Overview. Climate change presents a fundamental threat to human health. It affects the physical environment as well as all aspects of both natural and human systems – including social and economic conditions and the functioning of health systems.

Air pollution greatest global threat to human health, says benchmark study.

A warmer climate is expected to increase the risk of illnesses and death from extreme heat and poor air quality. Climate change will likely increase the frequency and strength of extreme events (such as floods, droughts, and storms) that threaten human health and safety.

The Lancet Countdown works to ensure that health is at the centre of how governments understand and respond to climate change.