The JOIDES Resolution.

The JOIDES Resolution.

One of the most sudden and dramatic climate changes to impact the earth occurred some 30 million years ago: This was the transition from a Greenhouse World, when ice caps were largely absent and the earth was much warmer, to an Icehouse World with extensive polar ice sheets, exposed land along the continental margins, and glaciers that periodically extended into the lower latitudes. Investigating this climate switch, thought to be mediated by changes in atmospheric carbon dioxide concentration, will help scientists better understand what triggers vast environmental changes that fundamentally affect life on earth.

Ground zero in these studies is the area just off the coast of the East Antarctic Ice Sheet, the world’s oldest and largest polar ice field. By drilling into deep ocean sediments along Antarctica, scientists hope to uncover the earth’s climate history from a time when East Antarctica was largely ice-free, and to investigate its transition to the glacier-covered continent we know today. Investigating this history, and the effect of increased carbon dioxide and other greenhouse gases on polar ice sheets, will help fine-tune computer models and lead to a better understanding of the climate changes we’re experiencing in the present day.

An example of a cross-section of a sediment core.

Co-chief scientist Carlotta Escutia led an international team of marine geologists and climate scientists aboard the JOIDES Resolution, one of the most sophisticated ocean-drilling ships in the world. They set off from New Zealand in early 2010 to drill cores and collect sediment samples off the coast of Wilkes Land, a region of East Antarctica south of Australia that’s thought to have been the final area to become ice-covered during the last great climate transition.Marine geochemists Rob Dunbar and Christina Riesselman from Stanford University reported from this history-making expedition.

Planned drilling locations (yellow markers) for the IODP Wilkes Land Expedition.

The broken Larsen B Ice Shelf south of the Seal Nunataks, March 13, 2002.

Between January 31, 2002, and March 5, 2002, a chunk of the Larsen B ice shelf the size of Rhode Island disintegrated.

Scientists will take push core samples such as this one to study the seafloor sediment and animal life.

What happens when a dark polar ecosystem is suddently flooded with light? Does it explode with life, as happens every spring in Antarctica when phytoplankton in the polar seas reproduce in huge numbers to take advantage of the return of sunlight?

An NSF-sponsored research cruise investigated this question when it traveled to the Wedell Sea off West Antarctica, the site of a huge ice-sheet collapse seven years ago. When the Larsen B ice shelf disintegrated in 2002, it exposed nearly a million square miles of seafloor that had been shaded by the overhanging ice sheet for 10,000 years. Life in the undisturbed cold and dark before the collapse was supported by bacteria that thrive in the deep sea, subsisting on chemicals seeping from ocean vents rather than from photosynthesis.

The LARISSA (Larson Ice-Shelf Systems-Antarctica) project, which brings together an international team of scientists including lead ecosystem biologist Maria Vernet, traveled to this transformed seascape to investigate whether chemosynthetic organisms and ecosystems still dominate or whether they’ve been replaced in the food chain by light-loving phytopolankton from nearby polar sea communities. The research included examining the phytoplankton populations throughout the water column, analyzing sediment traps and characterizing the bottom community using remotely operated vehicles. Understanding how changes in ice sheets affect polar ecosystems will shed light on how life in arctic and antarctic ocean may respond to future loss of sea ice and ice shelves predicted under current climate change models.

Follow along as Maria and her team, doctoral candidate Mattias Cape and outreach coordinator Beth Simmons from Scripps Institution of Oceanography, will send dispatches from the research cruise in early 2010.

The new ice front near Cape Foyn, March 13, 2002.

This one-of-a-kind airplane features an array of instruments for studying the East Antarctic Ice Sheet and the bedrock below: radar, a magnetometer, laser altimeters, and a gravity meter. Skis allow the team to land nearly anywhere in Antarctica if necessary.

The specially-quipped C-47 aircraft is designed to conduct long-range airborne surveys in Antarctica and Greenland.

The East Antarctic Ice Sheet is the sleeping giant of the cryosphere: it covers more than 95% of the Antarctic continent and locks up more than 60% of the world’s supply of fresh water. Considered much more stable than its smaller counterpart in West Antarctica, scientists are turning more attention to studying the history, structure and dynamics of this mysterious icy world. Instead of taking the stability of the ice sheet for granted, scientists from many different countries are digging into East Antarctica’s climate history to help predict how this vast ice sheet could respond in a warming world.

Graduate students Dusty Schroeder (foreground) and Jamin Greenbaum (rear) monitor instruments during a survey flight.

