty, B et al. “Snowy backgrounds enhance the absorption of visible light in forest canopies.” Geophysical Research Letters 38 (2011): L06404.

About 100 miles east of Salt Lake City, the Uinta Mountains of northeastern Utah rise up out of the desert. These mountains are the highest east-to-west mountain range in the contiguous United States.; most mountain ranges, such as the Rocky, Appalachian, Cascade and Sierra Nevada Mountain ranges all run from north-to-south. Today, there are no glaciers on the Uinta Mountains, despite peaks as high as 13,500 feet. 17,000 years ago, however, glaciers covered much of these ranges, with the feet of the glaciers being as low as 8500 feet. The dynamics of the glaciers at this time illustrate a few points about the most recent episode of deglaciation:
•    Despite the extent of the Laurentide, or North American, Ice Sheet reaching its maximum extent about 20,500 years ago, the glaciers in the Uinta Mountains did not reach their maximum extents until about 16,800 years ago. Glaciers in the Wind River range of Western Wyoming began their retreat at about the same time as the Laurentide Ice Sheet, while glaciers in southwestern Colorado did not start their retreat until 18,900 years ago and glaciers in north-central Colorado did not start to retreat until around 18.4 thousand years ago.
•    Glacier extents are affected by both temperature and moisture availability. As the North American ice sheet retreated, temperatures in northeastern Utah likely rose. At the same time , the jet stream moved further north and was frequently sitting over the Uinta Mountains, bringing in moist air masses that build glaciers.
•    To the west of the Uinta Mountains lie the remains of Lake Bonneville, once as large as Lake Michigan but today mostly desert with a few remnant water bodies such as the Great Salt Lake. Analysis of the ancient extents of the Uinta glaciers indicates that glaciers closer to the lake were larger than glaciers farther away. When Lake Bonneville started to shrink significantly around 17,000 years ago, the glaciers in the Uinta Mountains soon followed. This illustrates the importance of local moisture sources, such as large lakes, for local precipitation and glacial growth.

Seasons: Winter, Spring, Summer, Fall

Sources: Munroe, JS et al. “Latest Pleistocene advance of alpine glaciers in the southwestern Uinta Mountains, Utah, USA: Evidence for the influence of local moisture sources.” Geology 34 (2006): 841-844 and Dyke, AS et al. “The Laurentide and Innuitian ice sheets during the Last Glacial Maximum.” Quaternary Science Reviews 21 (2002): 9-31.

Seasons: Winter, Spring, Summer, Fall

Source: Brierley, CM and Fedorov, AV. “Relative importance of meridional and zonal sea surface temperature gradients for the onset of the ice ages and Pliocene-Pleistocene climate evolution.” Paleoceanography 25 (2010): PA2214.

(Part 2 of 2)

The NEEM (North Greenland Eemian Ice Drilling) site is located at an elevation of 8,300 feet on top of the Greenland Ice Sheet. The population of this tiny outpost is an international mix of young and older scientists, researchers and ice core drilling experts. Many, like Dr. Jim White, director of the Stable Isotope Lab at the Institute of Arctic and Alpine Research (INSTAAR) at the University of Colorado, are renowned specialists in their fields. I was Jim’s guest for two weeks and was present when the drill reached bedrock after two years of hard work.

Scientists from 14 nations participated in the NEEM project, making it the most international ice core effort to date. Dr. White arranged the support of the National Science Foundation, and after Denmark, the NSF was the project’s second biggest funder.

Dorthe Dahl-Jensen, from the Centre for Ice and Climate in Copenhagen, is project leader.

There were 38 of us in the small camp, in the middle of a magnificent desolation of white. Almost everyone there had been involved in ice core research before and they made me feel right at home!

The field camp is no hotel and the conditions are tough. Need a shower? That means going outside and shoveling snow into the snow melter. While the sleeping arrangement consists of a twin bed in a tent heated to 30 degrees, the food is fabulous!

One of my most memorable moments was driving a Ski-Doo snowmobile out to a climate station two kilometers north of camp. At that distance, NEEM’s dome looked like a tiny dot in a world of blue and white. The 24-hour sunlight did take some getting used to, but my trip to Antarctica last year prepared me for that: I brought two sleeping masks with me!

Why NEEM is So Important

Year after year, the snow piles up in Greenland. As it gets buried and compressed, it eventually forms hard clear ice. That ice across most of the Greenland Ice Sheet is two kilometers (just over one mile) thick. The ice sheet is one of the two on Earth; the other is on Antarctica, where another major core drilling project is underway at WAIS Divide.

