Implementation constraints on natural climate solutions: A global literature review and survey

Natural Climate Solutions (NCS) – protection, restoration, and improved management of lands and waters that reduce greenhouse gasses – have large climate change mitigation potential. However, a lack of comprehensive information on NCS implementation challenges hinders NCS adoption and delivery of near-term mitigation. Using a global survey of NCS projects and a systematic review of recent NCS studies, we map 46 constraints in eight categories, yielding 15,572 geo-referenced NCS pathway-constraint observations from 501 studies and projects in 137 countries covering 20 of 22 UN subregions. Social-behavioral, Knowledge, and Government-organizational are the most-reported constraint categories, and lack of policy coordination or implementation capacity the most-observed constraint and most frequently top-ranking constraint for pathways and subregions. Despite broad congruence, top constraint and category rankings vary among subregions and pathways, respectively. NCS projects generally encounter multiple constraints in multiple categories, indicating complex challenges. Without enabling efforts, near-term NCS mitigation may remain well below its biophysical potential.