WHO & WMO: Supply Chain Risks After Concerns of Extreme Heat

The World Health Organization (WHO) and the World Meteorological Organization (WMO) publish a joint report warning that extreme heat linked to climate change is no longer only a health issue but also a supply chain risk.

The guidance, based on five years of evidence, urges governments, employers and unions to prepare workers and industries for higher temperatures. Without adaptation, productivity, safety and business continuity face disruption.

The Intergovernmental Panel on Climate Change frames the issue clearly: "Since systematic scientific assessments began in the 1970s, the influence of human activity on the warming of the climate system has evolved from theory to established fact." 

That warming translates into more frequent heatwaves, directly shaping how goods are produced, transported and delivered.

Workforce risks

WHO and WMO emphasise that the rise in extreme heat already affects billions of workers.

Manual sectors including agriculture, construction and fisheries are most exposed, but indoor industries reliant on machinery and warehouses also face risks. 

The WMO states: “Globally, population exposure to heatwaves will continue to increase with additional warming, with strong geographical differences in heat-related mortality affecting those with the least resources and without additional interventions and adaptation.”

Health impacts of heat stress include dehydration, kidney dysfunction, neurological disorders and heatstroke. These conditions not only endanger workers’ lives but also reduce available labour hours across global industries.

Productivity falls by 2–3% for every degree above 20°C, creating ripple effects along supply chains.

Ko Barrett, WMO Deputy Secretary-General, says: “Occupational heat stress has become a global societal challenge, which is no longer confined to countries located close to the equator, as highlighted by the recent heatwave in Europe.

"Protection of workers from extreme heat is not just a health imperative but an economic necessity.”

This link between labour capacity and supply reliability makes the issue central to business planning. 

Dr Jeremy Farrar, WHO Assistant Director-General, Health Promotion, Disease Prevention and Care, adds: “Heat stress is already harming the health and livelihoods of billions of workers, especially in the most vulnerable communities. 

“This new guidance offers practical, evidence-based solutions to protect lives, reduce inequality and build more resilient workforces in a warming world.”

Supply chain vulnerabilities

The report makes clear that supply chains relying on continuous human labour will face bottlenecks as temperatures climb. 

2024 ranks as the hottest year on record and daytime highs of 40°C and beyond are described as “increasingly common.” 

For agricultural supply chains, reduced harvesting hours and crop losses translate into unstable food distribution. For construction, logistics and manufacturing, stoppages from heat stress can delay deliveries, inflate costs and weaken resilience.

WHO and WMO estimate that half the global population experiences harmful effects from high temperatures. 

With over 2.4bn workers exposed to excessive heat worldwide, supply chains risk systematic disruption unless protective measures are implemented. 

Joaquim Pintado Nunes, International Labour Organization Chief of Occupational Safety and Health and the Working Environment, explains: “This report represents a critical milestone in our collective response to the growing threat of extreme heat in the world of work.

“Aligned with the ILO’s mandate to promote safe and healthy working environments as a fundamental right, it offers robust, evidence-based guidance to help governments, employers and workers confront the escalating risks of climate change. 

“Together with WHO and WMO, we call for urgent, coordinated action to safeguard the health, safety and dignity of the more than 2.4 billion workers exposed to excessive heat worldwide.”

The scale is vast. ILO data show that excessive heat already causes more than 22.85m occupational injuries annually, undermining supply reliability across sectors. 

Without adaptation, both short-term stoppages and long-term workforce attrition threaten continuity of production and distribution.

Building resilient industries

The report calls for occupational heat action plans tailored to industries and regions, created collaboratively with employers, workers, unions and health experts. 

Solutions include restructured shift patterns, shaded workspaces, cooling technology and hydration policies. WHO’s “Beat the Heat” initiative demonstrates practical approaches designed for vulnerable workers.

A particular focus is on those at highest risk: middle-aged and older employees, people with chronic health conditions and individuals with low fitness levels.

Training for employers, first responders and health professionals is also vital, as symptoms of heat stress are often misdiagnosed.

Local authorities, industry leaders and worker representatives are urged to design interventions that are affordable, effective and sustainable.

Adoption of technologies such as wearable monitors and adaptive scheduling tools can help balance worker safety with supply chain performance.

WHO and WMO also highlight the importance of ongoing research and evaluation to measure how policies affect both health and productivity. 

Strengthening evidence will allow industries to scale protection strategies while ensuring supply chains continue to operate under harsher climate conditions.

Unless workers are protected, industries that depend on their labour cannot guarantee stability of goods and services.

Through embedding heat resilience into workforce planning, employers can safeguard productivity while protecting lives.