NEEM’s mission was to pull up ice that once fell as snow in Greenland around 140,000 years ago, then to read it like a climate history book! This was the first time that significant science measurements were done on an ice core as it was being drilled (this usually takes place in separate ice core labs).

By drilling cores of ancient ice, scientists are getting a look at the Earth’s past climate in a resolution thought impossible a few decades ago. They can determine year-by-year data going back thousands of years into the past! The ice near the bedrock at NEEM first fell as snow during the last glacial period that preceded the Eemian.

Though you may not notice it, Earth is currently in an ice age called the Quaternary Ice Age. Ice ages are periods when ice sheets periodically extend into the mid-latitudes from polar regions. Within an ice age, Earth’s climate shifts between glacial periods (colder temperatures with more ice cover) and interglacial periods (relatively warmer temperatures with less ice cover). Earth is currently in an interglacial period called the Holocene.

The Eemian was the last warm period before the Holocene. It occurred before the Weichselian (also known as Wisconsin) glacial period, which was 12,000 to about 110,000 years ago. NEEM obtained an ice core that goes all the way back through the Holocene interglacial, the Weichselian glacial, the Eemian interglacial, and finally into the penultimate glacial period before the Eemian – the Saalian, which occurred 130,000 to 200,000 years ago! The NEEM core is a two-mile long climate book of exceptional detail.

Nature’s Thermometer

By counting the ratio of heavy oxygen atoms to lighter ones found in the ice, NEEM scientists can derive the air temperature from when that ice was snow falling from the sky. Most oxygen atoms have 16 neutrons (O16), but a small percentage has 18 neutrons (O18). The ratio of these isotopes acts as a natural thermometer. This amazing fact was discovered by Willi Dansgaard from Denmark, and the Danes have been leaders in climate research ever since.

As I mentioned, I was lucky enough to be there when the drill reached the bottom of the ice sheet. Not only that, but I also watched as they pulled up a rock inside the ice core. After two years of drilling through clear ice, it was the first overt sign that the bottom was near. That rock, sitting under two miles of ice, had not seen the light of day in 140,000 years.

Drilling a deep hole in ice is much more difficult than you might imagine. The ice at that depth is under incredible pressure and a special drilling fluid was developed that is slightly heavier than ice, so it keeps the hole open. Some days were better than others, on which many meters of core were obtained, while other days saw very little. You’ve likely seen the famous temperature reconstructions from previous ice cores, but I’ll never look at another one of those without knowing how incredibly difficult it was to obtain it.

The cores are logged carefully and cut into sections. A small amount of ice is melted to get data on isotopes, and electrical conductivity measurements are also made to determine how dusty the air was at the time the ice fell as snow. Glacial periods are dustier than interglacial periods in Greenland, and experienced drillers can tell a lot just by looking at the core! The core will be divided into many sections, and scientists who request samples will be sent vials of water from the melted section they are interested in. A section of the core will remain frozen as a reference for the future.

The NEEM staff and scientists work seven days a week during the summer season, but they do take Saturday night off. Ties are mandatory for the Saturday dinner, which is an event that everyone looks forward to. There is an ice bar built out of the snow and everyone relaxes to music, wine and dancing, all under a midnight sun!

After nearly two weeks at NEEM the trip back was memorable. It warmed into the low 20s and the snow was soft … That meant three memorable takeoff attempts on the LC-130. Back in Kangerlussuaq, we took a drive to the amazingly beautiful Russell Glacier 35 miles away. Those were two weeks full of fascinating experiences. But my number one memory will be the amazing people of NEEM, doing the real grunt work of science.

Within just a few months last year, I found myself standing both at the South Pole and a few hundred miles from the North Pole. The trip to Antarctica was courtesy of the National Science Foundation, and I saw first hand the science being conducted in the most remote location on Earth.

Some of the most urgent science underway right now is the connected with obtaining ancient cores of ice at the top and bottom of the world. Together, these ice cores will help scientists understand how atmospheric and oceanic circulation patterns changed in the deep past. These natural fluctuations in Earth’s climate are important because they will help researchers to better predict the consequences of climate change.

Thanks to Dave Jones at Storm Center Communications, I was asked to be part of a three person team that would visit NEEM – the North Greenland Eemian Ice Drilling project. We were going to be guests of lead U.S. scientist James White at the University of Colorado and Danish Scientists J.P. Steffensen and Dorthe Dahl-Jensen.

In late July, I found myself once again traveling with the amazing New York Air National Guard. The 109th wing flies U.S. scientists to the Arctic and Antarctic. We flew from its base in New York to Kangerlussuag, Greenland. Kanger, as the air crew and scientists call it, is an old World War 2 airbase just north of the Arctic Circle.

