first global – A new first-ever global map charts where mycorrhizal fungi—underground networks that trade carbon for nutrients with plant roots—are dense or nearly absent. The work estimates about 110 quadrillion kilometers of fungal threads in soils and aims to help decisio
In soil, there’s a connection most of us will never see: tiny fungal filaments that can run meters deep, linking plants into vast trading networks. A single teaspoon can hold up to 10 or even 100 meters of those mycelial threads—astonishing length packed into something you could hold in your hand.
Now, for the first time, researchers have produced a global map of that hidden infrastructure. The map. released by the Society for the Protection of Underground Networks. SPUN. charts the distribution of the mycorrhizal network across Earth. including striking hotspots such as the Florida Everglades and near-empty stretches such as the Sahara Desert.
Mycorrhizal networks are ancient. They have shaped life on land for around 450 million years. Unlike mushrooms above ground, they often don’t produce a fruiting body at all. Instead, they live as small filaments in soil—mycelial threads that form symbiotic associations with plants.
What makes them vital isn’t just their reach, but the exchange they enable. Plants use photosynthesis to make carbon. Mycorrhizal fungi. because they form intimate connections with plant roots. gain direct access to that carbon and funnel it deep into soils. In return, the plants receive nutrients—nitrogen and phosphorus—fed through the fungal network.
The scale of that transfer is enormous. Last year. researchers connected to the study estimated that around 11% of current CO2 emissions are being funneled to these fungal networks each year. At the same time, those nutrient flows nourish plants above ground. The result is a system that threads together planetary health, carbon cycling, and plant growth.
Mapping it required a rare convergence of data. Stewart. an ecologist involved in the work. said the timing mattered: scientists had collected just enough carefully prepared soil cores from across the planet—cores brought back to labs—then combined that ground truth with satellite data. Using AI predictive models, they estimated global density and length.
When the numbers are added up, the estimated total length of mycorrhizal networks is about 110 quadrillion kilometers—roughly 1 billion times the distance from Earth to the sun.
The point of having a map, Stewart said, isn’t only wonder. “You can’t protect what you don’t know.” Knowing where networks are dense—and where they face potential threats—creates a foundation for restoration and conservation practices. The goal is to hand a usable picture to decision-makers. so fungal networks can be included in climate agendas and carbon models.
Looking at the map, Stewart described it less as a dataset and more as a shift in perspective. The fungi form complex associations with plants and carry out trade decisions without any single place in their bodies where information is processed. Seeing that there are 110 quadrillion kilometers of these networks in Earth’s soils. he said. also offers a sense of scale—about other kinds of living systems humans can learn from.
For all its technical methods—soil cores, satellite data, and AI models—the map ultimately comes down to one lesson: the most consequential parts of how plants and the climate system interact may be happening underground, in networks too easy to ignore until someone finally measures them.
mycorrhizal fungi mycelial networks global map soil ecology carbon cycling CO2 emissions plant roots SPUN climate models underground fungi