Global climate change and health in Canadian children

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Climate change is the single, largest global health threat of the 21st century ^[1][2]. Rising temperatures are shrinking ice caps, raising sea levels, increasing humidity, and creating more extreme weather conditions and events, including heat waves, droughts, hurricanes, and forest fires. While many natural factors have contributed to rising global temperatures in the past, leading climate scientists now identify pollution, and especially fossil fuel emissions, as the main driver of current climate change effects. Numerous authorities warn of the critical need to undertake and adapt environmental efforts to protect human health ^[3]-[5].

Paediatricians and other health care providers need to be aware that emerging infections, health conditions arising from increased air pollution, and mental health effects related to natural disasters, are to be anticipated. Individual health status and overall population health will both be affected by climate change ^[6]. This practice point highlights specific health threats to the paediatric population and resources that address climate-related health challenges.

Anticipating future health challenges

As early as 2008, Health Canada collaborated with numerous international partners, including the World Health Organization (WHO), to publish the landmark report entitled Human Health in a Changing Climate: A Canadian Assessment of Vulnerabilities and Adaptive Capacity ^[7]. The report anticipated many climate-related health challenges, and 3 years later, the Canadian Medical Association published a statement which identified children as a vulnerable population and offered recommendations for action ^[8]. This report was endorsed by the Canadian Paediatric Society in 2013.

In the years since, climate change has accelerated and countries in high latitudes, such as Canada, are now directly experiencing climate change and related events. For some end points, environmental effects are also being experienced more dramatically than in mid- and low-latitude countries ^[9]. The need to adapt to unstable climate conditions is urgent at any level, but preserving the health of children is an especially practical—and pressing—reason to act ^[10].

Canada’s changing climate

The microclimates, ecosystems, and topographies contained within Canada’s vast land mass are many and varied. Demographically, more than 85% of the population live in urban areas, and only about 3% live above the 60th parallel.

Average temperatures in Canada have risen by an estimated 1.4°C between 1948 and 2009, with temperature fluctuations being more significant in sensitive environments, such as the Arctic tundra (Figure 1) ^[11].  

Figure 1. Annual temperature fluctuations s and trends, 1948 to 2013

Source: Statistics Canada, 2011. Environment Canada, 2010, Climate Trends and Variations Bulletin (CTVB): www.statcan.gc.ca/pub/16-002-x/2011001/ct016-eng.htm. View larger version

Climate change is thinning land and sea ice in the North, making traditional routes, and activities such as hunting, increasingly dangerous ^[12]. Sea ice is melting at rates that may soon open the Arctic passage year-round. Permafrost instability is negatively impacting health, housing, and infrastructure in Northern regions, where people’s lives and the economy are most closely tied to the land ^[13][14]. The past decade has also seen unprecedented seasonal flooding in cities, such as Calgary, Montreal, Thunder Bay, and Toronto. More intense and prolonged drought conditions in the prairies have made wildfires more frequent and difficult to control, while rising sea levels and coastal instability are eroding usable landmass ^[14].  

Children can be disproportionately affected by these and other climate-related changes because they metabolize more water, air, and food per kilogram of body weight than adults. Their rapid growth and developmental, physiologically dynamic systems, and risk exposure over a longer life course combine to increase vulnerability to environmental hazards. Children who are socio-economically disadvantaged, Indigenous, or living with a chronic disease are particularly at risk.

Specific climate-related risks

• Heat- and cold-related morbidity and mortality rates are highest in infants and young children. Heat-exposed infants are especially at risk because their temperature regulation systems are immature ^[15]. Such risks compound for children living with a chronic health condition or in substandard or contaminated environments.
• Natural hazards and extreme weather events can cause injury and death. Indirect effects may include displacement from home, life in an overcrowded emergency shelter, socio-emotional or longer term mental health effects from stress, or the loss of loved ones, possessions, family livelihood, and routines. Health effects due to food and water shortages or contamination may also occur. Interruptions in health care and education can impact life course and outcomes as well as physical and mental health ^[16].
• Increasing air pollution levels include climate change-related particulates from wildfires, smoke, and airborne dust as well as ground-level ozone, pollens, and spores. As air quality deteriorates, respiratory and cardiovascular morbidity and mortality rates increase ^[17][18], including asthma exacerbations ^[19]. Air pollution is an environmental risk factor for cancer and was identified as a ‘group 1 carcinogen’ by the WHO’s International Agency of Research in Cancer in 2013 ^[20]. Children’s higher respiratory rates, immature lungs, and time spent outside, make them more susceptible than adults to poor air quality. Prenatal and early life exposures to air pollution are particularly hazardous ^[21].
• Increasingly contaminated water sources, for drinking and recreation, spread water-borne infections such as S. typhi, Giardia, E. coli, Cryptosporidium, and amebiasis ^[22] when heavy rains or flooding overwhelm sewage treatment facilities. Toxic algal blooms and increased growth of pathologic Vibrio species are associated with warming seas ^[23]. Warmer seasons facilitate food contamination, increasing risk for gastrointestinal infections ^[24]. In Canada, children under 4 years old are more likely than adults to be reported with an infection from Campylobacter, Giardia, Salmonella or Shigella species ^[25].
• Infection risks associated with insects, ticks, and rodents are increasing as distribution patterns change. Certain vector-borne infections, such as Lyme disease, are on the rise in Canada (Figures 2,3) ^[26][27].

