Planetary Health,Climate Change,and Lifestyle Medicine: Threats and Opportunities

Abstract

Global environmental degradation and climate change threaten the foundation of human health and well-being. In a confluence of crises, the accelerating pace of climate change and other environmental disruptions pose an additional, preventable danger to a global population that is both aging and carrying a growing burden of noncommunicable diseases (NCDs). Climate change and environmental disruption function as “threat multipliers,” especially for those with NCDs, worsening the potential health impacts on those with suboptimal health. At the same time, these environmental factors threaten the basic pillars of health and prevention, increasing the risk of developing chronic disease. In the face of these threats, the core competencies of lifestyle medicine (LM) present crucial opportunities to mitigate climate change and human health impacts while also allowing individuals and communities to build resilience. LM health professionals are uniquely positioned to coach patients toward climate-healthy behavior changes that heal both people and the planet.

‘However, climate change and environmental degradation threaten to disrupt access to the very lifestyle interventions that can lessen the burden of chronic disease.’

Introduction

Global environmental degradation and climate change threaten the foundation of human health and well-being.^1,2 In fact, according to The Lancet Commission report on the global syndemic of obesity, undernutrition, and climate change, “The health gains achieved in the past 50 years of global economic development could be reversed by 2050 due to the consequences of climate change.”^3,4 Among those most vulnerable to climate change–related health harms are pregnant women, the unborn, young children, the elderly and, those with chronic diseases, including mental health conditions.^2,4-6

Chronic diseases, also known as noncommunicable diseases (NCDs), are already recognized as the leading cause of preventable morbidity, mortality, and health care expense, globally.^7-11 Annually, more than 80% of premature NCD deaths (32.4 million) can be attributed to cardiovascular disease, cancer, chronic respiratory disease, and diabetes.^7,11 Mental health conditions have also been identified as a significant cause of NCD morbidity and mortality, with close to 800 000 people dying by suicide every year.^12,13

In a confluence of crises, the accelerating pace of climate change and other environmental disruptions pose an additional, preventable danger to a global population that is both aging and carrying a growing burden of NCDs.^1,7-9,14 Because older age and presence of NCDs are mediating risk factors that can worsen the effects of climate change–related health harms, prevention, management, and reversal of these conditions may build resilience in the face of anticipated, worsening climate exposures.

Targeting just 5 modifiable lifestyle risk factors (unhealthy diets, physical inactivity, and exposure to toxic substances such as tobacco, alcohol, and air pollution) has been shown to be a cost-effective strategy to address the most common and deadly NCDs.^7,11,15 The field of lifestyle medicine (LM) has evolved to focus on these modifiable factors, with the addition of stress management, restorative sleep, and social connectedness/positive psychology, all playing a synergistic role in tackling root causes to prevent, treat, and reverse a wide variety of chronic diseases. ¹⁶

However, climate change and environmental degradation threaten to disrupt access to the very lifestyle interventions that can lessen the burden of chronic disease. Evidence suggests that rising global temperatures, unstable weather patterns, and other associated effects linked with climate change will continue to destabilize access to healthy, nutritious food, limit safe spaces for outdoor physical activity, increase exposure to toxic substances such as air pollution, worsen stress, interfere with sleep, and strain social connectedness and cohesion.^1-4,17 The threat to these lifestyle domains has significant implications for the health and well-being of the global population, especially as it relates to the increased risks for developing NCDs in a warming world. This threat is particularly stark for vulnerable populations in low-, middle-, and high-income countries, who often do not live in environments that can adapt easily to anticipated climate threats.^1-5,17

Encouragingly, data from multiple studies show that acting to mitigate emissions that cause climate change can also mitigate the root causes of NCDs, resulting in what are known as health cobenefits, in addition to economic benefits.^2-4,18-22 For example, moving toward a minimally processed, whole-food, plant-based diet and active transport (walking, bicycling) can lower greenhouse gas (GHG) emissions, lower health-harming air pollution, and decrease cardiovascular disease, diabetes, and obesity while also lowering health care costs.^2,3,17,18,20

Put another way, the evidence base shows that following a healthy lifestyle not only improves individual health, but has “side effects” that can mitigate climate change, strengthen community resilience, and improve the health of the planet, on which human health ultimately depends.^2,17,18,23 Framing the health cobenefits discussion through the lens of LM may encourage the prescribing of these “medicines” for both individuals and communities while improving planetary health as a potent side effect.

