Effects of climate change on human health
The effects of climate change on human health are increasingly well studied and quantified. Rising temperatures and changes in weather patterns are increasing the frequency and severity of heat waves, wildfires, droughts, floods, landslides, hurricanes, and other causes of injury and illness. Heat waves and extreme weather events have a big impact on health both directly and indirectly. Direct effects of exposure to high and extended temperatures include illness, reduced labour capacity for outdoor workers, and heat-related mortality.
In addition to direct impacts, climate change and extreme weather events cause changes in the biosphere. Climate-sensitive pathogens and vector-borne diseases may increase in some regions. Changes in temperature are creating conditions favorable to mosquito-borne diseases such as dengue fever, and waterborne diseases including diarrhoeal disease. 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 or developed immunity.
Changes in climate can cause decreasing yields for some crops and regions, resulting in higher food costs, food insecurity, and undernutrition. Water insecurity is also a concern. Increases in poverty, displacement, migration, violent conflict, and negative effects on mental health are all occurring.
Climate change affects human health at all ages, from infancy through adolescence, adulthood and old age. Factors such as age, gender and socioeconomic status influence to what extent these effects become wide-spread risks to human health.: 1867 Extreme weather creates physical and economic risks for whole families, particularly those headed by women. Temperature and heatwaves affect the earning capacity and economic stability of individuals and households. Populations over 65 years of age are particularly vulnerable to heat and other health effects of climate change. Health risks are unevenly distributed across the world. Disadvantaged populations are especially vulnerable to climate change effects.: 15
The health effects of climate change are increasingly a matter of concern for the international public health policy community. Already in 2009, a publication in the general medical journal The Lancet stated: "Climate change is the biggest global health threat of the 21st century". The World Health Organization reiterated this in 2015. In 2019, the Australian Medical Association formally declared climate change a health emergency.
Research shows that health professionals around the world agree that climate change is real, is caused by humans, and is causing increased health problems in their communities. Studies also show that taking action to address climate change improves public health. Health professionals can act by informing people about health harms and ways to address them, by lobbying leaders to take action, and by taking steps to decarbonize their own homes and workplaces. Studies have found that communications on climate change that present it as a health concern rather than just an environmental matter are more likely to engage the public.