Trees May Be Able to Warn Us When a Volcano Is About to Erupt

Predicting volcanic eruptions is a crucial science that can save many lives, and recent research suggests that the color of tree leaves near volcanoes might serve as an early warning sign before an eruption occurs.

Magma, Carbon Dioxide, and Greener Leaves

As volcanic activity intensifies and magma rises closer to the Earth’s surface, the amount of carbon dioxide released increases. This boost in CO₂ can enhance the health of nearby trees, causing their leaves to appear greener.

These changes, measured through the normalized difference vegetation index (NDVI), can be detected by satellites orbiting the planet. This technology could provide a valuable early warning system for eruptions without needing on-the-ground sensors or fieldwork, making it useful in remote or hard-to-reach volcanic regions.

“There are many satellites available that allow us to perform this type of analysis,” explains volcanologist Nicole Guinn from the University of Houston.

Case Study: Mount Etna

Guinn led a recent study investigating carbon dioxide emissions around Italy’s Mount Etna. By comparing data from ground sensors with satellite images, the research team found a clear link between higher CO₂ levels and greener tree foliage.

Over two years, they observed 16 distinct spikes in both carbon dioxide and NDVI, which aligned with magma movements beneath the surface. These patterns were evident even at some distance from the volcano’s fault lines.

The study built on earlier work from 2019 by volcanologist Robert Bogue at McGill University, who showed that CO₂ released by two active volcanoes in Costa Rica affected the coloration of tropical tree leaves in the surrounding area.

A Broader Collaborative Project

Now, Guinn, Bogue, and colleagues are collaborating on a NASA- and Smithsonian-led project that examines vegetation color changes around volcanoes in Panama and Costa Rica.

This initiative is part of the Airborne Validation Unified Experiment: Land to Ocean (AVUELO) mission, aimed at developing new satellite-based methods to monitor Earth’s health. Current tools, like NASA’s Orbiting Carbon Observatory 2, are only sensitive enough to detect large eruptions.

“A volcano emitting small amounts of carbon dioxide that could indicate an impending eruption might not be visible in satellite images,” notes Bogue.

“The goal is to find alternative indicators we can measure instead of carbon dioxide directly, providing a proxy to track volcanic emissions.”

A New Signal Among Many

Volcanic activity can be predicted through various signals, such as seismic tremors and ground deformation. Now, with leaf greening caused by increased CO₂ emissions, scientists have identified an additional measurable sign—though it may not apply to every location.

The AVUELO team is also investigating how higher carbon dioxide levels impact tree health on a broader scale. As human-driven CO₂ emissions warm the planet, understanding how vegetation responds is key to predicting future environmental changes.

We want to study not only how trees respond to volcanic CO₂ as an eruption warning but also how much CO₂ trees can absorb,” says climate scientist Josh Fisher from Chapman University in California, part of the AVUELO project. “This gives us insight into Earth’s future as all trees face elevated carbon dioxide levels.

Read the original article on: Science Alert

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