OPP 10-001 December 2009
Some reasons to perform scientific research in the Antarctic
- Largest ocean current. The Antarctic Circumpolar Current transports 130 million cubic meters of water per second towards the east, making it the mightiest of the ocean’s currents. It influences formation of cold, dense, and nutrient-rich bottom water that extends throughout much of the world ocean and is a key to understanding change in the world’s ocean circulation and its influence on global climate.1 Recent research has shown that understanding the carbon cycle in the Southern Ocean is critically important to understanding the global carbon cycle.
- Marine ecosystem. Research on the marine ecosystem around Antarctica is providing an understanding of the strong coupling in the Southern Ocean between climate processes and ecosystem dynamics2 and helps to understand levels at which harvesting can take place without damaging the ecosystem. Adding to that uncertainty is the problem of ocean acidification, a gradual change in oceanic chemistry due to uptake of atmospheric carbon dioxide by the sea. The extra carbon dioxide that is produced by anthropogenic activity lowers the oceanic pH, potentially affecting the physiology of marine organism and the ability to form shells. Due to its significant role in absorbing anthropogenic carbon dioxide, the Southern Ocean is predicted to be particularly vulnerable to ocean acidification.
- Sea ice. The annual eightfold growth and decay of sea ice around Antarctica has been termed the greatest seasonal event on Earth.3 It affects regional climate and the global heat budget. Particularly near the edges, it nurtures some of the world’s most productive ecosystems.4
- Ozone hole. One of the best examples of basic research about Earth’s environment that led to important public policy decisions is the story surrounding the Antarctic ozone hole. The discovery of the annual Antarctic ozone depletion, the research that uncovered the cause of the ozone depleting reactions, and the subsequent decisions about phasing out ozone depleting CFC’s is a compelling illustration of the value of science to society. Starting in 1979, ozone in the stratosphere over Antarctica has been observed almost to disappear every austral spring. In the 1990’s seasonal ozone depletion in the Arctic was first observed. Elsewhere, stratospheric ozone depletions are only incremental. Stratospheric ozone keeps much of the Sun’s harmful ultraviolet radiation from reaching the Earth’s surface and therefore, the ozone hole has received widespread attention.
- Finding the cause. Research in Antarctica, particularly at McMurdo, was key to explaining how Antarctic natural phenomena conspire with the global buildup of manmade chemicals to cause the ozone hole.5
- Removing the cause. The research led to an international decision (the Montreal Protocol) to reduce production of the destructive chemicals. Annual consumption of CFCs dropped from 1,100,000 tons in 1986 to 150,000 tons in 1999. Without the protocol, consumption would have reached 3,000,000 tons by 2010.6
- Monitoring the recovery. While atmospheric concentrations of the harmful manmade chemicals are in decline, it might take another 10 years of observation before we can be sure the Antarctic ozone hole is shrinking. The best estimates are that annual depletion will occur for another 50 years. Current Antarctic research continues to provide further understanding of the ozone hole.7
- Effect on life. The ozone hole lets abnormally high levels of the Sun's ultraviolet-B radiation penetrate to the Earth's surface and oceans. Scientists have documented how UV-B affects bacteria, phytoplankton, and the embryos of Antarctic invertebrates and fish.8
- Effect on climate. Research indicates that the ozone hole has increased the winds around Antarctica and reduced rainfall in Australia and elsewhere.9
- Delayed warming. The ozone hole, by increasing winds over the Southern Ocean, has isolated Antarctica from the warming that’s happening elsewhere; in the last 30 years surface temperature over much of the continent has changed little.10
- Economic impact. Damage avoided through implementation of the Montreal Protocol’s measures to protect the ozone layer is valued at US$235-billion. The benefit of reduced damage to fisheries, agriculture, and materials is twice that amount. The benefit of reduced numbers of eye disorders and skin cancers is not expressed in economic terms. Without the Montreal Protocol, CFC consumption would have risen to 3 million tons by 2010 and 8 million tons by 2060, depleting 50 percent more of the ozone layer by 2035.11
- The 1995 Nobel Prize in Chemistry was awarded to three professors who explained that the ozone layer is sensitive to anthropogenic emissions.12
- The 1999 National Medal of Science (the Nation's highest scientific honor) was awarded to Dr. Susan Solomon, who led U.S. Antarctic Program expeditions in 1986 and 1987 giving the first direct evidence that anthropogenic chlorine depletes stratospheric ozone.
