{"id":236986,"date":"2022-12-30T18:59:25","date_gmt":"2022-12-30T17:59:25","guid":{"rendered":"https:\/\/climatescience.press\/?p=236986"},"modified":"2022-12-30T18:59:27","modified_gmt":"2022-12-30T17:59:27","slug":"bering-land-bridge-formed-surprisingly-late-during-last-ice-age-say-researchers","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=236986","title":{"rendered":"Bering Land Bridge formed surprisingly late during last ice age, say researchers"},"content":{"rendered":"\n
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Credit: alaskapublic.org<\/p>\n\n\n\n

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From Tallbloke’s Talkshop<\/a><\/p>\n\n\n\n

December 30, 2022 by\u00a0oldbrew<\/strong><\/p>\n\n\n\n

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A researcher said: \u201cRemarkably, the data suggest that the ice sheets can change in response to more than just global climate,\u201d calling into question some long-held ideas. A professor connected to the study commented: \u201cThese findings appear to poke a hole in our current understanding of how past ice sheets interacted with the rest of the climate system, including the greenhouse effect.\u201d Well, fancy that. The commentary notes that \u2018global temperatures were relatively stable at the time of the fall in sea level, raising questions about the correlation between temperature, sea level and ice volume\u2019. In short, the ice sheets grew faster than scientists had thought.<\/em>
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Princeton scientists found that the Bering Land Bridge, the strip of land that once connected Asia to Alaska, emerged far later during the last ice age than previously thought, says Eurekalert.<\/a><\/em><\/p>\n\n\n\n

The unexpected findings shorten the window of time that humans could have first migrated from Asia to the Americas across the Bering Land Bridge. <\/p>\n\n\n\n

The findings also indicate that there may be a less direct relationship between climate and global ice volume than scientists had thought, casting into doubt some explanations for the chain of events that causes ice age cycles.<\/p>\n\n\n\n

The study<\/a> was published on December 27 in the Proceedings of the National Academy of Sciences.<\/p>\n\n\n\n

\u201cThis result came totally out of left field,\u201d said Jesse Farmer, postdoctoral researcher at Princeton University and co-lead author on the study. \u201cAs it turns out, our research into sediments from the bottom of the Arctic Ocean told us not only about past climate change but also one of the great migrations in human history.\u201d<\/p>\n\n\n\n

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Insight into ice age cycles<\/strong><\/p>\n\n\n\n

During the periodic ice ages over Earth\u2019s history, global sea levels drop as more and more of Earth\u2019s water becomes locked up in massive ice sheets.<\/p>\n\n\n\n

At the end of each ice age, as temperatures increase, ice sheets melt and sea levels rise. These ice age cycles repeat throughout the last 3 million years of Earth\u2019s history, but their causes have been hard to pin down.<\/p>\n\n\n\n

By reconstructing the history of the Arctic Ocean over the last 50,000 years, the researchers revealed that the growth of the ice sheets \u2014 and the resulting drop in sea level \u2014 occurred surprisingly quickly and much later in the last glacial cycle than previous studies had suggested.<\/p>\n\n\n\n

\u201cOne implication is that ice sheets can change more rapidly than previously thought,\u201d Farmer said.<\/p>\n\n\n\n

During the last ice age\u2019s peak of the last ice age, known as the Last Glacial Maximum, the low sea levels exposed a vast land area that extended between Siberia and Alaska known as Beringia, which included the Bering Land Bridge. In its place today is a passage of water known as the Bering Strait, which connects the Pacific and Arctic Oceans.<\/p>\n\n\n\n

Based on records of estimated global temperature and sea level, scientists thought the Bering Land Bridge emerged around 70,000 years ago, long before the Last Glacial Maximum.<\/p>\n\n\n\n

But the new data show that sea levels became low enough for the land bridge to appear only 35,700 years ago. This finding was particularly surprising because global temperatures were relatively stable at the time of the fall in sea level, raising questions about the correlation between temperature, sea level and ice volume.<\/p>\n\n\n\n

\u201cRemarkably, the data suggest that the ice sheets can change in response to more than just global climate,\u201d Farmer said. For example, the change in ice volume may have been the direct result of changes in the intensity of sunlight that struck the ice surface over the summer.<\/p>\n\n\n\n

\u201cThese findings appear to poke a hole in our current understanding of how past ice sheets interacted with the rest of the climate system, including the greenhouse effect,\u201d said Daniel Sigman, Dusenbury Professor of Geological and Geophysical Sciences at Princeton University and Farmer\u2019s postdoctoral advisor.<\/p>\n\n\n\n

\u201cOur next goal is to extend this record further back in time to see if the same tendencies apply to other major ice sheet changes. The scientific community will be hungry for confirmation.\u201d<\/p>\n\n\n\n

Full article here.<\/a><\/em>
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Study: The Bering Strait was flooded 10,000 years before the Last Glacial Maximum<\/a><\/p>\n\n\n\n