What are hidden volcanoes, capable of cooling the Earth and creating avalanches?

The probability of an event tends to be judged by how easily examples come to mind (this mental shortcut is known as the availability heuristic). Well-known volcanoes or eruptions, such as the 2010 Icelandic ash cloud, are familiar and can seem ominous, while remote volcanoes without recent eruptions are rarely recorded.

These biases create a dangerous pattern: we only invest more heavily after a disaster has already happened (response bias). El Chichón, for example, only began to be monitored after the 1982 catastrophe. However, three-quarters of major eruptions (such as El Chichón and larger) come from volcanoes that have been inactive for at least 100 years and, as a result, receive less attention.

Preparing for volcanic eruptions needs to be proactive rather than reactive. When volcanoes are monitored, when communities know how to respond, and when communication and coordination between scientists and authorities are effective, thousands of lives can be saved.

Disasters were avoided in this way in 1991 (at Mount Pinatubo, in the Philippines), in 2019 (at Mount Merapi, in Indonesia) and in 2021 (at La Soufrière, on the Caribbean island of Saint Vincent).

To close these gaps, the world needs to turn its attention to under-monitored volcanoes in regions such as Latin America, Southeast Asia, Africa and the Pacific — places where millions of people live near volcanoes with little or no historical record. This is where the greatest risks lie and where even modest investments in monitoring, early warning and community preparedness could save the most lives.

*Mike Cassidy is Associate Professor in the School of Geography, Earth and Environmental Sciences at the University of Birmingham