A volcano erupted on Sunday on the island of La Palma, in the Spanish Canary Islands archipelago.
As the lava progresses slowly, between 6,000 and 11,500 tonnes of sulfur dioxide are released into the atmosphere daily.
interviewed two vulcanologists to find out whether the release of toxic gases represented an environmental hazard.
A lava flow seems to tirelessly swallow the landscape.
On the island of La Palma, in the Spanish Canary Islands, the Cumbre Vieja volcano erupted on Sunday, forcing many residents to abandon their homes.
According to the latest report, 154 hectares of land and 320 buildings have already been destroyed.
The eruption could last "between 24 and 84 days", with the key to significant emissions of gas and smoke, indicates the Volcanological Institute of the Canaries (Involcan).
The black cloud, which has already reached the Moroccan coasts and the Iberian Peninsula, should then rise towards the Balearic Islands and the south of France.
For what environmental impact and what health risks?
Is this black smoke dangerous?
Rest assured, the Spanish volcano would not be the most dangerous. “This is a lava rash, which is moderately explosive. It's spectacular and destructive, but on a scale of 0 to 8, I would place this eruption at 2, so it remains modest, ”suggests Jacques-Marie Bardintzeff, volcanologist and professor at the University of Paris-Saclay. Despite the significant damage - already estimated at more than 400 million euros - and the evacuation of more than 6,000 people, the eruption has so far caused no deaths or injuries. “The smoke that we see is gas and ash. The eruption produces sulfur dioxide and carbon dioxide, polluting gases but it remains very local, ”adds the specialist, author of the blog volcamania. According to the Canary Islands Volcanological Institute (Involcan), between 6,000 and 11.500 tonnes of sulfur dioxide are thus spat out into the atmosphere daily.
“A volcano releases several components: magma, which spread over 166 hectares.
Water and ash, light particles that can travel long distances and prevent air traffic.
And gas which can be toxic, in particular sulfur, but the concentrations of which today are not dangerous for the population ”, also reassures Marina Rosas Carbajal, volcanologist at the CNRS and at the Institut de physique du globe de Paris.
Why are we afraid of lava reaching the ocean?
The main fear of scientists is that the moving lava will reach the Atlantic Ocean. “In contact with the sea, this risks increasing the explosiveness of the whole. The magma can be pulverized into fragments, dangerous like shards of glass, and there is also the risk of seeing clouds of toxic elements like sulfuric acid appear on contact with water vapor ”, relates Jacques-Marie Bardintzeff . The local government, which has advised the islanders to cover their noses and mouths when they go out, has decreed a "two nautical mile exclusion radius" [nearly 4 km] around the area. where lava could come in contact with the ocean.
Originally scheduled for Monday evening, this potentially explosive meeting may never take place.
The lava could stop on its own, although its slowdown has been very marked in recent hours.
What more global impact for the environment?
Beyond the human risk, this eruption should have a limited impact on the environment.
"If it lasts a long time, it can increase the ecological impact on the south of the island, but not at the level of the continent or the ocean," says Jacques-Marie Bardintzef.
“There can be damage to the national park, the surrounding environment.
But we are not in a scenario of great eruption, as we experienced for example in the Middle Ages and which had an impact on the climate.
Every day, there are about twenty eruptions on the planet, and the climatic impact is minimal, ”says Marina Rosas Carbajal.
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