As a member of a research group at the University of Texas, Austin, Jack Holt participated in a multinational project called ICECAP to survey an enormous, unexplored part of the East Antarctica Ice Sheet. Building on their research experience of the last two decades, the UT team employed a ski-equipped aircraft outfitted with unique instrumentation, including an ice-penetrating radar capable of mapping the surface, internal layers, and the bottom of the ice. Other instruments revealed information about the density and type of the underlying rocks. The aircraft was also fitted with a suite of secondary instruments including specialized GPS receivers and cameras. One of the goals of ICECAP was to find the oldest ice on the continent, the site of a future ice-coring project to unlock climate records that go back a million years.

Data from the ICECAP project will help scientists understand how the East Antarctic Ice Sheet, with its enormous supply of fresh water, might react to changing environmental conditions. The ice in the target area is generally over 2 miles (3.5 km) thick and the bedrock lies mostly below sea level, making this ice potentially more likely to make a rapid contribution to sea level rise than the ice sheets in Greenland or West Antarctica. But the largely unknown continent buried beneath is also important for forecasting how the ice might respond to a warming world: The slope and roughness of the ground, the presence of water (including subglacial lakes), and the type of rocks are all factors.

ICECAP season 1 flight lines.

Chief Scientist Ken Taylor and science tech Anais Orsi looking at layers in backlit snowpit.

A one-meter long piece of ice core illuminated with a light. The green netting on the core is used to help hold the ice together in case it spontaneously fractures.

The bubbles visible in this piece from an Antarctic ice core sample contain carbon dioxide and other gases that were trapped in the ice when formed thousands of years ago. Researchers carefully crush the piece and capture the gases that escape when the bubbles break. This allows them to better understand what carbon dioxide levels were over time.

Heidi Roop, a science technician, worked with more than 100 scientists to recover a 2-mile-long (3.5-km-long) ice core from the West Antarctica Ice Sheet (WAIS) Divide. Imagine, that’s a column of ice twice as tall as the Grand Canyon is deep! The properties of each layer of an ice core reveal a slice of climate history. The WAIS team estimates that this ice core will reveal climate changes that have happened as far back as 100,000 years, a time when woolly mammoths still walked the earth.

During the 2009–2010 season, Heidi helped the WAIS team uncover new chapters of the climate story by drilling deeper into the ice. The WAIS scientists were able to decipher the climate year by year back approximately 40,000 years and at decadal (10-year) resolution from 40,000 to 100,000 years, making it the most detailed ice core record ever collected in the Southern Hemisphere. With the ability to extract annual (1-year) to decadal climate information such as past greenhouse gas concentrations, the climate record developed from WAIS can be directly related to ice cores from Greenland. By comparing records from the Southern and Northern hemispheres, our understanding of global climate change will be more complete. The earth’s climate history will be known in more detail than ever before—and it’s bound to be an interesting story!

Standing in a polygon trough on a snowy day in Beacon Valley.

Helicopter day trip away from our main camp in Beacon Valley.

Coring of the underlying glacial ice, Beacon Valley.

Beacon Valley: home for the next 7 weeks.

Taking orientation of sand veins within the buried ice.

A collapse of the Antarctic ice sheets would raise global sea levels approximately 180 feet (60 m) with devastating consequences for near-shore and low-elevation communities. To better understand the response of the Antarctic ice sheets to future changes in climate, quantitative geomophologist Doug Kowalewski and colleagues from Boston University are working to understand the ancient climate of Antarctica and the corresponding stability of the glaciers and ice sheets. Buried alpine glacier ice was discovered two decades ago in the McMurdo Dry Valleys, a predominantly ice-free region roughly the size of Rhode Island. The buried glacier is allegedly the oldest on earth with an age of more than 8 million years; that would be almost ten times older than ice currently being cored from the Antarctic ice sheets.

If the ice is indeed that old, gases trapped within the buried glacier ice represent a potential archive of climate data stretching back to the time of the earliest hominids. Doug Kowalewski (UMass, Amherst) along with colleagues from Boston University, Brown University and Colgate spent October to December camped in Beacon Valley (77.859 S, 160.574 E) coring the alpine glacier ice. The ice cores were shipped to Boston and Princeton universities where analysis of the trapped gases will provide a more robust chronology for the glacier and provide insight about past atmospheric temperatures and precipitation.

