Ecosystem destruction, such as this pollution from a gold mine, is a primary driver of zoonotic disease reproduction and transmission. Natural ecosystems act as a buffer zone, preventing spillover of certain pathogens from animals to people.
Opinion | To prevent future pandemics, we need to rethink human environmental impact
The COVID-19 pandemic has swiftly changed our lives. In a matter of months, we have altered the way we go about pretty much everything, shifting how we work and go to school, to the ways we socialize, spend our leisure time, and even how we approach grocery shopping.
None of this is normal. And yet, none of it is entirely too surprising. Scientists have long been warning of the potential for a pandemic. The time and disease was never known, but the possibility was always there.
While much about the future remains uncertain, there is one thing we can predict: This is not the last pandemic humanity will face. And if we want to prevent future pandemics, we need to seriously consider how we interact with the environment, and how seriously we combat climate change.
COVID-19 and the human-environment interaction are intertwined
The new coronavirus, COVID-19, is a zoonotic disease. Zoonotic diseases are diseases that come from pathogens that spill from wildlife (including animals, insects, and ticks) into humans, causing everything from mild to deadly illnesses including global pandemics.
Zoonotic diseases make up about 60% of all total diseases, and represent about 75% of emerging infectious diseases, and you’ve probably heard of more than a few of them. SARS, MERS, rabies, Lyme disease, salmonella, Zika, Avian “bird” flu, and West Nile are all zoonotic diseases.
Zoonotic diseases are nothing new. But they are increasing, and many of the drivers are a direct result of human interaction with the environment.
For example, ecosystem destruction is a primary driver of zoonotic disease reproduction and transmission. Natural ecosystems act as a buffer zone that prevents spillover of certain pathogens from animals to people.
Unfortunately, human activities including deforestation, agriculture, mining, and urbanization have caused large scale ecosystem fragmentation, impinging upon this essential buffer zone. This elicits more densely populated flocks of animals with more opportunities to congregate diseases, and with less of a barrier to prevent spillover into humans.
Increased and intensified animal agriculture further feeds the problem. The demand for meat and dairy products encourages intense animal agricultural practices that serve as incubation grounds for zoonotic diseases.
In many factory farms, large amounts of genetically similar animals are clustered together. Because they lack large genetic diversity, they become a group less resistant to infection, and thus more likely to fall ill and spread disease. Indeed, livestock often serve as the disease bridge between wildlife and human life.
Furthermore, intensification of livestock not only contributes to ecosystem destruction, but also increases the amounts of animal waste contained in small spaces, and the amounts of fertilizer used, both of which can further foster environmental conditions that allow some pathogens to thrive. It also encourages antibiotic overuse, which itself is a risk factor for zoonotic disease emergence.
And of course, animal agriculture contributes to climate change, which is another major driving factor for zoonotic disease emergence.
Because climate change influences conditions that impact pathogen reproduction and transmission rates of pathogens, vectors, hosts, it can play a major role in infectious disease reproduction and transmission.
For example, climate change shifts changes in things like temperature, humidity, precipitation patterns, and seasonality. Extreme weather events related to climate change, like flooding, droughts, and wildfires, may exacerbate ecosystem fragmentation, or make environmental conditions even more amenable to disease outbreak.
All of these conditions impact how certain pathogens reproduce and spread, and certain changes driven by climate change may cultivate optimal conditions or extend seasons for select pathogens to thrive.
But the environmental risks don’t stop there. Air pollution, which kills an estimated 7-8 million people each year in non-pandemic conditions, threatens human health by increasing risks of chronic diseases like asthma and COPD, cardiovascular disease, cancer, and neurological distress. Many of these conditions are conditions considered ‘high risk’ for developing complications with COVID-19.
