Fungi: the invisible force protecting our planet – podcast

# Fungi: the invisible force protecting our planet – podcast

In a groundbreaking exploration of Earth's hidden ecosystems, evolutionary biologist Dr Toby Kiers is leading a global effort to map and understand the vast underground fungal networks that scientists now believe are critical to planetary health. Dr Kiers, founder of the Society for the Protection of Underground Networks and a MacArthur fellow, reveals in a new Science Desk podcast that these subterranean fungal systems extend more than 100 quadrillion kilometers in length—a network so immense it dwarfs all known surface ecosystems. Her research on the remote Palmyra Atoll in the Pacific Ocean is reshaping our understanding of how fungi regulate carbon cycles, support plant life, and act as a silent planetary immune system.

The scale of the underground fungal network

According to a major global mapping study published in June 2026, arbuscular mycorrhizal fungi form symbiotic relationships with approximately 80% of all terrestrial plant species. The study, which Dr Kiers co-authored, estimates the total length of these fungal networks exceeds 100 quadrillion kilometers—equivalent to more than 10,000 times the distance from Earth to the sun. This hidden infrastructure, Dr Kiers explains, is not merely passive soil dweller but an active, intelligent system that transfers nutrients, water, and chemical signals between plants.

"Think of it as a planetary-scale internet beneath our feet," Dr Kiers told the Science Desk. "These networks allow trees to share resources, warn each other of threats, and even support seedlings in shaded areas. We have only begun to quantify their true extent and function."

Palmyra Atoll: a living laboratory for fungal research

The remote Palmyra Atoll, located roughly 1,000 kilometers south of Honolulu, has become a critical research site for Dr Kiers and her team. The atoll's isolated ecosystem, largely undisturbed by human activity, offers a rare window into pristine fungal networks. Preliminary findings from the site indicate that fungal biomass in the atoll's soil exceeds 15 metric tons per hectare—more than double the global average for tropical systems.

"Palmyra is a time capsule," Dr Kiers said in the podcast. "The fungal networks there have evolved uninterrupted for millennia. They show us how these systems function when they are not under pressure from agriculture, deforestation, or climate change. The implications for carbon sequestration are enormous."

The role of fungi in climate regulation

The research has significant implications for climate science. Fungi play a critical role in soil carbon storage, with recent estimates suggesting that mycorrhizal networks may hold up to 40% of global terrestrial carbon. Dr Kiers' work suggests that protecting these underground networks could be as important as preserving forests themselves.

"We often focus on what we can see—trees, plants, animals—but the real action is below ground," Dr Kiers explained. "If we disturb fungal networks through intensive farming or deforestation, we risk releasing centuries of stored carbon back into the atmosphere."

Future directions and policy implications

The Society for the Protection of Underground Networks, founded by Dr Kiers in 2023, now coordinates mapping efforts across 30 countries. The group aims to create a global atlas of fungal biodiversity by 2030, with particular focus on regions under threat from industrial agriculture and urban expansion. Dr Kiers, who received the Tyler Prize for Environmental Achievement in 2025—often called the "green Nobel"—is calling for fungal networks to be included in international climate agreements.

"Fungi are the invisible force protecting our planet," she concluded. "We must give them the same legal and conservation protections we afford to rainforests and coral reefs. The future of our climate depends on it."

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