The impact of biofuel-induced food-price inflation on food demand and dietary greenhouse gas emissions

摘要

Background: Liquid biofuel production has increased dramatically in recent years and is expected to continue. This growth has led to concerns about the impact of biofuel production on food prices, which may show significant biofuel-related inflation. In consequence.biofuels may influence food intake and greenhouse gas (GHG) emissions through its effect on food prices and associated food demand. Aims: We estimated changes to energy (calorie) demand and embodied GHG emissions in average diets under different biofuel-related food-price scenarios for three countries: Brazil, China and the USA. Methods: We used published food-price projections, food-price elasticities and food demand data to predict dietary change under the different price scenarios. Estimates of embodied emissions in foods were taken from multiple studies in the literature. Uncertainty was explored with Monte Carlo simulations. Results: Average energy demand decreased in all countries, from about 40 kcal per person per day in Brazil under a moderate price inflation scenario - a reduction of 1% relative to the (2009) reference scenario -to over 300 per day in the USA with high price inflation - about 8% of reference levels. In terms of GHG emissions, the results are suggestive of reductions only in the USA, where average reductions ranged from 30-80 kg/CO2e/person/year. In China, the direction of impact is unclear, but the net change is likely to be minimal. Brazilian results were sensitive to parameter values and the direction and magnitude of impact is therefore uncertain. Conclusions: Our results demonstrate that biofuel-induced food-price inflation is likely to influence the quantity and composition of future diets. These changes will affect dietary GHG emissions and have important implications for public health. Reduced energy intake in food-insecure populations may result in higher levels of undernutrition, whereas it could benefit populations suffering from overnutrition.