Fungi, Carbon, And The Climate Risk Map We Missed

Soil fungi may not have ticker symbols but they move carbon at planetary scale, drawing an estimated 13 billion tons of CO₂ into the soil each year, equivalent to nearly a third of global fossil fuel emissions. And yet, they’ve been almost entirely absent from climate risk models, ESG reports, and conservation agendas.

Scientists from the Society for the Protection of Underground Networks (SPUN) have released the first-ever high-resolution global maps of mycorrhizal fungal biodiversity, alongside the launch of a groundbreaking public platform called the Underground Atlas. The research, published in the journal Nature, marks the first large-scale scientific application of the global mapping initiative launched by SPUN in 2021. Built using over 2.8 billion fungal DNA sequences from 130 countries, the Atlas reveals a profound oversight: more than 90% of the planet’s most diverse underground carbon ecosystems are unprotected.

“Soils store 75% of Earth’s terrestrial carbon and contain ~59% of Earth’s biodiversity. Yet, we’ve neglected to map, monitor, and protect fungal systems,” says Dr. Toby Kiers, executive director of SPUN. “With the Underground Atlas, we’re making these invisible networks visible, and therefore measurable.”

The Underground Carbon Crisis

Mycorrhizal fungi form vast underground networks that connect and sustain over 90% of all terrestrial plant species, channelling nutrients, supporting food systems, biodiversity, and ecosystem resilience. Critically, they also draw carbon from plants into the soil, playing a major role in carbon sequestration and climate regulation. But until now, these fungal networks have gone unmapped and unmonitored, and the implications of this are significant.

“We were surprised to learn that fungal biodiversity didn’t align with traditional conservation indicators like plant richness,” says Dr. Kiers. “That means we’re missing high-value underground ecosystems that are being degraded or lost, increasing global warming and disrupting nutrient cycles.”

The Atlas is also set to help regenerate degraded ecosystems. “Restoration practices have been dangerously incomplete because the focus has historically been on life aboveground,” said Dr. Alex Wegmann a lead scientist for The Nature Conservancy. “These high-resolution maps provide quantitative targets for restoration managers to establish what diverse mycorrhizal communities could and should look like.”

Urgent action is needed to incorporate findings into international biodiversity law and policy. For example, the Ghanaian coast is a global hotspot for mycorrhizal biodiversity. But the country’s coastline is eroding at roughly two meters per year and scientists are concerned that such critical biodiversity could soon be washed into the sea.

A Data Science Breakthrough

To build the Atlas, SPUN and partners used machine learning models trained on billions of environmental DNA sequences, geospatial data, and climate variables. For the first time, decision-makers, restoration managers, and investors can explore mycorrhizal biodiversity at a 1km² scale, identifying underground ecosystems critical to carbon cycling, crop resilience, and biodiversity.

“This is the most data-rich global compilation of fungal eDNA ever assembled,” says Dr. Michael Van Nuland, SPUN’s lead data scientist. “There just aren’t many high-resolution global maps for soil organisms, especially for ecosystem engineers like fungi.”

The Atlas supports biodiversity predictions even in unsampled areas, identifying fungal richness, rarity, and degradation risk. This will enable regulators and restoration practitioners to anticipate biodiversity loss and carbon vulnerability at a landscape scale.

​SPUN is already working with a number of different actors and institutions operating in the space of nature risk and ecosystem restoration, and was granted observer status at last year’s COP16 biodiversity summit. That shows a recognition that, without understanding what’s happening beneath the ground, there is no real understanding of how to most effectively protect and restore nature and biodiversity.

Implications For ESG And Restoration

The new maps also reveal a critical blind spot for companies and governments relying on nature-based solutions, sustainable agriculture, and biodiversity finance. “Conservation is about protecting the systems that sustain life, and those systems don’t stop at the soil surface,” says Dr. Rebecca Shaw, chief scientist at WWF. “Healthy fungal networks are tied to higher aboveground biodiversity and greater ecosystem resilience.”

