Deadly heat, deadly floods: Europe | Hajj | China | WION Wideangle

The effects of climate change on human health are increasingly well studied and quantified.^[1][2] Rising temperatures and changes in weather patterns are increasing the severity of heat waves, extreme weather and other causes of illness, injury or death. Heat waves and extreme weather events have a big impact on health both directly and indirectly. When people are exposed to higher temperatures for longer time periods they might experience heat illness and heat-related death.^[3]

In addition to direct impacts, climate change and extreme weather events cause changes in the biosphere. Certain diseases that are carried by vectors or spread by climate-sensitive pathogens may become more common in some regions. Examples include mosquito-borne diseases such as dengue fever, and waterborne diseases such as diarrhoeal disease.^[3][4] Climate change will impact where infectious diseases are able to spread in the future. Many infectious diseases will spread to new geographic areas where people have not previously been exposed to them.^[5][6]

Changes in climate can cause decreasing yields for some crops and regions, resulting in higher food prices, food insecurity, and undernutrition. Climate change can also reduce water security. These factors together can lead to increasing poverty, human migration, violent conflict, and mental health issues.^[7][8][3]

Climate change affects human health at all ages, from infancy through adolescence, adulthood and old age.^[7][3] Factors such as age, gender and socioeconomic status influence to what extent these effects become wide-spread risks to human health.^[8]: 1867 Extreme weather creates climate hazards for whole families, particularly those headed by women. It can also reduce the earning capacity and economic stability of people. Populations over 65 years of age are particularly vulnerable to heat and other health effects of climate change.^[7] Health risks are unevenly distributed across the world.^[8] Disadvantaged people are particularly vulnerable to climate change.^[3]: 15

The health effects of climate change are increasingly a matter of concern for the international public health policy community. In 2009, a publication in the general medical journal The Lancet stated that "Climate change is the biggest global health threat of the 21st century".^[9] The World Health Organization reiterated this in 2015.^[10]

The danger is that feedbacks and further developments will accelerate the temperature rise even more. Critical in this respect is the condition of Arctic sea ice. The image below, adapted from the Danish Metereological Institute, indicates that Arctic sea ice volume is at a record low for the time of year, as it has been for most of the year. At the same time, sea ice extent is still relatively large; Arctic sea ice extent was 3% below average in June 2024, close to the values observed most years since 2010, according to Copernicus. The implication is that sea ice must be very thin.