Inequalities in health-care carbon footprints and implications for demand-side interventions: a global assessment across population groups

Background

Reducing emissions from health care is now recognised as an urgent priority on the climate–health agenda. Although studies have quantified the environmental impacts of health systems at national and global scales, inequalities in health-care carbon footprints (HCFs) across population groups (both between and within countries) and their trajectories remain unexplored. This study quantified these disparities and evaluated the potential of targeted demand-side interventions to achieve equitable, low-carbon health care while expanding delivery of care.

Methods

We estimated the HCFs of different income groups within 121 countries from 2005 to 2017 by integrating consumer expenditure surveys, national health expenditure data, and a global multiregional input–output model. Our approach enabled the disaggregation of emission patterns by income groups, health expenditure groups, health-care expenditure category, as well as health-care products and services. Scenario analyses were then carried out to evaluate the potential of demand-side interventions in reducing health care-related carbon emissions under different strategies.

Findings

Our analysis revealed disparities in HCFs both between countries and among population groups within them. By 2017, the top 10% of high-spending health-care consumers contributed 48% (1128 Mt CO2 equivalents [CO2e]) of the total HCFs, in comparison to the less than 10% of the total HCFs contributed by the bottom 50%. In addition, the top 1% contributed 2857 kg CO2e per capita, more than eight-times the global per-capita average and nearly 66-times that of the bottom 50%. In addition to high-income countries, which maintained consistently high levels of HCFs over time, upper-middle-income countries also contributed to a substantial rise, with total HCF increasing from 181 Mt CO2e in 2005 to 760 Mt CO2e in 2017, representing more than a three-fold increase. By estimating the health expenditure–carbon elasticity, we found that health-care spending embodies higher marginal emissions among high-spending groups than that among low-spending groups. Scenario analyses indicated that without compromising on health outcomes, demand-side controls targeting carbon-intensive overuse of health care among the top 10–20% while simultaneously advancing ambitious universal health coverage could deliver a 25–40% reduction in carbon footprints and even ease costs.

Interpretation

Our study moves beyond cross-country comparisons based on national averages or totals by examining HCFs across different population groups within countries. The highest-spending populations were found to contribute disproportionately to health-care carbon emissions, thus highlighting that achieving equitable, low-carbon health-care transitions requires attention to within-country population disparities to target interventions. Our findings provide quantitative evidence for pathways to meet fair health-care emission-reduction targets while maintaining care quality. Expanding access to essential health care, combined with addressing carbon-intensive overuse among high-spending populations, could achieve substantial reductions in emissions.