A volcanic eruption usually results in (a little) cooling of the Earth. The eruption releases sulfur, among other things. Some of them end up in the stratosphere at an altitude of 20 km.
Ultrafine sulfuric acid droplets are formed there, which reflect part of the sunlight. This means that the Earth could be slightly cooler for a longer period of time after a volcanic eruption.
The difference with Honga Tonga is that this is an undersea volcanic eruption. This undersea explosion blew up the equivalent of 60,000 Olympic-sized swimming pools filled in the stratosphere.
This did not lead to a cooling of the Earth, but rather to an increase in its temperature. Preliminary calculations show that the Hunga Tonga volcanic eruption may have caused global temperatures to rise by 0.1 degrees in 2023.
This is because water vapor, a greenhouse gas, has exploded into the stratosphere. “Water vapor ensures that you get a downward and upward heat flow. This downward heat flow heated the atmosphere in the lower regions,” explains meteorologist Raymond Klassen of Weerplaza.