Health professionals have a responsibility to help patients understand and minimize the health risks that they face. The compounding hazards from both the growing burden of NCDs along with climate and environmental crises, require attention from health professionals and interventions for patients that fit squarely within the “wheelhouse” of medical providers. LM providers have the tools to work at the nexus of both crises. They have the necessary skill sets not only to prescribe lifestyle interventions, but also to effectively use behavior change techniques and health coaching as a routine part of clinical practice, moving the conversation from theory to application (ie, from “what needs to be done” to “why and how can it be done”).^24-26

In this review, we will (1) provide a limited overview of how planetary health and climate change affect human health, particularly NCDs; (2) examine the role that climate and environmental disruption play in threatening the domains of a healthy lifestyle and address how a LM framework (utilizing LM interventions) can be used to mitigate and adapt to the risks of climate change while also strengthening individual and community resilience; and (3) explore how LM professionals are positioned to deliver lifestyle interventions in the health care and community settings to help mitigate both crises.

Planetary Health, Climate Change, and Human Health

Scientists agree that to stave off the worst health consequences from climate change, global GHG emissions must be cut almost in half within the next 10 years and brought to net zero by 2050. ²⁷ However, based on the current trajectory, the world is poised to overshoot a global temperature rise of “well below 2 °C” even if all nations are able to meet the emissions goals agreed upon during the 2015 UN Framework Convention on Climate Change Paris Agreement.^28,29

Although climate change is the most urgent environmental crisis threatening the health of current and future generations, it is critical to understand that it is not the only environmental hazard affecting human health.^1,17 Human activity is also driving biodiversity loss; deforestation and change in land use; depletion of fresh water resources; air, water, and soil pollution; and change in “biogeochemical cycles,” such as carbon and nitrogen, all of which interact with each other and have massive implications for adverse impact on planetary and, therefore, human health.^17,30,31

Planetary health is a growing field that recognizes the complex interactions between degradation of the planet’s natural systems secondary to human activity and the interconnected human health impacts.^17,32 Adverse health outcomes can result from direct impacts such as exposure to higher temperatures, polluted air and water, and fatalities from more frequent extreme weather events (wildfires, hurricanes, and flooding) and also from indirect pathways such as power failures, disruptions to health care access, food scarcity, displacement, and increased risks for extreme poverty.^2,23,30,33

According to the World Health Organization’s (WHO’s) projections from 2015, between the years 2030 and 2050, approximately 250 000 annual deaths could be linked to climate-sensitive adverse health effects from increased exposure to heat in the elderly, certain infectious diseases, malnutrition, and coastal flooding.^23,34 Many experts believe that this projection vastly underestimates the number of deaths without taking into account increases in disease and disability, associated with a broader range of anticipated risks such as higher rates of food insecurity (which alone is projected to cause 529 000 deaths annually by 2050), poorer air quality, increased mental health impacts, and more heat exposure for a global population that is currently trending toward becoming more urbanized, older, and sicker from a wide range of NCDs.^{1,2,17,23,35,36}

Health effects are mediated not only through exposure, but also susceptibility to harm based on a combination of social and environmental determinants.^1,37 For the unborn and young children, there is potential for harm from climate-sensitive exposures during critical windows of development, epigenetic changes from climate and environment stresses, and the prospect of multiple exposures over the course of a lifetime, increasing the risk for long-term effects.^1,17,30,38 Urbanization poses increased susceptibility secondary to multiple drivers, including urban heat island effects (higher temperatures relative to rural areas because of limited green space and more heat absorbing surfaces in the built environment), which put large swathes of an increasingly urbanized population at risk for heat-related illness.^1,39,40

Those with chronic conditions, including mental health conditions, are more susceptible to a broad range of direct and indirect climate-related risks from rising temperatures, emerging infectious diseases, poor air quality, food insecurity, and extreme weather events through a variety of mechanisms.^1,2 For example, diabetes and cardiovascular disease can impair vasodilation close to the skin limiting the ability to dissipate heat.^41,42 Older people may have a higher burden of NCDs combined with a weaker thermoregulation response, putting them at higher risk from heat stress. ⁴²

