Arctic 21: Understanding the history of the Greenland Ice Sheet
ฝัง
- เผยแพร่เมื่อ 5 ก.พ. 2025
- Dr. Paul Bierman, Professor of Environmental Science at the University of Vermont, presents on a major paper released last month.
Within the past million years, the center of Greenland - currently buried under a 3-kilometer-thick sheet of ice - supported plant life, indicating that it was completely ice-free even when CO2 concentrations were far lower than today’s levels. Authors examined ancient remains of soil from the base of an ice core drilled at Summit Station decades ago, and nearly miraculously preserved. They found unmistakable remains of a tundra plant ecosystem that could only have formed in the absence of ice; and when the ice is gone at the summit, at least 90% of Greenland’s ice must have melted. Link to the full paper is below.
Dr. Bierman recently published a popular science book on this effort ("When the Ice is Gone") and shares about his experience translating "hard" science into something for a more general public.
Full paper: www.pnas.org/d...
When the Ice is Gone: wwnorton.com/b...
#Greenland #SeaLevelRise #Glaciers
Fascinating, thank you.
Thank you for a wonderful talk on the paleo climate of Greenland. You might be interested in in the MIS 5e exposures produced by heavy equipment on large construction sites in the coastal river valleys in north western San Diego County that record a very rapid sea level rise between 130,000 to 120,000 years before present. One particular site, the "Wanis View Estates" project, records 20 meters or 60' of sea level rise in a tributary canyon of the main San Luis Rey river valley or "SLRV" Here, mass grading produced 3 main exposures totaling around 1000 meters laterally north south. As sea level rose, the main SLRV drainage filled with over a hundred feet of fluvial deposits in response to the rise in world wide sea levels, damming a tributary canyon with ever thickening deposits, producing a lake that simply migrated up stream in response to the thickening of the sediment package due to sea level rise. Sand deltas with 2 meter high fore sets entered the lake from the south, marching north across the lacustrine mud, each stopping a short distance into the lake. This produce a stacked sequence of sand deltas in response to sea level rise. As the SLRV sediment dam thickened to the south, a new sand delta would overshoot the older one never able to fill the lake indicating a sea level rise faster than the rate of sedimentation. The lake would simply shift higher in elevation and further up stream with each sand delta. Once sea level rise slowed, sedimentation would finally fill in the lake with flood plain overbank fine grained deposits. Today the southernmost basal contact of the lowest sand delta today is 46' MSL in elevation while the highest basal contact is at an elevation 108' MSL at the northern most exposure. Coastal San Diego preserves many transgressive estuarine valley fills covering a large portion of the Pleistocene. We have 21' to go to beat this old MIS 5e record plus an added anthropogenic cause to make things even more interesting!
Thanks, very interesting lecture.
Loss of Greenland ice will match while the ice loss in the Antarctic will be ten fold. A very dynamic overturn of waterfront property. Here today and gone tomorrow.
sea rise by 7 meters
Greenland was ice free in the last interglacial.
carry on.
😂😂😂 mass extinctions have happened in the past, nothing to worry anout
My picture of a map of Greenland 400k years ago would have an inland sea with rocky perimeter islands.
How fast isostatic rebound? Could that lift the center of Greenland above sea-level when the ice was gone?
Any plans for more ice-cores?
The first Sumerian cities began to develop about the same time sea-level rise slowed enough for stable coastlines to develop.
Stable coastlines are an essential need for our civilization.