View article

Protected areas (including other effective area-based conservation measures) are a cornerstone of biodiversity conservation. Many countries are increasingly committed to expanding protected area coverage to 30%, which requires an increase in global annual spending from $24b to ~$140b (between $103b and $177b). We find that by trading nature-based carbon credits in voluntary carbon markets at the current average market price of $5 t⁻¹CO₂, 79 countries and territories can expand protected areas without capital deficit, together generate return on investments of $121b yr⁻¹ and sequester 3 GtCO₂eyr⁻¹. Another 30 countries can meet at least half of their investment costs, and sequester an additional 2.8 GtCO₂e yr⁻¹. Additionally, we show that protection can extend to 33% of the Key Biodiversity Areas (KBAs) outside the existing protected area network. Our results point to the largely untapped potential of …