Mushroom-forming fungi drive 15–20% of global terrestrial carbon sequestration through mycorrhizal networks that channel plant carbon into soil and stabilize it long term. Forests dominated by these fungi can store up to 70% more below-ground carbon, while saprotrophic species break down plant waste and convert a significant portion into stable soil organic matter. They also degrade pollutants and support a growing bioeconomy, with mycelium materials projected to exceed $5 billion by 2030, linking climate impact to real-world industry.