A satellite orbiting the Earth captured the immediate aftermath of the volcanic eruption under the sea in Tonga on January 15, 2022./European Space Agency
The Earth’s ozone layer, which blocks powerful ultraviolet rays, is under threat. The cause is a large amount of water vapor created by a huge volcanic eruption that occurred last year. Additionally, rockets flying into space are emitting substances that destroy the ozone layer.
The research team led by Stephanie Evan, a postdoctoral researcher at the Institute of Atmospheric and Cyclone Research at the University of Réunion in France, reported that 50 to 60% of ozone in the atmosphere disappeared depending on the region due to the Hunga-Tonga Hapai submarine volcanic eruption in the South Pacific in January last year. The research results were published in the international academic journal Science on the 20th.
The Tongan volcano in the South Pacific erupted on January 15 last year (local time). Tonga’s volcano was more powerful than any volcanic eruption in the past 30 years, spewing out massive amounts of ash, gas and steam. Unlike regular volcanoes, because it was a submarine volcano, it was characterized by the generation of a huge amount of water vapor along with chemicals. The pillar created by the volcanic eruption rose up to 58 km in the sky.
Ozone is a substance made up of three oxygen atoms and floats 24 to 32 km above the Earth. In particular, at an altitude of 25 km, ozone molecules gather together to form an ozone layer, which plays the role of absorbing ultraviolet rays coming from the sun and entering the Earth. Powerful solar ultraviolet rays cause skin cancer and cataracts and destroy the ecosystem by reducing chlorophyll and plankton.
The ozone layer was mentioned as an object of protection when an ‘ozone hole’ was discovered over Antarctica in 1985. This is why the Montreal Protocol was signed in 1987 to restrict the use of freon gas (chlorofluorocarbon, CFC), which is used as a refrigerant in sprays and refrigerators and air conditioners. Since then, Freon gas usage has decreased by 99%, and hydrofluorocarbons (HFC) are being used as a substitute. The United Nations Environment Program (UNEP) predicted earlier this year that the ozone layer will recover to the 1980s level by 2040.
Volcanic clouds created by the Hunga Tonga eruption in January 2022 reached record heights. /JMA
However, a variable occurred: the Tongan volcanic eruption. The researchers launched an observation balloon on January 20 last year, five days after the explosion, and used satellite data to determine changes in the stratospheric ozone layer. The Tongan volcanic eruption destroyed the ozone layer because of the chemicals and large amounts of steam in the erupted gas. Sulfur dioxide contained in volcanic eruption gas reacts with ozone (O3) in the atmosphere and turns into sulfuric acid aerosol. Additionally, a large amount of water vapor increases the relative humidity of the stratosphere and creates a warm temperature, and aerosols cause chemical reactions with substances such as hydrogen chloride (HCI), chlorine monoxide (CIO), and nitrogen oxides (NOx). These substances interact with ozone and play a role in depleting ozone.
The research team explained that a week after the explosion, ozone 25 to 29 km above Reunion Island, east of the African continent, decreased by 10 to 45 percent compared to before. Additionally, ozone in Antarctica decreased by 60% compared to before, and in the southwestern Pacific and Indian Oceans, it decreased by 5%. Unlike previous volcanic eruptions, the Tongan volcano sent a lot of water vapor into the atmosphere when it erupted, reducing ozone worldwide.
The research team said, “The Tongan volcanic eruption is exceptional in that it injected a lot of water vapor into the atmosphere after satellite observation,” and added, “Aerosols and water vapor from the Tongan volcanic eruption provide insight into chemical reactions in the stratosphere.” He explained, “We need to understand volcanic eruption plumes and ozone depletion and establish follow-up research and response strategies.”
Not only volcanic eruptions but also the space industry, which has recently been booming around the world, destroys the ozone layer. As rockets fly into space, they emit carbon dioxide, water vapor, hydrogen chloride, black carbon, and nitrogen oxides. Researchers at Purdue University and the National Oceanic and Atmospheric Administration (NOAA) published research results showing that pollutants generated from rockets and atmospheric frictional heat increase atmospheric temperature in the international academic journal ‘PNAS’ on the 16th of this month (local time). did.
Daniel Cziczo, a professor at Purdue University, said, “Metal particles of the same proportion as alloys used in spacecraft remain in the stratosphere atmosphere, threatening the ozone layer and changing the composition of meteorites falling to Earth.” He added, “Human activities have a greater impact on the Earth than expected.” “It is a warning sign that it may have negative effects,” he explained.
References
Science, DOI: https://doi.org/10.1126/science.adg2551
