{"id":360304,"date":"2025-01-03T15:46:43","date_gmt":"2025-01-03T14:46:43","guid":{"rendered":"https:\/\/climatescience.press\/?p=360304"},"modified":"2025-01-03T15:46:45","modified_gmt":"2025-01-03T14:46:45","slug":"central-greenland-was-recently-ice-free-and-covered-with-plants-when-co2-was-under-300-ppm","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=360304","title":{"rendered":"Central Greenland Was Recently Ice-Free and Covered with Plants When CO2 Was Under 300 ppm"},"content":{"rendered":"\n
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From NoTrickZone<\/a><\/p>\n\n\n\n

By\u00a0Kenneth Richard<\/a><\/em><\/p>\n\n\n\n

Today, with CO2 levels supposedly in the \u201cdangerously high\u201d range, Central Greenland has 3 kilometers of ice piled atop it.<\/strong><\/h4>\n\n\n\n

Scientists have known since the GISP2 borehole was drilled in 1993 that Central Greenland deglaciated at least once in the late Pleistocene (Bierman et al., 2024<\/a><\/strong>). Indeed, the Summit of the modern Greenland ice sheet was actually ice-free at some point between 250,000 and 1.1 million years ago \u2013 which is relatively recent from a geological perspective.<\/p>\n\n\n\n

Plants, wood, insects, fungi and other remnants suggestive of vegetation were recovered from the bottom of the boring site. This is quite a contrast to today\u2019s 3000-meters-high ice sheet at this same location.<\/p>\n\n\n\n

\u201cThe presence of poppy, spike-moss, fungal sclerotia, woody tissue, and insect parts in the GISP2 till shows that tundra vegetation once covered central Greenland, mandating that the island was largely ice-free.\u201d<\/em><\/p>\n\n\n\n

The atmospheric CO2 concentration is presumed to have ranged between 275 and 290 ppm during the Late Pleistocene, or during this same period when Greenland was ice-free. These sub-300 ppm CO2 levels are thought to be the same as they were from 1700 to 1900 (the Little Ice Age), when, as today, Central Greenland has remained buried in kilometers of ice.<\/p>\n\n\n\n

The authors of this study use existing knowledge of Greenland\u2019s climate (for example, Summit\u2019s mean July temperature is -7\u00b0C) to calculate how much warmer Central Greenland was \u201cwhen the ice was gone\u201d during the last 1.1 million years. Controlling for lapse rate, Central Greenland\u2019s average surface air temperatures were likely +3 to 7\u00b0C in July when it had no ice sheet.<\/p>\n\n\n\n

The atmospheric CO2 concentration thus appears to be largely unrelated to either Greenland\u2019s climate or its state of glaciation.<\/p>\n\n\n\n

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Image Source:\u00a0Bierman et al., 2024<\/a><\/strong><\/figcaption><\/figure>\n\n\n\n

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