{"id":64303,"date":"2009-01-13T00:00:00","date_gmt":"2009-01-13T00:00:00","guid":{"rendered":"https:\/\/www.uri.edu\/news-draft\/uncategorized\/uri-researchers-great-lakes-water-level-sensitive-to-climate-change\/"},"modified":"2009-01-13T00:00:00","modified_gmt":"2009-01-13T00:00:00","slug":"uri-researchers-great-lakes-water-level-sensitive-to-climate-change","status":"publish","type":"post","link":"https:\/\/www.uri.edu\/news\/2009\/01\/uri-researchers-great-lakes-water-level-sensitive-to-climate-change\/","title":{"rendered":"溏心vlog免费B站 researchers: Great Lakes water level sensitive to climate change"},"content":{"rendered":"
\n\t\tEarly Holocene dry climate caused lakes to become disconnected<\/p>\n


\n\tNARRAGANSETT, R.I. \u2013 January 13, 2009 \u2013 The water level in the Great Lakes has varied by only about two meters during the last century, helping them to play a vital role in the region\u2019s shipping, fishing, recreation and power generation industries. <\/p>\n


\nBut new evidence by scientists from the 溏心vlog免费B站 and colleagues in the U.S. and Canada, published last month in the journal Eos, indicates that the water level in the lake system is highly sensitive to climate changes. <\/p>\n


\n\u201cIn the distant past, there were great fluctuations in the water level of the Great Lakes, but it was thought to have been related entirely to the advance and retreat of the glaciers,\u201d said 溏心vlog免费B站 geological oceanographer John King, who led the study with 溏心vlog免费B站 visiting scientist Michael Lewis, emeritus scientist with the Geological Survey of Canada. \u201cBut the last time lake levels fell dramatically \u2013 down to 20 meters below the basin overflow outlets \u2013 it was due to dry climate conditions.\u201d <\/p>\n


\nThat event, which occurred between 7900 and 7500 years ago in the early Holocene period, caused the lakes to become disconnected as their overflow rivers, including the Niagara River, ran dry.<\/p>\n


\n\u201cPeople used to say that the oceans are so big, we can dump whatever we want in them and nothing will happen,\u201d said King. \u201cThey thought of the Great Lakes in the same way, that the system is too large to be sensitive to climate variations. But now we know that to be untrue. We\u2019ve demonstrated that at least once in the last 10,000 years, climate drove the lake levels down pretty substantially.\u201d<\/p>\n


\nResearchers had long assumed that the Great Lakes had been \u201chydrologically open\u201d and connected since their formation 16,000 years ago during the retreat of the last ice sheet, but recent evidence has found this to be false. Ancient shorelines, submerged beaches, and tree stumps on the floor of some lakes indicate that the water line had been as much as 20 meters below the present lake level.<\/p>\n


\n\u201cWe had a multi-proxy approach to this study, and through many lines of evidence we identified this as a dry interval with a climactic cause as opposed to a glacial-related cause,\u201d King said.<\/p>\n


\nThe climate and water levels in the Great Lakes region are determined by the interplay of three air masses: dry, cold Arctic air from the North, dry warm Pacific air from the West, and warm, moist tropical air from the Gulf of Mexico. The scientists found that during the period when lake levels receded significantly, the dry air from the Arctic and Pacific was dominant. Later, when precipitation from the tropical air mass became more frequent, the Great Lakes began to flow from one to another as they do today.<\/p>\n


\nKing worries about the economic impact to the Great Lakes region if the present climate changes lower water levels significantly. Navigation, water usage and hydropower would be severely affected.<\/p>\n


\n\u201cThe climate interval that occurred back then is different from what we\u2019re going through now,\u201d King said. \u201cIt would take a pretty big change to close the basins again. But the sorts of temperatures and precipitation amounts that happened then are within the range of what is predicted for 2100. In the worst-case scenarios, a lot of things become possible.<\/p>\n


\n\u201cThe range of lake-level changes that are likely to happen in the next 100 years is probably larger than the range of levels observed during the last century,\u201d he added.<\/p>\n

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Early Holocene dry climate caused lakes to become disconnected NARRAGANSETT, R.I. \u2013 January 13, 2009 \u2013 The water level in the Great Lakes has varied by only about two meters during the last century, helping them to play a vital role in the region\u2019s shipping, fishing, recreation and power generation industries. But new […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[],"class_list":["post-64303","post","type-post","status-publish","format-standard","hentry","category-archives"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/posts\/64303","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/comments?post=64303"}],"version-history":[{"count":0,"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/posts\/64303\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/media?parent=64303"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/categories?post=64303"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.uri.edu\/news\/wp-json\/wp\/v2\/tags?post=64303"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}