Query: temperature under the ice is fixed at -2C.  Thus elevated winter   air temperatures

Relevant passages:
Earth <=SEP=> Earth ( from Eorðe -LSB- Γαῖα , Gaia -RSB- Terra ) , otherwise known as the World or the Globe , is the third planet from the Sun and the only object in the Universe known to harbor life . It is the densest planet in the Solar System and the largest of the four terrestrial planets .   According to radiometric dating and other sources of evidence , Earth formed about 4.54 billion years ago . Earth 's gravity interacts with other objects in space , especially the Sun and the Moon , Earth 's only natural satellite . During one orbit around the Sun , Earth rotates about its axis over 365 times ; thus , an Earth year is about 365.26 days long . Earth 's axis of rotation is tilted , producing seasonal variations on the planet 's surface . The gravitational interaction between the Earth and Moon causes ocean tides , stabilizes the Earth 's orientation on its axis , and gradually slows its rotation .   Earth 's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years . About 71 % of Earth 's surface is covered with water , mostly by its oceans . The remaining 29 % is land consisting of continents and islands that together have many lakes , rivers and other sources of water that contribute to the hydrosphere . The majority of Earth 's polar regions are covered in ice , including the Antarctic ice sheet and the sea ice of the Arctic ice pack . Earth 's interior remains active with a solid iron inner core , a liquid outer core that generates the Earth 's magnetic field , and a convecting mantle that drives plate tectonics .   Within the first billion years of Earth 's history , life appeared in the oceans and began to affect the Earth 's atmosphere and surface , leading to the proliferation of aerobic and anaerobic organisms . Some geological evidence indicates that life may have arisen as much as 4.1 billion years ago . Since then , the combination of Earth 's distance from the Sun , physical properties , and geological history have allowed life to evolve and thrive . In the history of the Earth , biodiversity has gone through long periods of expansion , occasionally punctuated by mass extinction events . Over 99 % of all species that ever lived on Earth are extinct . Estimates of the number of species on Earth today vary widely ; most species have not been described . Over 7.4 billion humans live on Earth and depend on its biosphere and minerals for their survival . Humans have developed diverse societies and cultures ; politically , the world has about 200 sovereign states .

Precipitation <=SEP=> In meteorology , precipitation is any product of the condensation of atmospheric water vapor that falls under gravity . The main forms of precipitation include drizzle , rain , sleet , snow , graupel and hail . Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor , so that the water condenses and `` precipitates '' . Thus , fog and mist are not precipitation but suspensions , because the water vapor does not condense sufficiently to precipitate . Two processes , possibly acting together , can lead to air becoming saturated : cooling the air or adding water vapor to the air . Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud . Short , intense periods of rain in scattered locations are called `` showers . ''   Moisture that is lifted or otherwise forced to rise over a layer of sub-freezing air at the surface may be condensed into clouds and rain . This process is typically active when freezing rain is occurring . A stationary front is often present near the area of freezing rain and serves as the foci for forcing and rising air . Provided necessary and sufficient atmospheric moisture content , the moisture within the rising air will condense into clouds , namely stratus and cumulonimbus . Eventually , the cloud droplets will grow large enough to form raindrops and descend toward the Earth where they will freeze on contact with exposed objects . Where relatively warm water bodies are present , for example due to water evaporation from lakes , lake-effect snowfall becomes a concern downwind of the warm lakes within the cold cyclonic flow around the backside of extratropical cyclones . Lake-effect snowfall can be locally heavy . Thundersnow is possible within a cyclone 's comma head and within lake effect precipitation bands . In mountainous areas , heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation . On the leeward side of mountains , desert climates can exist due to the dry air caused by compressional heating . The movement of the monsoon trough , or intertropical convergence zone , brings rainy seasons to savannah climes .   Precipitation is a major component of the water cycle , and is responsible for depositing the fresh water on the planet . Approximately 505000 km3 of water falls as precipitation each year ; 398000 km3 of it over the oceans and 107000 km3 over land . Given the Earth 's surface area , that means the globally averaged annual precipitation is 990 mm , but over land it is only 715 mm . Climate classification systems such as the Köppen climate classification system use average annual rainfall to help differentiate between differing climate regimes .   Precipitation may occur on other celestial bodies , e.g. when it gets cold , Mars has precipitation which most likely takes the form of frost , rather than rain or snow .

