Here’s a crazy speculation: global warming could cause earthquakes.
How? As glaciers on land melt, the water will flow into the seas, resulting in the transfer of mass and therefore weight from the continents to the seafloor.
The reduction in weight will cause the land to rise and trigger movement along fault lines. Also, because large glaciers are mostly in the eastern hemisphere, there will be a net transfer of mass and thus weight from the eastern hemisphere to the western hemisphere.
Let’s consider Greenland, the largest island in the world. Wikipedia says:
“Three-quarters of Greenland is covered by the only permanent ice sheet outside of Antarctica. … The Greenland ice sheet covers 1,755,637 km2 (677,855 sq mi) (81%) and has a volume of approximately 2,850,000 km3 (680,000 cu mi). … The weight of the ice sheet has depressed the central land area to form a basin lying more than 300 m (984 ft) below sea level, while elevations rise suddenly and steeply near the coast. … If the Greenland ice sheet were to melt away completely, the world’s sea level would rise by more than 7 m (23 ft).” – https://en.wikipedia.org/wiki/Greenland
If all of that ice melts it’s estimated that this would cause sea level rise of 23 feet, which would be a problem for all coastal cities and low lying areas.
But there’s another issue: when all of that weight of ice melts and becomes seawater, it will reduce the weight on the Greenland landform, which will rise, and may displace the local fracture zones.
And there’s yet another issue: when all of that weight of ice melts and becomes seawater, it will increase the weight of the oceans on the underlying seafloor.
The Pacific Ocean is larger than the Atlantic ocean and the Pacific ocean is surrounded by this thing called the Ring of Fire, which are fracture zones that give rise to earthquakes and volcanoes.
If sea level were to rise by 23 feet, the Pacific Ocean, which has an area of approximately 165,250,000 km2 (63,800,000 sq mi), would gain 277,917 cubic miles of water.
The Atlantic Ocean is smaller than the Pacific, with an area of “only” 41,100,000 sq. mi. So more of the extra water would end up in the Pacific.
A cubic mile of water weighs approximately 9.2 trillion pounds.
So that’s an added load in the Pacific basin of 2,556,833 trillion pounds of weight.
Again, because the Pacific Ocean is larger than the Atlantic Ocean, this would be a net transfer of mass and therefore weight on the underlying earth from the eastern hemisphere to the Western hemisphere. This could cause ruptures in those fractures.
Remember that there are also great ice loads in northern Canada and Alaska, Russia and Siberia, and the Himalayas; and of course Antarctica. Those weights will also flow to the seas, increasing sea level rise, and transfer weight off the continents and onto the sea floors. The continental areas will rise, and the sea floors will be burdened by more mass of water.
Voila’ – earthquakes and volcanoes.
Follow-up links to consider:
Image credit Eric Gaba (Wikimedia Commons user Sting)
@Copyright 2021 Bruce Merchant