Acting on climate change for a healthier future

Health impacts of climate change in Canada

Climate change describes deviations of long-term weather patterns leading to increased frequency, severity, or duration of extreme events.⁵ These events interact in complex ways with the physical world and our social systems, contributing to negative health outcomes already evident today and projected to accelerate in the future.^6,7 Notwithstanding this complexity, the Intergovernmental Panel on Climate Change, representing global scientific consensus, found that health outcomes will be overwhelmingly negative, with “very high confidence.”⁸ Human activities are a major driver of climate change and also exacerbate the related problem of air pollution.⁹ Along with releasing greenhouse gases (GHGs), the combustion of fossil fuels contributed to an estimated 17 574 avoidable deaths in Canada owing to air pollution in 2015—more than all causes of injury, accidents, and trauma combined.^10,11

Pathways to the health impacts of climate change are commonly grouped into 3 categories: direct effects from weather events, indirect effects from natural systems, and indirect effects mediated through human systems.⁸ Examples in Canada include links to vector-borne disease, disruption of health services, mental illness, population migration, and mortality (Figure 1).^12-19 Just as shutdowns due to COVID-19 have broken medical supply chains, the increasing social, economic, and environmental effects of climate change present major risks to health and care delivery.^9,20,21

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Figure 1.

Simplified examples of pathways linking climate change exposures with health outcomes and Canadian examples: Direct and indirect effects are mediated through natural and human systems.

A number of factors promote resilience to climate change in Canada, such as high national income, high levels of public concern and education, and universal health coverage. Yet no one is immune, and people living with poverty or chronic illness are among those most likely to be affected.^8,17,22 Many First Nations, Metis, and Inuit experience persistent health disparities and intergenerational socioeconomic marginalization.^19,23 By virtue of close relationships with the land, Indigenous peoples are often the first to experience health effects of environmental degradation. Taken together, climate change will disproportionately harm people who have contributed least to, and benefited least from, climate-altering activities.^7,22

How does health care contribute to climate change?

The Canadian health care system is a major contributor to GHG emissions, rivalling those of large economic sectors such as aviation.²⁴ Medication is the largest polluting category, comprising more than a quarter of all health sector GHGs.²⁴ Emissions from pharmaceuticals may be owing to high consumption, especially for commonly prescribed drugs, or because of potent climate-altering effects in the atmosphere, such as those caused by drug propellants.²⁵ For example, delivery devices for inhaled bronchodilators can have dramatically different carbon footprints (Figure 2).^25,26

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Figure 2.

Estimated GHG emissions from dry-powder inhalers, metered-dose inhalers, and car travel

Compared with countries with similar health outcomes, Canada’s health care system also has high per capita carbon dioxide emissions (Figure 3).^27,28 Differences are partly explained by electricity sources, population density, and measurement variations: factors not directly modifiable by the health sector.²⁷ However, some health systems are making concerted efforts to reduce emissions within their control.²⁹ Notably, England’s national public health service improves sustainability through innovative models of care, technology, and behaviour change. Between 2007 and 2017, the institution reduced carbon dioxide emissions by 18.5% despite increasing clinical activity.³⁰

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Figure 3.

Comparison of emissions attributed to national health sectors in 2014

Compared with Canada and the United Kingdom, many low- and middle-income countries have fewer resources for adaptation to climate change yet are experiencing some of the strongest impacts. Globally, heat exposure, food insecurity, and vector-borne diseases threaten hundreds of millions of people.¹² Climate-related changes in global migration and disease patterns, alongside disruptions to labour productivity, transport, supply chains, and land use, may also have large-scale indirect effects on health and health care in higher-income countries, including Canada.^9,12 Examining this unequal access to the full enjoyment of health in the context of primary care values can offer insights into strategies for change.

Our responsibility to act

Social accountability has become a recognized duty of primary care providers and all health professions to meet the changing needs and emerging challenges facing people in Canada.³¹ In conflict with goals of promoting and protecting health, health system GHG emissions are associated with preventable and growing downstream harms.³⁰ Since the environmental side effects of care also affect work force, infrastructure, and personal health, managing health care–related pollution serves the full breadth of personal, professional, and societal interests.

