An international team of scientists has published the first global map of the underground mycorrhizal fungal network, estimating its total length at 110 quadrillion kilometers. The study, based on 322 scientific papers and nearly 16,000 soil samples, reveals that this hidden system stores 300 megatonnes of carbon in its biomass. Each year, roughly 4 billion tonnes of CO2 equivalent pass through these fungi into the soil, equal to about 11 percent of human-caused emissions. The network acts as a natural carbon sink, helping to regulate the climate. But the research also highlights a problem. The density of fungal networks in agricultural land is half that of natural ecosystems. Grasslands are being converted four times faster than forests, degrading this underground system. Less fungal network means less soil carbon sequestration, which could weaken a key natural buffer against warming. For anyone tracking nature based carbon removal or soil health, this study puts a number on something that was previously hard to measure. The question is whether land management practices can be adjusted to protect or restore these networks at scale.
