COVID is a climate issue
With two new variants and an updated booster shot on the way, COVID has once again been making the headlines. It’s an unwelcome reminder that we’re not out of the woods. There’s still a public health crisis; it’s still a different world than it was 3 and a half years ago.
It’s also a reminder of climate change.
Viral disease and emission-related global warming might not seem like they have anything to do with each other, but the two are actually intimately connected. The changing climate alters human and animal patterns, strengthens viral resilience, compromises public health strategies, and increases the potential for comorbidities.
COVID is a zoonotic disease, an illness caused by pathogens that are passed between animals and humans. Zoonotic diseases can be spread by direct contact with infected animals, contact with infected surfaces or living areas, or even by insect bites, like mosquitoes and ticks.
Zoonotic diseases are incredibly common, but that doesn’t mean they’re not dangerous. H.I.V., Rabies, Ebola, Avian flu, and malaria are all zoonotic diseases that have had devastating human health impacts, and evidence suggests that 75% of emerging infectious diseases originate from animals.
As the climate changes, humans are put at greater risk of contracting zoonotic diseases. A warmer climate means that both humans and animals are changing their lifestyles and behaviors. Animals migrate to new areas searching for suitable habitat and people encroach further and further into previously undeveloped land, increasing the likelihood of contact.
The exact origins of COVID are still debated, but as a zoonotic disease, climate change increased its probability of spreading from animals to people.
Climate change and subsequent warming also influence the resilience of viruses and the capability of our immune systems. Part of the human immune response involves raising the body temperature in order to destroy viral proteins (aka fever). As global temperatures warm, there is concern that viruses will adapt to these new conditions. Viruses will be stronger and more resistant to high temperatures, and human immune systems will be less equipped to fight back.
Additionally, other anthropogenic impacts on the planet, such as air pollution and large-scale agriculture have adverse effects on human health. Increases in respiratory disease from pollution, or diabetes from nutrient-poor diets are comorbidities that can heighten the danger of COVID infections.
Disease and climate change also have more subtle and complex feedbacks.
2020 and 2021 were both some of the hottest years on record, with several instances of extreme weather. Incidents like tropical storms, wildfires, and flooding already influence public health, causing illness and injury, and forcing people to congregate to escape environmental disasters. Without these climate-related emergencies, COVID may have been easier to control and public health strategies like social distancing wouldn’t have been compromised.
Climate change didn’t directly cause COVID, but it created an ideal set of circumstances for it to spread from animals to humans, and then to people all over the world.
And as climate change becomes more severe, we can expect more zoonotic epidemics in the future. We’ve already seen a significant increase in zoonotic diseases over the past decade, and without drastic measures to curb warming and increase biodiversity, there will undoubtedly be more.
People can sometimes feel removed from climate change, especially if they live in a wealthy country, in a region with stable weather, and in relative financial comfort. But COVID affects all of us; it’s impossible to ignore.
It’s alarming to see COVID creep into the news again, but I hope that it can serve as a wake-up call for more than just public health measures. Climate change reaches deeply and insidiously into every facet of our lives, and the world is becoming a more dangerous place.