Search for: All records

Abstract Reducing wasted food has been identified as a key strategy to meet food security goals and attain human nutritional needs and food preferences in an equitable, sustainable, and resilient manner. Yet, mathematically modeling how reducing wasted food contributes to sustainability, equity, and resilience objectives, and the possible interactions and tradeoffs among these metrics, is limited by challenges to quantifying these characteristics. Using the process of convergent science, we develop a prototype wasted food model to evaluate how a set of common equity, sustainability, and resilience measures interact. We consider prevention (consumer education) and treatment (anaerobic digestion and composting) options for wasted food diversion from landfills. The model applies a convex nonlinear optimization to determine the allocation of wasted food to different management alternatives, optimizing for economic (net cost), sustainability (emissions reductions or energy savings), or equity (distribution of per-capita cost or emissions reduction impacts). The model developed in this research is available online as open-source code for others to replicate and build upon for future studies and analysis. Our findings illustrate that optimal wasted food management alternatives may vary when targeting different metrics and that strategies promoting cost-effectiveness may be in tension with sustainability or equity goals and vice versa. The implications of this study could be used by policy makers to evaluate how wasted food reduction measures will impact sustainability, equity, and resilience goals. 

We introduce a novel simulated certainty equivalent approximation (SCEQ) method for solving dynamic stochastic problems. Our examples show that SCEQ can quickly solve high-dimensional finite- or infinite-horizon, stationary or nonstationary dynamic stochastic problems with hundreds of state variables, a wide state space, and occasionally binding constraints. With the SCEQ method, a desktop computer will suffice for large problems, but it can also use parallel tools efficiently. The SCEQ method is simple, stable, and can utilize any solver, making it suitable for solving complex economic problems that cannot be solved by other algorithms. 

Abstract Forests play a critical role in mitigating climate change, and, at the same time, are predicted to experience large-scale impacts of climate change that will affect the efficiency of forests in mitigation efforts. Projections of future carbon sequestration potential typically do not account for the changing economic costs of timber and agricultural production and land use change. We integrated a dynamic forward-looking economic optimization model of global land use with results from a dynamic global vegetation model and meta-analysis of climate impacts on crop yields to project future carbon sequestration in forests. We find that the direct impacts of climate change on forests, represented by changes in dieback and forest growth, and indirect effects due to lost crop productivity, together result in a net gain of 17 Gt C in aboveground forest carbon storage from 2000 to 2100. Increases in climate-driven forest growth rates will result in an 81%–99% reduction in costs of reaching a range of global forest carbon stock targets in 2100, while the increases in dieback rates are projected to raise the costs by 57%–132%. When combined, these two direct impacts are expected to reduce the global costs of climate change mitigation in forests by more than 70%. Inclusion of the third, indirect impact of climate change on forests through reduction in crop yields, and the resulting expansion of cropland, raises the costs by 11%–38% and widens the uncertainty range. While we cannot rule out the possibility of climate change increasing mitigation costs, the central outcomes of the simultaneous impacts of climate change on forests and agriculture are 64%–86% reductions in the mitigation costs. Overall, the results suggest that concerns about climate driven dieback in forests should not inhibit the ambitions of policy makers in expanding forest-based climate solutions.