The white continent is a real world apart. Located around the South Pole, it is the southernmost and coldest continent on our planet. Covered with 98% ice, it is home to breathtaking landscapes and unique biodiversity, adapted to extreme conditions. Although it is often nicknamed the “white desert” (because of the very little precipitation it receives), it is not just a long arid and frozen plainpunctuated by a few glaciers.
It actually shelters dozens of mountains, valleys and above all more than a hundred volcanoes, some of which show worrying signs of activity. Global warming and melting ice could encourage their awakening, according to new studies carried out on Mount Erebus and Mount Waesche.
The natural laboratory of Mount Erebus
Mount Erebus (photo at the top of the article) constitutes an exceptional case study in the field of volcanology. Culminating at 3,794 meters above sea level, it is the northernmost active volcano on our planet. Its permanent lava lake, a rare phenomenon in the volcanic world, has persisted for decades.
The latter, 20 meters wide, harbors complex dynamics that scientists are trying to decipher. “ We observe the tip of a magma system that extends perhaps 150 km into the mantle “, says Rick Aster, a geophysicist at Colorado State University.
The new seismic installations, deployed in extreme conditions where the mercury can drop as low as -59° C, as reported by Glen Mattioli, vice president of instrumentation at the EarthScope Consortium, will allow continuous monitoring of activity from Mount Erebus.
Ronni Grapenthin, a geophysicist at the University of Alaska Fairbanks, points out a paradox about the latter. Although the lava lake theoretically acts as a decompression valve, long-term pressurization cycles inflate and deflate the volcano’s flanks, suggesting a gap in the understanding of its magmatic system.
Although it is its internal dynamics that are studied, the melting of the ice could influence the stability of its volcanic system. Strengthened monitoring of Mount Erebus could thus help to better understand how external factors, such as the melting of ice caps, could act as a catalyst to awaken the volcanoes of this isolated but geologically active region.
The enigma of Mount Waesche
Research carried out on Mount Waesche, located 1,500 km from McMurdo, an American base, reveals that there is a correlation between volcanic activity and climatic periods. Matthew Zimmerer and his team at the New Mexico Institute of Mining and Technology analyzed lava samples dating back more than 100,000 years. Their results, as yet unpublished, are nevertheless indisputable: “ The correlation was totally unexpected “, says Zimmerer.
Geological records indicate that almost 90% of breakouts occurred between ice ages, during warming phases similar to the one we experience today.
A discovery that resonates with observations of Adelina Geyer, volcanologist at Géosciences Barcelona: “ As soon as glaciers begin to retreat, volcanic activity intensifies “. This phenomenon, already documented in Iceland and the northwest of the United States, could be explained by a simple but formidable mechanism: the reduction in glacial pressure would release magmatic gaseslike uncorking a bottle of champagne.
A domino effect with global consequences
The prospect of a volcanic awakening in Antarctica would be a new environmental problem to add to the (too) long list which already weighs on our shoulders. If an isolated eruption would only have a localized impact on glacial dynamics, the synchronous activation of several volcanic centers could trigger a cascade of events with considerable consequences.
The initial melting, caused by anthropogenic warming, would relieve the pressure exerted on the magma chambers. This decompression would promote the release of volcanic gases and, by extension, the occurrence of eruptions. The latter would in turn accelerate glacial melting, thus creating a feedback loop positive likely to amplify the initial phenomenon.
If the melting of the ice accelerates, the phenomenon would have repercussions on global ocean circulation, in particular through the massive supply of fresh water into the southern oceans. This modification of the physicochemical parameters of deep waters could disrupt ocean currents, which act as thermal regulators of our planet.
This is why the scientific community intensifies its research efforts on the active volcanoes of the South Pole. To better understand the interactions between climate and volcanism on the continent, a global approach to the issue is necessary, which involves a combination of different approaches: geological, geophysical and climatological. Integrating these feedback mechanisms into climate models will allow us to better anticipate and perhaps to mitigate their consequences on planetary balance.
- Melting ice in Antarctica could trigger an increase in volcanic activity, influenced by the release of pressure on magma chambers
- Studies show a link between periods of warming and peak eruptions, fueling a feedback loop with visible repercussions on glacial dynamics.
- This phenomenon could disrupt ocean currents and affect the global climate balance.
