Heroic Age of antarctic exploration began with an 1895 declaration that Antarctica was the only great region remaining to be explored. It ended with Earnest Shackleton's death on the island of South Georgia in 1922. This extraordinary period stimulated world attention that within 40 years resolved conflicting territorial claims in favor of international collaboration in science. Then, beginning with the 1957-1958 International Geophysical Year, scientists demonstrated that the Antarctic is key to understanding global processes and that it offers research opportunities in planetary science and in astrophysics available nowhere else on the planet. By the end of the Twentieth Century, the original list of 12 participating nations had grown to 29.
Shackleton in 1916 had entered a region that was unseen and unknown. The Weddell Sea ice that sank Endurance remained so forbidding that not until 1992 did a large-scale research expedition go there. Icebreakers from the Soviet Union and the United States established Ice Camp Weddell, providing an unprecedented opportunity to study the circulation of ice, atmosphere, and ocean. The work helped to cement understanding of the Weddell Sea as one of the main contributors of deep and bottom waters to global thermohaline circulation. It enhanced understanding of the Antarctic Circumpolar Current as the most powerful current system on earth, exerting a strong influence on climate. The Cold War ended during the 4-month sojourn at the Weddell Sea camp, and scientists who had gone there as citizens of the Soviet Union to collaborate with their U.S. colleagues went home as Russians.
Each year, anywhere from 1 to 8 million square miles of sea ice melts and freezes. It was sea ice that sealed Shackleton's fate. We now understand that the Weddell Sea is never entirely free of sea ice. The freezing and melting of sea ice is the greatest seasonal event on Earth, with the ocean freezing at an astounding rate of 22 square miles per second. The gravity-driven Katabatic winds (winds flowing down from high elevations of mountains, plateaus and hills to the valleys or planes below) produce frigid air that sweeps with great force off of the antarctic continent and hastens the formation of sea ice. The influence on global climate is significant.
With 90 percent of the world's ice, the continent stores the equivalent of 200 feet of sea level. If one portion of this ice--the West Antarctic Ice Sheet--melted, it could raise sea level 20 feet. A rise in sea level from greenhouse warming is of obvious economic importance. Projections about the impact typically include great uncertainty because the stability of the West Antarctic Ice Sheet cannot be guaranteed, even over the brief time scale of human economies. Thus, the low-probability/high-impact collapse of west antarctic ice has stimulated vigorous research over the last 30 years.
At the farthest southern reach of the West Antarctic Ice Sheet lies the South Pole -- Earth's spin axis -- 90o South latitude. Shackleton's journey, had it succeeded, would have taken him to this highly symbolic place. Humans first reached it in 1911 and 1912. After that, the next human visitors to set foot on the South Pole were Americans, who in 1956 established a research station that has operated continuously to this day. The Americans named it Amundsen-Scott South Pole Station after Roald Amundsen and Robert Falcon Scott, the Norwegian and British explorers who got there first. Today scientists from many nations work there in collaboration with their U.S. colleagues. Because it's located in a place that has the cleanest air on Earch, the station provides unparalleled opportunities to perform research on atmospheric change and to do astrophysical research on such topics as the earliest moments of the universe.
After leaving the South Pole, Shackleton would have traversed to Ross Island, the coastal area on the other side of Antarctica from the Weddell Sea. This is where British explorer Scott started his historic and fatal trek to the South Pole and where McMurdo Station exists today. The station has the largest human habitation in the Antarctic and is the operational hub of the United States Antarctic Program. McMurdo's airplanes, helicopters, surface vehicles, comfortable living quarters, modern communications, and sophisticated research laboratories -- resources of which Shackleton could only have dreamed -- provide support for modern science throughout Antarctica.
Antarctica is the only continent where science serves as the principal expression of national and international interests. These Antarctic Treaty nations, appropriately, house their antarctic programs in their science agencies. In the United States, this agency is the National Science Foundation, which supports basic research and education in the sciences and engineering.