Mycorrhizal fungi are responsible for holding up to 36 per cent of yearly global fossil fuel emissions below ground - more than China emits each year.
The fungi make up a vast underground network all over the planet underneath grasslands and forests, as well as roads, gardens, and houses on every continent on Earth.
Researchers are now calling for fungi to be considered more heavily in conservation and biodiversity policies, and are investigating whether we can increase how much carbon the soil underneath us can hold.
The underground network of fungi stores over 13 gigatonnes of carbon around the world, roughly equivalent to 36 per cent of yearly global fossil fuel emissions, according to new research.
It is widely believed that mycorrhizal fungi could store carbon, as the fungi form symbiotic relationships with almost all land plants and transport carbon, converted into sugars and fats by the plant, into soil, but until now the true extent of just how much carbon the fungi were storing wasn't known.
A team of scientists, including researchers from the University of Sheffield, are looking into whether it would be possible to increase how much carbon the soil can store.
A meta-analysis of hundreds of studies looking at plant-soil processes was undertaken to understand how much carbon is being stored by the fungi on a global scale.
The findings estimate that 13.12 gigatonnes of CO2 is transferred from plants to the fungi annually, transforming the soil beneath our feet to a massive carbon pool and the most effective carbon capture storage unit in the world.
The amount of carbon stored equates to roughly 36 per cent of yearly global fossil fuel emissions - more than China emits each year.
Researchers are now calling for fungi to be considered in biodiversity and conservation policies, given their crucial role in cutting carbon emissions. At the current rate, the UN warns that 90 per cent of soils could be degraded by 2050, which could be catastrophic for not only curbing climate change and rising temperatures, but for the productivity of crops and plants too.
Professor Katie Field, professor of plant-soil processes at the University of Sheffield and co-author of the study, said: "Mycorrhizal fungi represent a blind spot in carbon modelling, conservation, and restoration - the numbers we've uncovered are jaw-dropping, and when we're thinking about solutions for climate we should also be thinking about what we can harness that exists already.
"Soil ecosystems are being destroyed at an alarming rate through agriculture, development and other industry, but the wider impacts of disruption of soil communities are poorly understood. When we disrupt the ancient life support systems in the soil, we sabotage our efforts to limit global heating and undermine the ecosystems on which we depend.
"More needs to be done to protect these underground networks - we already knew that they were essential for biodiversity, and now we have even more evidence that they are crucial to the health of our planet."
"We always suspected that we may have been overlooking a major carbon pool," added lead author Heidi Hawkins, research lead at Conservation South Africa and research associate on plant-soil-microbe interactions at the University of Cape Town. "Understandably, much focus has been placed on protecting and restoring forests as a natural way to mitigate climate change. But little attention has been paid to the fate of the vast amounts of carbon dioxide that are moved from the atmosphere during photosynthesis by those plants and sent below ground to mycorrhizal fungi."
The researchers are now investigating how long the carbon is stored by the fungi in the soil, and are seeking to further explore the role that fungi plays in Earth's ecosystems.
