Impact of Recent Climate Change Events on Health

climate change
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Rising global temperatures have been linked to an increase in severe weather, which can have a significant negative impact on public health.

Over the years, we have experienced an increase in extreme weather-related events as a result of climate change. This global phenomenon affects health on many levels, making it of critical importance to physicians. Climate change refers to the change in temperature and weather patterns that have been occurring globally.1 According to the Intergovernmental Panel on Climate Change (IPCC) within the United Nations, the main drivers of climate change have been human activities, including burning fossil fuels such as gas, coal, and oil.2 Given the consistent change in global temperatures, extreme weather events will continue to occur until serious action is taken.

Climate Change Is a Public Health Crisis

At the 2022 annual meeting of the American Medical Association (AMA), climate change was declared a public health crisis. AMA Board Member Ilse R. Levin, DO, MPH, stated that “the scientific evidence is clear — our patients are already facing adverse health effects associated with climate change, from heat-related injuries, vector-borne diseases, and air pollution from wildfires to worsening seasonal allergies and storm-related illness and injuries. Taking action now won’t reverse all of the harm done, but it will help prevent further damage to our planet and our patients’ health and well-being.”3

Human health can be both directly and indirectly affected by climate change. The rising global temperatures are directly leading to an increase in severe weather, causing storms, floods, droughts, heat waves, and wildfires. These severe weather events can cause injury, starvation, heat stroke, and burns, for example. However, these weather events can also indirectly affect health by disrupting water quality and food availability, and causing air pollution, among other adverse effects.

Severe Weather Events Affect Patient Health

At present, more than 800 active wildfires are burning throughout Canada and more than 200 wildfires are burning in the United States, causing serious air pollution across both nations.4 The smoke from these wildfires is composed of toxic gases and fine particulate matter that can irreparably damage the lungs.5

These particulates have also been linked to cardiovascular disease, including stroke, heart attack, heart failure, and atrial fibrillation.6 Damage to the lungs and heart can also leave patients susceptible to infectious diseases,7 which continues to be a significant concern with the recent COVID-19 pandemic still looming.

In 2016, persistent rainfall from a summer storm resulted in disastrous flooding in the state of Louisiana, having dropped 7.1 trillion gallons of water on the state.8 This storm was later attributed to climate change. Authors of a study published in 2016 estimated that the rise in global warming since 1985 has increased rainfall by up to 20%.9 In addition to leaving nearly 150,000 homes damaged as a result of flooding,10 a major result of this and similar floods is the rise in mosquito populations.11

The increase in precipitation and rising temperatures due to climate change encourage mosquito survival and replication. Certain infectious diseases — including those spread by mosquitoes — are increasing as a result of climate change. These diseases — referred to as vector-borne diseases — are caused by living organisms that transmit infections to humans.12 An example of vectors are blood-sucking insects, including mosquitoes, ticks, and fleas, which transmit such diseases as malaria, Zika, Lyme disease, and plague, among many others. 

Malaria — a blood-borne disease caused by the Plasmodium parasite — can progress to severe illness and death within 24 hours if left untreated.13 Malaria outbreaks in the United States are rare, with the last outbreak occurring in 2003. As of July 2023, there have been 8 confirmed, locally acquired cases of malaria, with more likely to occur by the end of the year.14 The frequency of mosquito-borne diseases like malaria is predicted to increase in the years to come as a direct result of climate change.15

Mental Health Risks Due to Climate Change

In addition to physical health effects, climate change is also having direct effects on mental health. Changes in mental health as a result of climate change may be difficult to detect; however, addressing them is critical to ensuring overall well-being.

“Climate grief” is the experience many patients feel as a result of the looming effects of climate change. This phenomenon includes anxiety and fear about how the Earth will change over the coming years, as well as depression and stress over how to help reduce global warming, given the scope of the problem.16 

Climate change can also affect mental health directly, as in the case of anxiety, depression, or/or post-traumatic stress disorder (PTSD) experienced by in those who experience a natural disaster, including floods17 and wildfires.18

Authors of a 2021 study published in Behavioral Sciences reported that patients who lived in communities damaged by wildfires experienced increased rates of PTSD up to 10 years after the fires ceased.18

Authors of another study published in 2022 in Neurotoxicology found that those who live in communities affected by heavy smoke exposure are at increased risk of developing anxiety and depressive disorders. These diagnoses have been linked to living in areas with drastically elevated air pollution levels.19

How Can Physicians Be Prepared To Discuss Climate Change With Patients?

Climate change affects human health in widespread and complex ways. Physicians therefore need to be prepared to handle the health-related effects of climate change.

The first step toward helping patients is to become educated on how climate change can affect health. The health effects of climate change are expansive and multifaceted. Numerous online continuing medical education (CME) courses on the health effects of climate change are available for physicians.20-22 These courses provide background information on the types of events caused by climate change, as well as the health risks to patients and treatment options for physicians.