Already, 60% of American adults have at least 1 chronic disease, and 40% of American adults have 2 or more chronic conditions, a leading driver of the United States’ almost $4 trillion a year in health care costs, likely to increase in the age of climate change.^43,44 At the same time, a small group of low-cost lifestyle interventions not only prevent 80% of the most common chronic diseases, but also treat and reverse these conditions.^45,46 Two of these lifestyle interventions (moving toward a plant-based diet and increased physical activity through active transport) can also play a significant role in mitigating climate change.^2,18 By prescribing lifestyle interventions, health professionals can encourage behavior changes that address modifiable risk factors for NCDs, augment both individual health and community resilience in the face of multiple climate change–related threats, lessen GHG emissions, and close the health equity gap for the most vulnerable.^2,45,47

We recognize that unhealthy behaviors are not simply a product of choice, but rather the result of a complex interplay of biopsychosocial, political, and environmental factors. Additionally, addressing climate change and health will require a multisectoral approach, including policies affecting the energy, industrial, agricultural, and transportation sectors.^48-55 Although health professionals have a role to advocate for large-scale policy solutions, here we explore how a focus on LM allows health care providers to use powerful health-promoting tools to address climate change and health, directly, in the exam room.

Planetary Health, Climate Change, and LM: Threats and Opportunities

Climate change and its accompanying health hazards threaten to increase disease burden and compromise the tools of LM. However, LM practitioners have the unique training to offer care that can address disease in the individual and the community while also helping mitigate the climate crisis. Below, we outline climate change–related threats to lifestyle interventions and highlight opportunities to address the risks of climate change and NCDs through LM.

Nutrition

According to the global burden of disease, poor diet was the cause of 12.1 million deaths in 2015. ⁵⁶ Poor diets are also largely responsible for causing an estimated 2 billion people across the globe to meet criteria for obesity. ³ An estimated 2 billion people also suffer from deficiencies in micronutrients such as iron, iodine, zinc, and vitamin A, resulting in a variety of impacts, including effects on the immune system, reductions in cognitive function, and increases in all-cause mortality.^3,17,57

Although there is discussion around what exactly constitutes the optimal diet, there is little disagreement that diets high in animal protein (particularly red meat), saturated fats, sugar, sodium, and processed foods result in higher rates of metabolic disease, hypertension, diabetes, cardiovascular diseases, and certain cancers.^58-61 Conversely, plant-based diets that include adequate intake of whole grains, legumes, vegetables, fruits, nuts, and seeds, decrease the risk of NCDs, including depression, and in appropriate “doses” can also treat and reverse a host of metabolic conditions, including diabetes and coronary artery disease.^61-73

A variety of environmental disruptions, including climate change, threaten the ability to maintain a nutritious diet, particularly to the poorest populations globally. ¹⁷ Beyond decreased crop yields, increases in atmospheric CO₂ concentrations associated with climate change have been shown to decrease the protein concentrations of a variety of crops (10%-15% reductions in wheat, barley, and rice).^17,74 Concentrations of other nutrients in rice such as zinc, iron, and B vitamins (thiamine, riboflavin, folate) are also projected to decline significantly in higher CO₂ concentration scenarios. ⁷⁵

Biodiversity loss affecting pollinators may reduce the production of certain fruits and vegetables responsible for many micronutrients, including vitamin A, folate, and calcium, with models predicting the loss of these food sources leading to 700 000 excess deaths annually as a result of a combination of increased deaths from heart disease, strokes, and micronutrient deficiencies.^17,76

The risk of crop loss from extreme weather events and increase in crop pests and pathogens will also affect crop production, increasing costs and risks for food insecurity.^17,77,78 Lack of availability of nutritious food may translate to a shift to unhealthy, processed foods, leading to increases in NCDs.^3,79

The agricultural sector itself plays an outsized role in environmental degradation and carbon pollution, with approximately 20% to 30% of GHG emissions coming from the food system, with meat and dairy livestock responsible for the majority of emissions.^21,80 Foods with the highest carbon footprint include beef, then cheese, pork, and chicken, with vegetarian and vegan foods contributing the least to GHG emissions.^81,82

Additionally, industrial agriculture contributes to environmental disruption via deforestation, soil erosion, intensive water use, and pollution. For example, beyond carbon pollution, health-harming particulate pollution from ammonia (mostly from livestock, livestock manure, and synthetic nitrogen fertilizer) accounted for more than 12 000 deaths in the United States alone. ²² Destruction of and encroachment upon wild spaces for food production increases the risk of human exposure to pathogens that increase the risk of epidemics and pandemics. ⁸³

