On the morning of January 20th, President-elect Biden released a fact sheet on his priorities for the afternoon. Amanda Gorman’s poetry would steal the day, but for now the language was prosaic: “Day One Executive Actions Deliver Relief for Families Across America Amid Converging Crises.” The rhetorical framing of four historic and converging crises had carried Biden steadily through much of the summer and fall, over rough patches and around verbal stutters, all the way to the White House itself. Now it seemed almost an afterthought—a turn of phrase made for the campaign trail, tacked on and out of place at the end of a rambling heading. 

But our crises are real, and so too are the connections between them. Chief among these crises are a global pandemic and a rapidly changing climate. Even at a glance, their resemblance is unmistakable—in the science they require, in the disruption they threaten, in the borders they mock, in the racial and economic distribution of their burdens. And to those willing to look closer, climate change and SARS-CoV-2 reveal yet more alarming structural and ecological similarities. This first piece in a series will examine the scientific lineages of both crises. 


Trees are a good place to start, if only because so many places are losing them. The facts are startling. Nearly half of all the trees that were on earth when humans started cutting them down are now gone. Since 1990 alone, over 400 million hectares of forest have been lost—an area roughly equivalent to seven times the size of France. In much of the western world, as well as parts of Asia, forest cover is actually increasing. But moderate gains in northern latitudes are eclipsed by extraordinary losses in a band of equatorial rainforests running from Brazil to the Congo to Indonesia. In the tropics, ecosystems are erased at a rate of 25,000 hectares a day. 

Deforestation on this scale both accelerates climate change and makes pandemics more likely. On climate, the effects of deforestation are relatively overt. Trees take carbon out of the air; burning their corpses is what got us into this mess in the first place. The current estimate is that just over ten percent of annual global carbon emissions come from deforestation. But this statistic alone underestimates how important it is to reverse the trend. Many climate targets are now “net-zero” rather than “zero emissions,” meaning they rely on the enormous sequestration potential of expanded forest cover. This is a problem in its own right when it allows countries or corporations to slow their shift to clean energy. Yet it is undeniable that in tandem with rapidly dwindling emissions from other sectors, a transition from deforestation to reforestation would provide a huge boost to our chances of staying under the critical threshold of 1.5 degrees Celsius. 

On pandemics, the effects of deforestation are more subtle, but no less profound. Most newly emerging infectious diseases (EIDs) come from animal populations, jumping over to humans during cross-species contact. One study analyzing over 300 EIDs from 1940 on found that 60 percent were zoonotic in origin. During the same time period, the rate at which new diseases have emerged has steadily increased. We are barrelling toward what Dr. Anthony Fauci has described as “a pandemic era.” 

Causation at this scale is complex and various. Nevertheless, the connection between deforestation, cross-species contact, and new disease looms large. As trees are cut down and habitats intruded upon, animals are forced into human proximity. A number of recent disease emergences and re-emergences, including Eastern equine encephalitis, Zika, and the Hendra virus, have all been linked directly to deforestation and land-management practices. As Fauci has written, “the COVID-19 pandemic is yet another reminder… that in a human-dominated world, in which our human activities represent aggressive, damaging, and unbalanced interactions with nature, we will increasingly provoke new disease emergences.” 

Research has shown that the chance of these emergences is highest when the total perimeter between a forest and human encroachment is greatest—at around 50 percent deforestation. For anyone who has taken even a cursory look at recent satellite images of Borneo or the Amazon, this is worrying. The great tropical forests of the world increasingly resemble green honeycombs, with pockets of virgin forest interlaced by an ever-expanding web of human development. 

We should be careful here. The claim is not that deforestation was necessary for our current pandemic to emerge. Scientists are increasingly sure that SARS-CoV-2 is zoonotic in origin, but beyond that, little can be said with confidence. There is no immediate evidence connecting the birth of the virus with deforestation or the effects of climate change. (One recent paper attempting to make the connection by analyzing bat species in Southeast Asia is heavily disputed). But this is largely beside the point. There is no putting the genie back in the bottle with this pandemic—all we can do is try to prevent the next one from getting out. 

