What happened to cause this last time and why is today different?
Greenland ice completely melted 7,000 years ago and could happen again
A new study from GreenDrill — a project co-led by the University at Buffalo to recover rock and sediment buried beneath the Greenland Ice Sheet — has revealed that the Prudhoe Dome ice cap completely vanished about 7,000 years ago. This is far more recent than scientists had previously believed.
The findings, published in Nature Geoscience, show that this elevated region in the northwest part of the ice sheet is highly sensitive to even modest warming. The melting occurred during the Holocene, the relatively stable climate period that began 11,000 years ago and continues today.
“This is a time known for climate stability, when humans first began developing farming practices and taking steps toward civilization. So for natural, mild climate change of that era to have melted Prudhoe Dome and kept it retreated for potentially thousands of years, it may only be a matter of time before it begins peeling back again from today’s human-induced climate change,” says Jason Briner, PhD, professor and associate chair of the Department of Earth Sciences in the UB College of Arts and Sciences, who co-led GreenDrill with Joerg Schaefer PhD, research professor at Columbia University’s Lamont-Doherty Earth Observatory.
Obviously, the article completely ignores why the melting back then was different from the melting now. The answer would be inconvenient.
The Prudhoe ice dome has an area of about 1000 square miles (the Greenland ice sheet is about 800,000 square miles). That’s just over 1% melted.
As explained in the article…
The Holocene Climate Optimum (HCO) was a warming period some 8000 to 6000 years ago where the Earth (especially the Northern Hemisphere) warmed. The warming was primarily driven by long-term changes in Earth’s orbit, leading to increased summer solar radiation (insolation) in the Northern Hemisphere.
The current bout of rapid warming appears to be caused by the accumulation of greenhouse gases, not by changes in the Earth’s orbit.