NASA scientists might soon be able to forecast volcanic eruptions by monitoring how trees respond from space. Now, in a new collaboration with the Smithsonian Institution, they have discovered that tree leaves grow lusher and greener when previously dormant volcanic carbon dioxide seeps up from the ground — an early warning that a cone of magma is pushing upwards. Now, using satellites such as Landsat 8 and data from the recent AVUELO mission, scientists think this biological response could be visible remotely, serving as an added layer of early warning for eruptions in high-risk areas that currently menace millions worldwide.

As per the research by NASA's Earth Science Division at Ames Research Centre, greening occurs when trees absorb volcanic carbon dioxide released as magma rises. These emissions precede sulfur dioxide and are harder to detect directly from orbit.

While carbon dioxide does not always appear obvious in satellite images, its downstream effects — enhanced vegetation, for example — can help reinforce existing volcanic early warning systems, notes volcanologist Florian Schwandner. It could be important because, as the U.S. Geological Survey says, the country is still one of the most volcanically active.

Globally, about 1,350 potentially active volcanoes exist, many in remote or hazardous locations. On-site gas measurement is costly and dangerous, prompting volcanologists like Robert Bogue and Nicole Guinn to explore tree-based proxies.

Guinn's study of tree leaves around Sicily's Mount Etna found a strong correlation between leaf colour and underground volcanic activity. Satellites such as Sentinel-2 and Terra have proven capable of capturing these subtle vegetative changes, particularly in forested volcanic areas.

To confirm this method, climate scientist Josh Fisher led NASA-Smithsonian teams in March 2025 to Panama and Costa Rica, collecting tree samples and measuring gas levels near active volcanoes. Fisher sees this interdisciplinary research as key to both volcano forecasting and understanding long-term tree response to atmospheric carbon dioxide, which will reveal future climate conditions.

The benefits of early carbon dioxide detection have been demonstrated in the 2017 eruption of Mayon volcano in the Philippines, where it allowed mass evacuations and saved more than 56,000 lives. It has its limitations, like bad terrain or too much environmental noise, but it could be a game-changer.