Climate warming and loss of ice unprecedented in last 14,000 years.Byline: ANI Washington, November 7 (ANI): A new analysis has revealed that the period of climate warming and loss of ice being witnessed currently in the Antarctic Peninsula Antarctic Peninsula, glaciated mountain region of W Antarctica, extending c.1,200 mi (1,930 km) N toward South America; in the south, volcanic peaks rise to c.11,000 ft (3,350 m). Most of its NE coast is fringed by the Larsen ice shelf. has been never been seen in the last 14,000 years. "At no time during the last 14 thousand years was there a period of climate warming and loss of ice as large and regionally synchronous as that we are now witnessing in the Antarctic Peninsula," said team member Dr Steve Bohaty of the National Oceanography Centre, Southampton The National Oceanography Centre, Southampton (NOCS) is a purpose-built, joint venture between the University of Southampton and the Natural Environment Research Council (NERC). (NOCS NOCS Nucleo Operativo Centrale di Sicurezza (Italian National Police High-Risk Intervention Unit) NOCS Network Operations Center System NOCS Norden Graduate School for the Construction Sector NOCS Nevada Office of Community Services ). The findings are based on a detailed analysis of the thickest Holocene sediment core yet drilled in the Antarctic Peninsula. "By studying the climate history of the past and identifying causes of these changes, we are better placed to evaluate current climate change and its impacts in the Antarctic," said Dr Bohaty. As part of a 2005 research cruise aboard the American icebreaker icebreaker, ship of special hull design and wide beam, with relatively flat bottom, designed to force its way through ice. When the icebreaker charges into the ice at full speed, its sharply inclined bow, meeting the edge of the ice, rises upon it, and the weight of RV/IB Nathanial B. Palmer, the scientists drilled down through the sediments at Maxwell Bay, a fjord fjord or fiord (fyôrd), steep-sided inlet of the sea characteristic of glaciated regions. Fjords probably resulted from the scouring by glaciers of valleys formed by any of several processes, including faulting and erosion by at the northwest tip of the Antarctic Peninsula. They drilled down as far as the bedrock, obtaining a nearly complete 108.3-metre sediment core. Back in the lab, they performed a battery of detailed sedimentological and geochemical analyses on the core. Radiocarbon dating radiocarbon dating n. The determination of the approximate age of an ancient object, such as an archaeological specimen, by measuring the amount of carbon 14 it contains. Also called carbon dating, carbon-14 dating. showed that the oldest sediments at the bottom of the core were deposited between 14.1 and 14.8 thousand years ago, and sedimentation rates at the site varied from 0.7 to around 30 milimetres a year through the Holocene; that is, the geological period that began around 11,700 years ago, continuing to the present. The researchers conclude that ice was grounded in the fjord during the Last Glacial Maximum The Last Glacial Maximum (LGM) refers to the time of maximum extent of the ice sheets during the last glaciation (the Würm or Wisconsin glaciation), approximately 20,000 years ago. This extreme persisted for several thousand years. - the height of the last ice age - and eroded older sediments from the fjord. Later, the grounded ice retreated, leaving a permanent floating ice canopy. The evidence points to a period of rapid glacial retreat from 10.1 to 8.2 thousand years ago, followed by a period of reduced sea-ice cover and warm water conditions occurring between 8.2 and 5.9 thousand years ago. An important finding of the study is that the mid-Holocene warming interval does not appear to have occurred synchronously throughout the region, and its timing and duration was most likely influenced at different sites by local oceanographic controls, as well as physical geography. "Atmospheric warming trends linked to global climate change are an obvious culprit for the observed regional climate changes," according to the researchers. (ANI) Copyright 2009 Asian News International The Asian News International (ANI) agency provides multimedia news to China and 50 bureaus in India. It covers virtually all of South Asia since its foundation and presently claims, on its official website, to be the leading South Asia-wide news agency. (ANI) - All Rights Reserved. Provided by Syndigate.info an Albawaba.com company |
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