- The 2002 National Medal of Technology (the Nation's highest honor for technological innovation) was awarded to the DuPont Company for leadership in the phase-out and replacement of chlorofluorocarbons (CFCs).13
- Polar adaptations of biota. Antarctica’s cold, desert conditions, and annual light cycles have led to molecular, biochemical, and physiological adaptations that enable biota to survive, reproduce, and indeed thrive under environmental extremes not experienced elsewhere. Unique chemical reactions that provide energy to microbes and consequently, ecosystems, have been uncovered in lakes and under glaciers. Studies provide a basic understanding of these unique adaptations and help us understand how life evolved and may respond to environmental change.14
- Atmospheric background levels. Antarctica is the planet’s farthest region from human population centers and is ideal for recording the world’s background levels of atmospheric constituents. Measurements since 1956 at the geographic South Pole have documented changes in worldwide levels of greenhouse gases such as carbon dioxide and methane. Measurements in the data-sparse Southern Hemisphere are important to understanding and predicting global levels of these gases and their impact on (or forerunner to) climate change.15
- Weather and climate. The unbroken collection of weather data from manned and unmanned stations in Antarctica, now 50 years for some locations, provides a data base and real-time information from which to make operational forecasts, study the dynamics of the Antarctic atmosphere, and chart the progress of human-induced global warming.16
- Ice sheets and ice shelves. Antarctica’s ice sheets contain 90 percent of the world’s ice and 70 percent of the world’s fresh water. Melted, it would raise sea level 65 meters (200 feet).
- Global process. Antarctica’s ice—the world’s largest area of cold (the Arctic is 35oF warmer)—affects and responds to world climate change. Just 20,000 years ago, the ice sheet was far larger, and correspondingly, sea level was 11 meters (36 feet) lower, as the water was locked up in Antarctic ice.17
- Climate history. The ice, deposited as snow over millions of years, traps past atmospheric constituents that reveal climate history with a precision not equaled by other proxies such as ocean sediments and tree rings. The world's deepest ice core (3,650 meters) and another core containing the world’s oldest ice (possibly 1 million years old) were both drilled in Antarctica.18
- West Antarctic Ice Sheet. The West Antarctic Ice Sheet if melted would raise sea level 5 meters. It is less stable than the East Antarctic Ice Sheet because its base is below sea level. Its low-probability/high-impact collapse has stimulated vigorous research over the last 30 years, revealing that it has largely or completely disappeared in the past after it formed but at an unknown rate. Portions of it are changing rapidly now, while averages over the whole ice sheet show little change. Some models project stability, while others suggest the possibility of rapid change.19
- Ice shelf dynamics. Ice shelves—extensions of continental ice sheets that are afloat on the ocean—can control the rate at which their parent ice sheets or glaciers move into the sea and can respond more quickly than ice sheets to environmental change. The Larsen Ice Shelf on the east coast of the Antarctic Peninsula lost massive sections in 1995 and 2002, in response to atmospheric and oceanic warming over the last several decades. Some scientists call it a model for what could happen to larger ice shelves farther south.20 Recently observed excursions of intermediate depth water from the Antarctic Circumpolar Current have the potential to deliver tremendous thermal energy to the underside of the floating ice shelves. Current research is aimed at quantifying the amount of energy delivered and developing models to understand the physical processes of ocean-ice shelf interactions. 21
- Subglacial lakes. More than 70 lakes lie beneath the ice sheet, most of them several kilometers long. One, Vostok Subglacial Lake, is an order of magnitude larger and represents the closest analog to both Europa (a moon of Jupiter) and a Neoproterozoic (“Snowball Earth”) subglacial environment. Lake Vostok is likely oligotrophic—an environment with low nutrient levels and low standing stocks of organisms. Life there may depend on alternative energy sources and survival strategies.22
- Monitoring Ice Mass Change and Sea Level Rise. The Gravity Recovery and Climate Experiment (GRACE) satellite mission offers important observations about changes in mass in the Antarctic region. This mass change is predominantly due to two interwoven processes; 1) changes in ice mass and 2) the response of the lithosphere beneath the ice sheet to change in ice loading. However, GRACE observations alone cannot separate these processes. Consequently, the ground observations of crustal response to changes in ice loading that will be provided by the Polar Earth Observing Network (PoleNet) are essential to fully understanding how total ice mass is changing.23
- Polar landmass. Almost 10 percent of the Earth's continental crust resides in Antarctica. The continent is old and stable and has been in a near-polar position for over 100 million years. It thus contains unique high latitude environmental records of a time when Earth changed from greenhouse to icehouse conditions. The landmass is different from the other continents in that Antarctica's crustal structure—or its underlying mantle—has allowed the continent to remain essentially fixed on Earth's surface for a long time.
