For too long, we have treated the natural world as an infinite commodity. In the wake of unchecked human population growth and consumption, we’ve destroyed natural habitats for the sake of creating housing in cities and suburbs, and for vast commercial farms that produce agriculture and livestock. This habitat erosion decimates wild animal populations and renders surviving animals homeless — both of which ultimately endanger humans, as well.
With fewer barriers between us and animals, viruses can more easily jump the species barrier to become zoonoses.
In the most recent example, the U.S. Fish and Wildlife Service proposed removing 23 more animals and plants from the endangered species list Wednesday — because they're extinct. Included on this list is the ivory-billed woodpecker, which spanned from coastal North Carolina to East Texas before logging and slaughter for private collectors and hat-makers dwindled the population. Hawaii had a total of eight birds listed as extinct, including the Kaua’i ’o’o, which is known to have a beautiful flute-like call, because invasive species and warming temperatures allowed mosquitoes carrying diseases to access elevations they were once unable to reach.
Habitat loss and climate change are burning the candle at both ends, leading to the tragedy of extinction while also increasing the amount of contact between humans, livestock and the animals that do remain. These complex dynamics then fuel animal-borne infections — in the form of viruses like Covid-19. With fewer barriers between us and animals, viruses can more easily jump the species barrier to become zoonoses, a term for animal-to-human infectious diseases that will inevitably become more familiar to everyone in the years to come.
As our nation reckons with the impact of the coronavirus pandemic, we must also recognize the larger picture: The proliferation of animal-borne diseases that ignite horrific pandemics will escalate so long as human activity continues to alter and destroy the delicate ecosystems of the natural world. We cannot afford to talk about Covid without talking about climate change, too.
To be sure, there is still much debate about the precise origins of this pandemic. The “lab leak” theory regarding the Wuhan Institute of Technology is under investigation, and this May a group of 18 international scientists wrote a letter in Science saying, “We must take hypotheses about both natural and laboratory spillovers seriously.” At the same time, a group of researchers concluded that climate-driven shifts in global bat distribution suggest that “climate change may have played a key role in the evolution or transmission of SARS-CoV-1 and SARS-CoV-2,” the latter being the specific virus strain behind the current pandemic.
Whatever the ultimate origins of the coronavirus, it’s clear that we should be prepared for more pandemics. The Food and Agriculture Organization of the United Nations has determined that 70 percent of the new diseases that have emerged in humans are of animal origin. According to numerous studies, our reliance on animal meat has a causal relationship to pandemics, for instance. While this causality is complex, it has to do with both habitat destruction necessitated by factory farming and the scale of production and overcrowding on factory farms, which creates an environment where viruses can more easily develop and spread to humans.
One such example is swine flu, which the Centers for Disease Control and Prevention estimated infected 60.8 million people in the U.S. alone. With more than 9 billion animals raised and slaughtered in the U.S. for human consumption each year, and 41 percent of all U.S. soil used for grazing livestock or to grow feed, modern animal agriculture is essentially a breeding ground for more global disease outbreaks.
In 2019, more than 30 scientists wrote a passionate (and terrifying) consensus statement in Nature outlining a broad array of additional reasons to worry about the multiple ways people are altering the ecosystem — and how that could lead to more disease spread among humans.
Greenhouse gas emissions and warming temperatures increase the regions in which viruses thrive. More warmer days in historically cooler regions facilitates the spread of disease vectors (an organism that transmits disease), such as migratory animals and birds, which then accelerate and widen transmission. Just this month, a study in the journal Ambio raised concerns that changing winter weather in Northern ecosystems alone will drive elevated human zoonotic risk.
Prior to Covid, the world was already fighting numerous viral epidemics, such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), Zika and Ebola. According to the World Health Organization, about 1 billion cases of illness and millions of deaths occur every year already from zoonoses. In the modern era, these diseases had relatively minimal impact in the U.S., and thus most public discourse overlooked the larger pattern they revealed.
Now, with the rampant effects of climate change and Covid, none of us are or will be left unscathed.
If all of this doesn’t give you pause, a guest report published by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services last year stated that as many as 1.7 million unidentified viruses that can infect people are believed to still exist in mammals and water birds, and that “Any one of these could be the next ‘Disease X’ — potentially even more disruptive and lethal than COVID-19. Future pandemics are predicted to occur more frequently, spread more rapidly, have greater economic impact and kill more people.”
As we continue to grapple with the devastation of the pandemic and severe weather events, it’s imperative that we integrate climate action into Covid recovery plans. These problems cannot be solved in isolation.
Resources abound: The EPA will help you calculate your carbon footprint, and The New York Times can suggest how to reduce it. The Harvard School of Public Health offers ways to cut down on red meat. The BBC can help you calculate your dietary footprint. You can contact your elected officials to insist they support President Joe Biden’s efforts to reduce emissions and create new clean energy jobs. Ultimately, all of our lives are at risk, and we need to think about our consumption and choices, from food and travel, to voting and investments.
Undoubtedly, Covid won’t be the last pandemic we confront. As a palliative care physician who has cared for patients dying of Covid for the last year and a half, I’m distressed about facing more devastating losses from future pandemics and the compounding impact of climate change. There is deep work ahead and the time to act is now. Because from what I’ve seen in the hospital, the catastrophe is already here.