2024 Hajj Heat Exceeded Survivability Thresholds for Prolonged Outdoor Exposure

Climate change is creating serious and growing risks for millions of pilgrims performing the Hajj, with a new study finding that heat stress conditions during the 2024 Hajj exceeded survivability thresholds for young, healthy adults during a period of approximately four consecutive hours. The paper presented at the European Geosciences Union assembly 2026 warned that conditions at the Hajj will be increasingly dangerous in the decades ahead.

In June 2024, the combined impact of heat and humidity created conditions during which prolonged outdoor exposure became potentially fatal even for physically fit young adults without access to cooling or immediate relief for approximately four continuous hours. The Day of Arafat, during which pilgrims spend the entire day outdoors in ritual observance, was identified as the highest risk phase of the Hajj. The study was prepared by researchers from Weather and Climate Services, Islamabad, and Climate Analytics, Berlin.

The Hajj requires millions of pilgrims, many of them elderly and from a wide range of health backgrounds, to walk long distances in the open sun at the height of the Arabian summer. Saudi Arabia has invested substantially in cooling infrastructure and heat emergency services, but the scale of the gathering — typically over two million pilgrims concentrated in a small geographic area — creates management challenges that technology and logistics alone cannot fully resolve. Climate projections indicate that the frequency and intensity of extreme heat events in the Arabian Peninsula will increase significantly through the remainder of the century.

The study's authors are calling for pilgrimage authorities to develop more rigorous heat risk assessment frameworks incorporating wet-bulb temperature thresholds rather than dry-bulb temperature alone, and to plan for scenarios in which outdoor ritual activities may need to be modified or supported by mandatory cooling interventions. Longer term, the Islamic world faces difficult questions about how pilgrimage practice can be adapted to a hotter climate while preserving the spiritual integrity of rituals defined by outdoor physical engagement. International climate diplomacy and finance flows to the Gulf region may need to address pilgrimage resilience as part of a broader adaptation agenda.

Key figure — 4 consecutive hours of conditions exceeding survivability thresholds during 2024 Hajj