To establish further evidence that buried glaciers can persist for over 8 million years in the dry, albeit cold environment of Antarctica, Doug conducted in-situ experiments and modeling studies to calculate the existing rate of glacier ice sublimation (the change of state from solid directly to gas, a process that slowly reduces the size of glacier and over time may eliminate the glacier completely). Doug also ran regional climate model simulations at the UMass Amherst Climate System Research Center to resolve whether sustained cold climate conditions necessary for long-term ice preservation occurred during the lifetime of the glacier specifically during warmer times in Earth’s history (episodes of higher atmospheric CO2 and increased solar radiation due to Earth’s orbital changes). For model input, Doug and his colleagues monitored atmospheric temperatures, wind speed, amount of solar radiation received, and relative humidity. Glacier ice temperatures and overlying rock and soil temperatures were monitored in Beacon Valley. These modeling efforts provide increased evidence that buried ice and a super-arid, cold-polar climate have sustained in parts of Antarctica for millions of years.

Doug Kowalewski’s field site, Beacon Valley (yellow square), sits at 1500 m in elevation and is in close proximity to the East Antarctic Ice Sheet (left of image).

The Ceremonial South Pole

NOAA’s Atmospheric Research Observatory

NOAA’s Atmospheric Research Observatory (ARO) at the South Pole is part of a network of stations around the world that monitor properties of the earth’s atmosphere. This station is part of NOAA’s Earth Systems Research Laboratory (ESRL), Global Monitoring Division (GMD) located in Boulder, CO. Some of the items that GMD monitors are aerosols, radiation, carbon cycle gases (CO₂), ozone and water vapor, as well as halocarbons and other trace gases. NOAA has been maintaining some of these measurements, including tracking the increasing concentration of carbon dioxide in the atmopshere, dating back to the International Geophysical year of 1957 giving more than 50 years of continuous data.

The Amundsen-Scott South Pole Station

Long term data is extremely useful when studying the earth’s climate. Due to climate’s high variability, it is necessary to have a long set of continuous data to pick out trends and to help predict the state of the atmosphere in the future. Because it is in such a remote location, far from any source of emissions or human activities, the ARO gives scientists a baseline level of the global average measurements. Air at the South Pole is the “cleanest on earth,” free of local influences from humans such as factories and cars, as well as natural effects from things like volcanoes.

SCINI examines an anemone under the ice in Antarctica.

In the darkness under the ice, SCINI’s 22 forward pointing and 12 downward pointing LEDs provide enough light to capture high resolution images.

All Antarctic marine scientists struggle with one common challenge: how to get through the frozen surface of the ocean. Geological, chemical, physical, and biological oceanographers are all “in the same boat.” Some wait until summer months when the sea ice melts, allowing traditional oceanographic techniques and tools to be used. But Stacy Kim can’t wait. She wants to study ecological processes in the remote areas under permanent ice shelves that have been in place for thousands of years, and annual cycles in areas that are covered by pack and fast ice for 10 or 11 months of the year. To overcome the ice barrier, a team of engineers from Moss Landing Marine Laboratories designed and built SCINI, the Submersible Capable of under Ice Navigation and Imaging. SCINI is a Remotely Operated Vehicle (ROV), tethered to the surface for real time imagery and remote control between the pilot on the surface and the vehicle hundreds of meters beneath

Launching SCINI through a 20 cm diameter hole in 7 m thick ice.

Permanent ice shelves are disappearing in Antarctica, but scientists don’t know how the benthic, or seafloor, ecosystems underneath them will be affected. Since 1992, seven Antarctic ice shelves have collapsed catastrophically. Disintegrating ice shelves allow access to the underlying seafloor, as the overlying permanent ice that was several hundreds of meters thick is replaced by sea ice that is only a few meters thick. The ecological change that follows is rapid, but since what was there before the collapse is unknown, there is no baseline to assess the shift. SCINI is a powerful tool in the race to describe normal benthic communities under ice shelves before they vanish.

Stacy dives with SCINI on a test mission.

An Aerosonde UAV

The Terra Nova Bay polynya.

Climate scientists are increasingly looking at interactions between the atmosphere and the ocean to better understand our climate and how it’s changing. This project focused on Terra Nova Bay in the Ross Sea region of Antarctica, which, even in the heart of winter, is often ice free. Open water in the sea ice, known as a polynya, means that heat and moisture can be transferred from the water to cold air flowing over it.

