Volcanic supereruptions may cool the climate to a much lesser extent than previously thought. Simulations conducted by NASA researchers showed that if one of them occurred today, its impact on life on Earth would be comparable to an “ordinary” explosion. This also has significant implications for how we fight climate change.
Volcanic supereruptions are extremely powerful explosions during which a volcano ejects 1,000 cubic kilometers of magma. They are powerful, but also rare – the last supereruption took place over 22,000 years ago in New Zealand. The eruption of the Toba volcano, which occurred 74,000 years ago, led humanity to almost complete extinction.
Scientists have long been wondering whether the cooling of the climate after the supereruption, also called “volcanic winter”, could potentially pose a threat to humanity. Previous research has shown that the average temperature on Earth will drop by 2-8 degrees Celsius after a massive explosion. As a study published in the Journal of Climate shows, the cooling could be much smaller than expected.
The impact of volcanic supereruptions on the climate
Computer simulations conducted by experts from the institute NASA Goddard Institute for Space Studies prove that the cooling after the supereruption will be small. Researchers analyzed the size of sulfur particles injected high into the atmosphere during the eruption. In the stratosphere, sulfur dioxide undergoes chemical reactions that condense into liquid sulfate particles. They can affect the Earth’s surface temperature in two ways: by reflecting incoming sunlight (causing cooling) or by trapping outgoing thermal energy (a type of greenhouse effect).
By modeling different droplet sizes, scientists found that they are unlikely to be able to change global temperatures any more than the largest eruptions of modern times. For example, the 1991 eruption of Pinatubo in the Philippines caused global temperatures to drop by about half a degree over two years.
“No single supereruption has given us strong evidence that it will cause a global catastrophe,” said Zachary McGraw, the study’s lead author.
Cooling the atmosphere
The cooling phenomenon is sometimes mentioned in the context of the fight against global warming. According to the concept of geoengineering, intentionally injecting aerosol particles into the stratosphere could contribute to lower temperatures.
Luis Millán of NASA’s Jet Propulsion Laboratory in Southern California, who was not involved in the study, said the mysteries of supereruption cooling require further study. He added that a comprehensive comparison of models should be carried out, as well as more laboratory and model research on the factors determining the size of volcanic aerosol particles.
– For me, this is another example showing that geoengineering using stratospheric aerosol is very, very far from being a real solution – he said.
Tonga volcano eruptionNASA Earth Observatory image by Joshua Stevens using GOES imagery courtesy of NOAA and NESDIS
Main photo source: NASA Earth Observatory image by Joshua Stevens using GOES imagery courtesy of NOAA and NESDIS