On June 26, the temperatures south of Portland, Oregon, approached 105 degrees Fahrenheit (40.6 degrees Celsius). That didn’t stop Sebastian Francisco Perez, a Guatemalan farm worker, from going to work moving irrigation lines at a nursery. At some point, as the scorching afternoon dragged on, he collapsed and died. When Occupational Safety and Health officials turned up to write a preliminary report on the incident, they were concise with their description: “Heat.”Perez was one of at least 384 workers who died of heat-related causes in the U.S. over the past 10 years, according to a recent report by NPR and Columbia Journalism Investigations. Despite new protective measures just announced by President Joe Biden’s administration, the next decade is shaping up to be worse. With higher temperatures and longer heat waves already threatening outdoor workers, few employers or regulators have taken adequate steps to protect them. Even under normal circumstances, there are no shortages of risks on the farm. Machinery, animals and chemicals all present potential hazards. Weather adds to these dangers, especially during planting and harvest, when the work simply can’t stop, and farm workers (often paid by the piece) typically don’t want to. Floods, lightning and high winds are constant threats. But in the U.S., at least, heat remains the leading cause of weather-related injury and death.According to one study, farm workers are 35 times more likely to die of heat-related illnesses than those in other occupations. The strenuous nature of the work is one reason. But so, too, is the nature of the workforce. Of the more than 1 million crop workers in the U.S., three-quarters are foreign-born and only about half are documented. With limited legal standing, these workers are reluctant to report injuries and vulnerable to exploitation. Only a handful of states have permanent heat regulations for outdoor workers. The need for change is urgent. Currently, the average American farm worker is exposed to 21 unsafe working days due to extreme heat each year. If global temperatures rise by 2 degrees Celsius — the goal established by the Paris climate agreement — those workers will face 39 days of extreme heat. According to a new study from the Union of Concerned Scientists, the number of days that feel like they exceed 100 degrees Fahrenheit could more than double by midcentury. For many workers, it will be even worse. Imperial County, California, a major agricultural region, could see heat-indexed extremes topping 115 degrees, a level that U.S regulators label “high risk” for illness.The human costs of this warming became all too evident this past summer. The heat wave that struck the Pacific Northwest in June led to some 600 excess deaths, according to one analysis, including Sebastian Perez. Less certain, but no less real, were the financial losses imposed on workers and businesses. By one estimate, a collective $55 billion in outdoor workers’ earnings could be at risk annually in the U.S. by midcentury due to extreme heat. If farm workers are idle, the food supply chain will need to adjust, most likely with higher prices.Regulation could help forestall the worst. Perez’s death was one factor inspiring Oregon to issue emergency heat-related rules for outdoor workers this summer. The new regulations mandated shaded breaks, access to adequate drinking water, training to recognize heat illness and similar measures. Other states — especially those that employ lots of farm workers — should do the same. Promisingly, Biden’s initiative should lay the groundwork for a long-overdue federal heat standard, even though the process will likely take years. Any of these steps would be a benefit to workers. But they shouldn’t obscure the bigger picture. Without meaningful action to curb heat-trapping carbon emissions, temperatures will continue to rise inexorably. In recent years, farmers and other contributors to the food supply chain have become far more vocal about the need to adapt their practices to a changing climate, or face lower yields and profits. So far, policy makers haven’t done much in response.In that sense, at least, tragic figures like Sebastian Perez are a harbinger of worse days to come. Failure to act won’t make these problem go away. Instead, they’ll just grow hotter.