Editing Environmental and Public Health (section)

=== Wet-Bulb Temperature and Human Survivability ===
The danger of extreme heat is intrinsically linked to atmospheric humidity, a relationship measured by the '''wet-bulb temperature'''. Sweating only cools the body if the sweat can evaporate into the air. If the air is already saturated with moisture (high humidity), evaporation slows or stops entirely.

If the ambient wet-bulb temperature approaches 35°C (roughly 95°F at 100% humidity), the human body can no longer dissipate heat into the environment, regardless of age, health, or hydration status. Under these conditions, core body temperature rapidly rises, proteins begin to denature, and hyperthermia becomes lethal within hours. As global temperatures increase, regions in the Middle East, South Asia, and the tropics are increasingly at risk of crossing these strict physiological thresholds of human survivability.