Amundsen–Scott South Pole Station <=SEP=> The Amundsen -- Scott South Pole Station is a United States scientific research station at the South Pole , the southernmost place on the Earth . The station is located on the high plateau of Antarctica at an elevation of 2,835 metres ( 9,301 feet ) above sea level and is administered by the Division of Polar Programs within the National Science Foundation under the United States Antarctic Program ( USAP ) .   The original Amundsen -- Scott Station was built by Navy Seabees for the Federal government of the United States during November 1956 , as a part of its commitment to the scientific goals of the International Geophysical Year ( IGY ) , an international effort lasting from January 1957 through June 1958 , to study , among other things , the geophysics of the polar regions of Earth .   Before November 1956 , there was no permanent human structure at the South Pole , and very little human presence in the interior of Antarctica at all . The few scientific stations in Antarctica were located on and near its seacoast . The station has been continuously occupied since it was built . The Amundsen -- Scott Station has been rebuilt , demolished , expanded , and upgraded several times since 1956 .   Since the Amundsen -- Scott Station is located at the South Pole , it is at the only place on the land surface of the Earth where the Sun is continuously up for six months and then continuously down for six months . ( The only other such place is at the North Pole , on the sea ice in the middle of the Arctic Ocean . ) Thus , during each year , this station experiences one extremely long `` day '' and one extremely long `` night '' . During the six-month `` day '' , the angle of elevation of the Sun above the horizon varies continuously . The Sun rises on the September equinox , reaches its maximum angle above the horizon on the summer solstice in the Southern Hemisphere , around December 20 , and sets on the March equinox .   During the six-month `` night '' , it gets extremely cold at the South Pole , with air temperatures sometimes dropping below -73 ° C . This is also the time of the year when blizzards , sometimes with gale-force winds , strike the Amundsen -- Scott Station . The continuous period of darkness and dry atmosphere make the station an excellent place from which to make astronomical observations , although the Moon is up for two weeks of every 27.3 days .   The number of scientific researchers and members of the support staff housed at the Amundsen -- Scott Station has always varied seasonally , with a peak population of about 200 in the summer operational season from October to February . In recent years the winter-time population has been around 50 people .

Winter storm <=SEP=> A winter storm is an event in which varieties of precipitation are formed that only occur at low temperatures , such as snow or sleet , or a rainstorm where ground temperatures are low enough to allow ice to form ( i.e. freezing rain ) . In temperate continental climates , these storms are not necessarily restricted to the winter season , but may occur in the late autumn and early spring as well . Very rarely , they may form in summer , though it would have to be an abnormally cold summer , such as the summer of 1816 in the Northeast United States of America .

Climate <=SEP=> Climate is the statistics of weather , usually over a 30-year interval . It is measured by assessing the patterns of variation in temperature , humidity , atmospheric pressure , wind , precipitation , atmospheric particle count and other meteorological variables in a given region over long periods of time . Climate differs from weather , in that weather only describes the short-term conditions of these variables in a given region .   A region 's climate is generated by the climate system , which has five components : atmosphere , hydrosphere , cryosphere , lithosphere , and biosphere .   The climate of a location is affected by its latitude , terrain , and altitude , as well as nearby water bodies and their currents . Climates can be classified according to the average and the typical ranges of different variables , most commonly temperature and precipitation . The most commonly used classification scheme was the Köppen climate classification . The Thornthwaite system , in use since 1948 , incorporates evapotranspiration along with temperature and precipitation information and is used in studying biological diversity and how climate change affects it . The Bergeron and Spatial Synoptic Classification systems focus on the origin of air masses that define the climate of a region .   Paleoclimatology is the study of ancient climates . Since direct observations of climate are not available before the 19th century , paleoclimates are inferred from proxy variables that include non-biotic evidence such as sediments found in lake beds and ice cores , and biotic evidence such as tree rings and coral . Climate models are mathematical models of past , present and future climates . Climate change may occur over long and short timescales from a variety of factors ; recent warming is discussed in global warming . Global warming results in redistributions . For example , `` a 3 ° C change in mean annual temperature corresponds to a shift in isotherms of approximately 300 -- 400 km in latitude ( in the temperate zone ) or 500 m in elevation . Therefore , species are expected to move upwards in elevation or towards the poles in latitude in response to shifting climate zones '' .