Above, Bill Nye touches on recent research about melting ice on Greenland, and
(related) slowing of the North Atlantic Circulation.
Significant areas of Greenland’s melted ice sheet are now producing vegetation, risking increased greenhouse gas emissions, rising sea levels and instability of the landscape.
A study has documented the change since the 1980s and shows that large areas of ice have been replaced with barren rock, wetlands and shrub growth, creating a change in environment.
Analysis of satellite records has shown that over the past three decades an estimated 11,000 sq miles of Greenland’s ice sheet and glaciers have melted, an area equivalent to the size of Albania and amounting to 1.6% of its total ice cover.
As ice has retreated, the amount of land with vegetation growing on it has increased by 33,774 sq miles, more than twice the area covered when the study began.
The findings show a near-quadrupling of wetlands across Greenland, which are a source of methane emissions.
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As Nye explains, (not very well, but it’s complicated) – increased freshening of North Atlantic Waters from Greenland’s melting ice is a factor in an observed slowing of the North Atlantic Meriodonal Overturning Circle
A reminder:
Also, one more data point on Greenland that came in the last week.
LiveScience:
The flow of glaciers off the edges of Greenland is causing the landmass to rise like a decompressing mattress.
The uplift of Greenland is a long-term and well-known process. Since the end of the last ice age about 11,700 years ago, the retreat of the ice sheet has taken a weight off of Greenland, allowing its bedrock to rise — a process known as glacial isostatic rebound.
On top of this long-running process, Greenland is now losing ice due to modern-day climate change. The Greenland Ice Sheet is shedding approximately 262 gigatons of ice each year. Its peripheral glaciers, the ice rivers found at the coastline flowing into the sea, are losing about 42 gigatons of ice alone, according to 2022 research.
Harkening back to where it all began for me: geology, vulcanology, cracked eggshells floating around on a partially boiled egg … I wonder how transferring all that weight from a concentration on land to a diffusion into the sea impacts the magma beneath, and Iceland and the Mid-Atlantic Spreader
A cascading effect from that single grain of sand
‘Read’, some years ago, when the Grace satellites were still functioning, from Memory, that Greenland’s north rose 4 inches and the south dropped 3 inches.
Continental crust “dents” the top of the mantle (the slightly runny asthenosphere) roughly in proportion to the weight on top. For example, the crust beneath the Himalayas, the current tallest mountain range, sticks down farther than the Alps. When weight is removed it results in slow isostatic rebound (gradual lifting) of the crust. Ice can melt very very quickly in geologic time, so crust under the last places that lost weight, like Norway, are still rebounding to compensate for the “rapid” removal of ice.
Because weight is most often in the form of ice, the more commonly used term is glacial rebound, but a supervolcano eruption or a bolide impact can redistribute mass, too.
So much water mass has been extracted from California’s Central Valley aquifers that the deep crust underneath has had significant measurable isostatic rebound. So, while the near-surface subsidence of lands there have dropped quickly, the crust has started to bow up to compensate.
Right! I think Hudson Bay is the best example that no one seems to know about
Offhand I would think it’s negligible on multi-century time scales just based on the overwhelmingly massive thickness & weight of the crust+lithosphere beneath the 1.6 km thick ice. Slowly over Millenia yes it would be measurable.
Sometimes I scare myself: A Vicious Circle Linking Climate Change And Earthquakes?