New article in PNAS by Francesco S. R. Pausata: "Impacts of high-latitude volcanic eruptions on ENSO and AMOC"

Volcanic eruptions have long-lasting global climate effects

Strong volcanic eruptions at high-latitudes have large impacts on the global climate system that can last for several decades. This is shown in a new study from Stockholm University published in the scientific periodical, PNAS

“Our study shows, for the first time, that large high-latitude eruptions in the Northern Hemisphere have major impact on the global climate for decades”, says Francesco S.R. Pausata, postdoc at the Department of Meteorology, Stockholm University.

Earlier research has focused on short-term impacts since the residence time of volcanic aerosol from strong eruptions is roughly two to three years. Most studies have focused on tropical eruptions; high-latitude eruptions have drawn less attention because their impacts were thought to be merely hemispheric rather than global.

Large summer high-latitude eruptions in the Northern Hemisphere cause strong hemispheric cooling, which could induce a change in the atmospheric and ocean circulation patterns in the equatorial Pacific during the first eight to nine months. The induced atmospheric circulation changes trigger a weakening of the trade winds over the western and central equatorial Pacific that leads to an El Niño-like response. In the model used by the Department of Meteorology, Stockholm University, the specified high-latitude eruption also leads to a strengthening of the ocean circulation over the Atlantic in the first 25 years after the eruption, followed by a weakening lasting at least 35 years.

“This change in the ocean circulations are able to affect the climate over the tropics and hence worldwide for decades”, Francesco S.R. Pausata says.

 

Press release in Swedish

Link to the article

Bolin Centre for Climate Research
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