Modelling the effect on chronic disease health of changing food prices based on greenhouse gas emissions

Abstract

BackgroundClimate change has been described as the biggest global health threat of the 21st century. There are potential health co-benefits of climate change mitigation strategies, and several studies have investigated effect on health of so-called carbon-friendly diets. Taxation based on greenhouse gas (GHG) emissions is a potential method of internalising the wider costs of climate change to society; such a tax on food and drinks would substantially reduce UK GHG emissions and raise revenue, but the effect on health is unclear. The aim of this study was to model the health effect, the reduction in GHG emissions, and the revenue raised from a tax based on the GHG emissions of food consumed in the UK. MethodsWe modelled a tax of £27·19 per tonne carbon dioxide equivalents (tCO2e)/kg product applied to all products with emissions greater than 4·10 kg CO2e/kg, the mean value for UK emissions across all food groups. Baseline UK consumption data were from the 2010 DEFRA Family Food survey and associated food-specific GHG emissions were taken from a World Wildlife Fund report. We weighted food GHG emissions by country of origin using data for UK imports and exports from UN Food and Agriculture Organization food balance sheets. Derivation of the tax level was based on the DEFRA marginal abatement cost curve for agriculture, which plots the cost effectiveness of different mitigation strategies; this approach estimates that 16·2% of annual UK agriculture-related emissions could be mitigated against at a cost of £27·19/tCO2e. Cross-price and own-price elasticities calculated from Family Food survey purchasing patterns were applied to food groups from the survey to derive changes in consumption after application of the tax. Health outcomes were modelled by a comparative risk assessment model that used age-specific and sex-specific relative risk estimates from meta-analyses to link the consumption of different food categories to mortality. FindingsThis study showed 6751 (95% CI 6147–7347) deaths averted per year and an annual reduction in GHG emissions of 18 765 ktCO2e (41% of the 2010 DEFRA figure of 46 200 ktCO2e for UK emissions relating to agriculture). Revenue generated from this tax scenario was £3·32 billion per year. In this scenario, the most taxed product was beef at £1·76 per kg, with other meats, fish, and coffee also being taxed. Of the 6751 deaths averted, 73% (4915, 95% CI 4379–5461) were due to cardiovascular disease and 15% (1032, 824–1227) were due to cancer. InterpretationTaxation of foods based on their GHG emissions has the potential to reduce emissions from the UK agriculture sector as well as reduce the number of premature deaths in the UK population and generate substantial tax revenue. This analysis included only health benefits from dietary change and not the wider effect on health of reduced atmospheric pollution and slowed climate change. The health implications of fiscal intervention on food based on GHG emissions has not been previously investigated and offers a further approach to climate change mitigation strategies. FundingBritish Heart Foundation.