Antarctica, the world’s southernmost and fifth largest continent. Its landmass is almost wholly covered by a vast ice sheet.

Often described as a continent of superlatives, Antarctica is not only the world’s southernmost continent. It is also the world’s highest, driest, windiest, coldest, and iciest continent. Antarctica is about 5.5 million square miles (14.2 million square km) in size, and thick ice covers about 98 percent of the land. The continent is divided into East Antarctica (which is largely composed of a high ice-covered plateau) and West Antarctica (which is largely an ice sheet covering an archipelago of mountainous islands).

The ice surface dramatically grows in size from about 3 million square kilometers (1.2 million square miles) at the end of summer to about 19 million square kilometers (7.3 million square miles) by winter. Ice sheet growth mainly occurs at the coastal ice shelves, primarily the Ross Ice Shelf and the Ronne Ice Shelf. Ice shelves are floating sheets of ice that are connected to the continent. Glacial ice moves from the continent’s interior to these lower-elevation ice shelves at rates of 10 to 1,000 meters (33-32,808 feet) per year.

Without any ice, Antarctica would emerge as a giant peninsula and archipelago of mountainous islands, known as Lesser Antarctica, and a single large landmass about the size of Australia, known as Greater Antarctica. These regions have different geologies.

Greater Antarctica, or East Antarctica, is composed of older, igneous and metamorphic rocks. Lesser Antarctica, or West Antarctica, is made up of younger, volcanic and sedimentary rock. Lesser Antarctica, in fact, is part of the “Ring of Fire,” a tectonically active area around the Pacific Ocean. Tectonic activity is the interaction of plates on Earth’s crust, often resulting in earthquakes and volcanoes. Mount Erebus, located on Antarctica’s Ross Island, is the southernmost active volcano on Earth.

Climate

Antarctica has an extremely cold, dry climate. Winter temperatures along Antarctica’s coast generally range from -10° Celsius to -30° Celsius (14° Fahrenheit to -22° Fahrenheit). During the summer, coastal areas hover around 0°C (32°F) but can reach temperatures as high as 9°C (48°F).

In the mountainous, interior regions, temperatures are much colder, dropping below -60°C (-76°F) in winter and -20°C (-4°F) in summer. In 1983, Russia’s Vostok Research Station measured the coldest temperature ever recorded on Earth: -89.2°C (-128.6°F). An even lower temperature was measured using satellite data taken in 2010: -93.2°C (-135.8°F).

Tourism is one facet of the ACTM’s climate change outline, discussed during meetings in Norway in 2010. Climate change disproportionately affects the Antarctic region, as evidenced by reductions in the size of the Antarctic Ice Sheet and the warming waters off the coast. The ACTM recommended that treaty-states develop energy-efficient practices that reduce the carbon footprint of activities in Antarctica and cut fossil fuel use from research stations, vessels, ground transportation, and aircraft.