By Matt Nathan, M.D., and Susan Carney Lynch, Dr.PH
Dr. Renee N. Salas is Affiliated Faculty and previous Burke Fellow at the Harvard Global Health Institute (HGHI) and a Yerby Fellow at the Center for Climate, Health, and the Global Environment (C-CHANGE) at the Harvard T.H. Chan School of Public Health. She is also a practicing emergency medicine physician in the Department of Emergency Medicine at Massachusetts General Hospital and Harvard Medical School. Dr. Salas has served as the lead author of the Lancet Countdown on Health and Climate Change U.S. Brief since 2018 and founded and leads its Working Group of over 70 U.S. organizations, institutions, and centers working at the nexus of climate change and health. Dr. Salas was a Co-Director for the first Climate Crisis and Clinical Practice Symposium -- in partnership with The New England Journal of Medicine -- and co-leads the broader Initiative. She also serves on the planning committee for the National Academy of Medicine’s Climate Change and Human Health Initiative and has testified before Congress for the full House Committee on Oversight and Reform on how climate change is harming health. She engages in research on how climate change is impacting the healthcare system and developing evidence-based adaptation. She lectures and serves on committees at the nexus of climate and health nationally and internationally, advises and publishes in high impact journals, and her work and expertise are regularly featured in mainstream media outlets like the New York Times, NPR, Time, and the Associated Press.
Matt Nathan: Dr. Salas, congratulations on an amazing career trajectory and journey. We look forward to hearing more about it. So, you're an accomplished attending physician in emergency medicine. Where did your passion for climate change come from? Are you a climate change scientist who became interested in medicine or are you an emergency medicine specialist who became interested in climate change?
Renee Salas: Thank you. It’s an honor to speak with you both. So, it's a great question. I was actually a first-year emergency medicine attending when I really learned how climate change was harming health, as outlined in The Lancet Commission Reports. I saw that climate change was here and now, and the greatest health threat of our time. I also recognized that it was going to increasingly make it harder for me to fulfill the obligations to my patients as an emergency medicine physician having taken the Hippocratic oath and for us -- as a healthcare system -- to continue to deliver accessible, high quality, affordable care. In my profession, I see firsthand how environmental and social vulnerabilities contribute to health harms and individuals ending up in my emergency department. Oftentimes, I feel like I’m putting a band aid on a bullet wound. Given the gravity of the climate crisis, I felt I also had an obligation to go further upstream to address these health harms before they occur. This led to a clear fork in my career path when I decided to also obtain a Masters of Public Health in Environmental Health and make this intersection the focus of my career. I truly feel that it is my calling.
Nathan: Your research and investment of time in the intersection of health and climate change is inspiring and impressive. In various prestigious publications, you have talked about the logistical issues that are created by climate change that affect health, including logistical access and economic barriers. What are other subtle or not-so-subtle things about climate change that healthcare professionals may not appreciate?
Salas: Climate change has very direct and clear health impacts, but then there's also the more indirect and insidious ones -- which can compound or lead to cascading failures. This aspect of climate change is often less recognized because it can be more hidden. I think of climate change as a metaproblem, which as you know, means it underlies so many of the other pressing health challenges of our time. But it is also a threat multiplier -- meaning that it is making those problems worse. It can be easy to see that hotter temperatures are going to lead to more heat-related illness or that the intensification of extreme weather will cause a mental health toll. However, this is in addition to other climate exposures that harm health in a compounding fashion such as air quality impacts like wildfire smoke exposure or longer and more intense periods of pollen exposure, threats to our food supply and its safety or our availability and quality of water, alterations in vectorborne diseases like Lyme disease or malaria, or social factors like forced displacement. For health, other indirect or more insidious impacts also include how these exposures can lead to healthcare system disruptions -- whether through the destruction of infrastructure, increasing the frequency or length of power outages, or supply chain interruptions. These can cause cascading failures, especially as threats increasingly overlap and overstretch our capacity. I think of our current understanding of how climate change harms health and disrupts health care as an iceberg…and I realize the irony of the metaphor… in the sense that what we currently know is just what we see above the water surface. What is below the surface is what I’m most concerned about and why we desperately need an evidence-based pathway forward because we can’t optimally prepare for what we don’t fully understand. For example, a recent paper showed that rising microbial resistance to antibiotics is potentially linked to higher temperatures. That is a potentially catastrophic threat multiplier implication for all clinicians who count on our antibiotics to be effective when needed.
