Carbon dioxide removal (CDR), is the deliberate removal of carbon dioxide (CO₂) from the atmosphere through a range of human activities. CDR is a process meant to reverse the global warming effects caused by greenhouse gasses through “negative emissions.” Also called carbon drawdown, this involves storing or locking carbon into plants (reforestation or afforestation), oceans (ocean-based carbon retention), soils (soil carbon sequestration), and biomass materials (biomass carbon removal) among others. SPUN aims to encourage the continued sequestration of carbon in mycorrhizal networks, and to stop the carbon release caused by loss of fungal networks.

Underground ecosystems and the mycorrhizal fungi they contain play a critical role in climate regulation, by storing  75% of Earth’s terrestrial carbon. As a key entry point thourgh which carbon enter into soil systems, mycorrhizal fungi annually draw down an estimated 13 billion tons of CO₂ from plant partners into the soil. This is about 36% of global fossil fuel emissions. This potential to combat climate change makes these fungi essential partners inclimate mitigation strategies.