Building climate resilience in the face of unprecedented threats will require ambitious policies and actions that prioritize health and equity. Effective strategies to reduce greenhouse gas emissions will reduce the health impacts of climate change and bring many near-term health (co-) benefits. This chapter draws on key findings from the report of the Lancet Pathfinder Commission on pathways to a healthy net-zero future,[1] and highlights the potential for transformative changes in sectors such as energy, transport, food systems, and housing to address both climate and health challenges.
Introduction
The climate crisis is a health crisis, driven by an unsustainable status quo that threatens to undermine and reverse progress on health and development. Climate change is already impacting health in a variety of direct and indirect ways, including through extreme weather events, increased risk of infectious disease spread, reduced yield and nutritional quality of crops, effects on mental health, and reduced labour productivity.[2],[3] Impoverished communities, the elderly and pregnant women are disproportionately impacted by climate breakdown, but no country or population is unaffected.
Both mitigation – reducing greenhouse gas (GHG) emissions, and adaptation – addressing changes that cannot be prevented, are vital to protect health and build climate resilience. This paper focuses primarily on the health benefits of climate mitigation actions, highlighting evidence and recommendations from the Lancet Pathfinder Commission report on pathways to a healthy net-zero future.1
The 2023 UN Emissions Gap report suggests that current action is insufficient and that GHG emissions must fall by 42% by 2030 to limit global temperature rise to the Paris Agreement goal of 1.5°C above pre-industrial levels and 28% to limit warming to below 2°C.[4] Climate mitigation actions can bring major near-term benefits to human health, in addition to reducing the health impacts of climate change. These health co-benefits are delivered through three main pathways: reduced air pollution from phasing out fossil fuels and replacing them with clean, renewable sources of energy; the consumption of healthier, more sustainable diets; and increased physical activity from promoting active travel (walking and cycling) and public transport.1 Figure 1 illustrates these and other pathways.
To capitalize on the health benefits that can be achieved and tackle the interlinked crises of climate change, biodiversity loss and global inequity, a whole-of-society, systemic approach that integrates mitigation and adaptation actions is required to trigger transformative changes in all sectors. Decision makers must use the best available evidence to implement solutions at scale, as well as monitoring and evaluating the impact of actions on GHG emissions, health and equity to ensure accountability and inform further action. Strengthened collaboration between policymakers, researchers, funders, civil society organizations, and practitioners, as well as co-design of solutions with local communities, will be key to accelerating the transition to healthier, more equitable, climate resilient societies.
Figure 1. Key pathways and connections between climate mitigation actions and health. (Source: Whitmee, S., Green, R., Belesova, K., et al. (2024). Pathways to a healthy net-zero future: Report of The Lancet Pathfinder Commission. Lancet, 403(10421), 67–110. doi:10.1016/s0140-6736(23)02466-21).
The health co-benefits of climate action
Current GHG-intensive food, energy and transport systems are harming public health.[5] Over 5 million deaths per year are attributable to air pollution from fossil fuel burning (Figure 2);[6] over 5 million deaths annually are attributable to physical inactivity;[7] and over 10 million deaths annually could be prevented from transitioning to healthier, more sustainable diets that include more whole grains, nuts, vegetables and fruits by 2050.[8]
GHG emission reductions in line with the Nationally Determined Contributions (NDCs) to achieve the Paris Agreement goals in just nine countries could prevent each year by 2040: 1·2 million air pollution-related deaths, 5·9 million diet-related deaths, and 1·15 million deaths due to physical inactivity, when compared with the current emissions scenario (with some overlap between the prevented deaths).[9]
While decarbonising the healthcare sector, which accounts for over 4% of global GHG emissions,[10] is an important contribution to achieving net zero, cutting emissions across all sectors is vital to protect and promote health.
Figure 2. Country average, all cause deaths per 100 000 population per year attributable to fine particulate matter (PM2.5) and ozone (O3), and with fossil fuel related and all anthropogenic emissions removed. (Source: Lelieveld, J., Haines, A., Burnett, R., et al. (2023). Air pollution deaths attributable to fossil fuels: Observational and Modelling Study. BMJ, 383, e077784. doi:10.1136/bmj-2023-0777846).
