Study Halves Estimate of Volcano Cooling in North
Researchers find mid-latitude eruptions amplify Northern Hemisphere cooling about twofold, not the 7.5-fold previously claimed.
Updated on Nov. 10, 2026 in Geology
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A study led by Dr. Zachary McGraw of Columbia University found that extratropical volcanic eruptions amplify Northern Hemisphere cooling only twofold under a favorable scenario, far below the previously claimed 7.5-fold. The research, published in Geophysical Research Letters, used a NASA climate model to simulate tropical and mid-latitude eruptions.
Why it matters
Volcanic eruptions cool the Earth's surface for years by dispersing reflective sulfuric acid aerosols into the stratosphere, so accurate estimates of their effect shape climate assessments. The researchers say the results will help forecast risks to agriculture and assess global food security.
The study simulated 100,000 hypothetical extratropical eruptions and found mid-latitude cooling amplified only twofold under a favorable scenario, versus the 7.5-fold previously claimed. Extratropical aerosols persist up to nine months, while tropical eruption aerosols can remain up to three years, and the full range of unfavorable scenarios is not described.
The players
Dr. Zachary McGraw
A researcher at Columbia University who led the study on whether volcanic cooling intensity depends on eruption location.
Columbia University
A private Ivy League research university in New York City whose researchers led the study.
NASA
The United States National Aeronautics and Space Administration, whose climate model was used to simulate the eruptions.
The details
Eruptions release sulfur dioxide into the stratosphere, where it forms microscopic sulfuric acid droplets that reflect sunlight. The researchers attributed the smaller cooling difference to aerosols remaining confined to the Northern Hemisphere after mid-latitude eruptions.
Timeline
1783: Iceland eruption analyzed in historical climate data.
1815: Indonesia's Mount Tambora eruption caused global climate disruptions.
1816: The Year Without a Summer followed the Tambora eruption.
750 CE onward: Tropical eruption climate records compared with simulated eruptions.
The Big Picture
The 1815 Mount Tambora eruption caused global climate disruption and the 1816 Year Without a Summer, a benchmark that shaped how scientists model volcanic cooling. This study revises earlier estimates for mid-latitude eruptions, which had suggested they could cool the Northern Hemisphere far more than tropical eruptions of similar size.
Accurate volcanic cooling estimates help scientists forecast climate and agricultural risks from future eruptions. The findings suggest that the climate impact of a mid-latitude eruption may be smaller than earlier models implied.
The takeaway
A volcano's latitude matters for how long and how strongly it cools the planet, and this study suggests earlier estimates overstated the effect of mid-latitude eruptions. Keeping these estimates accurate supports better forecasts for food security.
Further reading
Explore more on Geology to see how volcanic activity shapes Earth's climate over time.
Source note: This article includes information reported by RBC-Ukraine.
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