Articles

The Hidden Risk of Heat: Why You Need to Address Heat Risk in Your Supply Chain Now

Article key points

  • Heat is already reducing factory productivity during peak production months, increasing supply chain risk.
  • Productivity losses from extreme heat translate directly into margin pressure, fill rate gaps, and supplier instability.
  • Regulatory scrutiny on worker heat exposure is increasing, expanding compliance risk across global supply chains.
  • Simple, low-cost interventions can reduce heat-related productivity loss and improve supplier performance.
  • Mapping, engaging, and measuring heat exposure helps companies protect revenue and strengthen resilience.

The heat your supply chain is already feeling

Walk into a garment factory in northern India on a September afternoon and the air is thick. Sewing machines and bodies packed into a production floor generate heat, trapped by concrete walls and a metal roof. Workers spend nearly a quarter of their shift with core body temperatures above the 38°C (100.4°F) threshold. They slow down. They make mistakes. Some stop working entirely.

This scene represents current conditions at tens of thousands of factories across South and Southeast Asia, Latin America, Africa, and the Middle East. Every hour of reduced output at those factories due to heat compromises worker health and leads to later shipments, unfilled purchase orders, and retail seasons that underperform. 

This results in lower fill rates, compressed margins, strained supplier relationships, and inhumane working conditions.

Heat is a risk hidden in plain sight

Conversations about climate risk in supply chains focus on highly visible physical disruptions: floods washing out factories, droughts drying out verdant fields, hurricanes shutting down trade routes. Heat doesn’t make headlines in the same way. It accumulates quietly, not as a single catastrophic event but as a slow bleed that takes a toll on local communities and global supply chains if not managed properly.

Companies are facing increased risk and exposure from heat now  

Better Work assessments of over 800 Cambodian factories during peak heat months found that 82 percent had indoor temperatures above 32°C (89.6°F) — the high heat stress threshold. An analysis of 12,000 supplier sites in the U.S., mainland China, and Taiwan found that 93 percent of Chinese and Taiwanese sites had experienced an increase in climate variability — and nearly all had seen an increase in heat waves specifically. Only 11 percent of all sites across the three countries were fully prepared for climate-related disruptions. The supplier base companies depend on is, in most cases, running without a safety net.

The hottest seasons are also the highest production seasons 

At 2°C (3.6°F) of warming, average annual heat stress duration in exposed regions could grow from under 12 weeks to roughly 16 weeks. This compresses the window of full-capacity production precisely when seasonal schedules are tightest.

Heat risk has a ripple effect 

Heat-related losses cascade through global trade networks, amplifying well beyond the site where the stress originates. A factory in Tamil Nadu running at reduced capacity in June doesn’t just affect that factory’s revenue and the well-being of local workers. It affects the buyer’s fill rate, the retailer’s in-stock position, and eventually the end-consumer who finds an empty shelf. 

Heat risk compounds supplier relationship risk 

Research has found direct links between heat exposure at supplier locations and operating income impacts for both suppliers and their buyers. When that exposure was “unexpected,” meaning buyers hadn’t accounted for it, the relationship outcome was often supplier termination. Companies that see the heat signal early can act on it, whether they focus on adaptations or changing the relationship. Companies that don’t do this will suffer disruptions.

Local economies will suffer from heat and climate 

Under a no-adaptation scenario, the apparel industry in Bangladesh, Cambodia, Pakistan, and Vietnam is projected to forego $65.8 billion U.S. dollars in potential export earnings by 2030 — a 22 percent greater loss than in a climate-adaptive scenario. By 2050, that gap grows to 69 percent.

Revenue and margin impact

  • Supplier output losses during peak heat months — which are often also peak production months — translate directly into unfilled purchase orders and missed revenue targets.
  • Reduced factory productivity increases cost-per-unit, compressing margins across affected product lines.
  • Losses cascade through trade networks: A capacity problem at a Tier-2 supplier can become a fill rate problem for a retailer several steps removed.

We have the solutions to mitigate heat stress

In late 2025, researchers from the University of Sussex and Royal Holloway used wearable sensors to track the core body temperatures of 160 workers at an apparel factory in Noida, India throughout their working shifts. They found that workers spent an average of 1.5 percent of their shift at temperatures above 38°C (100.4°F) — the point at which the body overheats. In thread-cutting departments, that figure was above 2 percent, and women workers were more affected than men. Translate 1.5 percent across a full production run, across dozens of workers, across weeks of summer heat, and it becomes meaningful lost output. This output loss doesn’t appear in any report as “heat loss” but shows up as capacity shortfall against plan.