Terra Nova Bay is an area of very strong katabatic winds—cold, dense air that flows from the interior of the Antarctic continent. Climate scientist John Cassano and his team studied how the katabatic winds influence the formation of the polynya and how the presence of the polynya modifies the katabatic winds. These winds are most intense during the Antarctic winter, but because of the harsh conditions, very few observations of the horizontal and vertical extent of these winds have been made during that season. John’s research provides some of the first three-dimensional observations of these defining features of the Antarctic climate.

The strong winds and cold air temperatures mean that the exchange of heat and moisture between the ocean and the atmosphere is greatest during the winter. But our current knowledge of this interaction is limited to what we can infer from satellite observations, data from automated weather stations and ocean moorings, and computer models and theory. To verify what scientists have inferred from these indirect sources of data, John’s team made direct measurements of the atmosphere over the Terra Nova Bay polynya.

John Cassano with Mt. Erebus in the background.

John traveled to Antarctica in late August 2009 as winter was ending. To study the winds, water, and atmosphere in this inhospitable place, he and his team used technology developed to gather data in hurricanes—a fleet of unmanned aerial vehicles (UAVs).

His team brought four Aerosonde UAVs to Antarctica and flew them from the main United States runway near McMurdo Station on Ross Island to Terra Nova Bay. During flights of twenty hours or more, they acquired a wealth of meteorological data needed to understand this poorly observed part of the Antarctic climate system.

The JOIDES Resolution

Assistant driller Fernando “Nandy” Punsalan on the piperacker. Unlike other rigs, the JR stores pipe horizontally. Each stand of pipe is 30 meters in length.

Scientist Howie Scher taking physical properties samples of a sediment core in the core lab.

From July to September 2009, the scientific drilling vessel JOIDES Resolution undertook a nine-week expedition in the Bering Sea. (JOIDES stands for “Joint Oceanographic Institutions for Deep Earth Sampling.”) Led by co-chief scientists Christina Ravelo and Kozo Takahashi, aboard the ship was an international team of about 35 scientists, 25 technicians, and high school science teacher Doug LaVigne, who was the Ice Stories correspondent for the project.

The team drilled more than 600 meters (2,000 feet) into the sea floor to extract sediment cores that will provide the first comprehensive records of environmental and oceanographic conditions in the Bering Sea over the past 5 million years. The scientists hope to reconstruct the history of this shallow sea, which acts as a fence between the North Pacific and the frigid waters of the Arctic Ocean.

So what can be learned from sediment cores? Fossils of microscopic shelled organisms can tell scientists a lot about ocean temperatures in the past, which can help scientists understand climate shifts.

The earth’s climate has alternated between colder glacial periods and warmer interglacial periods. From sediment cores and other evidence gathered from places around the world, scientists have a global picture of the earth’s climate history. What causes glaciation, however, is not understood. While various conditions seem likely to contribute to glaciation, it appears that there must be a number of factors interacting in complex ways.

Learning the local climate history of the Bering Sea and how it may have affected other regions, particularly the North Pacific, may help solve the mystery of why glaciers advance and retreat. And if scientists can understand the mechanisms of past climate change, they’ll be better able to predict what might happen to our climate in the future.

Drill sites for the JOIDES Resolution’s nine-week expedition to the Bering Sea. Map courtesy of IODP/TAMU.

Polar bear tracks in the snow along the Arctic coast in northern Alaska, in October 2008.

Dr. Henry Harlow, Dr. Merav Ben-David, and John Whiteman (left to right) with an adult male polar bear who has been sedated for measurements. They’re sitting in front of a temporary windbreak (to make measurements easier) on sea ice off the northern coast of Alaska in October 2008.

Summer is a critical time for polar bears and climate change is lengthening Arctic summers, which could have a substantial effect on bear populations. However, much of what is known about polar bears comes from studying them out on Arctic sea ice during late winter and spring. During summer, most sea ice retreats far to the north, leaving some bears on shore for several months. Scientists suspect that these bears face difficult conditions on land; temperatures are warm and there’s little to eat. In contrast, some bears follow the retreating ice north, where temperatures are cooler and there may be opportunities to hunt seals.

To find out how polar bears fare in the summer, PhD candidate John Whiteman and his advisors Drs. Henry Harlow and Merav Ben-David are collaborating with scientists from the US Geological Survey and the US Fish and Wildlife Service. They are capturing and examining bears in early summer and attaching GPS-tracking collars, then re-capturing the same bears in late summer and examining them again. Comparing early- and late-summer indicators of body fat, muscle, and diet tells the scientists how well polar bears are faring in summer months. Additionally, they can use this information to forecast how longer Arctic summers may affect polar bear populations.