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Observations unambiguously show the Antarctic Peninsula to be warming. Trends elsewhere on the continent show both warming and cooling but are smaller and dependent on season and the timespan over which the trend is computed. More recent results from Steig et al. show warming over the entire continent.〔 Climate models predict that temperature trends due to global warming will be much smaller in Antarctica than in the Arctic, mainly because heat uptake by the Southern Ocean acts to moderate the radiative forcing by greenhouse gases. The apparent contradiction in the observed cooling behavior of Antarctica between 1966 to 2000 became part of the public debate in the global warming controversy, particularly between advocacy groups of both sides in the public arena, as well as the popular media. Novelist Michael Crichton asserted that the Antarctic data contradict global warming.〔 ''Speech at the National Press Club, Washington, D.C.'' (restored from archived copy)〕 The few scientists who have commented on the supposed controversy state that there is no contradiction,〔 while the author of the paper whose work inspired Crichton's remarks has said that Crichton "misused" his results. There is no similar controversy within the scientific community, as the small observed changes in Antarctica are consistent with the small changes predicted by climate models, and because the overall trend since comprehensive observations began is now known to be one of warming. At the South Pole, where some of the strongest cooling trends were observed between the 1950s and 1990s, the mean trend is flat from 1957 through 2013. In a study released in 2009, historical weather station data was combined with satellite measurements to deduce past temperatures over large regions of the continent, and these temperatures indicate an overall warming trend. One of the paper's authors, Eric J. Steig of the University of Washington, stated "We now see warming is taking place on all seven of the earth’s continents in accord with what models predict as a response to greenhouse gases." A follow-up study by O'Donnell and others that strongly criticized the Steig et al. work nevertheless found significant warming in West Antarctica. O'Donnell et al. also confirmed that Antarctica overall has been warming since the 1950s, but disagreed with Steig et al. about the strength of that warming. Subsequent measurements of temperatures in a borehole at the center of the West Antarctic ice sheet, by Orsi and others, found even larger positive trends than Steig et al. ==Observations of trends== Antarctica has few long-term records. There are less than twenty permanent stations in all and only two in the interior. More recently AWSs supplement this, but their records are relatively brief. Hence calculation of a trend for the entire continent is difficult. Satellite observations only exist since 1981 and provide surface temperature measurements only in cloud-free conditions. The 2007 IPCC Fourth Assessment Report states that ''Observational studies have presented evidence of pronounced warming over the Antarctic Peninsula, but little change over the rest of the continent during the last half of the 20th century''. Chapman and Walsh note that "Trends calculated for the 1958–2002 period suggest modest warming over much of the 60°–90°S domain. All seasons show warming, with winter trends being the largest at +0.172 °C per decade while summer warming rates are only +0.045 °C per decade. The 45-yr temperature trend for the annual means is +0.082 °C per decade corresponding to a +0.371 °C temperature change over the 1958–2002 period of record. Trends computed using these analyses show considerable sensitivity to start and end dates, with trends calculated using start dates prior to 1965 showing overall warming, while those using start dates from 1966 to 1982 show net cooling over the region." Several scientific sources〔 PDF available at AMS Online〕〔 PDF available at Annular Modes Website〕 have reported that there is a cooling trend observed in the interior of the continent for the last two decades of the 20th century, while the Antarctic Peninsula shows a warming trend. Doran et al. (2002)〔 in Letters to Nature 2002-01-13〕〔 PDF version: advance online publication Letters to Science〕 find that "Although previous reports suggest slight recent continental warming our spatial analysis of Antarctic meteorological data demonstrates a net cooling on the Antarctic continent between 1966 and 2000, particularly during summer and autumn. The McMurdo Dry Valleys have cooled by 0.7 °C per decade between 1986 and 2000, with similar pronounced seasonal trends... Continental Antarctic cooling, especially the seasonality of cooling, poses challenges to models of climate and ecosystem change". In early 2013, David Bromwich, a professor of polar meteorology at Ohio State University, and a team including Antarctic weather station experts from the University of Wisconsin, published a paper in ''Nature Geoscience'' showing that the warming in central West Antarctica was unambiguous—and likely about twice the magnitude estimated by Steig et al. The key to Bromwich et al.'s work was the correction for errors in the temperature sensors used in various incarnations of the Byrd Station record (the only long record in this part of Antarctica); miscalibration had previously caused the magnitude of the 1990s warmth to be underestimated, and the magnitude of the 2000s to be overestimated. The revised Byrd Station record is in very good agreement with the borehole temperature data from nearby WAIS Divide.〔 〕 A new statistical reconstruction shows significant warming over all of West Antarctic in the annual mean, driven by significant warming over most of the region in winter and spring. Summer and fall trends, are insignificant except over the Antarctic Peninsula where they are widespread only in fall. These finding are in good agreement with the 2009 study in Nature, though in general the new results show greater warming in West Antarctica and less warming over East Antarctica as a whole. Nicholas and Bromwich〔 argue that while the warming in East Antarctica is not statistically significant, it would be greater in magnitude if not for the ozone hole. There is no evidence that any significant region of Antarctic has been cooling, except in fall. There has been a public dispute regarding the apparent contradiction in the observed behavior of Antarctica, as opposed to the global rise in temperatures measured elsewhere in the world. This became part of the debate in the global warming controversy, particularly between advocacy groups of both sides in the public arena,〔(Antarctic Cooling Down; The Antarctic Ice Sheet is Growing; Hansen Downgrades Warming Threat | )〕 including politicians, as well as the popular media. In contrast to the popular press, there is no evidence of a corresponding controversy in the scientific community. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Antarctica cooling controversy」の詳細全文を読む スポンサード リンク
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