TAIPEI (Taiwan News) — Academia Sinica and Harvard researchers have found that extreme heat reduces outdoor labor output by 29-41.3%, warning of mounting economic costs.

The study, conducted with Harvard T. H. Chan School of Public Health, found that light-duty workers were the most vulnerable, losing up to 50% of their productivity under extreme heat conditions, per CNA.

Between 2016 and 2018, researchers tracked 101 construction workers at 10 sites in Taipei and New Taipei using wearable sensors developed by Academia Sinica’s Institute of Information Science. Data showed that construction sites in Taipei’s basin regularly reached 47-48 C with humidity close to 100%.

Lung Shih-chun (龍世俊), Deputy Executive Secretary of Academia Sinica’s Center for Sustainability Science, explained that Taipei’s topography traps heat and reinforced concrete absorbs and radiates it, turning building sites into steamers. She noted that the results confirmed the economic burden heat stress imposes on labor-intensive industries.

Light-duty workers such as masons and welders showed greater productivity losses than those performing heavy labor. Lung explained that while heavy lifting causes quick fatigue and encourages breaks, lighter tasks often leave workers in the sun for hours, leading them to overlook rest.

The study also showed that while local workers were analyzed for heavy labor tasks, many such jobs are carried out by migrant workers. Lung cautioned that losses may be even more severe if migrant labor is included.

According to the Occupational Safety and Health Administration, over the past five years, more than 9,000 outdoor heat hazard inspections were conducted annually, with more than 3,000 cases requiring corrective measures, CNA reported. From 2020 to 2024, labor insurance compensated 28 cases of heat-related illness, including three deaths.

Lung recommended that authorities adopt the Wet Bulb Globe Temperature system used in Europe, arguing it better reflects real on-site dangers.