---
title: "Volcanoes and Climate: Scientists Clarify How Eruption Geography Affects Global Cooling"
description: "Columbia University scientists, using a NASA climate model, clarified that extratropical eruptions cool the Northern Hemisphere only twice as strongly as tropical ones, rather than 7.5 times as previously believed."
date: 2026-11-04T09:09:56.445Z
lang: en
url: https://xab.info/en/posts/volcanoes-and-climate-geography-eruption-cooling
tags: [volcanoes, climate, stratosphere, aerosols, columbia-university, nasa, geophysical-research-letters]
author: "Alexander Buran"
publisher: "XAB.info"
---

# Volcanoes and Climate: Scientists Clarify How Eruption Geography Affects Global Cooling

![Eruption of a snow-covered volcano in a harsh mountainous area under a cloudy sky](https://xab.info/media/2026/11/04/vulcany-i-klimat-geografiya-izverzheniya-poholodanie/vulcany-i-klimat-geografiya-izverzheniya-poholodanie-1.webp)

## Key Points

- A study in Geophysical Research Letters showed extratropical eruptions cool the Northern Hemisphere only 2 times more than tropical ones, not 7.5 times
- Scientists used a NASA climate model and simulated 100,000 hypothetical eruptions for verification
- Cooling in the Northern Hemisphere more frequently coincides in time with tropical eruptions
- The only mechanism for stronger extratropical eruption impact is aerosol distribution patterns
- The findings are crucial for predicting agricultural risks and global food security

Volcanic eruptions can cool the Earth's surface for months or even years, but the scale of this impact, as it turns out, is largely determined by the geographical location of the emission source. This is reported by RBC-Ukraine with reference to the results of a study published in the peer-reviewed journal Geophysical Research Letters. The work, carried out by Dr. Zachary McGraw from Columbia University and his colleagues, challenges established views that extratropical eruptions vastly outperform tropical ones in their climatic impact.

### The Mechanism of Volcanic Cooling: From Sulfur Dioxide to Aerosols

The physics of the process is well studied. Powerful eruptions inject significant amounts of sulfur dioxide into the stratosphere. There, this gas interacts with water vapor and oxygen, resulting in the formation of microscopic droplets of sulfuric acid. These form so-called "reflecting aerosols," which scatter and reflect solar radiation back into space. Less thermal energy reaches the planet's surface, and the Earth experiences cooling that can last from several months to several years. A classic example is the eruption of the Indonesian volcano Tambora in 1815, the consequences of which led to 1816 going down in history as the "year without a summer.
"

### The Hypothesis of Mid-Latitude Superiority and Its Testing

A number of recent studies have pointed to an extremely large impact of extratropical eruptions on temperatures in the middle latitudes of the Northern Hemisphere. Preliminary calculations suggested that eruptions in the 30° to 70° latitude range could cause cooling up to 7.5 times stronger than tropical eruptions of similar magnitude. To test this hypothesis, McGraw's team used a NASA climate model: eruptions were simulated in both the tropics and the middle latitudes, taking into account various volumes of sulfur gas emissions and the season in which the event occurred. The results obtained did not confirm the preliminary assumptions: under the most favorable scenario, a mid-latitude eruption enhanced cooling by only a factor of two, rather than 7.5.

### Historical Data and 100 Thousand Simulated Scenarios

To verify the results of the numerical modeling, the researchers analyzed data on historical eruptions: in Iceland (1783), in the middle latitudes (approximately 536 AD), and in Alaska (43 BC). In addition, experts simulated 100,000 hypothetical extratropical eruptions to compare their consequences with climate data on tropical eruptions that occurred after 750 AD. The results showed that cooling in the Northern Hemisphere most often coincides in time precisely with tropical eruptions rather than extratropical ones.

### Single Mechanism and Practical Significance

The scientists stated that the ratio of extratropical to tropical cooling consistently falls within a twofold range. According to them, the only identified reason for the stronger influence of extratropical eruptions is the specific pattern of aerosol distribution in the atmosphere. The difference between scenarios can be additionally explained by the seasonality of the eruption, the volume of emissions, and specific meteorological conditions. The practical significance of the work goes beyond pure science: refined estimates of volcanic cooling are necessary for predicting risks in agriculture and assessing global food security. A sudden drop in temperature can lead to crop failures, food shortages, and heightened competition for resources, creating additional risks for society as a whole.

## Fact-Check & Sources

- [Извержения вулканов меняют климат: ученые уточнили риски для Северного полушария](https://www.rbc.ua/ukr/news/viverzhennya-vulkaniv-zminyuyut-klimat-vcheni-1793782168.html) - The primary source contains all key facts: GRL publication, McGraw team (Columbia University), NASA model, 2x ratio instead of 7.5x, historical eruptions of 1783/536/43 BC, 100k simulated scenarios. All data transferred without distortion.

## FAQ

### Why do volcanic eruptions cool the Earth?

Powerful eruptions inject sulfur dioxide into the stratosphere, which turns into microscopic sulfuric acid droplets. These aerosols reflect solar radiation back into space, reducing the flow of thermal energy to the planet's surface.

### How much stronger do extratropical eruptions cool compared to tropical ones?

According to the new study published in Geophysical Research Letters, the ratio stays within a twofold range. Previously, some works indicated values up to 7.5 times, but these assumptions were not confirmed.

### What method did scientists use to test the hypothesis?

Dr. Zachary McGraw's team from Columbia University applied a NASA climate model, simulating eruptions in the tropics and middle latitudes with various emission volumes and seasons. Additionally, historical eruptions and 100,000 hypothetical scenarios were analyzed.

### What is the practical significance of this study?

Refined estimates of volcanic cooling help predict risks for agriculture and global food security. A sudden cooling can cause crop failures, food shortages, and increased competition for resources.