Energy transition
A clean and equitable energy transition through fossil fuel phase out is critical to achieving net zero and will bring major health benefits by reducing air pollution.1 Co-benefits of improved air quality result largely from lower PM2.5 levels and include reduced risk of non-communicable diseases (NCDs) such as ischaemic heart disease, stroke, diabetes, chronic obstructive pulmonary disease (COPD) and lung cancer, as well as acute respiratory infections.1 Almost the entire global population (99%) breathes polluted air that exceeds WHO air quality limits.[11]
The health benefits of reducing air pollution would be greatest in Asia where fossil fuel related air pollution levels are high,1 and in high-income countries that have economies powered by fossil energy.6 Air pollution levels are rising in countries across Africa, but there are opportunities to adopt low carbon development pathways.1
Phasing out coal will bring the largest climate and health benefits, with coal combustion being responsible for over 50% of fossil fuel-related air pollution globally.1 Gas is less polluting than coal, but still a significant source of GHG emissions from gas leaks that release methane (CH4) and from CO2 when burnt.1
Though investments in renewables increased globally in 2022, investments in fossil fuels have continued and increased in some countries.4 Higher ambition is needed to achieve net zero by 2050 at the latest, and countries with greater capacity and responsibility will need to make the deepest, most rapid emissions cuts.
The climate and health benefits of renewable energy are illustrated by studies of the US power sector between 2005 and 2016, which show that in 2015 alone, 147 megatonnes of CO2 were avoided from replacing some of the US’ coal and natural gas energy generation with solar and wind power.[12],[13],[14],[15] Between 2007 and 2015, improved air quality prevented between 3,000 to 13,000 premature deaths, with health benefits valued between 30 and over 100 billion US dollars.15
Clean cookstoves
In low and middle-income countries, replacing solid fuels with clean energy sources can also bring health benefits from reduced household and ambient air pollution. The Pathfinder Initiative review of evidence highlighted that clean cookstove provisions in India could save an estimated 1,279 years of life per 100,000 population per year.1,[16],[17] Although the climate benefits of clean cookstoves are modest, providing universal access to clean energy is imperative for a just transition.1
A recent review also showed, however, that improved solid fuel combustion stoves do not reduce air pollution sufficiently to achieve the WHO interim target PM2·5 level, and the adoption of cleaner fuels such as ethanol, liquefied petroleum gas, and increasingly electricity from clean renewable sources for cooking, should be prioritised.[18]
Sustainable and active transport
Global emissions from the transport sector must fall by around a quarter by 2030 to align with the International Energy Agency’s Net Zero Scenario.[19] System-wide changes that combine promotion of active travel and increased use of public transport with reduced private car use are needed to achieve climate and health benefits.1
Single interventions have limited effects, for example, switching to electric vehicles will reduce GHG emissions and air pollution, but will not bring health benefits from increased physical activity.1 In addition, effects on PM2.5 from brakes and tires depend on vehicle weight, driving style, and the use of regenerative breaking.[20]
Many cities are taking action to promote active travel. For example, Buenos Aires introduced the “Más Bicis, Menos Emisiones” programme, a network of cycle lanes and a bicycle sharing scheme, that resulted in a 131% increase in cycle trips since 2013, a reduction of over 12,000 tons of CO2 emissions, and safer roads for cyclists.[21],[22]
Healthy, sustainable food systems
The agriculture, forestry and other land use (AFOLU) sector contributes to around a quarter of global GHG emissions,[23] largely from methane (CH4) produced by livestock, CO2 from deforestation, and nitrous oxide (N2O).1
Sustainable diets that are predominantly plant-based and low in animal-sourced foods, particularly red and processed meats (in high-consuming countries),[24] can bring health benefits such increased life expectancy and reduced risk of a range of NCDs.[25]
A study in the UK found that intermediate to high adherence to the ‘Eatwell Guide’ to a healthy balanced diet (Figure 3) led to an estimated 7% reduction in mortality and 30% reduction in emissions compared with low adherence (an average reduction of 0.58 tonnes GHGe/person/year).[26]
Ensuring equitable access to and affordability of healthy, sustainable food choices should be a priority to encourage the necessary shifts in dietary patterns.[27] Sustainable diets also need to be properly implemented to avoid micronutrient deficiencies.[28],[29]
Figure 3. Eatwell Guide. (Source: OHID in association with the Welsh government, Food Standards Scotland and the Food Standards Agency in Northern Ireland.[30] Crown Copyright 2016).
