What 1,000 Women Workers Can Teach Us About Surviving Extreme Heat

In September 2026, the United Nations Environment Program revealed that the world had failed to limit global warming to 1.5°C above pre-industrial levels, signaling an urgent need for action. That same week, NPR reported that extreme heat claimed nearly five times more lives in the United States than official records showed. This followed two consecutive summers marked by brutal heatwaves, which dominated news cycles in Europe as aging infrastructure struggled to keep up.

"Heat domes" trapped heat in various parts of the United States, affecting over 100 million people at a time. Among those impacted were construction workers, outdoor laborers, delivery workers in unairconditioned vehicles, farmworkers, the homeless, the economically disadvantaged, individuals with mental health disorders, and those with limited access to healthcare.

While death counts from heatwaves provide a measure of heat's impact, they often miss the broader consequences on human life. According to the International Labor Organization, billions of workers worldwide are exposed to extreme heat every year, many of whom do not succumb to the heat but suffer greatly from its relentless, unforgiving nature.

The quantification of heat's impact on mental health, physical well-being, wages, food security, habitat, and infrastructure is notably complex. To address this, a thousand women from India's informal labor economy have joined the Self Employed Women’s Association in India's Community Heat Adaptation and Treatment Strategies (CommHATS) study.

This study, in collaboration with Harvard, involves women from various trades such as street vendors, waste recyclers, home-based artisans, and farmers. Over 13 months, each participant wears a wearable wrist device that measures heat and humidity at home and work, undergoes lab tests for critical biomarkers, and completes surveys documenting their living and working conditions, well-being, and wages.

The data collected from this comprehensive study aims to create one of the largest databases globally on the impact of heat on human health. It seeks to answer questions such as the effectiveness of cool roofs, the appropriate metrics for measuring success, and the threshold for heat insurance products. In India, where over half of women of reproductive age suffer from anemia, heat further strains the heart.

Community meetings and WhatsApp groups facilitate the dissemination of research findings to all participants, who actively engage in discussions about how the data can improve their lives. Early results indicate devastating wage losses on hot days, reduced sleep spans, and heightened cardiac stress. These findings underscore the need for heat adaptation measures beyond OSHA regulations and market solutions, especially in regions like India, where over 90% of workers are informally employed and lack employer accountability.

The project, implemented by grassroots workers, emphasizes its ease of use and potential to adapt to communities worldwide. The data collected not only measures exposure but also evaluates the effectiveness of interventions, revealing that the cost of inaction is already borne by the most vulnerable. While millions may endure extreme heat without entering official death counts, their lives remain compromised and diminished, highlighting the urgent need for comprehensive heat adaptation strategies.