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Climate Change Multiplies the Threats of Infectious Diseases

Global warming can lead to compromised immune systems, which in turn makes individuals more susceptible to diseases.

People walk in flood water after a heavy rainfall in Peshawar, Pakistan, on April 15, 2020.

As the novel coronavirus continues to rage like a wildfire across the planet, its devastating toll has left many asking whether climate change — another multifaceted phenomenon with global reach — has played a part in spreading, even triggering, the pandemic. Some, like Katharine Hayhoe, a climate change scientist and professor of public policy at Texas Tech University, have been able to provide answers.

“Climate change didn’t cause the pandemic, and climate change directly causes very few of them,” Hayhoe told Truthout. “But what climate change does is it interacts with, and in many cases has the potential to exacerbate the impacts.”

For those well-versed in the mechanics of climate change, this comes as no surprise — scientists, policy makers and other experts have long acknowledged the links between global warming and the spread of infectious diseases, promulgating the sorts of findings described in the wide-ranging 2018 Intergovernmental Panel on Climate Change report, detailing what efforts are needed to limit global warming to 1.5 degrees Celsius.

Dig down, and this multilayered issue has knock-on effects — from the way rising temperatures exacerbate certain health problems to the disruptions that extreme weather events have on the global supply chain — that are inextricably linked with one another. What’s more, the governmental response to the coronavirus crisis, say experts, offers a troubling glimpse into what might happen in the future as the global thermometer inches upwards.

“What it underscores in the first instance is how underprepared we are,” said Sherri Goodman, a senior fellow at the Wilson Center’s Environmental Change and Security Program and Polar Institute. As a former first deputy undersecretary of defense in environmental security, she coined the term “threat multiplier” to describe climate change’s kaleidoscopic impacts.

“Our systems — institutional, infrastructure, health, emergency response — could all be overwhelmed from the climate crisis,” Goodman said, warning that the time for wholesale climate resiliency preparedness is upon us. “What we have now is history accelerating itself — things are happening so fast.”

“Where Can These People Go?”

Perhaps most salient in terms of current events is the issue of zoonotic diseases spread between animals and humans, like the COVID-19 virus, which is believed to have originated in bats before being transferred to humans via scaly animals like pangolins. As the world’s population growth continues to rise, natural habitats will continue to be encroached upon and destroyed, not only removing valuable carbon sinks like rainforests but creating environments in which notorious zoonotic disease carriers like bats and rats thrive.

Climate change is also likely to encourage the spread — both in terms of seasonal risk and geographic reach — of “vector-borne” diseases. These are illnesses like West Nile Virus and Lyme Disease that are borne by mosquitoes, ticks and fleas, and already account for a significant number of deaths annually.

According to Sheri Weiser, a professor of medicine at the University of California, San Francisco (UCSF), there’s still much to learn about how rising temperatures are impacting the spread of infectious diseases. “But we know the common cause of climate change and COVID-19 — the globalization that’s driving fossil fuel emissions — contributes to the pre-conditions that pave the way for viruses like that,” Weiser said.

Indeed, there’s already an extensive library of medical literature detailing how climate change can impact human health. Extreme weather events — a symptom of a warming planet — can lead to fluctuating temperatures which have been shown to contribute to and worsen cardiovascular and cerebrovascular diseases, kidney disorders and a host of other illnesses. On top of that, extreme heat and humidity can limit the effectiveness of certain medications used to treat these conditions.

Of course, the burning and consumption of fossil fuels can be a dirty business, responsible for the majority of global greenhouse gas emissions and worsening air quality. Air pollution is the fifth leading cause of death worldwide, killing nearly 5 million every year through issues like respiratory and heart disease, strokes, lung cancer, diabetes and pneumonia.

“We even have data showing very strong links between metrics of climate change and HIV prevalence,” Weiser said, noting how converging risks from global warming can lead to compromised immune systems, which in turn makes individuals more susceptible to diseases like COVID-19.

And so, which communities are most at risk?

“Well, how are people placed in certain areas, and why?” asks Adrienne Hollis, the senior climate justice and health scientist at the Union of Concerned Scientists, pointing to low-income communities of color who bear the brunt of the impacts from climate change, and suffer the highest rates of chronic health problems. African Americans are three times more likely to die of asthma than any other group, and are bedeviled with higher rates of heart disease, for example. Prison populations — who are on average five times more likely to be living with HIV than the non-incarcerated — are also especially vulnerable to the spread of diseases like Covid-19.