Additionally, the World Health Organization (WHO) provides information on climate change and how it affects human health, and this information can serve as a useful tool for physicians.23 The WHO also organizes a Global Conference on Health and Climate Change every 2 years; this symposium supports engagement, education, and policy change.24

It is important for physicians to be aware of the effects of climate change so that they can consider these environmental changes in diagnoses. For example, if a patient presents with unusual symptoms, physicians should consider the potential increase in vector-borne diseases that may otherwise be overlooked. In an episode of “AMA Moving Medicine,” Renee Salas, MD, MPH, MS, a climate and health expert and emergency physician at Massachusetts General Hospital, encourages physicians to approach medicine with a “climate lens.” This approach includes considering all the current and future climate changes and how they can affect health and the provision of health care.25 

In 2021, a physician treating a woman in the emergency department of a British Columbia hospital cited climate change as the underlying cause for her condition. The patient presented with dehydration and asthma, both of which occurred as a direct result of the heat wave and air pollution from wildfires caused by climate change.26 This unprecedented diagnosis serves as an example of how physicians need to consider the impact of climate change on health when evaluating patients.

By recognizing the effects of extreme weather caused by climate change, physicians can be better prepared to address symptoms and appropriately diagnose patients.

Physicians should also be aware of the mental health changes that can occur due to extreme weather events resulting from climate change, as well as the mental health changes that could be expected within their geographic region. Physicians should be prepared to talk to their patients about mental health and be aware of the resources available to them — including referring patients to mental health providers, when necessary.

Methods for Communicating Health Risks to Patients

The spread of misinformation within the United States has been on the rise in recent years.27,28 Physicians play an important role in countering misinformation as they have an ethical duty to provide patients with information regarding their health. By accurately educating patients on climate change and the health effects of climate change-related weather events, physicians can help overcome misinformation. However, some physicians may hesitate to discuss the effects of climate change with patients for a  number of reasons, including avoidance of political resentment, lack of time, and a lack of knowledge as to how to appropriately broach the subject.29 The following are several approaches that physicians can use to discuss this topic with patients.

1. Incorporate Brief Educational Messages

Physicians can broach the topic of climate change and health by using brief educational messages with their patients. This could include mentioning that air pollution is currently higher than usual due to wildfires in Canada and the United States, and that difficulty breathing and increased coughing may occur as a result. By simply mentioning the change that is occurring and how it can affect the patient, the physician can avoid controversy while still delivering an educational message.

2. Ask Permission to Discuss Controversial Topics

Physicians can ask permission of their patients prior to discussing controversial topics. By first asking permission, the physician respects the patient’s decisions and feelings. This strategy helps to build trust and mitigate resistance and arguments when discussing difficult or sensitive topics.

3. Emphasize the Consequences to the Patient

An effective method for discussing the effects of climate change is to emphasize the health consequences of the weather event. By starting a discussion about how a particular symptom is caused by climate change, physicians can appeal to the patient’s main interest. For example, if a patient presents with asthma and difficulty breathing, physicians can start the conversation by mentioning that the difficulty breathing is likely a result of high air pollution caused by climate change. By first beginning with the cause of their symptoms, physicians can set the scene and allow the conversation to evolve.

4. Acknowledge the Difficulties Associated With Changes

If air pollution is the current issue a physician is trying to convey, simply stating that a patient should not go outside can be met with resistance and dismissal. Physicians can make sure to include statements of understanding at the arduous task of avoiding pollution when being outside is a part of a patient’s daily lifestyle. Providing simple alternatives (eg, wearing a pollution-filtering mask when outside) and qualifying that they recognize how frustrating it is for the patient can help to convey the importance of the message while building trust through empathy.

5. Be Open to Different Approaches

It is important for physicians to be open to trying different approaches with their patients. Each patient has a unique set of experiences and world views. Strategies that work for one person might not be appropriate for another. While this can make effectively conveying health risks to patients difficult, it is essential that physicians alter their approach to fit each patient’s needs.

Be an Advocate for Change

Physicians should consider the impact they can make on climate change. Providing community assistance can mean volunteering at local shelters and food banks, giving talks on how people can prepare for weather-related health events (eg, air pollution or extreme heat), and advocating for changes to the environmental footprint. Physicians can work to reduce the energy bill at their practice or support programs that work to reduce the environmental footprint in the community. Physicians can also encourage eco-friendly transportation, such as the use of bike paths and public transportation, instead of commuting by car. Small changes can have a huge impact, and encouraging others to make changes is the first step toward a global effect on climate change.

“Climate Change is Widespread, Rapid, and Intensifying”

The IPCC reported that “climate change is widespread, rapid, and intensifying.”2 The effects we are seeing so far are only the beginning, and they will continue to worsen in years to come unless significant changes are implemented. The unfortunate reality is that we all need to be prepared to handle these changes, and it is the duty of physicians to be prepared to educate their patients on how to do this. Although this is a difficult task, becoming educated on the events, how they affect human health, how to effectively convey these messages, and how to help combat these changes are necessary for physicians to ensure positive outcomes among their patients.

