Workers farm at night to avoid intense heat – but it can lead to other negative effects

From farm workers in Brazil to India and the US midwest, shifting to a schedule where it’s dark out could mean dangerous conditions and less food

For years, Josana Pinto da Costa ventured out every morning on to the waterways lining Óbidos, Brazil, in a small fishing boat. Gliding over the murky, churning currents of the Amazon River basin, her flat nets brought in writhing hauls.

Scorching temperatures have now made that routine unsafe. The heat has “been really intense” this year, said Pinto da Costa, forcing her to shift her working hours to the dead of night.

She now sets off in the pitch dark to chase what fish are also awake before dawn. It’s taken a toll on her catch, and her wellbeing. But it’s the only way she can continue her work in the face of increasingly dangerous temperatures.

Many of the communities that catch, grow and harvest the world’s food supply are beginning to work when it’s still dark out, or even shifting to a fully overnight schedule as a way to cope with rising temperatures.

“The obvious piece of advice that you’ll see given is, ‘Work at night. Give workers head torches,’ and so on,” said Zia Mehrabi, a food security and climate researcher at the University of Colorado, Boulder. “But the reality is, that can lead to other rights violations, other negative impacts.”

Óbidos, Brazil: ‘More hours with less food’

For Pinto da Costa and other Brazilian fishers, night-time work has brought additional hardship to a community already struggling with the impacts of climate change. The region has experienced decades of severe drought causing fish to die off and physically isolating people as waterways dried up.

Research shows that regularly working during the night is physically and mentally disruptive and can lead to long-term health complications. Night-time fishing threatens social and communal routines: A daytime sleep schedule can curb time spent with loved ones, as well as limit when wares can be sold or traded in local markets.

It’s also affecting their ability to support themselves and their families through a generations-old trade. “We’ve actually been working more hours with less food, with less production,” said Pinto da Costa, who advocates nationally for fishing communities through the Movement of Artisanal Fishermen and Fisherwomen of Brazil.

Outdoor workers, with their typical midday hours and limited access to shade, face some of the greatest health risks during periods of extreme heat. A forthcoming analysis – previewed exclusively by Grist – found that, on average, the amount of time considered unsafe to work outside during a typical 9-to-5 workday will increase 8% by 2050, assuming greenhouse gas emissions stay on their current trajectory.

Currently, an estimated 21% of the global population already faces dangerous levels of heat stress during typical workday hours for more than a third of the year. By 2050, without cuts to planet-warming greenhouse gas emissions, that portion will jump to 39%, according to the analysis by Naia Ormaza Zulueta, a University of Colorado, Boulder PhDstudent, and Mehrabi.

“The number of days that people will experience a violation of their rights to a safe climate is going to substantially increase, but then also the number of possible working hours in a season, and productivity, is going to be substantially reduced,” said Mehrabi. “It’s a massive lose-lose situation.”

The analysis finds that outdoor agricultural workers will encounter the greatest health-related risks.

Workers in India, where there are roughly 260 million agricultural laborers, are projected to be among the most vulnerable. By 2050, 94% of the country’s population could face more than 100 days in a year when at least one hour exceeds a wet-bulb temperature of 82.4F – a conservative threshold of what is considered safe for “moderate” work. (Unacclimatized workers face higher risks.)

In Brazil, another top agricultural producer, outdoor workers also face substantial risk. By 2050, roughly 41% of the country’s population could experience more than 100 days a year of wet-bulb temperatures exceeding the recommended threshold for at least one hour a day, according to the Boulder analysis. In the United States they project that figure at 35% of the population.

Mary Jo Dudley, the director of Cornell University’s Farmworker Program and the chair of the US National Advisory Council of Migrant Health, said that the analysis was significant for what it reveals about how extreme heat affects the health of the world’s agricultural laborers. She’s seeing more outdoor agricultural workers in the US adopt overnight schedules, adding to the burdens and inequities they already face.

“This transition to a night-time schedule pushes an extremely vulnerable population into more difficult work conditions that have significant mental and physical health impacts,” said Dudley.

