To achieve a stable climate will require rapid, dramatic reductions in greenhouse gas emissions resulting from human activities. This can be done by transitioning energy generation from fossil fuels to clean energy sources, and by removing those gases—primarily carbon dioxide (CO₂)— from the atmosphere. The latter approach relies on the development of technologies that capture the gas from the air and store it underground, and the cultivation of “nature-based solutions” that increase ground-level absorption of airborne CO₂.