Natural carbon sinks—or nature-based solutions—are expected to be a critical contributor to meeting the global ambition of reaching net zero and they have exploded in popularity with private sector participants. Yet the impact of these solutions varies hugely, and they span multiple geographies and types of methods, often with large challenges and uncertainty about their true carbon mitigation potential. How can these solutions be categorized, and which ones will have most impact in the midterm? Forestry is a key solution, yet it is complex and includes afforestation, reforestation, and reducing emissions from deforestation and degradation (REDD). How do their costs/benefits compare? Should all be pursued, or should one be prioritized?