Landing at NEEM

Getting to the top of the icecap is a place only the NY Air Guard can take you, and after a night’s sleep, that’s were we were headed! We stayed at KISS – the Kangerlussuaq International Science Support facility. This is where we were given our cold weather gear and sleeping bags. Greenland in summer would not be nearly as cold as Antarctica, but I would soon find out that it’s a lot snowier!

NEEM is at an elevation of 8,000 feet on top of the icecap in Northern Greenland. During my visit, about 30 scientists were attempting to finish drilling an ice core all the way to bedrock before the end of the short summer. The weather can change from sun to blinding snow in an instant. At a latitude of 77 degrees North, there would be no dark for my entire stay.

Just before noon on the 20th of July the ski-equipped LC130 landed on the snow runway at NEEM. It’s a landing one does not forget. Suddenly, the back of the plane opened up and a large pallet of supplies was pushed out the back. It quickly fell onto the snow and disappeared in a swirl of white.

There is only one heated place at NEEM. The large hand grenade-shaped structure is home to the kitchen, dining room, offices and a shower. Bathrooms consist of pits dug into the snow, and the flag flying out front means “occupied!” Scientists, staff and visitors sleep on bunk beds in tents. A small heater keeps the temperature a little above freezing in order to to keep the humidity down. Three of us shared a tent about 300 feet from the main dome.

After settling in, we had a fabulous dinner and watched the weather get worse. By late evening it was snowing heavily with 30 mile per hour winds. I crawled into my sleeping bag and started to get warm. I drifted off to sleep, but was soon awakened by howling winds and a shaking tent. Nature called, and at 3 a.m. I gathered enough courage to get down from my bunk and head to the outhouse: the tent over it was gone!

The blizzard lasted three days (and no nights). When the sun finally came out, it was like living on an ocean of snow. Deep blue sky, and nothing but white. The Arctic has been called the “great white quiet,” and believe me, the name fits. In my next post, the ice core and the science of NEEM …

View photos of Dan’s trip to NEEM below. Click on an image to download a high resolution version.

	Working in the science trench, a covered area 10 meters below the surface. The temperature holds at near zero degrees Fahrenheit. (Credit: Dan Satterfield)
	Project leader Dorthe Dahl-Jensen holds up the final core with a rock embedded in it. That ice fell as snow around 140,000 years ago. (Credit: Dan Satterfield)
	A beaming Dr. Jim White in the science trench, after the drill reached bedrock. (Credit: Dan Satterfield)
	The snow melter: Toss in snow and out comes a warm shower! (By the time you finish shoveling, you need one!) (Credit: Dan Satterfield)
	The ice bar at NEEM under the midnight sun. (Credit: Dan Satterfield)
	Packing the ice cores for shipment to Denmark and America. Scientists from around the world will use the cores for research. (Credit: Dan Satterfield)

Estimating how Earth’s climate varied before the modern period of instrumental records requires looking at natural records. How much a tree grows each year depends on how optimal the conditions are (i.e. whether they get sufficient water and sunlight, have a longer frost-free season, etc.). Analyzing differences in tree ring width is therefore a reasonable way to study past climate variability. Another annual recorder of weather variability is ice sheet accumulation. Each year, the Antarctic and Greenland ice sheets accumulate layers of snowfall, which is compacted and covered by the following year’s snowfall. Annual variability in ice accumulation follows temperature and precipitation variability, which is in turn determined by sea-surface temperatures and large scale circulation patterns, such as the North Atlantic Oscillation (NAO). The NAO is a measure of the difference in atmospheric pressure between the Arctic and the subtropical Atlantic – this pattern has a strong influence over winter weather in the midlatitudes.

More than 80 ice cores have been taken from locations on the Greenland Ice Sheet where ground-based radar, aircraft and satellite altimetry measurements have also been made. These modern measurements, along with current temperature and precipitation data, enable researchers to establish relationships between weather variables and annual ice accumulation. Understanding this relationship, as well as having a written record of Icelandic volcanic eruptions that correspond to the volcanic ash that is recorded in the ice cores, gives us a record of annual weather variability in Greenland. One ice core with visible annual layers revealed atmospheric conditions back to the year 1673, based on an average accumulation of 14 inches of ice each year.

Learn more about how paleoclimatologists study past climate variability in the upcoming Climate Fact Sheet, Coring for Clues: Reconstructing Climates of the Past.

Seasons: Winter, Spring, Summer, Fall

Sources: Mosley-Thompson, E et al. “Regional sensitivity of Greenland precipitation to NAO variability.” Geophysical Research Letters 32 (2005): L24707 and Banta JR and McConnell, JR. “Annual accumulation over recent centuries at four sites in central Greenland.” Journal of Geophysical Research: Atmospheres 112 (2007): D10114 and Bales, RC et al. “Annual accumulation for Greenland updates using ice core data developed during 2000-2006 and analysis of daily coastal meteorological data.” Journal of Geophysical Research: Atmospheres 114 (2009): D06116.

