"Amidst all the hype over melting from above of the Antarctic and Greenland ice sheets due to global warming, little attention has been paid to melting from below due to the earth’s volcanic activity.
But the two major ice sheets are in fact melting on both top and bottom, meaning that the contribution of global warming isn’t as large as climate activists proclaim.
In central Greenland, Japanese researchers recently discovered a flow of molten rocks, known as a mantle plume, rising up beneath the island.
The previously unknown plume ... melts Greenland’s ice from below.
... To study the plume, the research team used seismic topography – a technique, similar to a CT scan of the human body, that constructs a three-dimensional image of subterranean structures from differences in the speed of earthquake sound waves traveling through the earth.
... The existence of a mantle plume underneath Antarctica, originating at a depth of approximately 2,300 km (1,400 miles), was confirmed by a California Institute of Technology study in 2017.
Located under West Antarctica ... the plume generates as much as 150 milliwatts of heat per square meter – heat that feeds several active volcanoes and also melts the overlying ice sheet from below.
... A team of U.S. and UK researchers found in 2018 that one of the active volcanoes drawing heat from the mantle plume in West Antarctica is making a major contribution to the melting of the Pine Island Glacier.
The Pine Island Glacier, situated adjacent to the Thwaites Glacier ... is the fastest melting glacier in Antarctica, responsible for about 25% of the continent’s ice loss.
... the team was surprised to find high concentrations of the gaseous helium isotope 3He near the Pine Island Glacier.
Because 3He is found almost exclusively in the earth’s mantle, where it’s given off by hot magma, the gas is a telltale sign of volcanism.
The study authors calculated that the volcano buried underneath the Pine Island Glacier released at least 2,500 megawatts of heat to the glacier in 2014 ...
A more recent study by the British Antarctic Survey found evidence for a hidden source of heat beneath the ice sheet in East Antarctica.
... From ice-penetrating radar data, the scientists concluded that the heat source is a combination of unusually radioactive rocks and hot water coming from deep underground.
The heat melts the base of the ice sheet, producing melt water which drains away under the ice to fill sub-glacial lakes.
... All these hitherto unknown subterranean heat sources in Antarctica and Greenland, just like global warming, melt ice and contribute to sea level rise. "