Energy efficient housing
Reducing GHG emissions in the housing sector will require decarbonising the energy system and retrofitting homes.1 Improving home insulation can increase energy efficiency and reduce cold exposure in temperate climates, leading to health benefits if ventilation requirements are met.[31]
A randomised controlled trial evaluating the impact of home energy efficiency and thermal comfort upgrades in Victoria, Australia, found that in intervention homes reduced gas and electricity use resulted in lower CO2eq emissions and energy cost savings.[32],[33] Intervention households were warmer and had lower healthcare costs than those in the control group, and householders reported better mental health and reduced breathlessness.
Nature-based solutions
Nature-based solutions (NbS) work to protect, sustainably manage and restore natural or modified ecosystems, protecting biodiversity while addressing societal challenges (Figure 4).[34] NbS enable integration of adaptation and mitigation actions, and can bring physical and mental health benefits.
There are significant opportunities to integrate nature into cities, for example through urban trees, which can improve air quality and provide climate mitigation benefits.1 However, benefits depend on the type of trees planted as some produce allergenic pollen or volatile organic compounds that are precursors of tropospheric ozone.
NbS such as forest protection, agroforestry and land restoration, can also provide mitigation benefits by sequestering and storing carbon, but quantitative estimates of health effects are limited.1
Figure 3. Pathways to health and equity from nature-based solutions (REDD+=Reducing Emissions from Deforestation and Degradation). (Source: Whitmee, S., Green, R., Belesova, K., et al. (2024). Pathways to a healthy net-zero future: Report of The Lancet Pathfinder Commission. Lancet, 403(10421), 67–110. doi:10.1016/s0140-6736(23)02466-2;1 Pathways adapted from the Global Commission on Adaptation).[35]
Climate resilient low carbon development
The large gap in per capita emissions between the highest and lowest emitting nations,[36] emphasizes the need for policies to prioritize emissions reductions in the highest emitters, while ensuring the needs of all are met. Provision of adequate financing for low-emission, resilient development in low and middle-income countries is crucial to meeting the Paris Agreement targets and Sustainable Development Goals.
Actions should aim to ensure that co-benefits of climate mitigation benefit all and that vulnerable groups, including Indigenous communities, displaced people, people with disabilities, and low-income communities, are protected from unintended consequences and trade-offs.[37] This will require careful planning of policies and interventions in partnership with local communities, and monitoring the impact of actions on health and livelihoods.
Transformative change
Moving towards a healthy, sustainable future requires cross-sectoral transformative changes that challenge the dominant social and economic systems that have caused the climate crisis. Incremental changes and undue reliance on unproven solutions such as carbon capture will be insufficient and potentially harmful to progress towards net zero, leading to missed opportunities to improve the health and well-being of populations.
Policies and actions should harness new technologies, but must go beyond seeking efficiency improvements while leaving in place unsustainable systems.1 Actions need to target systems change including by reducing demand for energy and materials in high consuming countries, and promoting and enabling widespread behaviour change. Circular economy approaches that reduce waste and encourage practices like refurbishing, repurposing and redistributing, have the potential to reduce environmental impact,[38] but more evidence is needed to understand health effects.1
Conclusion
This paper has focused on the major health benefits that can be achieved through well-designed climate mitigation actions. The climate crisis poses unprecedented threats to human health, but also presents an opportunity to create fairer societies and more resilient ecosystems that support the health of people and the planet.
Though data gaps on climate and health remain, there is more than enough evidence to inform and spur action across all sectors at multiple scales. Commitments such as the recent COP28 climate and health resolution, endorsed by more than 150 countries,[39] and increasing mention of health co-benefits in NDCs,[40] highlight growing political recognition of the need to integrate health and health co-benefits into climate policies.
Governments and decision makers, in collaboration with funders, researchers, civil society, practitioners and local communities, now need to scale up ambition and implement evidence-based solutions that are driven by the imperative to protect human health and the natural systems on which it depends. Concerted efforts to evaluate the impact of actions are also needed to ensure they achieve the intended effects on climate and health, and provide equitable distribution of benefits.
Acknowledgement
With thanks to the authors of the Lancet Pathfinder Commission report, including the Co-Chairs, Commissioners and the Pathfinder Initiative research team at the London School of Hygiene & Tropical Medicine.
[1] Whitmee, S., Green, R., Belesova, K., et al. (2024). Pathways to a healthy net-zero future: Report of The Lancet Pathfinder Commission. Lancet, 403(10421), 67–110. doi:10.1016/s0140-6736(23)02466-2
[2] Cissé, G., R. McLeman, H. Adams, P., et al. (2022): Health, Wellbeing, and the Changing Structure of Communities. In H.-O. Pörtner, D.C. Roberts, M. Tignor, E.S. et al. (Eds.), Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (pp. 1041–1170). Cambridge University Press. doi:10.1017/9781009325844.009.
