Ash clouds, lava flows and fertile soil: What are the effects of Mount Etna’s eruptions?

Human activities produce 100 times the carbon dioxide of the planet’s volcanic eruptions, according to NASA. Europe’s most active volcano has been putting on a fiery show, and experts predict that this is just the beginning. Tourists have flocked en masse to see molten lava spewing out of Mount Etna, a stratovolcano located on the east coast of Sicily. As the eruption enters its seventh consecutive day, plumes of thick black smoke have continued to trigger travel chaos in the region, grounding dozens of flights at Catania–Fontanarossa Airport and temporarily suspending arrivals. And yet, for all the fiery force Etna is displaying, the environmental consequences of its eruptions are not necessarily as far-reaching or devastating as they appear. Etna is almost always erupting For one, this kind of activity is not unusual for Etna. The volcano erupts several times a year, and sometimes multiple times a month. In fact, it erupted in late July. The Sicilian landmark is one of the world’s most active volcanoes and has produced more than 70 paroxysmal eruptions in the past six years, Giorgio Costa, a PhD student at the University of Catania’s Department of Biological, Geological and Environmental Sciences, tells Euronews Earth. These intense bursts of activity can send lava fountains hundreds of metres into the air and ash clouds several kilometres high. They typically last several hours. “In reality, the volcano’s activity is currently perfectly normal,” says Costa. Is Mount Etna an environmental disaster waiting? Volcanic eruptions send a cocktail of debris and emissions into the air. The most obvious is ash, but volcanoes also emit carbon dioxide and sulfur dioxide, as well as small amounts of hydrogen sulfide, hydrogen chloride and hydrogen fluoride. That might make Etna’s regular eruptions seem like potential environmental catastrophes, but the truth is more complex. The US Geological Survey explains that gases such as sulfur dioxide can cause global cooling while carbon dioxide has the potential to promote global warming. The impact is minimal, however. NASA says that human activities generate 100 times the carbon dioxide of the planet’s volcanic eruptions. And climate change itself doesn’t influence eruptions. “There is no correlation between meteorological events, including climate change, and the Earth's volcanic or tectonic activity,” Costa tells Euronews Earth. Ash is a bigger – but still small – concern “The main issue currently associated with the eruptions of Etna concerns the fallout of pyroclastic material, mostly ash and small lapilli, which can be carried by the wind to the slopes,” says Costa. Lapilli are small fragments of rock, which typically range from two to 64 millimetres. Costa explains that while ash and small lapilli are not dangerous to human health, they can become so when fine particles produced by the ash are lifted into the air. “Inhaling large amounts of this material is certainly not healthy for the respiratory system, so wearing a mask is recommended,” he adds. It can also pose a serious problem for aircraft. If a plane flies through an ash cloud, the particles can enter its engines, where they can melt and damage components and, in some cases, cause engines to lose power. This is why ash in the airspace around Etna can force Catania Airport to close. The airport is currently closed until 2am on Saturday, and hundreds of flights have been cancelled or diverted over the past week. Why Etna’s ash is also a boon for human life They may have a negative impact on aeroplanes, but these same materials can benefit the planet. Etna’s ash acts as a mineral-rich fertiliser and can improve soil drainage and water retention, helping farmers produce Sicily’s renowned wines, pistachios and citrus fruit. Research from the Scripps Institution of Oceanography in San Diego found that volcanic ash can do morethan simply add nutrients to soil, too. In experiments, ash helped revive microbial communities in degraded soil, increasing the activity of organisms that play a key role in breaking down organic matter and making nutrients available to plants. The researchers also found that plants grown in ash-rich soil developed larger root systems and produced more biomass. Volcanic ash can also improve soil drainage and water retention. Etna’s frequent eruptions mean it repeatedly deposits fresh layers of ash, creating a long-term cycle of destruction, enrichment and renewal. Even if ash causes problems when it falls, it eventually becomes part of the soil supporting new life, if not important crops for Sicilian farmers. The dangers of getting too close While some might be worried about Etna’s impact on the environment, the biggest immediate risk may come from people getting too close to the action. “The greatest risk factor is the presence of large numbers of onlookers who set out along Mount Etna’s most rugged trails to watch the ongoing eruption, completely lacking in mountain gear,” says Mirko Messina, the co-founder of Bùum, a specialised tour service that leads excursions of Italian volcanoes, including Etna. “The Alpine Rescue Service has already carried out numerous rescues, especially at night when law enforcement checks are not in place.” Messina adds that Etna’s northeast slope – which has just one small, uphill road – has become “gridlocked with hundreds of cars, preventing normal traffic flow and hindering rescue efforts”. While Etna erupting might be business as usual, Messina says, it should be anything but that for those looking to witness it up close. “It is impossible to predict in advance how the eruption will evolve in the coming days,” he explains, “but it will be constantly monitored.”