Climate change could cause more precipitation on volcanoes

Majority of Earth’s volcanoes could experience higher rainfall due to climate change, which could increase eruptions and mudslides


July 27, 2022

Merapi Volcano in Indonesia

Aditya Irawan/NurPhoto via Getty Images

Climate change could bring more extreme rainfall to the majority of Earth’s active terrestrial volcanoes. Precipitation has previously been implicated as a risk factor for eruptions and mudslides.

The geological record is replete with volcanoes altering the Earth’s climate by spewing gases and soot that reflect or trap radiation from the sun, such as the eruption of Mount Tambora in 1815 that made 1816 “the year without a summer” . The relationship seems to go both ways: melting glaciers, rising sea levels and precipitation can all affect volcanic activity.

Jamie Farquharson of the University of Strasbourg in France and Falk Amelung of the University of Miami in Florida wondered how many of Earth’s roughly 1,200 active volcanoes might receive an increased amount of precipitation due to climate change.

The pair ran nine different climate models under medium and high greenhouse gas emission scenarios, corresponding to 2-3ºC and 5ºC warming by 2100. They then examined where at least seven of the nine models matched.

In the high emissions scenario, they found that 716 volcanoes would see an increase in heavy rainfall, including most of the Pacific “Ring of Fire”, the African Rift System and some volcanic island chains in the Pacific. Antarctic and Pacific, and 506 in the medium emissions scenario. .

In both scenarios, about a hundred volcanoes would actually see a decrease in heavy rainfall by 2100. There were also several hundred in each scenario where the models did not agree well enough to make a decision.

The researchers also analyzed decades of reports from the Smithsonian Global Volcanism Program, which catalog volcanic activity. They found that heavy rains had been implicated in eruptions or other hazards such as mudslides for at least 174 volcanoes, including Vesuvius in Italy, St. Helens in Washington and Reventador in Ecuador, all of which would receive more heavy rains with warming.

Thomas Aubry, from the University of Cambridge, UK, says this “puts the nail in the coffin on the importance of rainfall for volcanic hazard”.

Heavy rains can cause eruptions as cold water seeps into lava domes and vaporizes or by ‘rotting’ a volcano’s internal structure over time, says Bill McGuire of University College London . Heavy rains can also cause mudslides of volcanic ash called lahars, which are the deadliest volcanic hazard. “Volcanoes tend to be quite fragile environments,” says Farquharson.

Aubry says the conditions under which increased precipitation would cause an eruption or lahar are complex and “could vary widely from volcano to volcano.” But the study demonstrates that rainfall should be considered as part of volcanic hazard monitoring, he said. Meteorological data is generally not taken into account by the monitors of many volcanoes.

Journal reference: Royal Society Open ScienceDOI: doi/10.1098/rsos.220275

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Teresa H. Sadler