[3] World Health Organization. (2023). Climate Change. https://www.who.int/news-room/fact-sheets/detail/climate-change-and-health.
[4] United Nations Environment Programme. (2023). Emissions Gap Report 2023: Broken Record – Temperatures hit new highs, yet world fails to cut emissions (again). https://wedocs.unep.org/20.500.11822/43922.
[5] Pathfinder Initiative. (2023). Summary of the Lancet Pathfinder Commission report: Pathways to a healthy net-zero future. https://climatehealthevidence.org/sites/default/files/uploads/files/lancet_pathfinder_commission_report_summary.pdf
[6] Lelieveld, J., Haines, A., Burnett, R., et al. (2023). Air pollution deaths attributable to fossil fuels: Observational and Modelling Study. BMJ, 383, e077784. doi:10.1136/bmj-2023-077784
[7] Lee I.M., Shiroma E.J., Lobelo F., et al. (2012). Effect of physical inactivity on major non-communicable diseases worldwide: an analysis of burden of disease and life expectancy. Lancet, 380(9838), 219–29. doi:10.1016/S0140-6736(12)61031-9
[8] Willett, W., Rockström, J., Loken, B., et al. (2019). Food in the anthropocene: The EAT–Lancet Commission on healthy diets from sustainable food systems. Lancet, 393(10170), 447–492. doi:10.1016/s0140-6736(18)31788-4
[9] Hamilton, I., Kennard, H., McGushin, A., et al. (2021). The Public Health Implications of the Paris Agreement: A modelling study. The Lancet Planetary Health, 5(2), e74–e83. doi:10.1016/s2542-5196(20)30249-7
[10] Health Care Without Harm. (2019). How the Health Sector Contributes to the Global Climate Crisis and Opportunities for Action. https://noharm-global.org/documents/health-care-climate-footprint-report
[11] World Health Organization (2022). Billions of people still breathe unhealthy air: new WHO data. https://www.who.int/news/item/04-04-2022-billions-of-people-still-breathe-unhealthy-air-new-who-data
[12] From coal and natural gas to renewables in the US. Pathfinder Initiative Climate & Health Evidence Bank. https://climatehealthevidence.org/case-studies/coal-and-natural-gas-renewables-us
[13] Barbose, G., Wiser, R., Heeter, J., et al. (2016). A retrospective analysis of benefits and impacts of U.S. renewable portfolio standards. Energy Policy, 96, 645–660. doi:10.1016/j.enpol.2016.06.035
[14] Burney, J. A. (2020). The downstream air pollution impacts of the transition from coal to natural gas in the United States. Nature Sustainability, 3(2), 152–160. doi:10.1038/s41893-019-0453-5
[15] Millstein, D., Wiser, R., Bolinger, M., et al. (2017). The climate and air-quality benefits of wind and solar power in the United States. Nature Energy, 2(9). doi:10.1038/nenergy.2017.134
[16] Venkataraman, C., Sagar, A.D., Habib, G., et al. (2010). The Indian National Initiative for Advanced Biomass Cookstoves: The benefits of Clean Combustion. Energy for Sustainable Development, 14(2), 63–72. doi:10.1016/j.esd.2010.04.005
[17] Wilkinson, P., Smith, K.R., Davies, et al. (2009). Public health benefits of strategies to reduce greenhouse-gas emissions: Household energy. Lancet, 374(9705), 1917–1929. doi:10.1016/s0140-6736(09)61713-x
[18] Pope, D., Johnson, M., Fleeman, N., et al. (2021). Are cleaner cooking solutions clean enough? A systematic review and meta-analysis of particulate and carbon monoxide concentrations and Exposures. Environmental Research Letters, 16(8), 083002. doi:10.1088/1748-9326/ac13ec
[19] International Energy Agency. Transport. https://www.iea.org/energy-system/transport
[20] Beddows, D.C.S., & Harrison, R.M. (2021). PM10 and PM2.5 emission factors for non-exhaust particles from road vehicles: Dependence upon vehicle mass and implications for Battery Electric Vehicles. Atmospheric Environment, 244, 117886. doi:10.1016/j.atmosenv.2020.117886
[21] More Bikes, Less Emissions. Pathfinder Initiative Climate & Health Evidence Bank. https://climatehealthevidence.org/case-studies/more-bikes-less-emissions
[22] City of Buenos Aires. (2020). Climate Action Plan 2050. https://buenosaires.gob.ar/sites/default/files/2023-02/pac_2050_buenos_aires_eng_0.pdf
[23] IPCC. (2022). Summary for Policymakers. In: P.R. Shukla, J. Skea, R. Slade, et al., (Eds.), Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. (pp. 3–48). Cambridge University Press. doi:10.1017/9781009157926.001.