The researchers then tested three simple interventions: 

  • Extra floor fans 
  • Extended breaks during heat events
  • Target-based self-paced work

All three interventions reduced time spent at dangerous temperatures and increased productivity. 

Fans delivered the largest productivity gain at 16 percent. The Ethical Trading Initiative, whose member company supplied the factory, framed the finding in terms buyers should find compelling: Effective actions do not need to be expensive, and the productivity gains from reducing unsafe temperatures are considerable. 

Investing in heat mitigation improves margins

Investment in reducing heat stress improves margins and mitigates risk. McKinsey found that across 20 heat adaptation measures globally, benefits outweigh costs by seven to one if climate change results in 2°C (3.6°F) increase in global temperatures. Air conditioning and cooling measures specifically have benefit-to-cost ratios of three to five times. The business case for heat mitigation increases as temperatures rise.

Compliance risk is also growing as governments ramp up regulation specifically on heat and worker safety. Vietnam mandates specific wet-bulb globe temperature thresholds tied to work intensity; Malaysia publishes detailed guidelines including factory design requirements; and China requires modified working hours when temperatures rise, with workers entitled to compensation for heat illness. 

For brands and retailers with European operations or investors, the EU’s Corporate Sustainability Due Diligence Directive (CSDDD) explicitly covers worker health and safety in supply chains. Failing to account for heat-related harm to workers increasingly falls within its scope — and creates legal liability for firms that don’t act.

Companies also put their reputation at risk if they ignore heat stress affecting their suppliers. Investigations by Climate Rights International in 2023 and 2024 found factories supplying major fashion brands had indoor temperatures regularly exceeding outdoor heat, caused by machinery and unventilated spaces. Heat stress has not yet produced a catastrophic moment like Rana Plaza, but the investigations are increasing and the regulatory environment is tightening.

The risks of not managing heat risk

  • The benefits outweigh the costs of mitigating heat risk. Companies that don’t mitigate heat risk will be at a competitive disadvantage. 
  • Several countries already have enforceable heat standards; non-compliant suppliers expose buyers to liability and production delays under those national laws.
  • The EU’s CSDDD covers worker health and safety in supply chains; failure to address heat-related harm creates direct legal liability for lead firms.
  • Companies that don’t mitigate heat stress in their supply chains risk reputational damage when high temperatures severely impact worker health.

Three steps you can take now to address supply chain heat risk 

  1. Map your supply chain. Companies should know which suppliers operate in high heat-risk environments. Not just by country, but by production season, factory type, and labor intensity. The most dangerous sites are those where high heat exposure combines with high revenue concentration and no risk mitigation measures. 
  2. Engage your suppliers. Heat management should become part of the sourcing conversation. The intervention menu is short and affordable: fans, scheduling adjustments during heat events, training, and a heat action plan. Buyers that support suppliers in implementing these aren’t just managing downside risk — they’re building production capacity.
  3. Measure and understand your social and environmental impact. Companies must quantify the revenue impact of productivity loss to make informed decisions about where to invest in resilience. Measuring it creates accountability, enables comparison against the cost of intervention, and builds the internal business case for action at scale. A supplier running at 84 percent output in June is a revenue risk and should be treated as one.

Mitigate heat to strengthen your business

As heat risk grows, companies without mapped exposure and mitigation programs will face escalating disruptions while better-prepared competitors maintain supply chain continuity. Companies that invest now in heat risk management build more reliable supplier capacity and predictable lead times — a structural advantage over competitors that don’t. 

Uncover hidden heat risks with Worldly Axion

Worldly Axion gives brands, retailers, and suppliers the ability to see their own primary supply chain data with global risk intelligence layered in. Identify risks—like heat stress—and hot spots, and mitigate them, to ensure business continuity and regulatory compliance across your supply chain. 

Explore Worldly Axion

Sources

Supply chain financial risk

Adaptation costs and investment gap

Factory-floor heat and productivity

Regulatory and legal risk

Heat trends in production centers

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