NASA warns that some volcanoes could warm the climate and destroy the ozone layer

A new[{” attribute=””>NASA climate simulation suggests that extremely large volcanic eruptions called “flood basalt eruptions” could significantly warm Earth’s climate and devastate the ozone layer that shields life from the Sun’s ultraviolet radiation.

The findings contradict prior research that found these volcanoes cool the climate. The simulation also suggests that while extensive flood-basalt eruptions on

Extremely large volcanic eruptions called “flood basalt eruptions” could dramatically warm Earth’s climate and devastate the ozone layer that protects life from the Sun’s UV rays, a new NASA climate simulation reveals. Credit: NASA/GSFC/James Tralie

Unlike brief, explosive volcanic eruptions such as Pinatubo or Hunga Tonga-Hunga Ha’apai in January that occur over hours or days, flood basalts are regions with a series of eruptive episodes lasting perhaps centuries. each and occurring over periods of hundreds of thousands of years. , sometimes even longer. Some occurred around the same time as mass extinction events, and many are associated with extremely hot periods in Earth’s history. They also appear to have been common on other terrestrial worlds in our solar system, such as Mars and Venus.

“We expected intense cooling in our simulations,” said Scott Guzewich of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “However, we found that a brief cooling period was overwhelmed by a warming effect.” Guzewich is the senior author of a paper on this research which was published February 1, 2022 in the journal Geophysical Research Letters.

Flood basalt deposit on Mars

Image of a flooded basalt deposit on Mars in the Marte Vallis region taken by the High Resolution Science Imaging Experiment (HiRISE) instrument aboard NASA’s Mars Reconnaissance Orbiter spacecraft. Credit: NASA/University of Arizona/HiRISE

Although the loss of ozone was not a surprise, the simulations indicated the potential magnitude of the destruction, “a reduction of about two-thirds from global mean values, roughly equivalent to the whole of the planet having a thinning of the ozone layer comparable to a severe ozone hole in Antarctica,” Guzewich said.

Researchers used the Goddard Earth Observing System’s chemical and climate model to simulate a four-year phase of the Columbia River Basalt (CRB) eruption that occurred between 15 and 17 million years ago. years in the Pacific Northwest of the United States. The model calculated the effects of the eruption on the troposphere, the lowest turbulent layer of the atmosphere with most water vapor and weather, and the stratosphere, the next layer of the atmosphere which is mostly dry and calm. The CRB eruptions were likely a mix of explosive events that sent material high into the upper troposphere and lower stratosphere (about 8 to 10.5 miles or 13 to 17 kilometers a.s.l.) and effusive eruptions that did not not extended above 1.9 miles (approximately 3 kilometers) in elevation. The simulation assumed that explosive events occurred four times a year and released about 80% of the sulfur dioxide gas from the eruption. They found that globally there was a net cooling for about two years before the warming overwhelmed the cooling effect. “The warming persists for about 15 years (the last two years of the eruption, then another 13 years or so),” Guzewich said.

“We expected intense cooling in our simulations. However, we found that a brief cooling period was overwhelmed by a warming effect. — Scott Guzewich

The new simulation is the most comprehensive ever for basalt eruptions and incorporates the effects of atmospheric chemistry and climate dynamics on each other, revealing an important feedback mechanism that previous simulations had missed.

“Eruptions like the one we simulated would emit massive amounts of sulfur dioxide,” Guzewich said. “Chemistry in the atmosphere rapidly converts these gas molecules into solid sulfate aerosols. These aerosols reflect visible sunlight, which causes the initial cooling effect, but also absorb infrared radiation, which warms the atmosphere aloft in upper troposphere and lower stratosphere. The warming of this region of the atmosphere allows water vapor (which is normally confined near the surface) to mix with the stratosphere (which is normally very dry). a 10,000% increase in stratospheric water vapor Water vapor is a very effective greenhouse gas, and it emits infrared radiation that warms the surface of the planet.

The predicted influx of water vapor into the stratosphere also helps explain the severity of ozone depletion. “Ozone depletion happens in different ways,” Guzewich said. “After the eruption, the circulation of the stratosphere changes in a way that discourages the formation of ozone. Second, all that water in the stratosphere also helps destroy ozone with the hydroxyl radical (OH).

Flood basalts also release carbon dioxide, a greenhouse gas as well, but they don’t seem to release enough to cause the extreme warming associated with some eruptions. Excessive warming of stratospheric water vapor could provide an explanation.

Although Mars and Venus may have had oceans of water in the distant past, both are currently very dry. Scientists are studying how these worlds lost most of their water to become inhospitable to life. If the influx of water vapor into the upper atmosphere predicted by the simulation is realistic, significant flood volcanism may have contributed to their arid fate. When water vapor is high in the atmosphere, it becomes susceptible to being broken up by sunlight and the light hydrogen atoms of water molecules can escape into space (water is made up of two hydrogen atoms bonded to an oxygen atom[{” attribute=””>atom). If sustained over long periods, this could deplete oceans.

Reference: “Volcanic Climate Warming Through Radiative and Dynamical Feedbacks of SO2 Emissions” by Scott D. Guzewich, Luke D. Oman, Jacob A. Richardson, Patrick L. Whelley, Sandra T. Bastelberger, Kelsey E. Young, Jacob E. Bleacher, Thomas J. Fauchez and Ravi K. Kopparapu, 1 February 2022, Geophysical Research Letters.
DOI: 10.1029/2021GL096612

The research was funded by the NASA Goddard Sellers Exoplanet Environments Collaboration and NASA’s Center for Research and Exploration in Space Science and Technology, NASA Cooperative Agreement Award #80GSFC17M0002.

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