Hot weather and heat extremes: health risks

Area of Science:

• Environmental Health
• Occupational Health
• Climate Science

Background:

• Extreme heat and heat stress are increasing globally, posing risks to public health and worker productivity.
• Nearly half the world's population and over a billion workers face high heat exposure, with a third experiencing adverse health effects.
• Climate change is exacerbating heat-related hazards, projected to increase morbidity and mortality, especially in tropical regions.

Purpose of the Study:

• To highlight the widespread health and productivity impacts of hot ambient conditions.
• To emphasize the preventable nature of excess deaths and heat-related health risks.
• To discuss the interaction of climate change with other global trends affecting heat hazards.

Main Methods:

• Review of existing literature on heat stress impacts.
• Analysis of global population and worker exposure data.
• Examination of projected trends in heat-related morbidity and mortality.

Main Results:

• Hot ambient conditions increase mortality, morbidity, adverse pregnancy outcomes, and negatively affect mental health.
• High heat stress reduces physical work capacity and motor-cognitive performance, impacting productivity and occupational health.
• Heat-related risks are projected to increase with climate change, potentially exceeding physiological heat tolerance limits.

Conclusions:

• Excess deaths and heat-related health risks are preventable through heat action plans, including behavioral and biophysical strategies.
• Urban heat is amplified by anthropogenic heat and building waste heat.
• Without investment in research and risk management, heat-related morbidity and mortality are likely to rise despite some adaptation efforts.