Consumption of ultraprocessed food also contributes to environmental disruption for the purposes of obtaining “empty calories” from high levels of water and energy use, GHG production, and land use required to produce these food products.^3,84

Increasing evidence, including from the EAT-Lancet commission, finds that shifting to a whole-food, plant predominant diet including fruits, vegetables, legumes, nuts, and seeds would lead to a more sustainable ecological footprint that could safely feed the growing global population while at the same time reducing the burden of chronic disease, preventing close to 11 million deaths per year.^17,85

In a 2021 modeling study, researchers looked at dietary and food systems improvements that would align with emissions goals consistent with a variety of pathways. One pathway modeled by researchers was consistent with meeting the Paris Agreement and UN sustainable development goals (SDGs) for 9 nations, ranging from low-, to middle-, and high-income. ¹⁸ Shifts toward a “flexitarian diet,” with significant reductions in red meat consumption (highest reductions in high-income countries where intake is highest) and increases in fruits and vegetables, legumes, nuts, and seeds resulted in about 5.9 million deaths avoided in 2040 compared with current Paris Agreement targets. According to the model, if diets increasingly shifted toward plant-based intake, with half of the population remaining flexitarian and half eating a balanced vegan diet, researchers found that an additional 572 000 deaths could be avoided in 2040. ¹⁸

A variety of climate-friendly eating plans, such as the Planetary Health Diet, Menus of Change, and “Reset the Table,” can be used as reference to aid in a shift to sustainable diets that decrease GHGs, reduce saturated fat intake, and improve the health of soils and ecosystems, while reducing the burden of NCDs.^86-88

Physical Activity

Physical inactivity has been linked to 3.2 million deaths a year and multiple NCDs, including obesity, diabetes, cardiovascular disease, and certain cancers, including colon and breast cancer.^89-93 Exercise has also been shown to play a role in alleviating mental health conditions such as stress and depression.^94,95 When exercise or physical activity such as walking or gardening are done outdoors in green spaces or parks, there may be synergistic effects on mood, social connectedness, and stress management.^17,96,97

Climate change causes more frequent and disruptive extreme weather events, higher risk of heatwaves, and higher average temperatures, particularly in urban heat islands, all of which can adversely affect time spent in outdoor physical activity.^23,98,99 Rising ambient temperatures can result in worsening ground-level ozone pollution, which can cause exacerbations of respiratory and cardiac disease. ¹⁰⁰ Additionally, ambient air pollution threatens the ability to safely perform physical activity outdoors.^101,102

The number of heat exposure days have increased dramatically. According to the Lancet Countdown on Health and Climate Change Policy Brief for the United States, people older than 65 years were exposed to more than 102 million heatwave days in 2019 compared to the 1986-2005 baseline. ²² This increase in heatwave days also has implications for occupational exposures for outdoor workers, military members, and youth sports participants. ²²

Inhospitable outdoor conditions resulting from heat, extreme weather events, and poor air quality may contribute to the development of NCDs through reductions in physical activity, particularly for vulnerable populations without easy access to indoor spaces for exercise.

In addition to modeling dietary patterns that aligned with the Paris Agreement and SDGs in their 2021 study, researchers also evaluated transportation sector targets that would increase active transport by creating infrastructure for walking and bicycling, reducing transportation-related GHGs and air pollution. ¹⁸ The model found that increased levels of active transport could result in 1.15 million avoided deaths in 2040 across the 9 countries in the study, with the greatest gains in the United States where active transport is most limited. ¹⁸

This finding aligns with a review by Patz et al ² where shifts to sustainable, active transportation were found to ameliorate 11% of cardiovascular risk and also 48% of colon cancer risk in men and 44% in women in Shanghai, China. In the United States, upper Midwestern cities with the highest active transport rates had lower rates of obesity (20%) and diabetes (23%) compared with cities with the lowest active transport levels.^2,103-105 It has been estimated that more than 1200 deaths a year could be avoided by shifting to bicycling for car trips <4 km. ¹⁰⁶

Avoidance of Toxic Substances

As a domain of LM, avoidance of toxic substances generally pertains to substance use, abuse, and addiction (tobacco, alcohol, opioids, and illicit substances).^16,61 We expand the domain to include toxic pollutants in air, water, soil, and consumer products because of the modifiable burden of disease and the size of the affected global population. ³⁰

