The effects of climate change on mental health and wellbeing are documented. This is especially the case for vulnerable populations and those with pre-existing serious mental illness.[105] There are three broad pathways by which these effects can take place: directly, indirectly or via awareness.[106] The direct pathway includes stress-related conditions caused by exposure to extreme weather events. These include post-traumatic stress disorder (PTSD). Scientific studies have linked mental health to several climate-related exposures. These include heat, humidity, rainfall, drought, wildfires and floods.[107] The indirect pathway can be disruption to economic and social activities. An example is when an area of farmland is less able to produce food.[107] The third pathway can be of mere awareness of the climate change threat, even by individuals who are not otherwise affected by it.[106]
An additional aspect to consider is the detrimental impact climate change can have on green or blue natural spaces, which in themselves have been proven to have beneficial impact on mental health.[108][109] Impacts of anthropogenic climate change, such as freshwater pollution or deforestation, degrade these landscapes and reduce public access.[110] Even when the green and blue spaces are intact, access to them is not equal across society, which is an issue of environmental justice and economic inequality.[111]
Mental health outcomes have been measured in several studies. These use indicators such as psychiatric hospital admissions, mortality, self-harm and suicide rates. People with pre-existing mental illness, Indigenous peoples, migrants and refugees, and children and adolescents are all vulnerable. The emotional responses to the threat of climate change can include eco-anxiety, ecological grief and eco-anger.[112][113] Such emotions can be rational responses to the degradation of the natural world and lead to adaptive action.[114]
Assessing the exact mental health effects of climate change is difficult; increases in heat extremes pose risks to mental health which can manifest themselves in increased mental health-related hospital admissions andsuicidality.[