Nathan: Do you feel that you are, as a prominent health care provider, educator, and practitioner that you are somewhat of a voice in the dark among your colleagues preaching and trying to educate on the linkage between healthcare and climate change? Especially things like COVID and pandemics and climate change or do you feel that there's a more general awareness now in the healthcare community about the challenge of healthcare and climate change?
Salas: The pandemic has shown us on an accelerated timeline what happens when we ignore the science and delay to act or fail to act equitably. This has already been playing out with climate change -- just on a longer time scale. People have begun to realize this. Thus, we need a healthy recovery from this pandemic -- and it must include acting on climate change so we can minimize our future suffering. I believe the recognition of the interconnectedness of these challenges, and the need to frame action accordingly is growing. Prominent medical journals like The Lancet engaged on climate change well over a decade ago, and we have produced a collaborative Lancet Countdown on Health and Climate Change U.S. Brief each year since 2018. The New England Journal of Medicine has also really stepped forward on making this issue a priority, like launching a topic page and supporting our first phase of the Climate Crisis and Clinical Practice Initiative. I was also part of the planning committee for the National Academy of Medicine’s Initiative on Climate Change and Health, which is forthcoming. Having these highly respected medical organizations step forward to say this is a clear threat to health and our ability do our jobs as health professionals is critical. And the movement is only growing. I believe that we are quickly reaching the tipping point of wider acceptance that climate action is a prescription for health and health equity.
Susan Lynch: Dr. Salas, you were just talking about the interconnectedness and the collective action nature of solving COVID. How do you think that interconnectedness is a blueprint, as you say in your article, or a way forward for climate change and what are some of the challenges that would make climate change more difficult to solve than COVID in that way?
Salas: I think that we have been experiencing, in a very profound way, the importance of global collective action. A virus does not respect country borders and mismanagement can lead to widespread implications around the globe. Similarly, greenhouse gases do not respect country borders. So what we do here has clear implications for others halfway around the globe. I think there's a moral and ethical obligation underlying that premise as well because the countries that contribute the most greenhouse gases will suffer fewer health impacts than those countries that have contributed the least. Yet, no one is immune -- we are all suffering health harms to some degree. So, we're also in this shared collective destiny with climate change -- just like with the pandemic. While we have been able to utilize the profound abilities of science to rapidly manufacture a vaccine for the pandemic, we must actualize this true shared collective destiny by disseminating the vaccine around the globe. This will also minimize the development of variants. The fix for climate change is unfortunately not as “simple” as a vaccine. There is nothing harder than when I have a patient in front of me that I don't have a treatment for. Thankfully, we have the treatments or solutions that we need for climate change. We have the tools to move away from fossil fuels to renewable sources because they are more available and affordable than ever before, especially when we remove fossil fuel subsidies. We just need the collective political will to choose this path. The fifth anniversary of the Paris Agreement was this past December and many have called it the most important public health agreement of our time -- and I agree wholeheartedly. The world has recognized the problem, which is the first step to solving it, but now we must urgently move to implementing the solutions at COP26 in Glasgow. Countries are going to make their commitments there on how they're going to reduce greenhouse gas emissions. Thus, this is a really critical point in history if we are going to successfully cut our emissions in half by 2030 -- only 9 years away -- to try to keep the global average of warming to 1.5°C by 2100.
Lynch: Please share your thoughts on the interconnectedness piece.
