The Story of Climate Change Is Being Written in the Kidney

"The first epidemic directly caused by global warming" exposes the inequities of climate change.

Photo by Haifsa Rafique on Unsplash

The kidneys are a pair of organs; they look a bit like beans. Each one is packed with one million nephrons, filtering units that remove waste and extra fluid, and keep a careful balance of water, salts, and minerals in your blood. The wastes and fluid leave your body as urine, and the substances your body can still use are returned to the bloodstream. The kidneys work nonstop, and filter about 200 liters of blood per day.

Because of its crucial role in maintaining blood volume, and minimizing fluid loss while also ridding the body of waste, the kidneys are susceptible to damage when our bodies heat up. And as the planet warms, year by year, so do we — putting undue stress on our kidneys.

But we're not all warming up equally, are we? And climate change's burden on our kidneys — which can lead to a lifelong, disruptive medical condition, or even death — is not shared equally either. To look at the rising rates of chronic kidney disease worldwide is to see the disparities of climate change: a global story written in miniscule blood vessels.

Why can't I stop thinking about the kidney, when I think about climate change and its inequitable impacts?

A Mysterious Epidemic

In 2002, researchers noticed a mysterious epidemic of kidney disease in Central America, concentrated among those working in manual labor, but particularly among sugarcane farmworkers, who work in hot, humid conditions outdoors. Between 2002 and 2015, over 20,000 people in Central America died of unexplained chronic kidney disease (CKD), many of them sugarcane farm laborers. Scientists dubbed it Mesoamerican endemic nephropathy, different from other types of kidney disease because it wasn't accompanied by diabetes or hypertension, the usual risk factors for CKD.

What was causing it? Was it exposure to environmental toxins through pesticides or other pollutants? Was it poor access to healthcare and inadequate health infrastructure? Was it that people had to rely on soda because they lacked clean drinking water? Or was it the punishing heat at work, temperatures far higher than the legal limit for workplaces in the US? Was it the near-constant state of dehydration that resulted from that heat?

There is still no definitive answer, and the truth is that all of those factors may have some impact. But as the planet has gotten hotter, increased reports of acute kidney injury and epidemics of CKD have emerged in other agricultural communities located in hot climates, including Andhra Pradesh in India, the north central province of Sri Lanka, central Florida, and the Central Valley of California. “This could be the first epidemic directly caused by global warming,” according to Richard J. Johnson of the University of Colorado Anschutz Medical Campus, who authored a paper called "Climate Change and the Kidney."

Why can't I stop thinking about this? I think it is because — like climate change — those at the greatest risk of kidney disease are already vulnerable to so many other disruptions. Like climate change, CKD exposes the cracks in so many broken systems, and heaps the falling rubble on the people already carrying more than their fair share.

In the US, there are no federal regulations to protect agricultural workers from extreme heat, one of many ways that farmworkers are shut out of federally-mandated workplace protections in this country. It took the heat-related death of a plant nursery employee to push Oregon to change its state regulations, now requiring employers to provide shade, rest breaks, and cool water when temperatures hit 80 degrees F. With the exception of a few other states that have enacted similar protections, these basic, commonsense, and humane regulations are missing. 

And there are other factors that make farmworkers additionally vulnerable to heat stress, an article from Grist points out:

Labor laws in the U.S. prevent most farmworkers from unionizing, so they lack leverage in negotiations with employers. Most farmworkers are either undocumented or in the country on H-2A temporary work visas, which are tied to a single employer —  if workers complain or otherwise cause problems for employers, they risk deportation. Many farmworkers don’t speak English and lack access to affordable healthcare. Workers often aren’t paid an hourly wage but on a piece-rate basis; getting paid by the bucket, bundle or pound can disincentivize workers from taking a break, advocates say. And crew leaders, who are employed by farms to oversee workers, often get paid bonuses based on how much their crews harvest. 

Who Bears the Burden?

Why can't I stop thinking about this? It's because I had a dietetic internship rotation at two dialysis sites in New Orleans, which I wrote about in an earlier essay:

The hard thing about my dietetic internship was that as this diagram [of the regional food and nutrition system] took shape, the inequities in the system were so clear, and the system was so full of them, it was overwhelming. And the people at a disadvantage were always disproportionately Black. For example, the dialysis clinics I worked in were almost entirely attended by Black clients—African Americans are almost four times more likely than white Americans to experience kidney failure, a difference attributed to racial disparities in food, housing, employment, education, and health care—and these undeniable numbers were gutting.

How I Became an Antiracist Dietitian

The hours upon hours spent in the dialysis chair multiple days a week; the phosphate binder pills that made some patients nauseous; the diet that restricted high-phosphorus foods like chocolate, cheese, ice cream, and beer, high-potassium foods like oranges, bananas, tomatoes, most greens, and beans, and high-sodium foods. I hated having to admonish people for eating red beans and rice, their mother's collard greens, last night's crawfish boil. Food is joy, especially in New Orleans — it felt wrong that this joy was being stripped from Black New Orleanians disproportionately because of racism, past and present, built into neighborhoods, schools, markets, and workplaces.

And then there was the heat, and what people with end-stage renal disease (ESRD) can do about it. Overhydration is dangerous, so fluid intake is limited. Have you been to New Orleans in August? Have you been to New Orleans in August and only allowed to drink 32 ounces of water — that's one Nalgene bottle — for the entire day? Access to air conditioning and neighborhood tree cover also have racial equity gaps, with Black households less likely to have air conditioning, and historically Black neighborhoods less likely to have tree-shaded streets.

(I'm not suggesting that life is hopeless if you have ESRD, but it is certainly more difficult than life without it, and those difficulties are disproportionately heaped onto BIPOC individuals, who face greater risk of CKD than white people.)

Our Bodies, Our Health, Our Histories

Why can't I stop thinking about the kidney, when I think about climate change and its inequitable impacts? Because I experienced the acceleration of extreme weather events as a result of climate change. My last hurricane season in Louisiana, in 2020, broke records for the number of named storms (30) and the number of storms that made landfall in the state (5). Hurricane Zeta hit New Orleans and knocked out power for a couple days, but it was nothing compared to Hurricane Ida the following year, the second most destructive hurricane to hit Louisiana.

I'm writing these words, but you can't understand the stress and disruption of the continual threat and inevitable aftermath of extreme weather events on the lives of people living on the Gulf Coast unless you have lived it. And I can't imagine the additional stress, fear, and health risks of these events for those who rely on dialysis to live. What do you do when there is no power or clean water? How do you find help when the streets are impassable, public transit is shut down, and you don't have a car? Who has to answer these questions in order to survive? Who has never had to think about them?

In Inflamed: Deep Medicine and the Anatomy of Justice, Rupa Marya and Raj Patel compare the inflamed systems of our bodies to the structural injustices of the world we live in.

The root of a diagnosis is a knowledge of antecedent parts that make sense of the present in order to change the future. Without taking into account the myriad ways systemic injustice impacts the body, the standard medical narrative connecting the past, present, and future falls short, lacking the explanatory power to address and change the course of illness….

Today’s medical and social sciences have a hard time navigating the connections between our health, our histories, and our societies. Academic silos are partly to blame. Hospitalists, historians, and sociologists rarely interact. But even this disconnect speaks to a deeper problem, woven into the origins of modern medicine. Most doctors—most humans, really—have unwittingly inherited a colonial worldview that emphasizes individual health, disconnecting illness from its social and historical contexts and obscuring our place in the web of life that makes us who we are.

Will we listen to the stories being written in the bodies of those at the frontlines of climate change? Can we afford not to?

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