Tonga volcanic eruption raises probability of 1.5 degree global warming

The January 2022 eruption of the Hunga Tonga-Hunga Ha’apai undersea volcano in the South Pacific will likely accelerate global warming. This is the result of a study in the journal “Nature Climate Change.” The explosion increased the probability of exceeding the 1.5-degree temperature increase by seven percent.

The Tongan eruption is one of the best-documented such events in human history, write scientists led by Stuart Jenkins of the University of Oxford (UK) in the study published on Thursday. The explosion is estimated to have ejected 146 megatons of water vapor and about 0.42 megatons of sulfur dioxide into the stratosphere.

Most volcanic eruptions mainly carry sulfur dioxide into the higher air layers. The researchers write that this causes the temperature to cool, as the aerosol particles scatter sunlight. However, it is possible that within a few years the Tongan explosion will have the opposite effect.

Volcanic eruption as a driver of climate change

This is due to high water vapor emissions that increase the water content in the stratosphere by 10 to 15 percent. Water vapor acts as a greenhouse gas. So if the steam stays there for a long time, it causes the surface temperature on Earth to increase. The volcanic eruption could become a driver of climate change, at least for a limited time, as the eruption on January 15, 2022 also released relatively small amounts of sulfur dioxide, which offsets the temperature rise.

The analyzes of scientists point to the fact that the global average temperature exceeds the pre-industrial level by 1.5 degrees Celsius. According to the calculations, the world’s chance of experiencing the first year that this limit is actually exceeded in the next five years will increase by around seven percent with the results of the Tonga eruption. But that doesn’t change the fact that the strongest driver of this development is man-made greenhouse gas emissions, the researchers write in the study.