Salas: It can be overwhelming when you recognize that climate change is a metaproblem and threat multiplier because it mandates tackling these complex, interconnected relationships. However, I view it as an enormous opportunity -- and actually a reason for hope -- because it means that we can find interconnected solutions that can help us rise above multiple problems at once. This is true whether we're thinking about trying to prepare for the next pandemic or address climate change or finally fundamentally address the health disparities that arise from systemic racism. One way to begin, and a way I often advocate, is to think of it as adding a climate lens to these other complex issues. All that means is understanding how climate change is impacting these issues now, and how it's going to impact them in the future. You can then start developing these interconnected solutions by breaking down silos and getting multidisciplinary experts to the table. We need to recognize that we really must take an all-hazards approach -- and that doing so will have widespread benefits, especially for health, and allow us to begin to remedy the inequities and injustices that are currently present.
Lynch: That is insightful and interesting to think about in terms of interconnectivity. I want to ask you a question now about Health Communication. So you know as we sit here today that a large percentage of the population is saying that they don't want to be vaccinated. There's an attempt to convey the message that vaccination is important, so how has health communication been, in your view, around COVID and do we have similar problems with health communication around climate change?
Salas: It's a wonderful question and a really critical topic. Communication is complex. We have really seen this play out with the pandemic, as you noted, because it's not as simple as just clearly stating the problem and the needed action or solution. If so, then everyone would be wearing masks and adhering to physical distancing, and we would have solved climate change decades ago when climate scientists first rang the alarm bells. I have really begun to recognize the immensity and complexity of the communication challenges as a member of a national working group addressing this very question. These complexities involve concepts like how we perceive threats, how we navigate individual and collective interests, the importance of the social context -- like political polarization, and the complexities of science communication in particular, especially in the era of misinformation and disinformation. While there are a lot of similarities between the challenges of communicating information on COVID-19 and climate change, we also have to recognize that there are likely a lot of nuanced differences. We have to consider what the actual message should be based on factors like the target audience, the mode of communication, and the messenger -- including who the optimal messenger should be. And so, in my mind, it just again speaks to the inherent need of multidisciplinary collaboration because we need social and behavioral scientists to lend their expertise and develop an evidence-based understanding. For example, experts have found that simple messages, repeated often, by trusted sources can be really powerful, but we also have to recognize that one message doesn't fit all.
Nathan: So let’s drop anchor a little bit on the interconnectivity. If you were lecturing second year medical students who are going through their didactic studies on various disease processes and you were asked as a harbinger of climate change and health about COVID-19 and its manifestations, diagnosis, and assessment, how specifically is climate affecting patients?
Salas: I love the question because it gets to how I think climate change should be taught, and that's adding a climate lens to what students and trainees are already learning. For example, learning the pathophysiology of pulmonary diseases should include how climate change and other environmental challenges like air pollution are contributing to the disease burdens or worsening existing illness. It is also important to note that climate change and air pollution are fundamentally interconnected because they both have the same root cause, the combustion of fossil fuels, which also means that moving away from fossil fuels gives us near-term health benefits by reducing air pollution while also mitigating climate change. Back to your question, climate change threatens our response to COVID-19, as we outlined, by factors like making it more difficult to maintain physical distancing, exacerbating coexisting conditions, and disrupting health care services. I’ll dive into the coexisting conditions as an example. We know that certain cardiopulmonary diseases make individuals more at risk for severe outcomes from a COVID-19 infection. We also know that air pollution, again interconnected with climate change, contributes to the development of those diseases. Cardiopulmonary diseases are also exacerbated by climate threats, such as extreme heat, wildfire smoke, heat-driven ground-level ozone, or higher pollen levels. This threatens our ability to minimize the risk factors for the development of severe COVID-19 outcomes. We can’t optimally tackle this pandemic or the next without action on climate change.
Nathan: Yes, I think your selling point to the students would be that they understand the risk factors for COVID-19 include diabetes, heart disease, underlying lung disease. And treatment of those is threatened by access to preventative health, nutrition, and the air we breathe, which in turn are directly threatened by climate change. This pandemic has illuminated the tragedy of healthcare disparity among populations based on poverty, race, and ethnicity. How do you see climate change intersecting with that?