Then there’s the issue of a growing homeless population nationwide. “At times of extreme heat and extreme weather, where can these people go? Especially when some shelters are only open for certain periods of time, and some people have been turned away based on gender identity,” said Hollis. What’s more, limited hygiene options, coupled with close living quarters, can exacerbate the problem for those who do find temporary shelter. “This is a very at-risk population.”

“Fear Is at the Very Bottom of This”

Global warming might shape the spread of infectious diseases in ways that aren’t quite as overt as mosquito-borne diseases. “Infrastructure problems” is an umbrella term involving anything from roads and bridges crumbling from over-pumping of groundwater during a drought, to commercial ports struggling under rising sea levels. As it relates to the spread of infectious diseases, these sorts of problems interfere with the distribution of supplies and goods, therefore hampering organized responses to a major health crisis.

Another pressure point under duress during the COVID-19 pandemic concerns the supply chain of food and other necessary items throughout the lockdown. Imagine, say experts, if the spread of the disease had coincided with an extreme weather event that disrupts the usual flow of essential goods into the marketplace — flooding in the Midwest, for instance, which destroys vast quantities of crops. In this event, food and other crucial supplies could become critically scarce. “The chances of this happening are only going to increase,” says Tracey Woodruff, director of UCSF’s Program on Reproductive Health and the Environment.

From a global perspective, climate change-related droughts, food shortages and extreme weather patterns are a driving force behind mass migration, which fosters the sorts of environments — unsanitary conditions in cramped refugee camps, for example — in which diseases proliferate all too easily.

“We already have the greatest wave of global migration since World War II, aggravated by political disorder and conflicts in the Middle East and North Africa, ungoverned spaces, violent extremism and oppressive regimes,” said Goodman. “But in-built upon that fact is that drought comes with water scarcity, water stress and food insecurity that puts vulnerable populations at risk.”

Which begs the question: What needs to be done to better prepare for the challenges that lie ahead?

First things first, “this should illustrate to people how important it is to have a strong government that can intervene where the private sector can’t,” said Weiser, noting how a solid foundation of science and data should guide any federal intervention. But in this regard, the Trump administration’s slash-and-burn approach to the scientific wing of the federal government is the elephant in the room during the COVID-19 pandemic.

Last September, for example, the U.S. Agency for International Development (USAID) effectively shuttered its PREDICT program, which was charged with identifying and combating new emerging viruses. With the COVID-19 death toll in the U.S. now well into five figures, USAID has injected more than $2 million to kickstart the program, at least temporarily. The Environmental Data and Governance Initiative recently found that the Trump administration has repeatedly, “and sometimes successfully,” sought to cut funding aimed at the Centers for Disease Control and Prevention for fighting global pandemics. Nevertheless, the Trump administration isn’t alone in neglecting science and research; for nearly two decades now, the amount of federal funds funneled toward basic research has shrunk markedly.

In the same vein, drastic action also needs to be taken to reverse the ongoing deterioration of the nation’s infrastructure, “which is going to take a massive investment,” said Hollis. Indeed, every four years, the American Society of Civil Engineers grades the state of the nation’s roads, bridges, water systems and electric grids. The last grade? A terrible D +.

“We’re still today building and rebuilding to outdated standards,” said Goodman, emphasizing the need to cater modernization efforts to demands peculiar to a warming planet. “We can no longer rely on the historical records to be an adequate predictor.”

Nevertheless, when it comes to the key ingredient in tackling climate change — reducing our dependency on fossil fuels — some, like Hayhoe, are skeptical that the COVID-19 pandemic will trigger the necessary economic reorientation.

“If you go to Wikipedia [or] Google ‘richest corporations in the world,’ this really brings it home,” said Hayhoe, highlighting how six of the top 10 wealthiest global companies are in oil and gas, while another is directly tied to the energy sector.

“The politicization of climate change, the public arguments, the lack of action and the stalemates are just a symptom of a greater problem that plagues our society: The incredible divisiveness … that is driven by different ideologies and perspectives which are ultimately driven by fear,” she added. “Fear is at the very bottom of this.”