Climate Change and Health: Why Emergency Physicians Must Lead the Charge

Emergency physicians should be environmental activists.

The effects of a warming planet contribute directly to exacerbations of chronic obstructive pulmonary disease, asthma, heart failure, atrial fibrillation, cardiac arrest, heat illness, and more.

As we see more severe and frequent extreme weather events, hospital systems will see increased strain — with mass casualty events affecting the function of emergency departments.

As emergency physicians, we should talk about climate change with our patients every day. Health-care providers are in a unique position to influence the social and policy landscape to effect climate change.¹ We should leverage that position to help our patients better understand the links between climate change and human health.

Emergency physicians should acknowledge that climate change is a contributor in the development of pathology. A paper published in 2020 by Sorenson et al describes the range of pathologies that are exacerbated by climate change.² This is further outlined by the Environmental Protection Agency (EPA).³

Compounding the issue is that climate change affects minority groups and the poor disproportionately.^4,5 These are some of the most vulnerable patients who present to our EDs.

According to the Intergovernmental Panel on Climate Change (IPCC), there are critical areas for change that can have a profound effect on limiting our current emissions and the subsequent impact on the climate. These include:

• Advocating for systemic and policy changes at the institution level⁶
• Transitioning away from fossil fuels to renewable, nuclear, and fossil fuel with carbon-capture technologies⁷
• Land-use change to repurpose for more significant carbon sequestration⁷
• Individual action daily to reduce emissions through consumer-driven change, including choosing renewable sources for energy production, reducing food waste, and reducing consumption of foods that have a high emissions footprint⁷

Possible co-benefits from addressing climate change include biodiversity conservation, water availability, food security, income distribution, efficiency of the taxation system, labor supply and employment, improved urban planning, and the sustainability of developing countries' growth.⁷

Climate Change Contributors, Ways to Address

Since the pre-industrial era, anthropogenic carbon emissions have been driving global warming. This has wide-ranging effects on the climate and inhabitants of the planet.

There is global consensus that we need to keep warming below 2 degrees Celsius by the end of the century to avoid climate catastrophe.⁷ We need to reduce carbon emissions significantly over the next decade to achieve this. While eliminating emissions, we need to simultaneously preserve land to act as a sink and sequester legacy carbon.

Johnson et al argued that bold and innovative action is possible and practical for reversing climate change.⁸ We need to stop emissions and regenerate ecosystems to sequester carbon. Practically, this means transitioning to renewable energy sources, halting and reversing deforestation, and finding innovative ways to relay this information to the public.

The pathways to achieve this mandate are complex. ACEP has a policy to “advocate for initiatives to reduce the carbon footprint of emergency departments and their affiliated institutions through energy conservation and health care waste reduction and recycling.”⁹

To generate willpower for change, we need to see the many co-benefits and leverage them to motivate policy action.

Fossil Fuel Combustion

The production of energy from combustion of fossil fuels is a leading cause of health-care sector emissions — so much so that if the U.S. health-care sector was a country, it would be in the top 15 global carbon emitters.¹⁰

Public sentiment supporting a transition away from fossil fuels as a means for energy production is gaining momentum and spans several industries. The drive for decarbonization of our economy is of utmost importance, and this includes the health-care sector.

Hospital systems have been working to reduce their emissions impact. There are numerous examples of hospital systems shifting to renewable energy and thus reducing their emissions footprint.¹¹ In 2011, Austin-Travis County EMS saved 14.2 metric tons of carbon emissions by changing its fleet to lighter vehicles and hybrid electric/gas vehicles.¹² A 4-step approach to curbing carbon emissions in Sweden has reduced emissions while simultaneously improving access to health care and more rapid management of disease.¹³

Deforestation

Deforestation may seem like an odd topic to include in an article directed at emergency physicians. However, when addressing the issue of climate change, it is unavoidable.

Deforestation contributes to climate change through land-use change with direct emissions associated with raising livestock and indirectly through reduced carbon dioxide sequestration. Deforestation is driven in large part by farming to support animal agriculture.¹⁴

Consumption of large quantities of red meat has been associated with increased risk of many chronic diseases, including coronary artery disease, diabetes, hypertension, and cancer. ¹⁵ Addressing the effects of deforestation on climate change will have a co-benefit of decreased production of red meat, thus increasing our production of plant-sourced foods for direct consumption.

