A newly quantified natural carbon sink has emerged from an unlikely source: a fungal network that spans an estimated 110 quadrillion kilometers. Arbuscular mycorrhizal fungi form symbiotic relationships with plant roots, and researchers have now calculated that these organisms transport an enormous amount of planet-warming carbon into the soil each year.
This fungal web sequesters approximately 13.12 gigatons of carbon dioxide annually—equivalent to over one-third of global fossil fuel emissions. The carbon is drawn from plant roots and locked away in the soil, preventing it from re-entering the atmosphere. That makes the network a major but previously underappreciated player in climate regulation.
The study highlights a natural process that operates at a staggering scale with minimal human intervention. Unlike engineered carbon capture technologies, which can cost hundreds of dollars per ton, this system functions at no cost. The findings underscore the potential of preserving soil health as a climate strategy, though no specific investment figures were cited in the research.
Geopolitically, the discovery adds weight to arguments for protecting underground ecosystems under international climate frameworks like the Paris Agreement. Countries with large agricultural or forested lands—where these fungi thrive—could benefit from accounting for this natural carbon storage in their emissions reporting.
The counter argument is that human activities such as intensive farming, deforestation, and soil degradation may already be disrupting these fungal networks. Without active conservation efforts, the carbon sink could shrink or reverse, releasing stored carbon back into the atmosphere. The study's authors caution that more research is needed to understand how vulnerable this system is to climate change itself.