Natural resource availability under future environmental change
The demand for agricultural and forest yield will continually increase as populations grow, though it is unclear how agricultural and forested ecosystem productivity will respond to the interactions of changing climate, carbon dioxide and ozone. In ecosystems essential to resource production, it is critical to understand how productivity will respond to these future changes. Previous research suggests that future climate and ozone can each decrease crop and timber yield, while future carbon dioxide might increase yield. However, the change in agricultural and forest yield in response to the interactions among these variables has not yet been determined. We use the Community Land Model (CLM) to determine changes in agricultural and timber yield in response to the interactions of all three variables (climate, carbon dioxide, and ozone).
Results suggest that the combination of climate, carbon dioxide, and ozone under future scenarios typically increases grain and timber yields. In important crop-producing regions, the future grain yield ranges between -20 and 70% compared to present-day, with crop types responding differently depending on the region. Timber yield in important timber-producing regions ranges from -25 to 15% in the future compared to present-day. Future ozone and climate both decrease forest and grain yield, while higher carbon dioxide concentrations increase forest and grain yield, offsetting the decreases. However, the overall yield increases are not as large as the projected population increase by 2100, suggesting that agricultural intensity and/or the proportion of land devoted to agriculture will need to increase to maintain food availability in the future.