Galaxy of fungal networks, ‘invaluable climate ally’ beneath our feet, to be mapped for first time

The networks are a vast natural sink for billions of tons of planet-heating carbon dioxide

Underground fungal networks, an “invaluable ally” in tackling the climate crisis, are to be mapped for the first time.

Mushrooms are just the surface “fruits” and a small fraction of the vast networks embedded in soil and interwoven with tree roots. Tiny “threads” of mycelium form a mycorrhizal network which act as pathways between plants to channel water, carbon and other minerals.

In just the top 10cm of soil fungal mycelium is 450 quadrillion kilometres, around half the width of the galaxy. Three-quarters of terrestrial carbon is stored in soil, triple the amount in living plants and animals.

The new initiative, led by the Society for the Protection of Underground Networks (SPUN), aims to save these webs of fungi. The networks are little-known about and poorly understood, SPUN says, despite holding a quarter of all species and providing a natural sink for billions of tons of planet-heating carbon dioxide (CO2).

By one estimate, 5 billion tons of CO2 flow into fungal networks each year, equating to more than half of human-caused CO2 emissions in 2021. And research currently underway has suggested that it may even be triple this amount.

Agricultural expansion, pollution, urbanisation and forest loss are destroying fungal networks, according to SPUN. On the current trajectory, more than 90 per cent of Earth’s soil will be degraded by 2050.

Advisers to the project include conservationist Jane Goodall, and New York Times best-selling food writer Michael Pollan.

“This is an extremely important conservation project. An understanding of underground fungal networks is essential to our efforts to protect the soil, on which life depends, before it is too late,” said Dr Goodall.

The new maps will use machine learning coupled with 10,000 observations from the GlobalFungi dataset and hundreds of layers of global environmental data. SPUN plans to work with researchers, activists, and local communities around the world on the project.

SPUN will gather an additional 10,000 samples from all continents in the next 18 months to identify carbon-sequestration hotspots. The maps will identify high-priority locations with the potential to store more carbon - and survive extreme impacts being caused by the climate crisis.

The project is being funded by the Jeremy and Hannelore Grantham Environmental Trust.

Jeremy Grantham, a British-born investor who has pledged 98 per cent of his multi-million dollar net worth to fighting the climate crisis, says: “Just below our feet lies an invaluable ally in mitigating climate change – vast hidden fungal networks. Billions of tons of carbon dioxide flow annually from plants into fungal networks. And yet, these carbon sinks are poorly understood.

In working to map and harness this threatened but vital resource for life on earth, the Society for the Protection of Underground Networks is pioneering a new chapter in global conservation.”