• Quinn Cook

“Connections of Climate Change and Environments to Pandemics/Infectious Disease”

Although we may ration a changing climate and warming globe mean decreases in sickness and pandemics, things we often associate with colder conditions, the thought is completely incorrect and dangerously problematic. There is a strong and unforgettable link between climate change and other environmental interferences, and our current and future vulnerability to pandemics and infectious diseases.

This article is not meant to say COVID-19 is the direct effect of climate change and environmental damages, although they didn’t help, but to explain this critical climatic-pandemic connection and its massive implications and tremendous future risks. This also naturally means, connections exist between the solutions for fighting climate change and stemming infectious disease. Due to length and depth, this article has been subdivided into sections by reason. Sources used and referenced will be included at the bottom of this post.


To start, we must establish that the main way infectious diseases and their pathogens come into our existence is Zoonotic transmission. Of emerging viruses, a recent May 2020 article from ProPublica titled “How Climate Change Is Contributing to Skyrocketing Rates of Infectious Disease” reported that “the U.S. Centers for Disease Control and Prevention report that fully three-quarters... have emerged from animals”(ProPublica). Major reasons for this are anthropogenic environmental encroachment, climate change and ecological imbalance. Before exploring why this relationship exists we must note that “almost every major epidemic we know of over the past couple of decades — SARS, COVID-19, Ebola and Nipah virus — jumped to people from wildlife enduring extreme climate and habitat strain”(ProPublica). Once we face up to that reality, we can look at why these trends are happening, and how to stop them.

One thing greatly contributing to both atmospheric climate change and infectious disease emergence is deforestation and habitat loss. As natural habitats are lost to human development and destruction, animals are not only pushed closer to each other unnaturally, but also to human populations. A blog titled “Fighting infectious diseases: The connection to climate change” from the World Bank reported that “according to EcoHealthAlliance, deforestation is linked to 31% of disease outbreaks such as the Ebola, Zika and Nipah viruses”(WorldBank1).

Within this major problem of wildlife movement and contact, human agricultural patterns are much to blame. As Dr. Aaron Bernstein, Director of Harvard Chan C-CHANGE, said, “Deforestation, which occurs mostly for agricultural purposes, is the largest cause of habitat loss worldwide. Loss of habitat forces animals to migrate and potentially contact other animals or people and share germs”(Harvard).

One of the largest sources of spillover risk comes from massive meat industry livestock farms. These farms are commonly overcrowded, dirty and characterized by unhealthy conditions breeding the chance for pathogens to emerge and transfer. They also greatly push emissions and are completely unsustainable in resource use. This makes for a very clear joint problem and solution relationship between climate change and pandemics. Massive and industrial scale livestock farming mean emissions and environmental effects, and also mean great risk for disease emergence and spillover. So, “less demand for animal meat and more sustainable animal husbandry could decrease emerging infectious disease risk and lower greenhouse gas emissions”(Harvard) all in one lifesaving swoop.

Finally within the Zoonotic spillover we see worrying trends of large-scale climate migrations by animal populations in response to climate change factors like temperature. This induces greater human interaction with animal population, as well as animal populations, “head[ing] to the poles to get out of the heat… [and] coming into contact with other animals they normally wouldn’t, and that creates an opportunity for pathogens to get into new hosts”(Harvard).


For many deeply scientific and intuitive reasons, our global health depends on our global climate. From physical safety from disaster, to our present environmental conditions and balance, “our health entirely depends on the climate and the other organisms we share the planet with… we must combat climate change and do far more to safeguard the diversity of life on earth”(Harvard).

Air pollution has an obvious connection to atmospheric climate change, but also a substantial one to our health and pandemic susceptibility. Air pollution’s emissions produce bad air qualities for human lungs and drive our population towards lung diseases. This naturally negatively affects our susceptibility to respiratory infections as many widespread infectious diseases are.

This means doing things necessary for our climate, such as combating air pollution, or eating better diets, will also greatly help our stem pandemics. Dr. Bernstein explains that “by some estimates, more than half the deaths in the United States are preventable, largely because of pollution, diet, exercise, and lifestyle habits like smoking”(Harvard). Taking sustainable actions such as combating air pollution “decreases harmful air pollutants such as nitrogen oxides, sulfur dioxide, and carbon dioxide that lead to more heart attacks and stroke as well as obesity, diabetes, and premature deaths that put further strains on our health care systems”(Harvard).

Similarly, climate change’s direct effects like increasingly erratic weather can directly harm human health. Climate change produces violent and unstable weather patterns, including “harsh swings from hot to cold, or sudden storms — exactly the kinds of climate-induced patterns we’re already seeing — [which] make people more likely to get sick”(ProPublica). One study from the journal “Environmental Research Letters linked the brutal 2017-18 flu season — which killed 79,000 people — to erratic temperature swings and extreme weather that winter, the same period in which a spate of floods and hurricanes devastated much of the country” (ProPublica).


Another direct connection of a changing climate is the ability of viruses and pathogens to survive and spread differently in new climate conditions. As the Earth warms, and conditions such as precipitation and weather change, diseases are able to expand into areas they previously hadn’t been able to, creating new problems for local populations. Specifically, traditionally tropical and subtropical diseases are reaching new areas of the world- especially the northern hemisphere.

Aside from physical conditions for the diseases, one large way this expansion happens is through the expansion of vector organisms- organisms that carry and transmit pathogens to hosts. As ProPublica explains, “Vector diseases like those carried by insects like mosquitoes and ticks and transferred in the blood of infected people — are also on the rise as warming weather and erratic precipitation vastly expand the geographic regions vulnerable to contagion”(ProPublica). There is also the question of human migration. Although we now have an almost seamlessly connected world, possible large-scale human migrations could further the exchange of germ sets.