Primary care, and the health care system in general, has the capacity to drive action through deep connections to people’s lives, large-market participation in hiring and purchasing, and a trusted position of leadership in agenda setting.⁷ Although mandates and resources for action from governing bodies are not yet fully in place, we already possess the ability to act rapidly through existing structures while advocating for necessary policy solutions and tools. Failing to meaningfully act on climate change threatens the viability of high-quality health services through economic and infrastructure disruption.^12,22 Whether we deliberately address these challenges or not, our health systems are both contributing to the problem of climate change and are poised to suffer its consequences.

The complex relationships between climate change and health necessitate a multifaceted and adaptive approach. While government actions, including carbon pricing, regulation, and investments in renewable energy, can be powerful interventions to limit further warming, they must be complemented by efforts from critical actors, including health institutions and professionals, to alleviate existing and expected harms (Figure 4).^12,30 Some policies, such as phasing out coal, can have real-time health benefits.¹² Depending on the manner of implementation, these approaches could require additional resources, involve reorienting existing resources, or be cost saving. Taking health gains into account, mitigating climate change would likely result in a large net benefit overall.³²

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Figure 4.

Conceptual model of primary care in health system sustainability

Primary care, as the largest medical work force, with a holistic commitment to the health of patients across the complete life cycle, has a distinctive interest in the pursuit of health co-benefits, the prevention of harm, and interventions to support well-being beyond medical services.³³ Potential roles of primary care in achieving an impact on climate change can be examined using a “macro, meso, micro” framework of social accountability.³¹

Macro: policies to take advantage of co-benefits

Advocating for health-in-all approaches to public policy can address the interconnected roots of both poor health and climate change.³⁴ Shifting to prevention or management earlier in the illness process can lower the intensity of care required to maintain or restore health. For example, dietary habits recommended in Canada’s Food Guide or policies to encourage active transport are likely to prevent chronic disease and premature mortality, while also lowering GHG emissions.^7,35 Targeting the social and structural determinants of health is necessary to limit the unequal impacts of climate change, including prioritizing the needs of populations at greatest risk, addressing historical and ongoing injustices, supporting just economic transitions, and reducing health inequities.^23,36,37 Advocacy and policy change must be carried out in partnership with groups at highest risk, many of whom already contribute critical knowledge and leadership.³¹

Meso: emphasize sustainability in education and health promotion

Health professionals, and especially primary care providers, are trusted sources of information to their communities and experienced with discussing complex issues.³⁸ Framing climate change in terms of health is known to be an effective communication strategy to help patients and health professionals conceptualize climate change as salient to their lives.³⁹ Most people recognize that climate change is a threat but do not appreciate its risks to their own health; describing health effects can close this psychological gap.⁴⁰ To that end, medical schools across Canada are beginning to introduce climate change into curricula.⁴¹ As a next step, family medicine academic programs can integrate concepts into training and continuing development that address sustainability-promoting practice changes.

Micro: innovation in quality improvement and care delivery

Innovative models of care can respond to unmet needs while also reducing unnecessary resource use. During the COVID-19 pandemic, a rapid shift to virtual care is expanding a model that can address challenges with geographic distribution and inequities of access for remote communities.⁴² Other interventions may combine patient-centredness with improved integration between clinical and community supports. For example, “social prescribing” is an emerging practice of linking patients with community activities such as volunteering, addiction support groups, and nature experiences.^43,44 Early projects have shown promise for improving wellness while shifting patients away from higher intensity care, and are opportunities for further research to evaluate effectiveness. Finally, quality improvement initiatives to avoid wasteful or unnecessary resource use are already well recognized. National recommendations for family physicians, nurse practitioners, and patients include imaging, prescribing, and laboratory testing that should not be performed.⁴⁵ If followed, these practices inherently promote financial and environmental sustainability, saving time, money, and emissions.