Hotspot volcanoes

Some volcanoes could warm the climate and destroy the ozone layer, according to NASA

WSHINGTON: 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 ultraviolet rays, a new NASA climate simulation suggests.

The simulation contradicts previous studies indicating that these volcanoes cool the climate. It also suggests that while extensive basalt eruptions on Mars and Venus may have helped warm their climates, they may have doomed the long-term habitability of those worlds by contributing to water loss.

“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.”

The research has been published in Geophysical Research Letters.

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.

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 seem to have been common on other terrestrial worlds in our solar system, such as Mars and Venus.

The team used the Goddard Earth Observing System’s chemistry-climate model to simulate a four-year phase of the Columbia River Basalt (CRB) eruption that occurred between 15 and 17 years ago. million years ago in the Pacific Northwest of the United States.

The CRB eruptions were likely a mix of explosive events that sent material high into the upper troposphere and lower stratosphere (about 13-17 km a.s.l.) and effusive eruptions that did not extend above about 3 km above sea level.

The simulation assumed that explosive events occurred four times a year and released about 80% of the sulfur dioxide gas from the eruption.

The team 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.

The predicted influx of water vapor into the stratosphere also helps explain the severity of ozone depletion.

“Ozone depletion happens in two 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 (OH) radical.”