A dietary pattern more centered on plant-based food will reduce the burden of many chronic diseases and, subsequently, the pressure on EDs for acute exacerbations of these diseases.¹⁶

Specifically, reducing red-meat consumption and preferentially increasing fruit and vegetable intake could avoid 5.1 million premature deaths per year through 2050.¹⁷ The EAT-Lancet commission demonstrated a reduction of 11 million premature deaths each year through 2050 with universal adoption of a plant-rich diet and severe limitation of red-meat consumption.¹⁸

Encouraging our patients to consume more plant-rich diets is an effective strategy to improve health as well as limit impact of direct and indirect emissions.

Climate Change-Related Illness

Air Pollution

The most significant environmental cause of disease and premature death is air pollution. In 2015, diseases caused by pollution were responsible for an estimated 9 million premature deaths, which represents 16% of all deaths worldwide — 3 times more than AIDS, tuberculosis, and malaria.¹⁹

According to Landrigan, pollution-related diseases also result in health-care spending of up to 1.7% in high-income countries and 7% in middle-income countries, particularly those which are rapidly developing. This represents approximately $4.6 trillion per year.

The main contributor to global pollution is the burning of fossil fuels. Combustion of these fuels disproportionately affects low-income countries. Burning of fossil fuels in high- and middle-income countries leads to 85% of airborne particulate pollution in low-income countries, contributing to the burden of climate change-related mortality in those countries.^19–22 Worldwide, air pollution is responsible for approximately 9 million premature deaths annually.

Air pollution is a mix of solid particles and gases in the atmosphere.²¹ Particulate matter emitted from factories, fires, dust, pollen, and mold spores may be suspended in the atmosphere. Ozone is a secondary pollutant that is generated when volatile organic compounds are oxidized in the presence of nitrogen oxides.²³ This ozone is generally concentrated in urban environments and is referred to as smog.

There is a positive association between ozone as an air pollutant and many conditions, including cardiopulmonary disease, hospitalization from all causes, and respiratory diseases (asthma and COPD).²¹ Pratt et al performed a burden assessment and found that the number of excess asthma exacerbations in EDs in the United States had a median of 2,403. There was an association with elevated ozone from smoke due to wildfires from 2005-14.²³

This positive association between exacerbation of respiratory disease and concentration of air pollutants (nitrogen oxide, sulphur oxide, ozone, PM10, PPM2.5) has been demonstrated throughout Asia, Australia, and Europe, representing a significant burden on health-care systems considering future projections of climate change.^24–28

Allergens and Pollen

Aeroallergens include tree pollen and grass seeds. Climate change affects surface temperatures and alters ecosystems, resulting in prolonged pollen seasons in the spring and increasing grass seed during the summer. These situations are especially susceptible to temperature changes.^29,30

Demain reviewed the indirect effect of prolongation of pollen seasons due to climate change through alterations in ecosystems.³¹ A retrospective chart review performed by May et al of an urban ED showed a positive correlation between asthma exacerbation presentations and tree pollen counts.³² Neumann projects a 14% increase in ED presentations due to pollen and seed-related exacerbations by 2090. They predict that this increase can be held to 8% with more controlled greenhouse gas emissions.²⁹

Diseases Carried by Vectors

With changes and interruptions to ecosystems and human encroachment into previously wild areas, interaction and potential for the breakthrough of vector-borne illnesses has become an area of concern. This has become particularly relevant following the 2020 global pandemic caused by the SARS-CoV-2 virus, which is thought to have come from horseshoe bats via an intermediary species, likely a pangolin.³³

As human settlements expand and our behaviors increasingly bring us into contact with animals, the risk of zoonotic disease breakthroughs into human populations will remain with associated ecosystem destruction. This presents challenges for emergency physicians and health-care workers alike, as their role in assessing and monitoring for such diseases will become increasingly important.³⁴

Temperature Extremes

As we experience the effects of climate change, extreme weather events will continue to become more frequent. These events include extreme heatwaves, which result in the exacerbation of several illnesses.

An analysis of ED visits following a heatwave in Sydney, Australia, in 2011 showed increases in all-cause visits by 2%, all-cause ambulance calls by 14%, and all-cause mortality by 13%, with people over 75 years at greater risk.³⁵

In 2003, an unprecedented heatwave in France led to 14,800 excess deaths. The effects were seen most prominently in Paris. The public health department noted 2,600 excess ED visits, 1,900 excess hospital admissions, and 475 excess deaths despite rapid organization aims to prevent harm.³⁶

Similar results have been found in the U.S., Asia, and Europe, with increases in ED presentations as a direct effect of heat-related illnesses as well as exacerbations of congestive heart failure, atrial fibrillation, and renal colic.^37–41 Kingsley et al projected up to a 1.6% increase in all-cause mortality and a 25% increase in heat-related mortality by the end of the century if global temperatures continue to rise at current trajectories, with disproportionate effects noted in those under 18 and over 65 years of age.⁴²

Wildfires

With wildfires come increased concentrations of particulate matter (PM), which have been associated with exacerbation of respiratory diseases.

