Greenland Ice Sheet Ice Loss Accelerating with Numerous Amplifying Feedbacks Towards Tipping Points
In the last week or so, there have been a number of peer-reviewed scientific papers that show the stability of the enormous ice sheets on both Greenland and Antarctica are much less resilient than we previously thought.
In this video, I focus on Greenland Ice Sheet melt, and in the next video I switch poles and chat about the Antarctic Ice Sheet loss and the effects on the Global Ocean Overturning Circulation.
For Greenland, we are fast approaching a tipping point whereby we lose all the ice sheet in Southern Greenland. An Earth System Model of Intermediate Complexity (EMIC) that incorporates all the known feedbacks shows that when the cumulative carbon emissions reach 1000 GtC we lose the southern ice on Greenland. Since cumulative human emissions to date have reached 500 GtC, it means that we are already half way there. The study also shows that when cumulative carbon emissions reach 2500 GtC then we lose essentially all the Greenland ice, which results in 7 meters of global sea level rise.
We also know that the increased melt rate on the surface of Greenland is greatly accelerating, and the meltwater is running through crevices and cracks in the ice, running downhill between the bottom of the ice sheet and the bedrock below, and entering the ocean. The turbulent flow of this meltwater is eroding away the ice at the bottom of the glacier, greatly increasing ice mass loss. I discussed this in great detail in some Greenland videos I published back in October and November.
Finally, a third crucial paper was just published online on March 29th, 2023 that shows how there is increasingly extreme Greenland ice sheet melting in northeast Greenland. What is happening is that there are increasing numbers of powerful Atmospheric Rivers (ARs) hitting the northwest of Greenland, where they cause great summer melting there when they are rain on snow events. As these ARs deposit their rain (at low altitudes) and snow (at high altitudes) they cross the peak of the ice sheet and descend down the lee side as very dry, warm (adiabatically heated) fast winds (called foehn winds). On their way downhill across the northeast Greenland ice sheet they cause extreme melting events that erode away the ice extremely quickly.
All of these mechanisms mean that global sea level will rise much faster than anybody thinks (apart from me).
All of these mechanisms mean that the Greenland Ice Sheet is destabilizing, and melting much faster than anybody has expected, apart from myself, of course (see my series of videos; Can Global Sea Level Rise 7 meters by 2070?).
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