New research conducted by a collaborative team, which includes atmospheric scientist Dr. Andrew Dessler from Texas A&M University, has examined the climate impact of the 2022 eruption of the Hunga Tonga volcano, challenging prevailing assumptions in the process. The eruption, which occurred over two days in mid-January 2022, injected significant amounts of volcanic aerosols and water vapor into the atmosphere.

Historically, large volcanic eruptions have had a cooling effect on the global climate by blocking sunlight with their aerosols. Past events like the Tambora eruption in 1815 and the Mt. Pinatubo eruption in 1991 are notable examples. However, the eruption of Hunga Tonga presented a unique scenario. Being a submarine volcano, it introduced an unprecedented amount of water vapor into the stratosphere, increasing the total stratospheric water content by approximately 10%.

Due to water vapor being a potent greenhouse gas, initial speculation suggested that it might have contributed to the extreme global warmth experienced in 2023 and 2024. However, the team's research, published in the Journal of Geophysical Research: Atmospheres, disproves this hypothesis. Contrary to expectations, the eruption actually aided in cooling the Earth, similar to other major volcanic events.

The research paper titled "Evolution of the Climate Forcing During the Two Years after the Hunga Tonga-Hunga Ha'apai Eruption" includes insights and analysis from Dr. Dessler, Dr. Mark Schoeberl, the chief scientist at the Science and Technology Corporation in Virginia, and multiple scientists from NASA. Their methodology involved analyzing satellite data observations from NASA and NOAA to estimate the energy balance of the Earth's climate system. Their findings reveal that the eruption resulted in more energy leaving the climate system than entering it, thereby inducing a slight cooling effect.

Dr. Dessler emphasized the importance of the research, stating that it refutes the notion that the volcano eruption caused the extreme warmth of 2023 and 2024. He stressed that the primary driver of global warming lies in human-generated greenhouse gas emissions, with the ongoing El Niño contributing significantly.

This research has broader implications for both scientists and the general public. By discounting the volcanic eruption as a major factor in recent warming, the study reinforces the understanding that human activities are primarily responsible for climate change. This emphasis becomes crucial given the ongoing debates and misinformation surrounding the causes of global warming.

Dr. Schoeberl also highlighted the importance of continued investment in satellite-based stratospheric measurements. These measurements enabled a greater understanding of the Hunga Tonga eruption's impact. However, he cautioned against a potential "stratospheric data desert," as important instruments are not being replaced.

While the research provides answers to significant questions, it also raises new uncertainties. The researchers identified unresolved issues such as the unexpectedly low levels of sulfur dioxide produced by such an intense eruption and the minimal impact on the 2023 ozone hole. Further analysis is needed to understand these aspects fully, as well as to advance comprehension of stratospheric circulation processes.

As scientists continue to delve into these questions and deepen their understanding of the stratosphere, Dr. Schoeberl emphasized the critical importance of continued research and the collection of precise data to address the challenges posed by climate change.

The research paper titled "Evolution of the Climate Forcing During the Two Years After the Hunga Tonga-Hunga Ha'apai Eruption" was published in the Journal of Geophysical Research: Atmospheres in 2024 and can be found under DOI: 10.1029/2024JD041296.