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Scientists have found New evidence that the Renland ice cap in eastern Greenland has repeatedly grown and shrunk over the last 12,000 years, sometimes smaller than it is today.
Aaron K of the University of Maine. In Medford’s first treatise, the team elaborated on the recent receding of the ice cap, which has not revealed radiocarbon dating of plants. Their results suggest that moss and willow shrubs grew near the current boundary of the glacier in two very recent periods. The first is about 1000 years ago and the second is about 500 years ago.
“The oldest age is [approximately] 900-1000 [years old]”The scientists said paperWas published in Quaternary Science Reviews in April. “Therefore, Renland’s ice cap must have been smaller than that of 2011 when these plants were inhabited, which allows them to grow in ice-covered spaces until recently. . “
The first period of presumed warming roughly corresponds to the optimal period of the Middle Ages, the warm period when Viking explorers reached Greenland and North America.
By studying glacier-supplied lake sediments, researchers have found that Renland’s ice caps are now more than about 9,500 years ago, and about 7,000 to 4,000 years ago. I guess it was small.
Kenneth Richard of Climate Change Depot Emphasized researchClaims that it supports the early Holocene view, date The mid-Holocene, from about 12,000 years ago to about 8,500 years ago, and from about 8,500 years ago to 4,200 years ago, was warmer than current temperatures in eastern Greenland and is now ice. There is a view that the coverage and temperature of the ice cubes are still constant. At the Holocene “cold stage”.
Medford and his team said their findings were consistent with other temperature proxies in the area. Insects remain From Lake Last Chance near Scoresby Bay. The latter data “show warmer summer temperatures than today throughout most of the early and mid-Holocene,” the authors write.
2004, International team We reviewed paleoenvironmental data including pollen macro fossils and various other proxies from sites that span the western Arctic. Of the 140 locations they surveyed, 120 “provided clear evidence of warmer conditions than they are today”, supporting the existence of Holocene fever maximums in the early Holocene region.
Intergovernmental Panel on Climate Change (IPCC) in the Fourth Assessment Report (AR4) of 2007 I got it Records from the North Atlantic, Arctic, and other regions “provide evidence of hundreds of years in regions that are up to several degrees warmer than the past few decades, from the early to mid-Holocene.”
However, the IPCC emphasized that the scope and accuracy of surrogate data “limits the ability to determine if there was a period of decades of global warming comparable to the latter half of 20 years.”NS century. “
To summarize recent research, the IPCC’s 2013 Fifth Assessment report Mid-to-high latitudes in the Southern Hemisphere may have shown a cooling trend during the Holocene, with mid-to-high latitudes in the Northern Hemisphere approximately 1 degree Celsius higher than current temperatures approximately 6,000 to 8,000 years ago. Please note that it may have happened.
In the Alps, Scandinavia, Greenland, Baffin Island and Spitzbergen, the report also “confidently” stated that many glaciers could be smaller than in the second half of the 20th century, the report said in the Northern Hemisphere from 1983 to 2012. We conclude that the average temperature in the world indicates that. The region said, “It is very likely that it is the warmest 30 years (reliable) in the last 800 years and the warmest 30 years (medium reliable) in the last 1,400 years.” I am.
As-discovered plants in eastern Greenland did not first appear on ice in the centuries.Ice-covered moss on Ellesmere Island in northern Canada for over 400 years Started to grow again After emerging from a shrinking glacier in 2013.
Nathan Worcester is an environmental reporter for The Epoch Times.
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