Originally appeared on Infectious Disease Advisor.


1. What is climate change? United Nations. Accessed July 20, 2023.

2. Climate change widespread, rapid, and intensifying – IPCC. Intergovernmental Panel on Climate Change. Published August 9, 2021. Accessed July 20, 2023.

3. AMA adopts new policy declaring climate change a public health crisis. Press release. American Medical Association. Published June 13, 2022. Accessed July 20, 2023.

4. Canadian Interagency Forest Fire Centre. Accessed July 20, 2023.

5. Kekatos M. Toxic smoke from Canadian wildfires could impact health of millions in the US. ABC News. Published July 17, 2023. Accessed July 20, 2023.

6. Smoke and stroke: investigating the long-term effects on wildfires on heart health. The University of Tennessee at Knoxville Department of Civil and Environmental Engineering. Published November 17, 2022. Accessed July 20, 2023.

7. Aguilera R, Corringham T, Gershunov A, Benmarhnia T. Wildfire smoke impacts respiratory health more than fine particles from other sources: observational evidence from Southern California. Nat Commun. 2021;12(1).

8. Samenow J. No-name storm dumped three times as much rain in Louisiana as Hurricane Katrina. Washington Post. Published August 19, 2016. Accessed July 20, 2023.

9. Wang S‐YS, Zhao L, Gillies RR. Synoptic and quantitative attributions of the extreme precipitation leading to the August 2016 Louisiana flood. Geophys Res Lett. 2016;43(22):11805-11814.  doi:10.1002/2016GL071460

10. Yan H, Flores R. Louisiana flood: worst US disaster since Hurricane Sandy, Red Cross says. CNN. Published August 19, 2016. Accessed July 20, 2023.

11. Domangue D. Louisiana experiencing a rise in mosquito problems after recent hurricanes. KALB. Published October 23, 2020. Accessed July 20, 2023.

12. Vector-borne diseases. World Health Organization. Published March 2, 2020. Accessed July 20, 2023.

13. Malaria. World Health Organization. Published March 29, 2023. Accessed July 20, 2023.

14. Bendix A, Alexander B. New malaria case in Florida brings national total to 8, the first U.S. acquired cases in 20 years. NBC News website. Published July 18, 2023. Accessed July 20, 2023.

15. Berger E. Experts say climate change likely to increase US malaria cases. The Guardian. Published July 6, 2023. Accessed July 20, 2023.

16. Knight V. “Climate grief”: fears about the planet’s future weigh on Americans’ mental health. KFF Health News. Published July 18, 2019. Accessed July 20, 2023.

17. Stanke C, Murray V, Amlôt R, Nurse J, Williams R. The effects of flooding on mental health: outcomes and recommendations from a review of the literature. PLoS Curr. 2012;4:e4f9f1fa9c3cae. doi:10.1371/4f9f1fa9c3cae

18. To P, Eboreime E, Agyapong VIO. The impact of wildfires on mental health: a scoping review. Behav Sci. 2021;11(9):126. doi:10.3390/bs11090126

19. Zundel CG, Ryan P, Brokamp C, et al. Air pollution, depressive and anxiety disorders, and brain effects: a systematic review. Neurotoxicology. 2022;93:272-300. doi:10.1016/j.neuro.2022.10.011

20. Harvard University: the health effects of climate change. edX. Accessed July 20, 2023.

21. Building resilience against climate effects: educating physicians. University of Illinois Chicago. Accessed July 20, 2023.

22. Internet-based studies in education and research. University of Pittsburgh. Published November 17, 2020. Accessed July 20, 2023.

23. Climate change. World Health Organization. Published August 9, 2019. Accessed July 20, 2023.

24. Climate change and health: global conferences on health and climate change. World Health Organization. Accessed July 20, 2023.

25. Lubell J. How physicians can see health care through climate lens. American Medical Association. Published January 26, 2022. Accessed July 20, 2023.

26. Hammond J. ‘Climate change’ diagnosis reflects latest trend in health care. NBC News website. Published December 17, 2021. Accessed July 20, 2023.

27. Muhammed TS, Mathew SK. The disaster of misinformation: a review of research in social media. Int J Data Sci Anal. 2022;13(4):271-285. doi:10.1007%2Fs41060-022-00311-6

28. van der Linden S. Misinformation: ssceptibility, spread, and interventions to immunize the public. Nat Med. 2022;28(3):460-467. doi:10.1038/s41591-022-01713-6

29. Crowley RA; Health and Public Policy Committee of the American College of Physicians. Climate change and health: a position paper of the American College of Physicians. Ann Intern Med. 2016;164(9):608. doi:10.7326/M15-2766