- Astronomy by high-altitude balloons. Antarctica's summer weather provides a stable ride for instruments suspended from a balloon, which floats around Antarctica at a steady height above most of the atmosphere, providing a relatively inexpensive way to get scientific experiments into near-space.
- The 2006 Balzan Prize for Astrophysics (one of four 1-million-Swiss-Franks awards made annually with the stipulation that half of each award must be used to support research of young investigators) was awarded to Dr. Andrew Lange of CalTech and his co-investigator Dr. Paolo de Bernardis of Italy in recognition of their contributions to cosmology, in particular the BOOMERANG Antarctic Long Duration Balloon experiment that produced the first images of structure in the Cosmic Microwave Background.25
- In 2008 NSF and the National Aeronautics and Space Administration (NASA) jointly achieved a new milestone in the almost 20-year history of scientific ballooning in Antarctica, by launching and operating three long-duration, sub-orbital flights within a single Southern-Hemisphere summer. Scientists from the United States, Japan, South Korea, France and other international collaborators concurrently used the high balloons to investigate the nature of ultra-high-energy cosmic rays and searched for anti-matter, as air currents that circle Antarctica carried the balloons and their instruments at the edge of space.26
- Astrophysics and astronomy from the surface. The cold, clean, dry atmosphere over the South Pole provides viewing conditions that in some wavelengths are equal to those in space. Amundsen-Scott South Pole Station has become a major astronomy and astrophysics center.27
- Cosmic Microwave Background Radiation (CMBR) has been studied at the South Pole with unprecedented accuracy. Predicted in 1980s, the CMBR polarization was revealed for the first time in experimental data obtained by the University of Chicago Degree Angular Scale Interferometer (DASI)28 in 2002. Current studies are trying to detect the B-mode polarization with the Caltech small telescope BICEP29. The 10-m South Pole Telescope30 received its first light in February 2007, and now focuses on determining the nature of dark energy and dark matter and tests cosmological models aimed at explaining the origin of the Universe.
- Neutrino detection. The ice sheet beneath the South Pole is 2,900 meters deep and is homogeneous and clear. Investigators buried downward-looking detectors to observe light produced by neutrinos (ultra-high-energy particles created by cataclysmic collisions in deep space) when they on rare occasions collide with ice molecules after they pass through the Earth. The data help in descriptions of galactic centers, dark matter, and supernovae.31
- BICEP Telescope at South Pole makes first maps of CMB Polarization on the angular scales that probe the physics of Inflation. Observations of the Cosmic Microwave Background (CMB) radiation from telescopes at high-altitude sites and on satellites have produced information about our Universe on its largest scales, precisely measuring the Universe's age, composition, and the seeds of its structure. BICEP is a novel mm-wave telescope designed to test theories of the origin of the Big Bang by using precise measurements of the CMB polarization. While making these observations, BICEP measured polarization originating closer to home and mapped the polarized emission from dust and free electrons that trace our own Galaxy's magnetic fields. Between March 2006 and December 2008, BICEP observed nearly continuously, targeting CMB polarization in a region of the Southern sky that is uniquely free of Galactic emission, and dedicated 15% of its time to mapping polarized emission from the Milky Way Galaxy. The resulting maps trace the large-scale magnetic fields essential to understanding the dynamics of star formation in our Galaxy. They also provide feedback to models that predict levels of Galactic foreground emission and their impact on future CMB missions like the Planck satellite. Finally, because BICEP's polarization response has been precisely referenced to artificial sources, these maps offer a unique astronomical calibration standard and will ultimately specify the orientation of polarized Galactic emission at three frequencies (100, 150, and 220 GHz) to the level of precision required for Planck to use this emission for in-flight calibration.
- Meteorites. Meteorites offer important information about the origin of our solar system and Antarctica is the principal source of meteorites for science. Since 1969, teams from the United States, Japan, and Europe have collected more than 30,000 meteorite specimens from the surface of the ice sheet and represent many meteorite classes (including some from the Moon and Mars), extending our knowledge of the solar system. Antarctica has yielded four-fifths of the meteorites known to science.32 Martian and lunar meteorites provide information about processes that helped form the crust of these bodies. The large numbers of meteorites available from the Antarctic collections have allowed unprecedented discoveries because more material has been available for destructive analysis. For example, common chondrites have yielded diamonds and other highly refractory grains that are remnants of the dust clouds that coalesced to form our solar system.
