Public Health Impacts

Science and Best Resources

Greenhouse gas emissions threaten public health by affecting local air quality and by contributing to climate change. Respiratory, cardiovascular, and mental diseases have all been tied to climate change or air pollution linked to climate change. In addition to these three main categories, climate change has also been linked to a rise in extreme weather disasters, as well as war and displacement, both of which often result in morbidity and physical and mental injury. Below, studies illustrate the increasing awareness of the public health crisis of climate change.


Climate-Health Links: Right Here, Right Now

  • In a recent survey, 65% of doctors from the American Thoracic Society said that climate change is relevant to their respiratory patient care, with 77% of doctors saying they had observed increases in air pollution-related diseases and 58% saying they saw a rise in allergy-related diseases.
  • Another landmark survey from the National Medical Association (NMA) found that 88% of NMA physicians think climate change is relevant to direct patient care, and almost two-thirds of doctors said their own patients’ health has been affected by climate change.

Cardiovascular Impacts

  • Heat-Related Illness: Heat is already the leading cause of direct weather-related deaths in the United States, and the average number of heat-related fatalities will continue to rise, especially among vulnerable populations like the poor and elderly. A British study from early 2014 found that heat-related deaths in the UK are likely to increase by 257% by 2050 if nothing is done.
  • Heart Disease: Climate change is strongly linked to heart-related diseases, which have been found to rise in tandem with increasing levels of ground-level ozoneparticulate matterextreme coldextreme heat, and stress and anxiety brought on by extreme weather events.
  • Stroke: Exposure to air pollution, even for a single day, can significantly increase the risk of stroke, according to a recent meta-analysis of 103 studies. Nitrogen dioxide, sulfur dioxide, carbon monoxide, ozone and particulate matter were all found to be associated with a rise in strokes and hospital admissions.

Respiratory Impacts

  • Asthma: High levels of ground-level ozone and fine particulate matter, both of which are produced in tandem with other greenhouse gases, are strongly linked to a rise in asthma attacks.
  • Allergies: Allergies, which affect 10 to 30% of people worldwide, are also getting worse as the climate continues changing and emissions continue to rise. Last month, a study found that air pollution makes pollen more potent; studies also show that warming is contributing to an earlier and longer pollen season and rising carbon dioxide in the atmosphere results in more pollen per plant.

Mental Health Impacts

  • Anxiety: Fine particulate matter, a type of air pollution also associated with greenhouse gas emissions, was recently linked to an increase in anxiety among women.
  • Aggression: A recent meta-analysis found that the results of 56 separate studies link climate change to a rise in violence and aggression, with an expected 20% rise in conflict in Africa for every increase of 1˚C. Last month, a study linked the civil war in Syria to an extreme drought driven by human-caused climate change.
  • Suicide: A 2012 study that looked at suicide over 37 years in Australia found that an increase in suicide among rural men was strongly correlated to a rising drought index–findings that were echoed earlier this year in skyrocketing suicide rates in drought-stricken states in India.
  • PhobiaNew research finds that one in ten Americans has a significant phobia to extreme weather.
  • Post-Traumatic Stress Disorder (PTSD): Communities affected by wildfirestsunamishurricanes, or other disasters experience high rates of PTSD and other psychopathologies, case studies show, especially in those more directly exposed to the threat.

Infectious Diseases

  • Lyme Disease: The number of reported cases of Lyme disease in the United States has doubled since 1991, partly because warming temperatures facilitate the spread of the ticks that carry the disease. Deer ticks prefer conditions with temperatures above 45˚F and humidity over 85%, and many parts of the US are expected to get warmer (and some wetter) as climate change continues.
  • Mosquito-Borne DiseasesMalariaWest Nile virus (which caused a record-high number of American deaths in 2012), and dengue fever are three examples of diseases transmitted by mosquitoes that are on the rise as temperatures warm. Floods can also increase the incidence of mosquito-borne illnesses, as mosquitoes depend on standing water for breeding.
  • Waterborne Parasitic DiseasesCholera, giardia, and other diarrheal illnesses are expected to pose a greater threat to humans as temperatures warm. Both increased drought and rain can challenge the capabilities of water filtration plants and create more standing water, which both expose people to higher levels of disease.

Extreme Weather

  • Extreme weather events can contribute to global war, conflict, and migration. For example, a persistent and extreme drought that has been linked to human-caused climate change destabilized Syria and contributed to the ongoing civil conflict and humanitarian disaster. (Source: PNAS)
  • Sea level rise and flooding are affecting millions of people around the world. In the Sundarbans, a group of islands off the coast of Bangladesh, sea level rise and saltwater intrusion are threatening the livelihood and health of over ten million people.
  • Climate-related disasters include storms, floods, extreme temperatures, drought and wildfires. From 1994 to 2013, the US was affected by more climate-related disasters than any other country, and in 2014, 87% of all disasters worldwide were related to climatological processes. In total, the frequency of global climate-related disasters has doubled since the 1980s.
  • Between 1994 and 2013, floods accounted for 43% of all recorded disasters and affected nearly 2.5 billion people. In 2014, hydrological disasters like floods and landslides were responsible for 71% of disaster-related deaths worldwide.
  • More than one billion people were affected by droughts over the past twenty years. Droughts contribute to malnutrition, disease, and displacement, so direct deaths from drought are harder to quantify.

Global Instability

  • Extreme weather events can contribute to global war, conflict, and migration. For example, a persistent and extreme drought that has been linked to human-caused climate change destabilized Syria and contributed to the ongoing civil conflict and resulting humanitarian disaster. Sea level rise and flooding are affecting millions of people around the world. In the Sundarbans, a group of islands off the coast of Bangladesh, sea level rise and saltwater intrusion are threatening the livelihood and health of over ten million people.