Albedo-induced global warming impact of Conservation Reserve Program grasslands converted to annual and perennial bioenergy crops

Abstract Climate benefit assessments of bioenergy crops often focus on biogeochemical impacts, paying little if any attention to biogeophysical impacts. However, land conversions required for large-scale crop production are substantial and may directly affect the climate by altering surface energy balance. In US, such likely be met in part converting Conservation Reserve Program (CRP) grassland crops. Here, we converted three 22 year old CRP smooth brome grass fields into no-till corn, switchgrass, or restored prairie We assessed impact using albedo changes relative unconverted reference grassland. The corn perennial had higher annual than they replaced—causing cooling local climate. field occurred solely during non-growing season—especially when surfaces were snow-covered, whereas was more prominent growing season. Compared impacts with fossil fuel offsets same over eight years, albedo-induced benefits add ?35% ?78% provided from switchgrass fields, respectively, offset ?3.3% greenhouse gas (GHG) emissions field. conclude that mitigation conversion lands but not can substantial, future should include addition GHG balances order better inform policies.