- Mount Erebus — one of Earth’s few long-lived lava lakes. The world’s southern-most active volcano, Mount Erebus is one of the few volcanoes in the world with a long-lived (decades or more) convecting lava lake. Although the volcano was discovered by James Ross in 1841, scientists still know relatively little about its geology because of extensive snow and ice cover, its remoteness, the extreme environment, and the short field season for study.33
- Interpreting the glacial history of Mars from research in Antarctica. Based on their experience working in the McMurdo Dry Valleys of Antarctica, researchers were able to interpret images of the Martian landscape to show that Mars has experienced varied glaciation. These include large ice sheets followed by small scale alpine glaciers in a single location. They also showed that some areas may harbor icy remnants of the final glacial episode, some hundreds of meters thick. These would be prime targets for future exploration for both life and climate records.
|1 “The Southern Ocean,” by Arnold L. Gordon, Current 15(3): 4-6, 1999. The bountiful recent literature on the topic includes “What drove past teleconnections?” by Frank Sirocko, p. 1336-1337, Science, 5 September 2003|
|3 The area of sea ice around Antarctica varies between 1 and 8 million square miles annually. See images 4 and 5 in https://www.nsf.gov/od/opp/antarct/images/start.jsp.|
|5 “Overview of the polar ozone issue,” by Solomon, S.; Schoeberl, M.R.(ed), Geophysical Research Letters, 15(8), p.845-846 (August 1988), introduces a special issue on polar ozone.|
|6 “Montreal Protocol Benefits Cited,” page 395, 30 September 2003 EOS.|
|7 http://www.cmdl.noaa.gov/ozwv/ozsondes/spo/ozhole.html (historical significance of the ozone hole)|
|8 Scroll down to “Ozone Hole Consequences” in http://www.theozonehole.com/|
|9 “Ozone and climate change,” p. 236-237, and “Simulation of recent Southern Hemisphere climate change,” p. 273-275, Science, 10 October 2003. www.sciencemag.org.|
|10 Antarctic Climate Change and the Environment, Scientific Committee on Antarctic Research, 155 p., December 2009|
|11 Montréal Protocol 1987-1997: Global Benefits and Costs of the Montréal Protocol on Substances that Deplete the Ozone Layer, Environment Canada, 80 p., 1997|
|14 See, for example, The Adélie Penguin: Bellwether of Climate Change,” Columbia University Press, October 2002 http://www.columbia.edu/cu/cup/catalog/data/023112/023112306X.HTM|
|15 The Climate Monitoring and Diagnostics Laboratory, National Oceanic and Atmospheric Administration, operates four baseline observatories worldwide, including the one at the South Pole in cooperation with NSF. See http://www.cmdl.noaa.gov/|
|16 The automatic weather station project, University of Wisconsin, is described at http://amrc.ssec.wisc.edu/aws.html|
|18 Russian, French, and U.S. investigators drilled and analyzed the world's deepest ice core (3,650 meters). The core spans four glacial-interglacial cycles, furnishing an unparalleled archive. “Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica,” by J.R. Petit and others, Nature (London), 399(6735), 429-436, 1999. European coring at Dome C, East Antarctica, in 2003 reached 3,200 meters, yielding some of the world’s oldest ice, possibly 1 million years old.|
|20 “Warmer ocean could threaten Antarctic ice shelves” (p. 759) and “Larsen Ice Shelf has progressively thinned” (p. 856-859), Science, 31 October 2003, www.sciencemag.org. See also http://nsidc.org/sotc/iceshelves.html.|
|24 A microwave telescope borne for 10½ days 120,000 feet over Antarctica provided detailed evidence that the large-scale geometry of the universe is flat (Nature, 27 April 2000). Following the Big Bang 12-15 billion years ago, the universe was smooth, dense, and hot. The intense heat still is detectable as a faint glow called cosmic microwave background radiation. Scientists had sought high-resolution images of the radiation since 1965, when a ground-based radio telescope discovered it. https://www.nsf.gov/od/lpa/news/press/00/pr0025.htm|
|25 See http://www.balzan.com/index_en.cfm|
|27 The University of Chicago (Yerkes Observatory) and 15 institutions from four nations installed telescopes at South Pole Station emphasizing infrared and submillimeter wavelengths. This large project, one of NSF's 24 Science & Technology Centers, in 2001 provided science with the strongest evidence to date for the theory of inflation, the leading model for the formation of the universe. https://www.nsf.gov/od/lpa/news/press/01/pr0138.htm|