Rebuking the human body’s circadian rhythms – that 24-hour internal clock that regulates when you sleep and wake – ramps up a person’s risk of health complications, such as cardiovascular disease and types of cancer, and diminishes the body’s ability to handle injury and stress. Working non-traditional hours also can reduce a person’s ability to socialize or participate in cultural, communal activities, which are associated with positive impacts on brain and body health.

Women are particularly vulnerable to the social and economic impacts of transitioning to night-time schedules. Despite making up nearly 45% of artisanal fishers in Brazil, women earn less than their male counterparts. When harvests decline with night-time fishing, their margins are even smaller. Night-time hours also clash with gendered family roles, such as caregiving, said Mehrabi. “When you talk about changing working hours, you talk about disrupting families.”

Shifting working hours to the night-time “is not a universally applicable solution”, said Zulueta, the Boulder study author. “When I saw that … people were giving this advice of changing their working shifts to the night, I was shocked,” she said, citing a paper published earlier this year.

Growing up in Ahmedabad, India, Bhavana Rabari has spent much of her life tending to her family’s buffalo. She is now an advocate for pastoralists but the routine is still ingrained in her: wake up, feed and milk the herd, and then tend to the fields.

But extreme heat threatens that schedule. When temperatures soar past 90F in Ahmedabad – now a regular occurrence – Rabari worries about her mom, who hand-collects feed for their herd.

“If we lose our livestock, we lose our culture, our dignity,” said Rabari.

Rabari said she didn’t see tending to the herd in the dark as safe or accessible for her family or others in her community, some who walk at least 10 miles a day. “We are not working at night,” she said. But her family does rise at 5am to beat the heat, collecting milk from their buffalo and preparing products to sell in the market.

Hotter temperatures have already caused pastureland to wither, meaning animals are grazing less and producing less milk. Fewer safe working hours means, on top of that, even less income.

The result has been an exodus from the trade. Rabari said that many younger pastoralists she knows are now seeking employment as drivers or cleaners in urban Ahmedabad. Rabari, an organizer with the Pastoral Women Alliance, said women are most often the ones left behind to tend to the herds.

They “have to take care of their children, they have to take care of the food, and they have to take care of the water”, she said. “They face the heat, they face the floods, or the excess rain.”

Iowa, United States: ‘It would be far more dangerous’

Halfway across the world, April Hemmes is facing unrelenting heat in Hampton, Iowa. A fourth-generation soya bean and corn farmer, Hemmes works more than 900 acres on her own.

Human-caused climate change has battered the midwest, one of the world’s leading agricultural producers. Scientists only recently declared an end to a drought that had devastated the region for 203 weeks. The conditions affected crop yields, livestock, the transportation of goods and the larger supply chain.

This past summer, the heat index in Iowa repeatedly soared past 100F. To avoid dangerous heat exposure, Hemmes took frequent breaks and made sure to finish the bulk of the day’s work in the morning. She began her day in the fields an hour or so earlier.

“This [farm] has been in my family for over 125 years,” said Hemmes, who took over operations after her grandfather and father both retired in 1993. “I do everything from banking to planting to spraying, everything. So it’s all on me, and it’s my family farm.”

But for Hemmes, night-time work is out of the question.

Not only are summertime mosquitoes in Iowa “terrible after dark”, and she’d need to install lights throughout the fields, but Hemmes says some of the chemicals she uses have restrictions on when she can spray them.

“It would take more energy to work at night,” said Hemmes. “I think it would be far more dangerous.”

As a member of the United Soybean Board, Hemmes advocates for women in agriculture and on ensuring solo operations like hers can access the technology they need to overcome heat spells.

On her own farm, she credits an autonomous tractor as one of the reasons she’s able to manage hundreds of acres on her own.

For workers around the world, it’s a race against time. Eventually, even working at night may not be enough to keep outdoor agricultural work viable. The Boulder researchers found that working overnight will not significantly reduce heat exposure in key agricultural regions – particularly across India. After all, heatwaves also occur at night, and overnight temperatures can rise even more rapidly than daytime highs.

“How do you solve a problem like that?” said Mehrabi. “The reality is that the workers most at risk are the people contributing least to the climate change problem.”

Cover photo: Dror Cohen/Grist