Post falsely claims glaciers melt due to heat from underground magma and not human activities

What is the claim?

A video posted on Facebook, with around 1,900 shares, claims that glaciers in Antarctica are melting from the bottom up due to internal heat from hot magma from "sub-glacial volcanos" and that human activity has nothing to do with the melting of Antarctic glaciers. 

Facebook post claiming there is no anthropogenic cause for Antarctic ice melting. (Source: Facebook/Modified by Logically Facts)

However, while scientific evidence shows that volcanic activity does have some effect on glaciers, to say that no anthropogenic factor exists is false.

What is the truth?

According to NASA, glaciers melt both from above and below. This means that warm air melts the surface of the glacier, and warm water below the glacier melts it from below. This process varies for different glaciers across the planet. 

According to a Scientific American explainer published on April 12, 2018, the direct connection between Antarctic glacial ice melting and climate change is still considered to be “complex.” It is generally agreed upon that Antarctic ice melting is mainly driven by warm water seeping underneath the ice, not heat from magma.

The explainer quotes Chad Greene, a University of Texas, Austin glacier expert, who says climate change is thought to affect wind patterns that affect Antarctic glacial melting. It also says, “Some models suggest that the winds driving certain major ocean currents circulating around Antarctica will become more intense as the climate warms.”

A 2017 study by NASA found that “a geothermal heat source called a mantle plume lies deep below Antarctica's Marie Byrd Land, explaining some of the melting that creates lakes and rivers under the ice sheet.” However, the researchers stressed that it "isn't a new or increasing threat to the West Antarctic ice sheet."

Screenshot of the NASA article by Alan Buis from NASA's Jet Propulsion Laboratory. (Source: NASA)

Alan Buis from NASA's Jet Propulsion Laboratory explained that while volcanoes in Antarctica do cause melting, there is no link between the recent loss of ice mass in Antarctica and volcanic activity. “The Antarctic ice sheet is at least 30 million years old, and volcanism there has been going on for millions of years. It's having no new effect on the current melting of the ice sheet,” he wrote in a May 6, 2020, NASA article. 

What did experts say about the viral video?

Professor Christian Schoof, from the Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, told Logically Facts that the viral video is an “average piece of poorly thought-out misinformation floating around on the internet.” He said that the interior of Earth as a heat source is a thousand times weaker than the Sun.

Regarding Antarctica, he said, “The connection with climate is all through changing surface winds that drive away colder surface water, which allows the deeper warm water to move up and spill over. As with all climate issues, you have to look at these surface winds statistically, and the climate connection is that we've been getting the "wrong" kinds of winds more frequently.”

He added that the video’s implication that all ice-melting in the Antarctic happens due to subglacial volcanoes is false. “You can't say that all changes in sub-ice-shelf melting are due to anthropogenic forcing, but to say that it's categorically nothing to do with it is false,” he concluded.

Professor Gwen Flowers from the Department of Earth Sciences, Simon Fraser University, told Logically Facts that the Facebook video was "ridiculous." She said that “human-caused contribution to melting of mountain glaciers around the world is large and well established,” but this is more difficult to do with Greenland and Antarctic Ice sheet melting “because these ice masses are much larger and respond more slowly to climate than small glaciers.”

Flowers added that “the subtlety that the video is trying to exploit is that there is a lot of bottom melting of ice shelves in Antarctica caused by warm ocean water, but not all the warming/melting, in this case, is a reflection of anthropogenic global warming.” She concluded, “Mountain glaciers, along with the Greenland and Antarctic ice sheets, are losing mass overall, driven in part by human-caused climate change.”

Professor Andrew Shephard, Head of the Department of Geography and Environmental Sciences at Northumbria University, told Logically Facts that the video’s proposition that “glaciers in Antarctica are melting from the bottom up due to the internal heat” is false as that is only one of the heat sources melting the glacier. He said the main sources of Antarctic ice melting are atmospheric and oceanic heat. 

The verdict 

While the direct relationship between human-caused climate change and Antarctic ice melting is complex and volcanic activity is behind some of the melting, multiple experts confirmed that saying no anthropogenic factor exists is false. Therefore we have marked this claim as false.