'Jaw

The role of a vast network of underground fungi can suck up roughly one-third of the Earth-warming carbon emissions that burning coal, oil and gas puts off each year. It's an amount previously unknown and that potentially can be expanded, a team of researchers said Monday.

Mycorrhizal fungi are responsible for holding up to13 gigatons, or 36%, of yearly global fossil fuel CL00, -0.51% emissions below ground. To get an idea of the significance, that percentage is more carbon than China emits each year. China, the U.S. and India are the globe's top polluters.

As such, fungi "represent a blind spot in carbon modeling, conservation and restoration," study coauthor Katie Field, a professor of biology at the U.K.'s University of Sheffield, said in a release.

"The numbers we’ve uncovered are jaw-dropping," Field said.

The fungi make up a vast underground network all over the planet beneath grasslands and forests, as well as roads, gardens and houses on every continent on Earth.

It was already widely believed that mycorrhizal fungi could store carbon, as the fungi forms symbiotic relationships with almost all land plants and transports 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.

The discovery by a team of scientists, including researchers from the University of Sheffield, that fungi is storing over a third of the carbon created from fossil fuel emissions each year indicates that it could be crucial as nations seek to tackle climate change and reach net zero.

The findings, published in Current Biology, revealed that an estimated 13.12 gigatons 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.

Carbon dioxide, or CO2, and other greenhouse gases act like a blanket or a cap, trapping some of the heat that Earth might have otherwise radiated out into space. Worldwide emissions of CO2 from burning fossil fuels total about 34 billion metric tons per year. About 45% of this is from coal, about 35% from oil and about 20% from gas NG00, +0.98%.

As the world takes on the so-far slow transition away from fossil-fuel reliance, the richest seven nations, meeting just a few months ago, emphasized the need to step up actions to reach existing climate goals. Those goals include cutting carbon emissions by around 43% by 2030, and 60% by 2035, relative to the 2019 level.

Researchers are now calling for fungi to be considered in biodiversity and conservation policies, given its crucial role in cutting carbon emissions. At the current rate, the United Nations warns that 90% 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, scientists warn.

It's biodiversity that keeps oceans healthy and can help feed the Earth's expanding population.

Professor Toby Kiers, senior author from Vrije University Amsterdam and co-founder of the Society for the Protection of Underground Networks, added: "The paper is part of a global push to understand the role that fungi play in Earth's ecosystems. We know that mycorrhizal fungi are vitally important ecosystem engineers, but they are invisible to most people."

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Rachel Koning Beals is a MarketWatch news editor in Chicago.