World Meteorological Organization (WMO), World Health Organization (WHO), August 2025

Climate Change and Workplace Heat Stress

The present guidance provides an overview and update of relevant evidence generated since 1969, when the technical guidance Health factors involved in working under conditions of heat stress was published by the World Health Organization.

The World Meteorological Organization has reported that 2024 was the warmest year on record, with the global temperature averaging 1.45°C above pre-industrial levels. The past ten years (2015–2024) have been the warmest on record, underscoring the continuing long-term trend of rising global temperatures due to climate change. The rise in global temperatures and especially the increased frequency of extreme heat events during the five decades since the publication of that seminal guidance underscore the need to update stakeholders. This guidance describes increased exposure risks, new discoveries and novel methodologies in the area of workplace heat stress, and evidence on solutions to prevent or minimize its negative consequences.