Mapping Extreme Heat to Protect Farmworkers in California

Sat Oct 25 2025 11:21:27 GMT+0300 (Eastern European Summer Time)

As climate change intensifies, researchers in California's Imperial Valley are studying the impact of extreme heat on farmworkers to develop strategies for better protection.

In the Imperial Valley, temperatures are rising, posing severe health risks for farmworkers like Raul Cruz. Researchers from San Diego State University study environmental factors and heat stress, hoping to develop effective interventions. With summer temperatures reaching dangerous levels, understanding heat patterns is critical for safeguarding these workers' health.

In the summers, the sky is jet black when Raul Cruz arrives at this Imperial Valley sugarcane field to start his day. He chops, cleans and bundles the crop, taking heed as the sun rises. It’s hard work, but so is starting at 4 a.m., even though he knows it’s the safest thing when temperatures in this California desert frequently soar into the triple digits.

“We just have to because we need to beat the heat,” said Cruz, who’s worked here for 15 years. They finish work by 9 or 10 a.m. to avoid the risk of heat stroke, he added, but when heat starts creeping up around 8 a.m., “mentally, it’s stressful.”

The hot climate that makes this Southern California region a farming powerhouse is also what makes it dangerous for farmworkers, who are increasingly vulnerable to rising temperatures due to greenhouse gas emissions from burning coal, oil and natural gas. Researchers from San Diego State University are working to understand the health consequences of heat stress on farmworkers and where heat is most extreme in this rural landscape. They hope their findings can lead to a better understanding of rural heat islands, identify gaps in research and help develop interventions that better protect them in the face of climate change.

“Workers could potentially be dying or having some serious issues,” said project leader Nicolas Lopez-Galvez, assistant professor in the School of Public Health at SDSU. “It’s better to start acting sooner.”

Since the start of the 20th century, California temperatures have increased almost 3 F (about 1.7 C), according to state and federal data. Warming has accelerated, and seven of the state’s last eight years through 2024 were the warmest on record. While all areas of the state have warmed, Southern California is heating up about twice as fast as Northern California.

Ana Solorio, an organizer with the farmworker advocacy group Líderes Campesinas that is working with researchers, remembered feeling “suffocated” in the Coachella Valley summer heat when she was a farmworker. “With the humidity, it felt awful,” said Solorio, who’s lived in the Imperial Valley for more than 30 years. The heat was so intense she didn’t return for another season, preferring instead the cooler winter harvesting months of lettuce in the Imperial Valley.

“This (heat) can cause a lot of harm to their health,” she said.

Through ongoing research, the authors have been able to recommend how frequently farmworkers should take rest breaks to protect themselves from heat stress, based on how often wet-bulb globe temperatures exceed safety thresholds across seasons and work shifts. While California has heat rules, they’re not strictly enforced, he added.