AntarcticThe Antarctic (ænˈtɑrtɪk or ænˈtɑrktɪk, American English also æntˈɑrtɪk or æntˈɑrktɪk; commonly æˈnɑrtɪk) is a polar region around Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau, and other island territories located on the Antarctic Plate or south of the Antarctic Convergence. The Antarctic region includes the ice shelves, waters, and all the island territories in the Southern Ocean situated south of the Antarctic Convergence, a zone approximately wide and varying in latitude seasonally.
Polar desertPolar deserts are the regions of Earth that fall under an ice cap climate (EF under the Köppen classification). Despite rainfall totals low enough to normally classify as a desert, polar deserts are distinguished from true deserts ( () or () under the Köppen classification) by low annual temperatures and evapotranspiration. Most polar deserts are covered in ice sheets, ice fields, or ice caps, and they are also called white deserts. Polar deserts are one of two polar biomes, the other being Arctic tundra.
Sea iceSea ice arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface (as does fresh water ice, which has an even lower density). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world's sea ice is enclosed within the polar ice packs in the Earth's polar regions: the Arctic ice pack of the Arctic Ocean and the Antarctic ice pack of the Southern Ocean.
StadialStadials and interstadials are phases dividing the Quaternary period, or the last 2.6 million years. Stadials are periods of colder climate, and interstadials are periods of warmer climate. Each Quaternary climate phase is associated with a Marine Isotope Stage (MIS) number, which describes the alternation between warmer and cooler temperatures, as measured by oxygen isotope data. Stadials have even MIS numbers, and interstadials have odd MIS numbers. The current Holocene interstadial is MIS 1, and the Last Glacial Maximum stadial is MIS 2.
Post-glacial reboundPost-glacial rebound (also called isostatic rebound or crustal rebound) is the rise of land masses after the removal of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression. Post-glacial rebound and isostatic depression are phases of glacial isostasy (glacial isostatic adjustment, glacioisostasy), the deformation of the Earth's crust in response to changes in ice mass distribution. The direct raising effects of post-glacial rebound are readily apparent in parts of Northern Eurasia, Northern America, Patagonia, and Antarctica.
Ice ageAn ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and greenhouse periods, during which there are no glaciers on the planet. Earth is currently in the ice age called Quaternary glaciation. Individual pulses of cold climate within an ice age are termed glacial periods (or, alternatively, glacials, glaciations, glacial stages, stadials, stades, or colloquially, ice ages), and intermittent warm periods within an ice age are called interglacials or interstadials.
NeanderthalNeanderthals (niˈændə(r)ˌtɑːl,neɪ-,-ˌθɑːl; Homo neanderthalensis or H. sapiens neanderthalensis), also written as Neandertals, are an extinct species or subspecies of archaic humans who lived in Eurasia until about 40,000 years ago. The reasons for Neanderthal extinction are disputed. Theories for their extinction include demographic factors such as small population size and inbreeding, competitive replacement, interbreeding and assimilation with modern humans, climate change, disease, or a combination of these factors.
Antarctic krillAntarctic krill (Euphausia superba) is a species of krill found in the Antarctic waters of the Southern Ocean. It is a small, swimming crustacean that lives in large schools, called swarms, sometimes reaching densities of 10,000–30,000 individual animals per cubic metre. It feeds directly on minute phytoplankton, thereby using the primary production energy that the phytoplankton originally derived from the sun in order to sustain their pelagic (open ocean) life cycle. It grows to a length of , weighs up to , and can live for up to six years.
Polar regions of EarthThe polar regions, also called the frigid zones or polar zones, of Earth are Earth's polar ice caps, the regions of the planet that surround its geographical poles (the North and South Poles), lying within the polar circles. These high latitudes are dominated by floating sea ice covering much of the Arctic Ocean in the north, and by the Antarctic ice sheet on the continent of Antarctica and the Southern Ocean in the south.
Quaternary glaciationThe Quaternary glaciation, also known as the Pleistocene glaciation, is an alternating series of glacial and interglacial periods during the Quaternary period that began 2.58 Ma (million years ago) and is ongoing. Although geologists describe this entire period up to the present as an "ice age", in popular culture this term usually refers to the most recent glacial period, or to the Pleistocene epoch in general. Since Earth still has polar ice sheets, geologists consider the Quaternary glaciation to be ongoing, though currently in an interglacial period.