Salas: As you said, the pandemic has really exposed these long-standing systemic health and social inequities that have impacted individuals who are Black, Indigenous, or other People of Color (often called BIPOC) -- and the same is true for climate change. The reality is that we cannot address these health disparities from structural racism without action on climate change -- end of story. I think about these vulnerabilities as having three key aspects: susceptibility, exposure, and the ability to adapt -- which is important to recognize these are levers that we can direct interventions at. As an example for susceptibility, individuals who are BIPOC can be more likely to suffer from asthma due to higher air pollution exposure by living closer to sources of air pollution, like power plants or highways. Asthma can then heighten susceptibility to other climate-related exposures. Secondly, their exposure to climate threats can be higher. For example, redlining was a racist housing practice that targeted Blacks -- now outlawed. However, areas of cities that had been previously redlined are almost universally hotter than surrounding areas -- even today. This can stem from a phenomenon called the “urban heat island” effect, often meaning there's more man-made materials than greenspace. Anyone who's stood on asphalt on hot days versus in a park can recognize the clear difference. Third, their ability to adapt can be hindered. For example, these populations are more likely to be uninsured or underinsured and have been shown to receive a lower quality of healthcare than white individuals on certain measures. This can further impede their ability to remain healthy from climate extremes. This forces us to recognize that policy decisions have contributed to these outcomes, and thus we can develop policies that remedy these problems. And these policies can minimize susceptibility, reduce exposure, and optimize one’s ability to adapt -- all with a climate lens.
Nathan: Clearly you have a passion for creating urgency in society, and for decision makers, and leaders understanding that climate change crisis is really a public health crisis.
Salas: The central driver for climate action needs to be our health, in my opinion. Our health is threatened now -- and will increasingly be threatened -- and this includes the health of our children, our aging parents, our neighbors, and our loved ones. Climate change needs to feel personal because it is. It's not about polar bears or icebergs, while I love polar bears. And that is why climate action needs to be seen as a prescription for better health and achieving health equity.
Nathan: This has been great and very enlightening. If you don’t mind, we cannot let an emergency medicine physician who attends at Massachusetts General Hospital go without asking you for your observations on COVID in the ER now versus a year ago when we were just starting to see the disaster of the pandemic unfolding across the world.
Salas: There was so much uncertainty last March. We had very limited information on the atypical presentations of COVID-19 or the typical progression of the disease. Thus, we were less confident on who was safe to send home. We also had no treatments other than oxygen and other traditional supportive care. The collective action within the health sciences has rapidly advanced our understanding between then and now so we really understand how the disease presents and some of the less typical manifestations. For example, some patients present with gastrointestinal symptoms like vomiting or diarrhea. We also understand the timeline for the severe pulmonary manifestations and have actually built programs so individuals who may worsen can be sent home and monitored there. This allows us to safely determine who's worsening and needs to come back to be admitted. We also have treatments, such as Remdesivir and Dexamethasone, which have helped build out our toolbox to treat COVID-19. But first and fundamentally, prevention remains critical. We've developed that ultimate preventative therapy in the form of the vaccine, which is not only protecting us as healthcare providers on the front line, but will also increasingly protect the general population. I hope everyone will step forward and receive the vaccine when their time comes, and I eagerly await the day when I no longer have to see patients struggling to breathe with severe COVID-19.
Nathan: I think that’s a great place to end emphasizing your advocacy for the vaccine based on your passion as an emergency medicine physician and a well-trained public health expert. Thank you for the difference and impact you continue to make to the lives of patients and populations.
About the Authors:
Matt Nathan, M.D., is a Harvard ALI Senior Fellow, previously the 37th Surgeon General of the Navy and most recently a Senior Vice President for a large tertiary care healthcare system.
Susan Carney Lynch, Dr.PH, is a Harvard ALI Senior Fellow and Editor-in-Chief of the Social Impact Review. Prior to ALI, Susan spent 20 years at the United States Department of Justice as Senior Counsel for Elder Justice, where she led federal civil long-term care quality prosecutions nationwide and elder justice policy work. Susan has also had adjunct faculty appointments teaching health, law, and policy at law and public health schools for the past two decades.
This interview has been edited for length and clarity.