Marco Springmann

Analysis and valuation of the health and climate change cobenefits of dietary change

Significance The food system is responsible for more than a quarter of all greenhouse gas emissions while unhealthy diets and high body weight are among the greatest contributors to premature mortality. Our study provides a comparative analysis of the health and climate change benefits of global dietary changes for all major world regions. We project that health and climate change benefits will both be greater the lower the fraction of animal-sourced foods in our diets. Three quarters of all benefits occur in developing countries although the per capita impacts of dietary change would be greatest in developed countries. The monetized value of health improvements could be comparable with, and possibly larger than, the environmental benefits of the avoided damages from climate change. What we eat greatly influences our personal health and the environment we all share. Recent analyses have highlighted the likely dual health and environmental benefits of reducing the fraction of animal-sourced foods in our diets. Here, we couple for the first time, to our knowledge, a region-specific global health model based on dietary and weight-related risk factors with emissions accounting and economic valuation modules to quantify the linked health and environmental consequences of dietary changes. We find that the impacts of dietary changes toward less meat and more plant-based diets vary greatly among regions. The largest absolute environmental and health benefits result from diet shifts in developing countries whereas Western high-income and middle-income countries gain most in per capita terms. Transitioning toward more plant-based diets that are in line with standard dietary guidelines could reduce global mortality by 6–10% and food-related greenhouse gas emissions by 29–70% compared with a reference scenario in 2050. We find that the monetized value of the improvements in health would be comparable with, or exceed, the value of the environmental benefits although the exact valuation method used considerably affects the estimated amounts. Overall, we estimate the economic benefits of improving diets to be 1–31 trillion US dollars, which is equivalent to 0.4–13% of global gross domestic product (GDP) in 2050. However, significant changes in the global food system would be necessary for regional diets to match the dietary patterns studied here.

Global and regional health effects of future food production under climate change: a modelling study

BACKGROUND One of the most important consequences of climate change could be its effects on agriculture. Although much research has focused on questions of food security, less has been devoted to assessing the wider health impacts of future changes in agricultural production. In this modelling study, we estimate excess mortality attributable to agriculturally mediated changes in dietary and weight-related risk factors by cause of death for 155 world regions in the year 2050. METHODS For this modelling study, we linked a detailed agricultural modelling framework, the International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT), to a comparative risk assessment of changes in fruit and vegetable consumption, red meat consumption, and bodyweight for deaths from coronary heart disease, stroke, cancer, and an aggregate of other causes. We calculated the change in the number of deaths attributable to climate-related changes in weight and diets for the combination of four emissions pathways (a high emissions pathway, two medium emissions pathways, and a low emissions pathway) and three socioeconomic pathways (sustainable development, middle of the road, and more fragmented development), which each included six scenarios with variable climatic inputs. FINDINGS The model projects that by 2050, climate change will lead to per-person reductions of 3·2% (SD 0·4%) in global food availability, 4·0% (0·7%) in fruit and vegetable consumption, and 0·7% (0·1%) in red meat consumption. These changes will be associated with 529,000 climate-related deaths worldwide (95% CI 314,000-736,000), representing a 28% (95% CI 26-33) reduction in the number of deaths that would be avoided because of changes in dietary and weight-related risk factors between 2010 and 2050. Twice as many climate-related deaths were associated with reductions in fruit and vegetable consumption than with climate-related increases in the prevalence of underweight, and most climate-related deaths were projected to occur in south and east Asia. Adoption of climate-stabilisation pathways would reduce the number of climate-related deaths by 29-71%, depending on their stringency. INTERPRETATION The health effects of climate change from changes in dietary and weight-related risk factors could be substantial, and exceed other climate-related health impacts that have been estimated. Climate change mitigation could prevent many climate-related deaths. Strengthening of public health programmes aimed at preventing and treating diet and weight-related risk factors could be a suitable climate change adaptation strategy. FUNDING Oxford Martin Programme on the Future of Food.