Dr. Shaw says the maps should be incorporated into frameworks like the 30×30 biodiversity targets, National Biodiversity Strategies (NBSAPs), and even carbon markets. “Much like the human gut microbiome transformed medicine, the soil microbiome is essential for planetary health,” she says.

She argues that mycorrhizal fungi need to be recognized as a priority in the ‘library of solutions’ to some of the world’s greatest challenges, biodiversity decline, climate change, and declining food productivity. “They deliver powerful ecosystem services whose benefits flow directly to people. This research maps where fungal communities are thriving or under threat,” she continues. “There is an opportunity to integrate this knowledge into decision-making about building resilience into our food systems.”

These insights are also guiding restoration and corporate risk assessments. SPUN is currently piloting a project with a corporate partner to evaluate the use of mycorrhizal biodiversity assessments in material supply chains. “This is helping us understand both the economic applications for our data and how these collaborations can contribute valuable information back to our global database,” says Dr. Van Nuland.

Soil fungi aren’t just climate assets, they’re agricultural assets. Research shows mycelial networks can reduce nutrient leaching by up to 50% and supply up to 80% of a plant’s phosphorus needs, positioning fungi as vital components of sustainable farming.

Incorporating fungal biodiversity into land use planning offers a powerful hedge against food system risk, helping companies navigate fertilizer volatility, regulatory pressures, and the growing need to demonstrate climate-resilient practices. For businesses navigating nature risk, this may be the data layer they didn’t know they needed.

A Legal And Regulatory Wake-Up Call

Soil fungi are also being considered in legal and regulatory contexts. Underground biodiversity is included in the Convention on Biological Diversity, but in practice, policies have focused almost entirely on aboveground ecosystems.

César Rodríguez-Garavito, director of NYU’s More-Than-Human Life Program explains, “Because fungal networks have been invisible in climate law, activities that disrupt them have gone largely unregulated, with serious consequences for carbon storage, soil health, and legal accountability. By making visible the presence of climate-significant soil fungi, this data can help prevent climate impacts that stem from their destruction.”

A litigation toolkit is also in development with NYU Law to help Indigenous communities protect underground ecosystems threatened by extraction.

Changing The Climate Narrative

Beyond risk and regulation, the Underground Atlas offers something deeper: a new way of seeing and valuing ecosystems.

As SPUN’s director of impact Dr. Merlin Sheldrake notes, “What we see above ground is in part an expression of what’s happening below the surface. This new tool brings attention to the communities of mycorrhizal fungi that form living underground infrastructure and support so much of life on Earth.”

This reframing helps bridge a persistent gap in how ecosystems are perceived, opening new possibilities for valuing and protecting foundational life systems. While forests and coral reefs have long symbolized ecological richness, the quiet complexity of underground fungal networks has rarely captured public imagination or financial attention.

Dr. Sheldrake calls this persistent oversight ‘fungus blindness.’ “Most fungi live out of sight and studying them is difficult,” he says. “But they are vital ecosystem engineers, and when we ignore them, we are more likely to disrupt and destroy them. If we’re not paying attention to these organisms, it’s no surprise they’re missing from conservation strategies.” That’s beginning to change.

Understanding that fungi store carbon, support biodiversity, and regulate water flows means that protecting them becomes a matter of long-term value, not just ecological virtue. These maps are not just analytical tools; they are conceptual ones, helping businesses and governments see what sustainability has missed.

Recognizing fungi as climate infrastructure could redfine how nature is factored into risk models, insurance products, and even accounting frameworks in the years to come.

Toward An Underground Strategy

Dr Van Nuland says that while the current launch represents the project’s first major milestone, this is only the beginning. SPUN is currently working on more than 10 additional mapping pipelines that will expand the platform’s capabilities, including maps of mycorrhizal carbon drawdown hotspots, underground threat assessments, and restoration potential analyses.

“We’re only beginning to explore the economic and ecological uses of this data,” he says. “We want to discover new applications and we’re inviting researchers, funders, and policymakers to help us.”

In a world increasingly focused on risk, resilience, and real assets, the lesson is clear: funghi, and the fungal networks beneath our feet, are the billion-ton blind spot we can no longer afford to ignore.