Abstract
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.
Generated Summary
This modeling study investigates the global and regional health effects of future food production under climate change. It links the International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT) with a comparative risk assessment of changes in fruit and vegetable consumption, red meat consumption, and bodyweight, estimating excess mortality by cause of death in 155 world regions for the year 2050. The study considers four emissions pathways and three socioeconomic pathways to account for variable climatic inputs. The research aims to quantify the health implications of dietary and weight-related changes in light of climate change and agricultural production, analyzing the impact of these changes on mortality related to cardiovascular diseases and cancer.
Key Findings & Statistics
- By 2050, climate change is projected to lead to a reduction 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 are associated with 529,000 climate-related deaths worldwide (95% CI 314,000-736,000), representing a 28% (95% CI 26-33) reduction in deaths that would be avoided by changes in dietary and weight-related risk factors between 2010 and 2050.
- The estimate of climate-related deaths represents a substantial reduction in the progress towards greater food and nutrition security that is projected to occur until 2050. In our model projections, it amounts to a 28% (95% CI 26–33) reduction in the number of deaths that could be avoided due to changes in dietary and weight-related risk factors between 2010 and 2050.
- Climate change scenarios project a relative reduction of global food availability in 2050 of 99 kcal per person per day (3.2% reduction; SD of climate change scenarios [CC SD] 11 kcal/person/day [0.4%]), of fruit and vegetable consumption in 2050 by 14.9 g per person per day (4.0% decrease; 2.7 [0.7%]), and of red meat consumption in 2050 of 0.5 g per person per day (0.7% decrease; 0.1 [0.1%]), when compared with the 2050 reference scenario without climate change.
- The study estimates the global and regional food availability and consumption in the baseline year of 2010, for the reference scenario without climate change in 2050, and for the mean of the main climate change scenarios in 2050.
- Without climate change, the agriculture-economic model projects an increase in global food availability of 289 kcal per person per day between the years 2010 and 2050 (a 10.3% increase); global fruit and vegetable consumption, net of food waste (ie, with food waste at the consumption level subtracted from the estimates), is projected to increase by 35.8 g per person per day, and global red meat consumption, net of food waste, to increase by 3.9 g per person per day.
- Climate change reduced the number of avoided deaths by 28% (95% CI 26–33), which led to 529000 climate-related deaths (95% CI of the relative risk distribution averaged over all climate scenarios 314000–736000; CC SD 105000) compared with the reference scenario in 2050.
- Most climate-related deaths occurred in the low-income and middle-income countries of the Western Pacific region
- Changes in fruit and vegetable consumption were the main risk factor for climate-related death in high-income countries (accounting for 58% [95% CI 49–64] of all changes in deaths) and in the low-income and middle-income countries of the Western Pacific (74% [65–79]), Europe (60% [46-69]), and the Eastern Mediterranean (42% [29–51%]).
Other Important Findings
- 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.
- Adoption of climate-stabilisation pathways would reduce the number of climate-related deaths by 29-71%, depending on their stringency.
- The main results were based on a “middle-of-the-road” development scenario (shared socioeconomic pathway 2 [SSP2]), and compared a scenario without climate change against scenarios that follow a high emissions pathway.
- Compared with the main scenario (SSP2), more sustainable development (SSP1) led to more avoided deaths in 2050, and more fragmented development (SSP3) led to fewer avoided deaths.
- Compared with the highest emissions pathway (RCP8.5), the number of climate-related deaths were reduced by 29% (SSP SD 3%) and 32% (SSP SD 2%) in two medium climate-stabilisation scenarios (RCP6.0 and RCP4.5), and by 71% (SSP SD 1%) in a stringent climate-stabilisation scenario (RCP2.6).
- 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.
- The increases in food availability and consumption in the reference scenario without climate change resulted in 1.9 million avoided deaths (95% CI 0.9–2.8 million) in 2050 compared with the baseline with 2010 levels of food availability and consumption.
- China and India had a high number of climate-related deaths per person.
- The changes in weight-related deaths exceeded the changes in consumption-related deaths (66/155 countries; figure 3B), and the number of deaths avoided because of reductions in overweight and obesity exceeded the number of deaths related to increases in underweight (119/155 countries; figure 3C).
Limitations Noted in the Document
- The effects of climate changes on crops that are comparatively less important but are of high importance for health, such as fruit and vegetables, would benefit greatly from further research.
- The economic responses of agricultural commodity markets to climatic shocks are subject to high uncertainty.
- The relation between changes in bodyweight and caloric availability might change in the future if other parameters, such as the amount of food waste, are not controlled for.
- Use of metabolic models of weight change would have been preferable to the approach, but existing estimates of food consumption and waste are too imprecise to apply such models at a global level.
- The global databases used for the analysis, such as the food balance sheets produced by the FAO that were used to calibrate the IMPACT model, and the health parameters adopted from the Global Health Observatory of WHO that were used in the health analysis, have been subject to substantial adjustment.
- Country-level aggregation might hide intra-regional inequalities that, when disaggregated, could increase the spread of results for specific regions and worldwide.
- Several factors not included in this analysis could change future estimates of climate-related mortality from dietary and weight-related risk factors.
Conclusion
This study provides critical insights into the potential health implications of climate change, particularly those related to dietary changes and weight-related risk factors. The findings underscore the substantial impact of climate change on global health, estimating a significant number of climate-related deaths by 2050 due to alterations in food availability, consumption patterns, and bodyweight. The research highlights the importance of focusing on dietary risk factors, such as fruit and vegetable consumption, and red meat consumption, which are major contributors to climate-related mortality. The study’s projections reveal that the effects of climate change on food systems can lead to substantial reductions in the progress towards greater food and nutrition security. The study also points out that climate change mitigation strategies, particularly those involving climate-stabilization pathways, could significantly reduce the number of climate-related deaths. This suggests that proactive measures to curb greenhouse gas emissions are essential for safeguarding public health. The study emphasizes the need for strengthening public health programs that focus on the prevention and treatment of diet and weight-related risk factors. It also underscores the regional variations in the health impacts, highlighting the disproportionate burden on low-income and middle-income countries, particularly those in the Western Pacific and Southeast Asia. This emphasizes the need for region-specific adaptation strategies. In conclusion, the research provides compelling evidence of the significant health impacts of climate change through its effects on food systems. It highlights the importance of implementing comprehensive strategies that address both climate change mitigation and public health interventions to protect populations from the adverse effects of dietary and weight-related risk factors.