With longer disease transmission seasons, incidence of infectious diseases native to Canada (e.g., eastern and western equine encephalitis, Rocky Mountain spotted fever) are likely to increase. 

• Stratospheric ozone depletion is caused by the same gases responsible for climate change and contributes to increasing exposure to ultraviolet (UV) radiation. This effect is experienced most in Canada’s North, where the ozone layer is thinner. While the ozone layer is slowly recovering ^[28], people living at mid-latitudes are at greater risk than previously for developing sunburns, skin cancers, cataracts, or immune system compromise ^[29]. Children are at lifetime risk for developing melanoma, due to intense and prolonged UV exposure at earlier ages.

Practice points for clinicians

To help counsel families on preventing or mitigating climate-related health issues and to improve clinical practice around associated infections and conditions, health care providers should consider the following:

• Learning more about climate-related health effects and diseases. (See recommended resources.)
• Expanding the differential diagnosis for common symptomatology, such as fever and malaise, as infection patterns change in Canada.
• Modifying anticipatory guidance for climate change-related effects (e.g., safe food handling in warmer weather, communicating risks for water contamination with heavy rain events, promoting protective clothing and repellents to prevent tick and mosquito bites).
• Understanding pollen and air quality forecasts, and counselling parents and caregivers to minimize exposures and maximize management of respiratory symptoms.
• Monitoring local UV index levels and counselling enhanced sun protection for region-specific UV hazards.

Figure 2. The number and incidence of reported Lyme disease cases (confirmed and probable) by year in Canada, 2009 to 2016

Source: Government of Canada, 2018. Surveillance of Lyme Disease:  https://www.canada.ca/en/public-health/services/diseases/lyme-disease/surveillance-lyme-disease.html. View larger version

Challenges and opportunities

As climate change accelerates in Canada, related health effects will continue to be felt and are likely to increase. Evolving best practice on children’s health issues will involve engaging with families, the community, and governments to prepare, prevent, or respond to specific climate change effects. Physicians and other health care providers can provide expertise and support to climate change initiatives by:

• Advocating all levels of government for actions to mitigate further climate change and adapt to existing effects. For example, policies to reduce reliance on automotive transport and improve walkability and bike paths in urban and suburban neighbourhoods, to facilitate transfer of outdoor sports to indoor facilities on poor air quality days, and to develop local infrastructure that reduces fossil fuel energy use and flooding or fire risks, are crucial for public health.
• Volunteering to serve on local or regional planning committees for heat/cold/disaster/extreme weather events, to ensure they consider and provide for children’s health needs.
• Recommending trainee education on climate-related health issues.
• Acting as role models, and encouraging individual, family, and community leaders to make choices that promote environmental sustainability and reduce greenhouse gas emissions.

Figure 3. Lyme disease risk where tick populations and Borrelia burgdorferi are known or most likely to occur (as of 2016)

View larger version

Recommended resources:

For clinicians

• Ahdoot S, Pacheco SE. Global climate change and children’s health: Technical Report. Pediatrics 2015;136(5), e1468-84: http://pediatrics.aappublications.org/content/136/5/e1468
• American Academy of Pediatrics, Council on Environmental Health. Global climate change and children’s health. Pediatrics 2015;136(5):992-97: http://pediatrics.aappublications.org/content/early/2015/10/21/peds.2015-3232?rss=1&cited-by=yes&legid=pediatrics%3Bpeds.2015-3232v1
• Etzel RA, Balk SJ, eds. Pediatric Environmental Health, 3rd edn. American Academy of Pediatrics, Council on Environmental Health, 2012:
• Sheffield, P. E., & Landrigan, P. J. (2011). Global climate change and children's health: threats and strategies for prevention. Environmental health perspectives, 119 (3), 291.
• Watts N, Amann M, Ayeb-Karlsson S, Belesova K, et al. The Lancet Countdown on health and climate change: From 25 years of inaction to a global transformation for public health. 2018;391(10120):581-630.

For families

• Environmental Protection Agency (U.S.), 2009. Climate change and children’s health (Brochure): https://www.epa.gov/sites/production/files/2014-05/documents/ochp_climate_brochure.pdf

• American Academy of Pediatrics. AAP Links Global Warming to the Health of Children: https://healthychildren.org/English/news/Pages/AAP-Links-Global-Warming-Health-Children.aspx

Acknowledgements

This practice point has been reviewed by the Community Paediatrics, Fetus and Newborn, Infectious Diseases and Immunization Committees of the Canadian Paediatric Society, by the CPS Action Committee for Children and Teens, and by the CPS Respiratory Section Executive. The authors would like to thank Dr. Lesley Brennan, PhD MPH, for her review of this paper and assistance with preparation, and Justine Klaver-Kibria, MSc, for assisting with research.

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CANADIAN PAEDIATRIC SOCIETY PAEDIATRIC ENVIRONMENTAL HEALTH SECTION

Executive members: Faruqa Ladha MD (President), Alvaro Osornio Vargas MD (President-Elect), Catherine Hervouet-Zeiber MD (Past President), Robert Issenman MD (Secretary-Treasurer), Irena Buka MD (Member at large), Arend Strikwerda MD (Member at large), Shazeen Suleman MD (Member at large), Robin Walker MD (Member at large)
Principal authors: Irena Buka MD, Katherine M. Shea MD

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References

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Disclaimer: The recommendations in this position statement do not indicate an exclusive course of treatment or procedure to be followed. Variations, taking into account individual circumstances, may be appropriate. Internet addresses are current at time of publication.