Temperature record 1558869 223776428 2008-07-05T19:19:49Z Wavelength 271168 adding heading "See also" and 2 internal links {{pp-semi-indef}} :''For extreme records instead of records as a set of data, see [[Temperature extremes]]'' The '''temperature record''' shows the fluctuations of the [[temperature]] of the atmosphere and the oceans through various spans of time. The most detailed information exists since 1850, when methodical thermometer-based records began. There are numerous estimates of temperatures since the end of the [[Pleistocene]] [[glaciation]], particularly during the current [[Holocene]] epoch. Older time periods are studied by [[paleoclimatology]]. [[Image:Instrumental Temperature Record.png|right|300px|Global surface temperatures]] == The Instrumental Period: from 1850 == {{main|Instrumental temperature record}} Detailed information exists since 1850, when methodical thermometer-based records began. See also [[Temperature record since 1880]]. == Tropospheric temperature (the satellite and balloon temperature records) == [[Image:Satellite Temperatures.png|thumb|right]] {{main|Satellite temperature measurements}} Satellites have been measuring the temperature of the troposphere since 1979. Balloon measurements begin to show an approximation of global coverage in the 1950s. Several groups have analyzed the satellite data to calculate temperature trends in the troposphere; RSS find a trend of +0.175 °C/decade while UAH find +0.134 °C/decade, to April 2008; Fu et al finds trends (up to the end of 2004) of +0.19 °C/decade when applied to the RSS dataset; Vinnikov and Grody find +0.22°C to +0.26°C per decade (Oct. 03). == Proxies: tree rings, ice cores: the last 2000 years == [[Image:2000 Year Temperature Comparison.png|right|thumb|250px|Comparison of many reconstructed proxy temperature studies covering last 2000 years]] {{main|Temperature record of the past 1000 years}} Longer records exist from [[Proxy (climate)|proxies]]: quantities such as [[tree ring]] widths, [[coral]] growth or isotope variations in [[ice core]]s. From these, proxy temperature reconstruction of the last 2000 years have been made for the northern hemisphere. <ref>[http://www.grida.no/climate/ipcc_tar/wg1/figspm-1.htm United Nations Environment Programme]</ref><ref>[http://www.grida.no/climate/ipcc_tar/wg1/069.htm#fig220 United Nations Environment Programme]</ref> However, coverage of these proxies is sparse: even the best proxy records contain far fewer observations than the worst periods of the observational record. Also, problems exist in connecting the proxies (e.g. tree ring width) to the variable of interest (e.g. temperature). === Indirect historical proxies === As well as natural, numerical proxies (tree-ring widths, for example) there exist records from the human historical period which can be used to infer climate variations, often in a less directly numerical way: reports of [[Frost fair]]s on the [[Thames]]; records of good and bad harvests; dates of spring blossom or lambing; extraordinary falls of rain and snow, and unusual floods or droughts. These too can be used to infer historical temperatures, but generally in a more qualitative manner than the natural proxies discussed above. Recent evidence suggests that a sudden and short-lived climatic shift between 2200 and 2100 BCE occurred in the region between [[Tibet]] and [[Iceland]], with some evidence suggesting a global change. The result was a cooling and reduction in precipitation. This is believed to be a primary cause of the collapse of the [[Old Kingdom]] of [[Egypt]].<ref>[http://www.bbc.co.uk/history/ancient/egyptians/apocalypse_egypt_04.shtml The Fall of the Egyptian Old Kingdom] Hassan, Fekri BBC June 2001</ref> == Paleoclimate == [[Image:Holocene Temperature Variations.png|thumb|left|250px|Plot showing the variations, and relative stability, of climate during the last 12000 years]] {{main|Paleoclimatology}} Many estimates of past temperatures have been made over [[History of Earth|Earth's history]]. The field of paleoclimatology includes ancient temperature records. As the present article is oriented toward recent temperatures, there is a focus here on events since the retreat of the [[Pleistocene]] [[glaciers]]. The 10,000 years of the [[Holocene]] epoch covers most of this period, since the end of the Northern Hemisphere's [[Younger Dryas]] millennium-long cooling. The [[Holocene Climatic Optimum]] was generally warmer than the 20th century, but numerous regional variations have been noted since the start of the Younger Dryas. == The long term [[ice core]] record: the last 800,000 years == [[Image:Ice Age Temperature.png|thumb|right|250px|Curves of reconstructed temperature at two locations in Antarctica and a global record of variations in glacial ice volume. Today's date is on the left side of the graph]] Even longer term records exist for few sites: the recent Antarctic [[EPICA]] core reaches 800 kyr; many others reach more than 100,000 years. The EPICA core covers eight glacial/interglacial cycles. The [[North Greenland Ice Core Project|NGRIP]] core from Greenland stretchs back 5 kyr into the [[Eemian interglacial]]. Whilst the large-scale signals from the cores are clear, there are problems interpreting the detail, and connecting the isotopic variation to the temperature signal. == Geologic evidence of past temperature changes == [[Image:Five Myr Climate Change.png|thumb|400px|Five million years of climate change]] {{main|Geologic temperature record}} On longer time scales, sediment cores show that the cycles of glacials and interglacials are part of a deepening phase within a prolonged ice age that began with the glaciation of [[Antarctica]] approximately 40 million years ago. This deepening phase, and the accompanying cycles, largely began approximately 3 million years ago with the growth of continental ice sheets in the Northern Hemisphere. Gradual changes in Earth's climate of this kind have been frequent during the Earth's 4500 million year existence and most often are attributed to changes in the configuration of continents and ocean sea ways. == References == <references/> * Global average temperature for the last [http://www.grida.no/climate/ipcc_tar/wg1/figspm-1.htm 150 years] and [http://www.grida.no/climate/ipcc_tar/wg1/056.htm#fig27 discussion] of trends * Preliminary data from the last [ftp://holocene.evsc.virginia.edu/pub/mann/mannjones03.pdf 2000 years] * [http://www.cru.uea.ac.uk/cru/data/temperature/ Temperature data] Climatic Research Unit, University of East Anglia, Norwich, UK. Philip D. Jones and other. * [http://www.met-office.gov.uk/research/hadleycentre/obsdata/globaltemperature.html Hadley Centre: Global temperature data] * [http://data.giss.nasa.gov/gistemp/ NASA's Goddard Institute for Space Studies] (GISS) &mdash; Global Temperature Trends. *[http://www.nap.edu/catalog/11676.html#toc Surface Temperature Reconstructions for the last 2,000 Years] ==See also== *[[CLIWOC]] (climatological database for the world's oceans) *[[Temperature record of the past 1000 years]] {{global warming}} [[Category:Climate change]] [[Category:History of climate]] [[hu:hőrekord]] [[ja:過去の気温変化]]