Thus, areas that have high levels of air pollution may have more people who are vulnerable to becoming seriously ill if they contract COVID-19. Sadly, high levels or air pollution are often found in lower income areas. Compounded with poverty, which is itself a risk factor for poor health, it is feasible that mixing air pollution with coronavirus could increase vulnerability of already vulnerable populations.
It seems as if there is a positive feedback loop at play — several activities which contribute to climate change, including human activities that augment air pollution, and modern animal agriculture, are both independent risk factors for zoonotic disease, and both also contribute to climate change.
Climate change, in turn, increases ecosystem destruction which increases risks further, while independently acting as a risk factor for increased reproduction and transmission of zoonotic diseases.
Thus, it seems we cannot decrease the risks of future pandemics if we do not simultaneously assess how we interact with our environment. The problems are deeply intertwined.
And although this is a dual burden, it also presents a unique dual opportunity to blunt two major global threats simultaneously.
So what can we learn, and how can we move forward?
There are many similarities between the COVID-19 crisis and the climate change crisis: both are global threats to human health, the economy, and have the potential to disrupt life as we know it.
The major difference between the two is the time scale at which they are unfolding.
With coronavirus, the threat is palpable; we see it unfolding daily as cases and fatalities continue to climb, and the world scrambles to find treatments, vaccines, and strategies to adapt to a new reality in the face of a major threat.
Climate change, on the other hand, is unfolding a bit more slowly. While some directly see and feel its effects, for many, it seems like a distant and personally irrelevant threat.
Yet, these two crises both require a global cooperative effort to mitigate their magnitude of their destructive potential, and rely heavily on work done by the scientific community to project their paths and to create and implement solutions.
And importantly, both require not only the cooperation of governments around the globe, but also action of everyday citizens.
When it comes to climate change, that means individual action to reduce personal carbon footprint while supporting policies for sweeping change, and when it comes to coronavirus, that means adhering to public health recommendations by sheltering in place, wearing a mask, and social distancing.
Both instances require personal sacrifices, a trust in science, and a respect for greater good. And unfortunately, both coronavirus and climate change have been politicized, with certain individuals casting shadows of doubt on science and experts to fuel political narratives, creating an illusion of personal safety and remission of personal responsibility.
Which is perhaps why, most importantly, both of these crises run the risk of giving in to the temptation to delay taking action until it’s too late. We’ve seen the impact of complacency in parts of the world that believed itself immune to the dangers of COVID-19, until the virus proved its potential to wreak havoc on communities.
There is the potential that the crises created by climate change will have similar implications for disrupting humanity, riddled with the devastation, death, and economic fallout happening across the globe. Some places will be hit harder than others, and some people and places are already feeling these effects.
Much like with the current pandemic, we must act swiftly and with global cooperation to implement solutions to mitigate the impacts of climate change, and, to make a parallel to COVID-19, to flatten the curve of its destructive potential.
We have seen that on some scale, this is possible. With COVID-19, the world has pulled together to fight a common enemy. People are staying home, helping their neighbors, and rising at opportunities to contribute to a greater good.
We have also learned with greater clarity what is really essential in terms of polluting activities we engage in in our daily lives. Perhaps more of us can truly work from home from time to time, avoiding long daily commutes, and perhaps we can continue to eat food we have in our homes rather than seek out other foods to suit our moods and let leftovers go to waste.
The pandemic has also exposed the gravity of modern health and economic disparities in our societies, and perhaps we can move forward with plans that better serve those in need.
And with coronavirus, as many around the world turn to medical and public health experts for guidance, eagerly waiting for scientists to create a treatment or vaccine, there’s a chance that this experience will perhaps bring about a returned trust in science and experts to guide relevant decisions.
As humans, we have grown, and can continue to learn from these experiences to create a brighter future.
All of these learned experiences will be helpful for working to better protect our environment, fight climate change, and prevent future pandemics.
There is no way to disentangle future pandemics and how we treat the environment. Luckily, this presents a dual opportunity: we can take better care of our planet, and by doing so, take better care of our health.