Heat stress cost India $9 per tonne of CO2 in lost labour productivity in 2025

Heat stress caused a significant loss to India's labour productivity in 2025, PTI reported, citing a study. According to a study published in Nature Climate Change, India lost an estimated $9 in labour productivity for every tonne of carbon dioxide emitted in 2025.

The study also included other countries, including Nigeria, which recorded a productivity loss of $6 per tonne of CO2, followed by China at $4 and Pakistan at $3. Globally, each tonne of carbon dioxide emitted in 2025 was estimated to have cost $41 in lost labour productivity, the study said.

"Our study contributes to the body of evidence about what the real costs of climate change are," said lead author Frances Moore, a professor in the Department of Environmental Science and Policy at the University of California, Davis.


"Based on these new numbers, labor is the second-largest contributor to the total social cost of carbon, just behind heat-related deaths," Moore said.

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What is the social cost of carbon?

The social cost of carbon, or SC-CO2, is the quantifiable cost of one additional tonne of carbon dioxide emissions. This measurement is highly relevant, as it could help in making policy-related decisions, infrastructure planning, utility regulation and carbon taxes, the researchers added.

The study also revealed that, on a per-capita basis, the damages were concentrated in parts of the Middle East, including Qatar, the United Arab Emirates and Iraq, as well as sub-Saharan African countries such as Niger, Somalia and Nigeria.

Outdoor jobs bear the brunt of rising heat

The research focused on projections related to the heat stress measure known as wet-bulb globe temperature (WBGT), along with job- and region-specific estimates of work intensity and outdoor exposure across economic sectors.

WBGT takes into account the risks posed by heat and weather conditions that can hamper the human body's ability to cool itself, such as humidity and wind speed.

Heat exposure varies across different regions and occupations. Agricultural and construction workers were found to face much higher exposure to heat than office and service workers. Indoor workers were not immune, particularly those working in spaces with little or no air conditioning.

"Heat is very dangerous. Employers and policymakers need to be treating it as the real health hazard that it is and thinking seriously about ways to mitigate those damages because we're going to keep seeing more frequent, more intense heat extremes," Moore said.

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How to deal with it

The researchers highlighted that some measures can be taken to reduce the impact of heat, such as providing more shade and water and allowing additional breaks. Meanwhile, strenuous work could be shifted to cooler hours, which would further lower the risk from heat and also help tackle productivity losses.