There have been significant fire events around the globe since 2000, the effects of which have been well-documented in the medical literature. In 2007, an extensive wildfire event occurred in Victoria, Australia, which showed a positive correlation between PM2.5 secondary to smoke and asthma exacerbation, increasing ED visits by 1.96% on the day of exposure.⁴³

A comprehensive analysis of ED visits from 1996-2007 showed increased same-day visits for asthma, COPD exacerbation, and all non-trauma presentations on days when PM10 and PM2.5 were above the 99th percentile, with the effect remaining for all days when the atmospheric particulate matter was elevated. The analysis also noted a 2-day lag in presentation for ischemic heart disease.⁴⁴

Following a Southern California wildfire event in 2007, there was an increase in presentation for dyspnea by 3.2 visits per day and asthma diagnoses by 2.6 visits per day for a single metropolitan ED.⁴⁵

In 2012, a significant wildfire event in Colorado demonstrated a positive association between local concentration of PM2.5 and asthma exacerbation. The effects between exposure and presentation extended for up to 3 days in this study.⁴⁶

These findings have been replicated in numerous studies, showing strong positive correlations between increased concentrations of PM2.5 and exacerbation of respiratory illness (asthma and COPD) that result in presentation to the ED.^47–49

Increased Strain on EDs, EMS

There is expert consensus that with climate change, there will be greater demand on particular hospital departments, namely the ED and on EMS in the prehospital setting. Clinically, emergency medicine will likely see a shift in demand for its services greater than current annual rates. The ED has a broad-based clinical mission and plays a vital role in urgent and emergent ambulatory care, safety-net provision, and increasingly urbanized populations.

As natural disasters such as floods become more regular occurrences as a result of climate change, it will be necessary for organizations and health-care workers to focus on disaster preparedness and take necessary steps to mitigate emissions at a systemic level through policy change and patient education.^38,50,51

Natural disasters will call upon departments to be resilient and flexible with their systems to care for patients in multiple scenarios. There may be surges of patients within a fully functioning department. There may be direct effects on the department, limiting its capacity to serve its primary function.

In 2017, Hurricane Harvey in Houston resulted in a severe flooding event, which reduced hospital capacity with loss of beds to water damage, reduced staffing, and inability to transfer patients. The department was able to show resilience through flexibility. However, it noted that emphasis needs to be placed on preparedness and flexibility and preventative measures through community education and direct policy action to limit emissions that would worsen climate change.⁵⁰

Conclusion

How is all this relevant to emergency physicians? To answer simply: We will increasingly shoulder the burden of a warming planet and its effects on human health unless we work to reduce emissions and reverse climate change. We must address the effects of climate change on the progression and exacerbation of disease. We should advocate to our hospitals to introduce changes and make our systems more sustainable and reduce their impacts on carbon emissions.

References

1. Howard C, MacNeill AJ, Hughes F, et al. Learning to treat the climate emergency together: social tipping interventions by the health community Lancet Planet Health. 2023;7(3):e251-e264.
2. Sorensen CJ, Salas RN, Rublee C, et al. Clinical Implications of Climate Change on US Emergency Medicine: Challenges and Opportunities. Ann Emerg Med. 2020;76(2):168-178.
3. US EPA O. Climate Change and Human Health. Published March 20, 2022. Accessed January 4, 2023. 
4. Bernstein AS, Stevens KL, Koh HK. Patient-Centered Climate Action and Health Equity JAMA. 2022;328(5):419-420.
5. Levy BS, Patz JA. Climate Change, Human Rights, and Social Justice. Ann Glob Health. 2015;81(3):310-322. 
6. Paavola J. Health impacts of climate change and health and social inequalities in the UK. Environ Health Glob Access Sci Source. 2017;16(Suppl 1):113. 
7. Sixth Assessment Report — IPCC. Accessed October 15, 2019. 
8. Johnson CN, Balmford A, Brook BW, et al. Biodiversity losses and conservation responses in the Anthropocene. Science. 2017;356(6335):270-275. 
9. Anonymous. Impact of Climate Change on Public Health and Implications for Emergency Medicine. Ann Emerg Med. 2018;72(4):e49.