[24] Jarmul, S., Dangour, A.D., Green, R., et al. (2020). Climate change mitigation through dietary change: A systematic review of empirical and modelling studies on the environmental footprints and health effects of ‘sustainable diets.’ Environ Res Lett, 15(12), 123014. doi:10.1088/1748-9326/abc2f7
[25] Milner, J., Green, R., Dangour, A.D., et al. (2015). Health effects of adopting low greenhouse gas emission diets in the UK. BMJ Open, 5(4). doi:10.1136/bmjopen-2014-007364
[26] Scheelbeek, P., Green, R., Papier, K., et al. (2020). Health impacts and environmental footprints of diets that meet the Eatwell guide recommendations: Analyses of multiple UK studies. BMJ Open, 10(8), e037554. doi:10.1136/bmjopen-2020-037554
[27] Springmann, M., Clark, M.A., Rayner, M., et al. (2021). The global and regional costs of healthy and sustainable dietary patterns: A modelling study. The Lancet Planetary Health, 5(11), e797-e807. doi:10.1016/s2542-5196(21)00251-5
[28] Chen, C., Chaudhary, A., & Mathys, A. (2019). Dietary change scenarios and implications for environmental, nutrition, human health and economic dimensions of food sustainability. Nutrients, 11(4), 856. doi:10.3390/nu11040856
[29] Eshel, G., Shepon, A., Noor, E., et al. (2016). Environmentally optimal, nutritionally aware beef replacement plant-based diets. Environ Sci Technol, 50(15), 8164–8168. doi:10.1021/acs.est.6b01006
[30] The Office for Health Improvement and Disparities (previously Public Health England). (2016). The Eatwell Guide. https://www.gov.uk/government/publications/the-eatwell-guide
[31] Milner, J., Turner, G., Ibbetson, A., et al. (2023). Impact on mortality of pathways to net zero greenhouse gas emissions in England and Wales: A multisectoral modelling study. The Lancet Planetary Health, 7(2), e128-e136. doi:10.1016/s2542-5196(22)00310-2
[32] Victorian Healthy Homes Program. Pathfinder Initiative Climate & Health Evidence Bank. https://climatehealthevidence.org/case-studies/victorian-healthy-homes-program
[33] Sustainability Victoria. (2022). The Victorian Healthy Homes Program: research findings. https://www.sustainability.vic.gov.au/research-data-and-insights/research/research-reports/the-victorian-healthy-homes-program-research-findings
[34] Cohen-Shacham, E., Walters, G., Janzen, C., et al. (2016). Nature-Based Solutions to Address Global Societal Challenges. doi:10.2305/iucn.ch.2016.13.en
[35] The Global Commission on Adaptation. (2019). Adapt now: a global call for leadership on climate resilience. https://gca.org/reports/adapt-now-a-global-call-for-leadership-on-climate-resilience/
[36] Chancel, L. (2022). Global carbon inequality over 1990–2019. Nat Sustain, 5(11), 931–938. doi:10.1038/s41893-022-00955-z
[37] Pathfinder Initiative. (2023). Pathfinder Policy Brief COP28: Healthy and Just Transitions. https://climatehealthevidence.org/sites/default/files/uploads/files/pathfinder_policy_brief_cop28_healthy_and_just_transitions.pdf
[38] European Environment Agency. (2024). Circular Economy. https://www.eea.europa.eu/en/topics/in-depth/circular-economy
[39] COP28 Presidency. (2023). COP28 UAE Declaration on climate and health. https://www.cop28.com/en/cop28-uae-declaration-on-climate-and-health
[40] World Health Organization. (2023). 2023 WHO review of health in Nationally Determined Contributions and long-term strategies: health at the heart of the Paris Agreement. https://cdn.who.int/media/docs/default-source/climate-change/9789240074729-v2.pdf?sfvrsn=f4c8b157_4