Carbon tariffs for financing clean development

In order to address carbon leakage and preserve the competitiveness of domestic industries, some industrialized Annex I countries have proposed to implement carbon tariffs. These tariffs would be levied on energy-intensive imports from developing non-Annex I countries that have not agreed to binding emissions reductions. This action could have detrimental welfare impacts, especially on those developing countries, and may not lead to significant reductions in leakage. A recent proposal is to use the revenues generated from carbon tariffs to finance clean development in the relevant exporting non-Annex I countries. This proposal is evaluated using an energy-economic model of the global economy. The model is supplemented by marginal abatement cost curves and bottom-up information on abatement potentials in order to represent how clean development financing affects emissions reductions. The results indicate that carbon tariffs could raise US

Meat consumption, health, and the environment

3.5–24.5 billion (with a central value of

Health and nutritional aspects of sustainable diet strategies and their association with environmental impacts: a global modelling analysis with country-level detail

9.8 billion) for clean development financing. This could reduce the emissions of non-Annex I countries by 5–15% and still leave funds available for other purposes, such as adaptation. Furthermore, recycling the revenues generated from carbon tariffs back to the exporting country itself could alleviate some of the negative welfare impacts associated with them. However, a net negative impact especially on the welfare and gross domestic product of developing countries would remain.

Feedlot diet for Americans that results from a misspecified optimization algorithm

The future of meat Meat consumption is rising annually as human populations grow and affluence increases. Godfray et al. review this trend, which has major negative consequences for land and water use and environmental change. Although meat is a concentrated source of nutrients for low-income families, it also enhances the risks of chronic ill health, such as from colorectal cancer and cardiovascular disease. Changing meat consumption habits is a challenge that requires identifying the complex social factors associated with meat eating and developing policies for effective interventions. Science, this issue p. eaam5324 BACKGROUND The global average per capita consumption of meat and the total amount of meat consumed are rising (see the figure), driven by increasing average individual incomes and by population growth. Growth rates vary across different regions, with consumption in high-income countries static or declining and in middle-income countries moderately to strongly increasing, whereas in low-income countries, meat consumption is on average low and stable. There has been a particularly marked increase in the global consumption of chicken and pork. The consumption of different types of meat and meat products has substantial effects on people’s health, and livestock production can have major negative effects on the environment. ADVANCES Meat is a good source of energy and some essential nutrients—including protein and micronutrients such as iron, zinc, and vitamin B12—although it is possible to obtain a sufficient intake of these nutrients without eating meat if a wide variety of other foods is available and consumed. In high-income Western countries, large prospective studies and meta-analyses generally show that total mortality rates are modestly higher in participants who have high intakes of red and processed meat. The strongest evidence of a specific adverse effect is the increased risk of colorectal cancer with high intakes of processed meat. Meat produces more emissions per unit of energy compared with that of plant-based foods because energy is lost at each trophic level. Within types of meat, ruminant production usually leads to more emissions than that of nonruminant mammals, and poultry production usually leads to less emissions than that of mammals. Meat production is the single most important source of methane, which has a relatively high warming potential but a low half-life in the environment compared with that of CO2. Careful management of grassland systems can contribute to carbon storage, but the net benefits are likely to be relatively modest. Agriculture uses more freshwater than any other human activity, with nearly a third required for livestock, so meat production in water-stressed areas is a major competitor with other uses of water, including that required to maintain natural ecosystems. Meat production can be an important source of nitrogen, phosphorus, and other pollutants and affects biodiversity—in particular, through land conversion to pasture and arable feed crops. OUTLOOK Governments act to shape food systems for economic purposes and to protect health from contaminated food. But there is less agreement over the degree to which the state should use health, environmental, or animal welfare considerations to control the supply of meat through interventions that affect the production, sale, processing, and distribution of meat and meat products or the price to the consumer. If we are to shape consumer demand, more evidence is needed about the effectiveness of different interventions to influence food selection. This may include interventions that affect either the conscious, reflective decision-making systems or nonconscious, automatic processes. Potential interventions within the rational choice paradigm include labeling schemes (based on health or environmental criteria) and certification programs (based on welfare or environmental considerations) or fiscal interventions (such as so-called fat taxes). Alternatively, the largely automatic responses to environmental cues that affect purchase and consumption behaviors can be manipulated by changes to the food environment, in retail and food consumption settings. History suggests that change in dietary behaviors in response to interventions is slow. But social norms can and do change, and this process can be aided by the coordinated efforts of civil society, health organizations, and government. However, successful interventions to improve health and environmental objectives are likely to require a good understanding of the impact of meat consumption on these outcomes, as well as a license from society for governments and other bodies to implement a suite of interventions to stimulate change. Total consumption of meat (in million metric tons) in different regions and (inset) globally. [Data are from www.fao.org/faostat/en/?#data.] Both the global average per capita consumption of meat and the total amount of meat consumed are rising, driven by increasing average individual incomes and by population growth. The consumption of different types of meat and meat products has substantial effects on people’s health, and livestock production can have major negative effects on the environment. Here, we explore the evidence base for these assertions and the options policy-makers have should they wish to intervene to affect population meat consumption. We highlight where more research is required and the great importance of integrating insights from the natural and social sciences.