(Part 1 of 2)

Within just a few months last year, I found myself standing both at the South Pole and a few hundred miles from the North Pole. The trip to Antarctica was courtesy of the National Science Foundation, and I saw first hand the science being conducted in the most remote location on Earth.

Some of the most urgent science underway right now is the connected with obtaining ancient cores of ice at the top and bottom of the world. Together, these ice cores will help scientists understand how atmospheric and oceanic circulation patterns changed in the deep past. These natural fluctuations in Earth’s climate are important because they will help researchers to better understand climate change today.

An Amazing Opportunity

Thanks to Dave Jones at Storm Center Communications, I was asked to be part of a three person team that would visit NEEM – the North Greenland Eemian Ice Drilling project. We were going to be guests of lead U.S. scientist James White at the University of Colorado and Danish Scientists J.P. Steffensen and Dorthe Dahl-Jensen.

In late July, I found myself once again traveling with the amazing New York Air National Guard. The 109th wing flies U.S. scientists to the Arctic and Antarctic. We flew from its base in New York to Kangerlussuag, Greenland. Kanger, as the air crew and scientists call it, is an old World War 2 airbase just north of the Arctic Circle.

Landing at NEEM

Getting to the top of the icecap is a place only the NY Air Guard can take you and after a night’s sleep, that’s where we were headed! We stayed at KISS – the Kangerlussuaq International Science Support facility. This is where we were given our cold weather gear and sleeping bags. Greenland in summer would not be nearly as cold as Antarctica, but I would soon find out that it’s a lot snowier!

NEEM is at an elevation of 8,000 feet on top of the icecap in Northern Greenland. During my visit, about 30 scientists were attempting to finish drilling an ice core all the way to bedrock before the end of the short summer. The weather can change from sun to blinding snow in an instant. At a latitude of 77 degrees North, there would be no dark for my entire stay.

Just before noon on the 20th of July the ski-equipped LC130 landed on the snow runway at NEEM. It’s a landing one does not forget. Suddenly, the back of the plane opened up and a large pallet of supplies was pushed out the back. It quickly fell onto the snow and disappeared in a swirl of white.

There is only one heated place at NEEM. The large hand grenade-shaped structure is home to the kitchen, dining room, offices and a shower. Bathrooms consist of pits dug into the snow and the flag flying out front means “occupied!” Scientists, staff and visitors sleep on bunk beds in tents. A small heater keeps the temperature a little above freezing in order to to keep the humidity down. Three of us shared a tent about 300 feet from the main dome.

After settling in, we had a fabulous dinner and watched the weather get worse. By late evening it was snowing heavily with 30 mile per hour winds. I crawled into my sleeping bag and started to get warm. I drifted off to sleep, but was soon awakened by howling winds and a shaking tent. Nature called and at 3 a.m. I gathered enough courage to get down from my bunk and head to the outhouse: the tent over it was gone!

The blizzard lasted three days (and no nights). When the sun finally came out, it was like living on an ocean of snow. Deep blue sky and nothing but white. The Arctic has been called the “great white quiet,” and believe me, the name fits. In my next post, the ice core and the science of NEEM …

View photos of Dan’s trip to Greenland below. Click on an image to download a high resolution version.

	Flying over Greenland on the way to Kanger. (Credit: Dan Satterfield)
	Landing near NEEM in the ski-equipped LC 130. (Credit: Dan Satterfield)
	Jamesway tents at the NEEM field site. (Credit: Dan Satterfield)
	The dome at the NEEM field site. (Credit: Dan Satterfield)
	A scientist measures a segment of the NEEM ice core. (Credit: Dan Satterfield)
	Dan Satterfield in Greenland. (Credit: Dan Satterfield)

For Comparison: The two degree Fahrenheit warming of large inland lakes between 1985 and 2009 is noticeably larger than the global surface temperature warming of about 0.7 degrees Fahrenheit observed over this same period.

Seasons: Fall, Winter, Spring

Sources: Schneider, P and Hook, SJ. “Space observations of inland water bodies show rapid surface warming since 1985.” Geophysical Research Letters 37 (2010): L22405 and NASA: Goddard Institute for Space Studies. “GISS Surface Temperature Analysis.” 18 February 2010. Accessed Online 28 November 2010  and Benson, BJ  and Magnuson, JJ. 2006. North Temperate Lakes Long Term Ecological Research Program, Center for Limnology, University of Wisconsin-Madison, Madison WI.