In 2015, tobacco use caused about 7 million deaths and alcohol 3 million deaths, globally, whereas pollution-related diseases resulted in 9 million deaths.^30,56,107 Pollution is the largest environmental cause of morbidity and premature mortality, with NCDs accounting for about 71% of the total pollution-related disease burden.^30,56 According to the 2015 Global Burden of Disease, a combination of all types of pollution was responsible for 21% of cardiovascular deaths, 26% of coronary artery disease deaths, 23% of stroke deaths, 51% of chronic obstructive pulmonary disease deaths, and 43% of lung cancer deaths.^30,56,108

Whereas the effects of various pollutants on human health and the environment is still being studied, there is growing data about the many pollution-related health hazards, including risks for developing NCDs, endocrine disruption, and epigenetic changes.^30,38

One of the main drivers of climate change - fossil fuel combustion for electricity production, transportation, and industry causing GHG emissions - is also one of the largest sources of environmental pollution. Fossil fuel combustion produces health-harming particulate air pollution, which detrimentally affects all organs.^30,109,110 Beyond the lungs, particle pollution enters the blood stream and causes both direct organ damage and systemic damage via oxidative stress and inflammation.^109,110 About 4.2 million deaths can be attributed to fine particulate pollution. ¹¹¹ Additionally, NCDs such as cardiovascular disease and diabetes can be attributed to particulate pollution, with about 3.2 million incident cases of diabetes linked to exposure. ¹¹²

Fossil fuel combustion can also produce pollutants that contaminate soil and water, with a variety of toxic materials, including heavy metals such as lead, cadmium, arsenic, and mercury.^17,30

More than 140 000 new chemicals and pesticides have been introduced over the past 80 years, and 5000 of these have resulted in extensive exposure to humans. ³⁰ According to the Lancet Commission on Pollution, these chemicals include neurotoxicants, endocrine disruptors, herbicides, insecticides, and plastics of various chemical composition, many of which were never tested for human health effects before widespread use. ³⁰ The negative health effects of these exposures are slowly being understood; however, avoidance of these substances to reduce total body burden is recommended. Choosing plant-based foods over animal foods has been shown to reduce polybrominated diphenyl ethers—a class of endocrine-disrupting flame retardant—burden by 27% after 1 year, as one example. ¹¹³ Another example, is plastic consumption, which requires enormous amounts of resources and emits enormous amounts of GHGs. The life cycle of plastics, alone, accounted for approximately 5% of global emissions in 2015. ¹¹⁴ The other impacts of plastic pollution on human and planetary health is beyond the scope of this article; however, they are significant and worth addressing.

The destabilizing force of climate change poses a new urgency to safely eliminate these exposures. Increasing frequency of extreme weather events, such as hurricanes and floods, may increase the likelihood of pollutants contaminating the water supply, whereas increased risks for wildfires and extreme heat threaten to further contaminate air.^17,115,116 Once air and water sources are contaminated, pollutants can travel hundreds of miles from the original source, affecting the health of communities along a broad geographic range.^116,117

In a recent modeling study described above, targeting GHG emissions from the energy, transport, and agriculture sectors to achieve Paris Agreement and SDG goals could result in 1.18 million avoided deaths from reduction in particulate air pollution alone. ¹⁸

Although it is difficult to eliminate exposure to ubiquitous pollutants on an individual level, health professionals can educate patients about the risks of these exposures. For example, health professionals can advise patients to utilize respirator masks as appropriate, obtain air purifiers for homes, and avoid exposure to outdoor air on poor air quality days. Health professionals can also educate patients about using high-quality water filters and avoiding products that contain endocrine disruptors, such as certain personal care products and plastic food containers, to reduce the pollution-related burden of disease.^30,118,119

The climate change–related impacts on substance use is an area that is actively being studied. Emerging work suggest that impacts from extreme weather events, especially those resulting in displacement, may result in increased risk for depression, anxiety, posttraumatic stress disorder, and increased alcohol and substance use.^2,6,120 Screening patients who have experienced extreme weather events or suffered from climate-related displacement for substance use and offering support and treatment may build individual and community resilience in the setting of climate impacts.