Carbon pricing of food in Australia: an analysis of the health, environmental and public finance impacts

Summary Background Sustainable diets are intended to address the increasing health and environmental concerns related to food production and consumption. Although many candidates for sustainable diets have emerged, a consistent and joint environmental and health analysis of these diets has not been done at a regional level. Using an integrated health and environmental modelling framework for more than 150 countries, we examined three different approaches to sustainable diets motivated by environmental, food security, and public health objectives. Methods In this global modelling analysis, we combined analyses of nutrient levels, diet-related and weight-related chronic disease mortality, and environmental impacts for more than 150 countries in three sets of diet scenarios. The first set, based on environmental objectives, replaced 25–100% of animal-source foods with plant-based foods. The second set, based on food security objectives, reduced levels of underweight, overweight, and obesity by 25–100%. The third set, based on public health objectives, consisted of four energy-balanced dietary patterns: flexitarian, pescatarian, vegetarian, and vegan. In the nutrient analysis, we calculated nutrient intake and changes in adequacy based on international recommendations and a global dataset of nutrient content and supply. In the health analysis, we estimated changes in mortality using a comparative risk assessment with nine diet and weight-related risk factors. In the environmental analysis, we combined country-specific and food group-specific footprints for greenhouse gas emissions, cropland use, freshwater use, nitrogen application, and phosphorus application to analyse the relationship between the health and environmental impacts of dietary change. Findings Following environmental objectives by replacing animal-source foods with plant-based ones was particularly effective in high-income countries for improving nutrient levels, lowering premature mortality (reduction of up to 12% [95% CI 10–13] with complete replacement), and reducing some environmental impacts, in particular greenhouse gas emissions (reductions of up to 84%). However, it also increased freshwater use (increases of up to 16%) and had little effectiveness in countries with low or moderate consumption of animal-source foods. Following food-security objectives by reducing underweight and overweight led to similar reductions in premature mortality (reduction of up to 10% [95% CI 9–11]), and moderately improved nutrient levels. However, it led to only small reductions in environmental impacts at the global level (all impacts changed by <15%), with reduced impacts in high-income and middle-income countries, and increased resource use in low-income countries. Following public health objectives by adopting energy-balanced, low-meat dietary patterns that are in line with available evidence on healthy eating led to an adequate nutrient supply for most nutrients, and large reductions in premature mortality (reduction of 19% [95% CI 18–20] for the flexitarian diet to 22% [18–24] for the vegan diet). It also markedly reduced environmental impacts globally (reducing greenhouse gas emissions by 54–87%, nitrogen application by 23–25%, phosphorus application by 18–21%, cropland use by 8–11%, and freshwater use by 2–11%) and in most regions, except for some environmental domains (cropland use, freshwater use, and phosphorus application) in low-income countries. Interpretation Approaches for sustainable diets are context specific and can result in concurrent reductions in environmental and health impacts globally and in most regions, particularly in high-income and middle-income countries, but they can also increase resource use in low-income countries when diets diversify. A public health strategy focused on improving energy balance and dietary changes towards predominantly plant-based diets that are in line with evidence on healthy eating is a suitable approach for sustainable diets. Updating national dietary guidelines to reflect the latest evidence on healthy eating can by itself be important for improving health and reducing environmental impacts and can complement broader and more explicit criteria of sustainability. Funding Wellcome Trust, EAT, CGIAR, and British Heart Foundation.

Mitigation potential and global health impacts from emissions pricing of food commodities

White and Hall (1) suggest that removing animals from US agriculture would create a food supply incapable of supporting the United States population’s nutritional requirements and increase nutritional deficiencies compared with the current food system. However, their analysis suffers from an uncritical use of nutritional values and optimization algorithms, and a highly unrealistic and narrow scenario design. In constructing their dietary scenarios, White and Hall use a linear-programming algorithm that optimizes diets to meet nutrient constraints at lowest cost. This approach is problematic: since 1945, it has been recognized to result in highly unrealistic and monotonous diets if not properly constrained (2), for example, by realistic serving sizes or deviation from current diets (3 … [↵][1]1To whom correspondence should be addressed. Email: marco.springmann{at}dph.ox.ac.uk. [1]: #xref-corresp-1-1

Integrating emissions transfers into policy-making

Objective: To estimate the impact of integrating the price of greenhouse gas emissions into the price of food commodities on dietary and weight‐related risk factors and associated disease burden in Australia, as well as on national emissions reductions and public revenues.