And on this task, the directive is clear: protecting forests would go a long way in curtailing the risk of future pandemics. A paper published in July by over a dozen ecologists, biologists, and environmental scientists found that a “40 percent reduction in the areas at highest risk of virus spillover” could be achieved by investing in anti-deforestation efforts, all at a cost of less than ten billion a year. The paper went on to calculate that the same anti-deforestation efforts would reduce carbon emissions by well over 100 million tons a year. McKinsey would call this a win-win. But it is only by recognizing that these connections should be expected—and that they are better thought of in terms of a broader non-loss—that we might begin to make some headway. 


Processes tied to climate change make pandemics more likely. They also make pandemics, when they do occur, more deadly. Air pollution is the most dramatic example of this. When we burn fossil fuels we release carbon dioxide, but we also set free hordes of particulates—tiny pieces of dust, smoke, and chemicals—that sit in the air and wait for us to breath them in. Over 90 percent of humanity lives in areas with air that the World Health Organization has designated as unhealthy. Somewhere on the order of seven million people a year are killed. Of course, much can be achieved by regulation that tackles only the pollutant side of the equation. (After all, most American cities are relatively more healthy than, say, Mumbai, even as the U.S. continues to have among the highest per-capita carbon emissions in the world). But fossil fuels remain the root of the problem, and it is only through a transition to clean energy that it is possible to imagine a world free from dirty air. 

Until we make this transition, air pollution will continue to exacerbate the health impacts of other diseases, including COVID-19. A growing body of literature has found higher death rates from COVID-19 in regions with greater particulate levels. Many of the underlying medical conditions (heart disease, chronic obstructive pulmonary disease, and lung cancer, to name just a few) that make people more vulnerable to COVID-19 can be traced to air pollution. And even those without clear preexisting conditions are likely to have weakened immune systems if they have spent decades breathing dirty air. It is not surprising then, that a Harvard study comparing over 3,000 counties across the U.S. found that “higher historical PM2.5 (fine particulate) exposures are positively associated with higher county-level COVID-19 mortality rates after accounting for many area-level confounders.” 

Putting numbers to the deaths caused by air pollution is difficult in the midst of a global pandemic influenced by so many variables at once. Still, recent attempts to do so have found startling results. One study calculated that nearly 10 percent of all COVID-19 deaths worldwide can be attributed directly to fossil-fuel related emissions, with even higher proportions in Europe, North America and East Asia. 

As air pollution makes COVID-19 more deadly, natural disasters wrought by climate change make treatment and isolation more difficult. This summer and fall saw a series of hurricanes, heat waves, and forest fires across the U.S. that added new layers to an ongoing tragedy. Medical researchers warned early on that the “climate crisis threatens efforts to contain SARS-CoV-2 transmission and improve COVID-19 outcomes, which include difficulty maintaining physical distancing, exacerbation of coexisting conditions, and disruption of health care services.” Sure enough, when forest fires swept down the West Coast in August and thousands lost their homes, reports emerged of evacuation sites turning people away to comply with social distancing rules. Others were reluctant to leave their homes in the first place for fear of contracting COVID, even as fires burned dangerously close. 

In a paper written in July, during a brief respite from the worst of the pandemic, Fauci told us to open our eyes. He described COVID-19 as “among the most vivid wake-up calls in over a century,” and one that would, with hope, bring us to live “in more thoughtful and creative harmony with nature.” The past year has brought a revolution in how we think about our problems—after all, who would have expected Biden to speak in the language of ‘converging crises’—even as we continue to miss the full extent of our disharmony. If we are to move beyond COVID-19 and turn a corner on climate we will have to foster a politics that reckons more seriously with the structural failures beneath our crises. Future columns will explore this politics, and where we might take it in the months and years to come.

Leave a comment

Your email address will not be published. Required fields are marked *