Stress Management

Chronic stress can lead to physiological changes that can increase risks from physical and mental health conditions, including cardiovascular disease, obesity, and depression.^61,120 The interplay between mental distress and physical disease is well-known and is exacerbated by maladaptive responses to stress such as substance use disorders and “comfort” eating, which often leads to consumption of ultraprocessed and high-sodium, high-sugar, and high-fat foods, and other unhealthy behaviors.^61,121

Climate change–related disasters and the slow but continuous degradation of the environment are, in part, responsible for the large and growing burden of mental health disorders, including anxiety, depression, and posttraumatic stress disorder.^120,122 Ongoing disruption of attachment of place and community because of physical displacement or dramatic environmental changes of peoples’ homelands can trigger mental distress or exacerbate existing mental health disorders, an emotion captured by the term solastalgia.^120,123 These exposures can be particularly harmful to children because a growing literature finds that adverse childhood experiences can have lifelong consequences for health and well-being. ¹²⁴

Higher average global temperatures pose risks for mental health effects such as depression, anxiety, and suicide. ¹²⁰ High heat exposure has been linked to an increase in substance use–related mental health disorders, higher emergency room visits for mood disorders and substance abuse, and higher rates of aggression and self-harm. ¹²⁰

Building resilience in the face of climate and environmental instability must be prioritized in order to protect the physical and mental health of individuals and communities through a trauma-informed care approach. Mind-body therapies such as yoga, meditation, and mindfulness along with cognitive behavioral therapy may be helpful to proactively help people address the climate change–related stresses that many are already experiencing.^61,125

Prescription of nature-based therapies also offer an adaptation and mitigation strategy for individuals and communities.^126,127 Green spaces have been shown to reduce the urban heat island effect while also increasing social connectedness and stress reduction.^128-136 Studies have found strong associations between higher percentages of tree canopy and lower rates of cardiovascular disease, depression, anxiety, and stress.^132,133 Properly managed green spaces with trees also play a role in sequestering carbon and reducing exposure to air pollution.^127,137

Social Connectedness/Positive Psychology

A growing body of literature explores the protective link between positive psychology interventions (gratitude, forgiveness, finding purpose, and social connectivity) and improvements in emotional well-being, quality of life, health behaviors, and outcomes. ⁶¹ Other benefits may include “enhanced social capital, volunteerism, and decreased violence and drug use.” ¹³⁷ Evidence shows that social connectedness, in particular, has benefits linked to longevity, whereas loneliness and social isolation have been linked to depression, cognitive decline, and higher all-cause mortality. ⁶¹

Interventions to bolster social connectedness may play a role in adaptation to climate change and environmental stressors, engendering individual and community resilience. ¹³⁸ Social cohesion through community groups, faith communities, and other social activities may allow for stronger community-based solutions during times of disaster. Protecting natural environments that may function as sacred spaces can play a role in mitigation against climate change, and building green spaces, which also have a role in increasing social cohesion, can function as an adaption measure to protect communities from climate stresses.^17,136 A focus on proactive positive psychology interventions may help individuals and communities build resilience as they face trauma from climate instability and work to find local solutions to anticipated climate and environmental effects.

Restorative Sleep

Restorative sleep is critical for health, including the prevention and management of chronic disease. ⁶¹ Insufficient sleep is associated with cardiovascular disease, diabetes, obesity, suboptimal immune function, and depression.^139-142 Poor sleep during adolescence has been linked to impaired cognition, and antisocial and suicidal behaviors.^141,143

Environmental disruption can wreak havoc on the ability to obtain restorative sleep. Many communities, particularly minority and socioeconomically disadvantaged communities, live in close proximity to the very sources that pollute the environment and produce large quantities of GHGs. ¹⁴⁴ In addition to air, water, and soil pollution, these communities also face noise and light pollution from sources such as heavy road traffic, airports, industrial operations, warehouses with high levels of nightly truck traffic, and energy infrastructure such as compressor stations.^144,145

Increased average temperatures, especially for those living within urban heat islands, also threaten the ability to obtain restorative sleep, increasing the risk for mental health disturbance and other detrimental physiological outcomes from higher rates of sleep deprivation. ¹⁴⁶

In a recent National Institutes of Health funded study of adolescent sleep, researchers found that even small increases in neighborhood noise had detrimental impacts on sleep. ¹⁴⁷ Adolescents who lived in areas with more green space and tree cover had better overall sleep times, suggesting that neighborhood noise and amount of tree cover may be important targets for sleep interventions. ¹⁴⁸ Safeguarding sleep through local interventions, such as increasing tree canopy and moving toward less polluting energy sources and vehicles (electric vehicles can decrease carbon, air, and noise pollution), may help communities both mitigate environmental degradation and adapt to climate change.

