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CLAIM
The melting of Antarctic ice is due to underwater subglacial volcanoes. It has no direct link with anthropogenic warming.
FACT
Global warming is leading to glaciers melting and increased volcanic activity. Many scientific studies proved that volcanic heat is not a significant contributor to the glacial melt observed in the ocean. But their impacts are interrelated. That is one event has the ability to trigger another.
WHAT THEY CLAIM
A misleading statement based on a video clip is going viral on Twitter with the hashtag climate scam (#climatescam). According to the video, the main culprit behind global ice melt is ‘underwater volcanoes’ and the linkage of global warming to the melting of ice is a blatant lie.
WHAT WE FOUND
According to data from NASA’s GRACE and GRACE Follow-On satellites, the land ice sheets in Antarctica have been losing mass since 2002 at a rate of roughly 150 billion tons per year. The main reason for this transition is global warming. Scientists have recently found the existence of underwater volcanoes. Many studies have been carried out to date to understand their role in glacier melts.
Climate change influences the Antarctic ice melt
The increase in temperature at high latitudes is far more pronounced than the increase in the average global temperature. This phenomenon is known as Polar amplification. Polar amplification refers to the phenomena wherein any change in the net radiation balance (for instance, greenhouse intensification) tends to create a bigger change in temperature near the poles than in the global average. The ratio of polar warming to tropical warming is the term used to describe this. According to the experts, the pressure on the mantle will decrease as climate change weakens and melts the glacier. That might cause more heat to escape from the rocks below, thus speeding up the ice-loss process even more.
There has been a decline in the average extent of sea ice in the Arctic during the past forty years, but not in the Antarctic. The sea ice extent has increased in certain locations while decreasing in others, compensating for each other to cause this statistically insignificant drop in the overall Antarctic sea ice extent (More…).
The Intergovernmental Panel on Climate Change (IPCC) concluded in its Sixth Assessment Report that the Antarctic’s temperature will continue to rise and its ice sheet mass will continue to shrink. The growth of this ice sheet is significantly slower than its retreat.
Why do glaciers melt?
Reduced air temperatures and/or an increase in solid precipitation usually cause glaciers to expand. It is believed that changes in the ocean currents and warm winds near Antarctica are causing the rapid glacier melt. Despite this, additional, non-climatic elements also come into play. Volcanic activity is one prominent example, which can directly influence glacier behavior and/or regulate glacial responses to climate forcing.
How are Volcanic Eruption and Glacier Melting Linked?
Our land, oceans, and atmosphere are all warming up as a result of climate change. Along with this, it has the ability to change the “cooling effect” that occurs after volcanic eruptions and boost volcanic activity. At the end of the last ice age, volcanic activity dramatically increased due to a combination of erosion and ice cap melting. There was a rise in both magma output and volcanic eruptions as the temperature warmed and the ice caps melted, releasing pressure on the Earth’s mantle. The majority of the time, snow and ice cover volcanoes found in high-latitude areas. The current loss of ice mass from the polar ice sheets in Greenland and Antarctica has led some to hypothesize that volcanic activity may be a factor.
Approximately 281 gigatonnes of ice mass have been lost from Greenland year since 2002, according to data from the U.S./German Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) satellite missions. The astounding loss of Greenland’s ice sheet at the moment is not caused by volcanic activity. There are no known mapped, dormant volcanoes in Greenland that were active during the Pliocene era of geological history, which began more than 5.3 million years ago. Volcanoes are considered active if they have erupted within the last 50,000 years. In truth, heat from the solid Earth is probably less important in the history of the Greenland ice sheet than heat from the atmosphere and the ocean.
Although there are no current volcanoes in Greenland, scientists are sure that a “hot spot”, a region where heat from Earth’s mantle rises up to the surface as a thermal plume of buoyant rock existed beneath Greenland. The current melting of the ice sheet is not being influenced by mantle plumes, despite the fact that they can cause some types of volcanoes.
Unlike Greenland, however, the Antarctic Ice Sheet has strong indications of the presence of volcanoes, some of which are active now or have been in the recent geologic past. Although it is uncertain how many volcanoes there are in Antarctica, recent research discovered 138 in West Antarctica alone.
A recent NASA study provides more proof that a mantle plume, a type of geothermal heat source, is located beneath Marie Byrd Land in Antarctica. This source could account for part of the melting that has caused lakes and rivers to form beneath the ice sheet. The heat source is not a brand-new or growing hazard to the West Antarctic ice sheet, but it might help scientists explain why the ice sheet collapsed quickly during a previous period of fast climate change and why it is so unstable now.
The amount of water that lubricates an ice sheet from below, enabling glaciers to move more readily, is directly connected to how stable it is. In order to predict the rate at which ice may be lost to the ocean in the future, it is crucial to understand the origins and future of the meltwater under West Antarctica. Long before the West Antarctic ice sheet was established, the Marie Byrd Land mantle plume originated between 50 and 110 million years ago. Similar to what is happening now, the ice sheet experienced a period of rapid and prolonged ice loss during the end of the last ice age roughly 11,000 years ago as a result of modifications to the world’s weather patterns and increasing sea levels.
Another study conducted by Loose et.al (2018) investigates evidence for volcanic heat flow beneath Pine Island Glacier, a section of the West Antarctic Ice Sheet close to the Amundsen Sea. The study makes no assertions regarding the origin of the observed modern ice loss, which could be related to this volcanic heat flux. It states that “the existence of subglacial volcanism impacts both the stable and unstable dynamics of an ice sheet such as the [West Antarctic Ice Sheet]”. A glacier’s base may thaw as a result of subglacial volcanism, which alters the way in which they function and makes them more susceptible to abrupt retreat.
Barletta et. al (2018) identified that, when weight (such as an ice sheet) is added to the Earth’s crust or withdrawn from it, the crust rises or sinks into the mantle. That is the bedrock underlying Antarctica is gradually rising, as the continent loses ice. And the ice sheet may stabilize after a catastrophic collapse.
The melting of ice is occurring from both sides (top and bottom). The presence of underwater volcanoes and the release of heat from these sources facilitates melting which existed in the past before scientists noticed it. But it doesn’t negate the fact that climate change due to man-made activities has a big role in recent melting. The noticeable effect of climate change is increased global temperature, which will disturb the natural balance of ice formation and melting (albedo-feedback), which may eventually lead to the frequent occurrence of volcanic eruptions as it exposes inactive volcanic vents.
References:
https://www.weforum.org/agenda/2023/03/antarctic-ice-sheet-is-melting-humanity-climate/
Pietro Sternai et al. ‘Deglaciation and glacial erosion: a joint control on magma productivity by continental unloading.’ Geophysical Research Letters (2016). DOI: 10.1002/2015GL067285
https://climate.nasa.gov/news/2649/hot-news-from-the-antarctic-underground/
https://www.sciencedirect.com/science/article/abs/pii/S0012825217305780
https://www.nature.com/articles/s41467-018-04421-3
