Two years ago, Michelle Tigchelaar, a climate scientist doing postdoctoral work at the University of Washington, learned about a blueberry picker in the state who had died following a period of high heat and smoke from nearby forest fires. His coworkers complained of infrequent breaks and inadequate access to water.
“That event opened my eyes to the human impacts of climate change and agriculture,” says Tigchelaar, who notes that most studies in that field “focus on biophysical factors like crop production or crop pests in row crops.”
Every year, about five farmworkers die, officially, from heat-related illness. But that number is likely an undercount, as some surveys exclude workers on small farms and heat deaths are often recorded as heart attacks or strokes. Occupational heat stress has also been linked to adverse mental health outcomes, increased risk for traumatic injuries, and kidney failure, according to a 2017 FERN story.
Whatever the true death toll from high heat, it’s expected to rise sharply in coming years. According to a study led by Tigchelaar, who is now at Stanford University, the number of unsafe days in crop-growing U.S. counties will jump from today’s 21 per season to 39 days per season by 2050, when global temperatures are predicted to rise by 2 degrees Celsius. The near doubling of unsafe days implies a near doubling in deaths.
By 2100, when the world is 4 degrees C warmer, the number of unsafe days each year is expected to rise to 62. Tigchelaar notes that her team’s estimates of harm are likely conservative: her models assume workers are young, healthy, and hydrated when in reality many farmworkers are older and have underlying conditions, including poverty, that increase their vulnerability to illness.
To explore how farmworkers might cope with extreme heat, Tigchelaar and her co-authors modeled four potential adaptations: slowing down in the field, taking longer breaks, wearing thinner and more breathable protective clothing, and shifting work breaks to air-conditioned rooms. Tigchelaar acknowledges that working less isn’t a perfect remedy.
“It’s not in farmworkers’ interest to lower their pace, because they’ll earn less,” have their piece rate reduced, or perhaps even get fired. The single most effective remedy, the researchers found, would be shifting to highly breathable clothing, but such material may not provide protection from agricultural chemicals and dust. More to the point, this perfect garment doesn’t yet exist.
Extreme heat will affect half of the nation’s agricultural counties by mid-century, but nowhere in the U.S. looks worse than the Southeast, where “the entirety of the growing season will be considered unsafe for agricultural work with present-day work practices,” according to the paper, published in Environmental Research Letters.
Analyzing hourly data from weather stations from 1975 to 2013, another group of researchers recently discovered that globally, extreme humid heat has more than doubled in frequency since 1979, with hot spots along the Gulf Coast in East Texas, Louisiana, Mississippi, Alabama, and the Florida Panhandle. High humidity is a problem for ag workers and others who toil outdoors because sodden air slows the evaporation of sweat, preventing the body from cooling itself.
Worker and workplace adaptations, it turns out, will go only so far in protecting farm laborers from high heat. The real remedy lies in systemic changes — shifting away from piecework, for example, and improving worker housing, which influences how well workers rest and recover from high temperatures. Farm owners could invest in mechanization or shift to crops that ripen in spring or fall instead of summer. More broadly, the federal government could adopt — and enforce — outdoor occupational heat standards that mandate appropriate breaks, adequate personal protective equipment, shade, hydration, and exposure monitoring.
But ultimately, Tigchelaar and her co-authors note, the impacts of extreme heat on farmworkers can be alleviated only by rapidly reducing carbon emissions and increasing carbon sequestration. In other words, by fighting global warming.