Epigenetics and Microbiome

The lifestyle-mediated ramifications of these environmental crises on epigenetic and microbiome changes are also still being studied.^38,149-152 There is growing evidence that the epigenome (affected by nutrition, stress) may also be affected by environmental toxins (air pollution, endocrine disruptors, heavy metals), and potentially climate (heat), adversely affecting transgenerational epigenetic inheritance.^{38,61,149-151}

Climate change–related biodiversity loss may also affect the ability to maintain a healthy gut microbiome, a key component of immune and central nervous system development and function. ⁶¹ Dysbiosis of the microbiome has been linked to a host of inflammatory, autoimmune, and infectious diseases. ¹⁵² A growing literature around the “biodiversity hypothesis” ¹⁵³ suggests that “reduced contact of people with natural environmental features and biodiversity may adversely affect the human comensal microbiota and its immunomodulatory capacity.” ¹⁵⁴

Role of LM Providers

For those with NCDs, climate change and environmental disruption function as “threat multipliers,” worsening the potential health impacts on those with suboptimal health. ¹⁵⁵ At the same time, these environmental factors threaten the basic pillars of health and prevention, increasing the risk of developing chronic disease.

In the face of these threats, the core competencies of LM providers present crucial opportunities to mitigate climate change and human health impacts while also allowing individuals and communities to build resilience.^24,25 This is of particular importance for marginalized, vulnerable communities already suffering the burdens of health inequity because of higher exposure to pollution, food insecurity, lack of green space, limited access to safe spaces for physical activity or active transport, and unequal access to behavioral health services.^30,47,156 Here, LM providers have a role to ensure that evidence-based lifestyle prescriptions for nutritious whole-food, plant-based diets, green spaces that provide solace, protect sleep, and function as safe spaces for physical activity, and social cohesion are accessible through individual prescription and community advocacy. A multisectoral approach through community-engaged LM (discussed in detail elsewhere) can be used to center equity in the practice of LM to help the most vulnerable communities prepare for and adapt to climate risks. ⁴⁷

Given the approach to prevent, manage, and reverse NCDs with lifestyle, an additional benefit in the time of climate change could be the reduced utilization of pharmacotherapies. NCDs often make people medication dependent which, in and of itself, can raise difficulties secondary to climate change. Extreme weather events can disrupt access to health care and create difficulties in safeguarding medical equipment and storing medicines such as insulin.^2,17 People may also suffer higher rates of adverse effects from medications that affect thermoregulation, sweating, and water hemostasis during times of elevated heat exposure (antidepressants, anticholinergics, β-blockers, diuretics).^157-159

Conclusion

Although daunting, humanity must move from adding 51 billion tons of GHGs to the atmosphere every year to adding zero within a 30-year window. ¹⁶⁰ To achieve this goal, innovations and technology affecting every sector (energy, industry, transportation, agriculture) will be necessary. Health professionals must use their trusted voices to advocate for changes that mitigate climate change and protect planetary health (comprehensive climate and health policy action agendas have already been detailed elsewhere^161,162). Beyond this, however, LM providers are uniquely positioned to help patients understand the links between a healthy lifestyle and a healthy climate and environment in the exam room. LM providers have an arsenal of behavior change tools to help people understand why and how to make necessary changes to protect health. ²⁶ Unless the foundational pillars of health are centered in all policies, technological innovations may get us to net zero GHGs but may perpetuate unhealthy, inequitable, obesogenic societies that do not foster healthy populations.

As we emerge from the COVID crisis, the fault lines that create massive health inequities in our communities have been exposed. We have also learned that no zip code or artificial boundary can protect us. Collectively, the sicker we are, the harder we fall. LM allows health professionals to confront the root cause of disease at the nexus of these crises, to emerge as stronger, healthier societies. LM providers are already part of a transprofessional, global movement poised to transform the field of medicine and medical education. A knowledge of the power of lifestyle interventions coupled with an understanding of the risks of climate change to the very foundation of health can empower health professionals and the patients whom they educate to make climate-healthy lifestyle changes.

As practitioners of LM, we have the voices and skills that can be used at the bedside, in our communities, and in our own lives to foster changes that have the potential to help mitigate climate change and environmental degradation while simultaneously helping to heal our patients.

Therefore, we propose a call to action for our fellow LM practitioners and colleagues. We ask you to use your time, talent, knowledge, and influence for dedicated, collective action to help solve the human and planetary health challenges we face, utilizing any available platform at the individual, local, state, or national level. There is no time to waste.