No evidence 2022 Tonga volcano emitted more CO2 than Earth does in a year

What's the claim?

A video on social media claims CO2 emissions from the 2022 Tonga volcano eruption exceeded annual human levels. The video shows a man saying, "Woke up this morning to see a volcano had erupted. A quick Google told me that when the Tonga volcano erupted in 2022, it emitted enough CO2 to cover the entire Earth's output for an entire year. So it doesn't matter how many solar panels, milk floats, yogurt pots you recycle, or anything like that." He further said, "Apparently, CO2 is killing the planet. So, it must be the volcano's fault, so let's have a go with the volcanos because before the industrial revolution, volcanos never existed, did they? So, therefore, oh hang on, so volcanos did exist, and they can output enough CO2 to cover the entire Earth's allowance for a year." The video gained over 3,700 reactions and 1,900 shares (archive here).

Screenshot of the viral video on Facebook. (Source: Facebook/Modified by Logically Facts)

However, there is no evidence the 2022 Tonga volcano eruption emitted more CO2 than humans produce in a year. 

What we found

Logically Facts contacted Dr. Marco Brenna, a Geologist teaching at the University of Otago, who has studied recent eruptions at calc-alkalic arc volcanoes at Mount Tongariro and Hunga Ha'apai (Tonga). Benna stated that no such estimation was published, but CO2 emissions will be around 10 million metric tons after the Tonga eruption. He said, "Based on conservative estimated eruption volume of 8 km3 and density of ~2500 kg per cubic m, that gives 2 x 10^10 metric tonnes of magma."

Dr. Brenna also confirmed that CO2 emissions from the Tonga eruption are much less than the annual global CO2 emission. 

"The CO2 concentration was probably around 500 ppm (note there is no actual measurement of the Hunga magma as yet, but it's unlikely to have been much different). That gives about 10 million metric tonnes of CO2, which I understand is 3000 less than global yearly emissions," Dr. Brenna said. 

Probable origin of the false claim

Vivienne Payne, a lead scientist at the NASA Jet Propulsion Laboratory, told Logically Facts, "Volcanic eruptions are a source of CO2, but in general, we expect the volcanic emissions worldwide to be at least 100 times smaller than the anthropogenic emissions in any given year."

Payne also directed us to an article titled "Researchers measure concentration of atmospheric carbon dioxide after Tonga eruption," which she thought might have led to the social media claim. "The article refers to a localized, short-term enhancement of around 2ppm in atmospheric CO2 in the volcanic plume relative to the background around the plume. It misleadingly compares that localized, short-term enhancement in atmospheric CO2 in the volcanic plume to the magnitude of the global annual growth rate in atmospheric CO2 (around 2 ppm per year), as measured by NOAA at the Mauna Loa observatory," Payne added. 

Payne further explained that the "CO2 emissions needed to increase the average atmospheric CO2 by 2ppm over a whole year, over the whole globe, is a far bigger number than the CO2 emissions needed to enhance the atmospheric CO2 over a small area for a given day."

Annual CO2 emissions in 2022

According to a report by the International Energy Agency, annual CO2 emissions reached 36.8 billion metric tons in 2022. The number is much higher than Dr. Brenna estimated regarding the Tonga volcano.

Payne added that anthropogenic emissions overwhelmingly drive the global growth rate in atmospheric CO2. She explained that the annual global growth rate of CO2 would have doubled in 2022 had the Tonga emission involved such a significant CO2 emission: "Note that the global annual growth rate in CO2 reported by NOAA for 2022 was 2.17 ppm per year, which was comparable to the global annual growth rate in preceding years. Definitely not double!" 

Logically Facts contacted Michael Manga, a geoscientist and professor at Berkeley Earth and Planetary Sciences. Professor Manga also refuted the claim and labeled it as false. 

Tonga volcano eruption 

On January 15, 2022, a Tongan archipelago underwater volcano, Hunga Tonga–Hunga Haʻapai, erupted, shooting ash and rock between 12 to 53 kilometers into the atmosphere, causing a shockwave and a tsunami along the coast. 

It affected 85 percent of the population. The disaster cost the country $90 million, led to the destruction or damage of over 600 buildings, and had a substantial impact on crops, livestock, and fisheries. According to a World Bank impact report, the event has caused $90.4 million in economic damage.

The verdict

No data has been published on the amount of CO2 emissions after the Tonga volcano eruption. Geoscience experts have confirmed the estimated CO2 emissions due to the eruption are much lower than Earth's annual emissions. Therefore, we have marked this claim as false.