31 July, 2026

When people think about ways in which nature protects the climate, they tend to picture forests: planting trees, protecting rainforests or restoring wetlands. But what if one of the world’s most important climate assets isn’t something we can see at all?

Last month, scientists at the Society for the Protection of Underground Networks published the first estimate of the vast underground networks created by mycorrhizal fungi, the microscopic threads that connect around 70% of the world’s plants. Their analysis is staggering: together, these networks stretch for around 110 quadrillion kilometres, enough to make the journey from the Earth to the Sun more than 700 million times.

Even more remarkable is what these networks do. They move water and nutrients between soil and plant roots, helping ecosystems grow stronger and more resilient. In return, plants feed them with carbon-rich sugars. Together, this ancient partnership locks away an estimated one billion tonnes of carbon every year. In other words, one of the planet’s most important pieces of climate infrastructure has been beneath our feet all along, and until now, we had no idea just how extensive it was.

What got us excited about this story isn’t just that we’ve found something new; it’s that we’re still uncovering fundamental parts of the natural systems our lives, economies, food systems, and businesses rely on every day.

Increasingly, businesses are being asked to understand and measure their impact on nature. And there are good reasons for doing that, and some well-evidenced solutions available to reduce your impact once you have. But discoveries like this are a reminder that we’re still learning how nature works. If scientists are only now beginning to map one of Earth’s largest living systems, perhaps we should approach the natural world with greater humility than we often do. The massive network of underground threads is a useful reminder that nature isn’t simply an asset to manage, it’s a system we’re still learning to understand.

By Justine Bahoumina