The average temperature on the planet has risen almost 1°C since the late 19th century, with the majority of the warming occurring in the past 40 years. This seemingly small change has manifested due to the decrease in size of Antarctica’s ice sheets, retreat of glaciers around the world, rising sea levels and an increased frequency of extreme weather events. While climate change is a natural and continuous process, human activities have drastically accelerated the rate at which these changes are occurring. Climate change has significant and often detrimental implications for marine and terrestrial ecosystems as well as impacts on human health in both developed and resource-limited countries. According to the World Health Organization (WHO), climate change will be the direct or indirect cause of approximately a quarter-million deaths within the next 30 years, and subsequently a massive burden for our healthcare system.
Elevated global temperatures contribute to diseases of the cardiorespiratory system, particularly in the elderly and immunocompromised. For example, an excess of 70,000 deaths were recorded during the heat wave which spanned across Europe in the summer of 2003. Increased temperatures can lead to heat stress for many individuals, and limit access to drinking water, nutritious food, and medical services. The opposite, extreme cold, poses risks which are equally as detrimental including arterial thrombosis and respiratory disease. In addition, damaged infrastructure and population displacement due to an increase in extreme weather events may make access to scientific, medical and essential resources a challenge for many and is a critical economic burden costing around $100 billion annually in terms of infrastructural repair and healthcare costs.
Poor air quality
The air we breathe has a significant impact on our overall health; city-wide warnings of low air quality due to pollution are becoming more widespread and increasing in frequency. Climate change contributes to a decreased air quality both through the release of greenhouse gases to the atmosphere, and as the repercussions of elevated temperatures and natural disasters increase air pollution. The prevalence and severity of asthma and severe respiratory conditions such as chronic obstructive pulmonary disorder (COPD) will increase with worsening air quality. Further, poor air quality can impair proper lung development in young children, and is associated with low birth weights in newborns.
With changes to temperatures, new infectious diseases will arise, and existing ones will migrate and show longer exposure seasons with the fluctuations in temperature. In the past 10 years, we have seen the emergence of infectious diseases Climate Changes Our Health around the world, including the Ebola virus, Middle East respiratory syndrome coronavirus (MERS-CoV), Zika virus, and most recently the novel coronavirus (COVID-19). Climate change thus has the capacity to enhance transmission of novel and re-emerging infectious diseases around the world, and allow for the introduction of novel species to different regions in parallel with shifting environmental conditions. Insect vectors have been reported to be more active at higher temperatures, while waterborne diseases such as cholera are a critical issue in cases of flooding or heavy rainfall, and pose a risk of contaminated water sources and poor sanitation. As a result, the WHO estimates that in the next 10 years, there will be a 10% increase in the prevalence of diarrheal disease due to climate change.
The ultimate effects of climate change on human health will likely be devastating. Risks of cancer, cardiovascular disease and immune abnormalities will increase, creating an additional burden on the physical and mental well-being of the individual, as well as on the health care system and economy. The deaths and impact on quality-of-life which result both directly and indirectly from events related to climate change will overshadow even those related to the current COVID-19 pandemic and have larger and longer lasting societal and economic implications. It will be necessary for science and medicine to adapt to these changes for our expanding and aging population, and it is imperative that we target the root of the problem, climate change, in order to mitigate the effects on human health.
- Climate Change: How Do We Know? Available at: https://climate.nasa.gov/evidence/ (Accessed March 2020)
- Climate change and health. Available at: https://www.who.int/news-room/fact-sheets/detail/climate-change-and-health (Accessed March 2020)
- Keatinge WR and Donaldson GC. 2004. The Impact of Global Warming on Health and Mortality. South Med J, 97(11):1093-9
- Wildfires, hurricanes and other extreme weather cost the nation 247 lives, nearly $100 billion in damage during 2018. Available at: https://www.washingtonpost.com/climate-environment/2019/02/06/wildfires-hurricanes-other-extreme-weather-cost-nation-lives-nearly-billion-damage-during/ (Accessed March 2020)
- Climate Change, Air Quality and Public Health. Available at: https://climateatlas.ca/climate-change-air-quality-and-public-health (Accessed March 2020)
- What to expect with climate change? Available at: https://www.canada.ca/content/dam/phac-aspc/documents/services/reports-publications/canada-communicable-disease-report-ccdr/monthly-issue/2019-45/issue-4-april-4-2019/ccdrv45i04a01-eng.pdf (Accessed March 2020)
- Shuman E. 2010. Global Climate Change and Infectious Diseases. N Engl J Med, 362:1061-1063.
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