Finally, airborne diseases can spread easier when greater levels of air pollution are present. The World Bank reports that “air pollution particles may also act as vehicles for viral transmission. An increase in fine particulate pollution of just 1 microgram per cubic meter corresponded to a 15% increase in COVID-19 deaths”(World Bank). Again, worsening climate equals worsening disease.


On the biological side of disease there are worrying connections as well. One of which is the possibility of melting ice and permafrost, due to rising temperatures, exposing multitudes of unknown diseases of any strength, spreadability or fatality, left over from thousands of years ago. Although this occurrence sounds like science fiction, the World Bank noted there have already been “researchers [who’ve] collected samples of the earth’s oldest glacial ice from 50 meters below the surface in Tibet and uncovered 28 ancient viruses previously unknown to scientists”(World Bank).

Another extreme threat is adaptation by current diseases. Scientists are worried that as our climate warms, it will allow diseases to mature and withstand hotter temperatures and heat-based defense mechanisms our bodies use. This is touched on in “a study published by Johns Hopkins University in January 2020 [which] raises concerns that climate change will cause new heat-tolerant diseases to evolve that jeopardize one of our key natural defenses – fever, the ability of mammals to maintain high temperatures to fight infections”(World Bank).


The connection between ecological imbalance and infectious diseases is very diverse and important. Ultimately, science is clear that upsetting biodiversity and ecological balance means great risk of new pathogen creation and transfer across all populations. ProPublica references that “as diversity wanes, the balance is upset, and remaining species are both more vulnerable to human influences and, according to a landmark 2010 study in the journal Nature, more likely to pass along powerful pathogens”(ProPublica). In this landmark 2010 study, the scientific journal Nature reported that “for pathogens already established within ecological communities, we have shown that biodiversity loss frequently increases the rate of transmission”(Nature).

The science mainly rests within that, “The loss of biodiversity can affect the transmission of infectious diseases by changing…the abundance of the host or vector, … the behavior of the host, vector or parasite, …. or the condition of the host or vector”(Nature). Our current anthropogenic climate crisis has meant and will mean untold loss of biodiversity and upsetting of global ecosystems. We are currently within our 6th great extinction, and only accelerating. Ecosystems across the globe will be increasingly and irreversibly altered meaning great infectious disease risk.

As well, when biodiversity decreases the species who often survive are those with more prior resilience like rats or parasites who are able to withstand a wide range of harsh conditions and resources. The proportional increase of these types of vector organisms will increase.


In terms of our ability to respond and defeat crises like pandemics and climate change, having multiple crises at once is a great obstacle. With both of the issues interacting and accelerating, it puts a great strain on governments and economy’s resources, energy and problem-solving focus. Climate disasters are only becoming more and more violent and destabilizing moving towards the point of eventually forcing regular large-scale life loss and migration, and so are pandemics. As Dr. Bernstein highlights, this simply means that “we cannot afford to deal with a crisis like this pandemic on top of another climate-related crisis—like a hurricane, tornado, wildfire, or heatwave”(Harvard).

As well, pandemics and climate change both destabilize our societies, and specifically harm communities of lower income and color, exacerbating the cycles of socioeconomic inequality. The intersections of race and climate and environmental degradation run deep in America, (something you can read about here) so when pandemics mix environmental strains with the health and economic vulnerabilities of these communities it spells disaster. Dr. Bernstein notes, “people with chronic health conditions, lower-income, and communities of color are disproportionately impacted by both COVID-19 and climate change”(Harvard). The climate change movement must be about social justice, with goals and solutions that’ll help us prevent further destabilizing outbreaks.

Finally, we cannot ignore the interactions of unrestrained consumption and resource use and the strains they put on our environments, climate and vulnerability to infectious diseases. ProPublica notes that “it’s human behavior driving the rise in disease, just as it drives the climate crisis… metals for iPhones and palm oil for processed foods are among the products that come straight out of [the] South Asian and African emerging disease hotspots”(ProPublica). Peter Daszak, the president of EcoAlliance, a global health, climate and disease non-profit explains that “we turn a blind eye to the fact that our behavior is driving this… we get cheap goods through Walmart, and then we pay for it forever through the rise in pandemics”(ProPublica). Though all of capitalism’s reach can not be simplified to Walmart’s supply chain, there’s a clear correlation between its unsustainable resource use, and our climate crisis and infectious disease problems. Harnessing the power of a green economics can derive wealth used to fund the solutions for both crises problems, and unleash the humongous potential of a more equitable wealth economy moving forward.


Conclusively, our climate and our diseases are forever linked. Between an existential climate crisis and the increases in frequency and severity of infectious diseases and pandemics there are great problems to come. But, all hope is far from lost. By recognizing these connections we can use the intelligence, science and technology we have to simultaneously fight and solve these crises.

Both issues uniquely have the power of halting human life’s path on a global scale. They won’t dissipate on their own, but only look to increase and unleash permanently lasting damage on life as we know it. Because these issues and fights are intertwined, our policy considerations about global health and disease prevention must always move hand in hand with our climate and environmental policies. The sciences, economics, policy, politics and more need to be synced. We can come out of this a better, safer and still existing world- we just have to commit to science.

Thank you for reading. I hope you were able to skim or read to the depth you needed to properly supplement your knowledge on the subject.


  1. Harvard- "Coronavirus, Climate Change, and the Environment, A Conversation on COVID-19 with Dr. Aaron Bernstein, Director of Harvard Chan C-CHANGE"

  2. World Bank- “Fighting infectious diseases: The connection to climate change”-

  3. ProPublica- “How Climate Change Is Contributing to Skyrocketing Rates of Infectious Disease”

  4. Nature- "Impacts of biodiversity on the emergence and transmission of infectious diseases”

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