Climate Change and Public Health

A synthesis of the Intergovernmental Panel on Climate Change (IPCC) in 2014 stated:  "Until mid-century, projected climate change will impact human health mainly by exacerbating health problems that already exist (very high confidence). Throughout the 21st century, climate change is expected to lead to increases in ill-health in many regions and especially in developing countries with low income, as compared to a baseline without climate change (high confidence). Health impacts include greater likelihood of injury and death due to more intense heat waves and fires, increased risks from foodborne and waterborne diseases, and loss of work capacity and reduced labour productivity in vulnerable populations (high confidence). Risks of undernutrition in poor regions will increase (high confidence). Risks from vector-borne diseases are projected to generally increase with warming, due to the extension of the infection area and season, despite reductions in some areas that become too hot for disease vectors (medium confidence). Globally, the magnitude and severity of negative impacts will increasingly outweigh positive impacts (high confidence). By 2100 for RCP8.5, the combination of high temperature and humidity in some areas for parts of the year is expected to compromise common human activities, including growing food and working outdoors (high confidence)."

The way in which climate change produces health impacts is shown in this graphic from the 2014 IPCC report.

An excellent short editorial in the Bulletin of the WHO by Alistair Woodward Climate change and health: recent progress summarises the situation to 2014, and the Lancet Commission on Health and Climate Change from 2015 is an excellent and comprehensive summary of the whole area (the papers are free, but you have to register in order to access them). 

Research has concluded that climate change is associated with an increased in acute and chronic mental health problems. Disasters caused by a changing climate tend to increase the risk of mental health illnesses such as depression, anxiety, and substance abuse. Chronic disorders such as Post Traumatic Stress Disorder (PTSD) may persist long after the disaster event. Furthermore, individuals with mental health disorders tend to be more vulnerable to health risks in environments with high temperatures. Additionally, stress, anxiety, and emotional distress are common reactions to the gradual impacts of climate change on society and the environment. Read the section "Mental Health Impacts" on pages 2-3 for a comprehensive understanding of climate-change related mental health impacts.

Evidence, in this publication from The American Psychological Association, shows that persistent gradual environmental, infrastructural, and societal changes due to climate change tend to have negative consequences on human mental health. Increased stress and anxiety are likely to increase behavioral issues such as substance use. Read the section "Effects of More Gradual Climate Impacts" on pages 22-24.

Indigenous communities are among the groups that are particularly vulnerable to the impacts of climate change due to their relationships with the environment and issues of marginalization and inequity, among others. As a result, the mental health impacts of climate change tend to be amplified in these communities, increasing their risk of depression, substance use disorders, and suicide. Read the article to understand the unique challenges that climate change presents for Indigenous communities and the potential repercussions on mental health. (Optional)

Case study on Dengue Fever from BMC PUblic Health: Climate change and the emergence of vector-borne diseases in Europe: case study of dengue fever. "Several vector-borne diseases are spread in Europe and the effect of climate change on disease distribution has been extensively discussed. Most authors consider that climate change is likely to have greatest impact on dengue fever, West Nile fever, chikungunya fever, malaria, leishmaniasis, tick-borne encephalitis, Lyme borreliosis, Crimean-Congo haemorrhagic fever, spotted fever rickettsioses, Yellow fever and Rift Valley fever.......This study allowed modelling of dengue fever risk in Europe based on actual clinical data. The model calibrated under Mexican conditions resulted in reliable and geographically meaningful patterns of projected dengue fever risk in Europe. The risk maps indicate that climate change is likely to contribute to increased dengue risk (and possibly other mosquito-borne diseases) in many parts of Europe, especially towards the end of the century. The areas of greatest increased risk are projected to be clustered around the Mediterranean and Adriatic coasts and in northern Italy. The exact incidence is dependent on several other factors, some of which we were unable to model at this stage (such as vaccine development)."

A paper in JAMA by Patz et al Climate change: challenges and opportunities for global health says: "The adverse health aspects related to climate change may include heat-related disorders, such as heat stress and economic consequences of reduced work capacity; respiratory disorders, including those exacerbated by air pollution and aeroallergens, such as asthma; infectious diseases, including vectorborne diseases and waterborne diseases, such as childhood gastrointestinal diseases; food insecurity, including reduced crop yields and an increase in plant diseases; and mental health disorders, such as posttraumatic stress disorder and depression, that are associated with natural disasters. Substantial health and economic cobenefits could be associated with reductions in fossil fuel combustion."

An editorial to introduce a 2018 series in PLoS Medicine Climate change and health: Moving from theory to practice says: "Research on the health risks from climate change has grown substantially, with findings suggesting that the global health gains achieved over the past half century are being undermined by climate change. Hazardous exposure pathways are many, from heat waves and air pollution episodes to infectious diseases, malnutrition, forced migration, and conflict. Impacts are experienced differently within segments of the population and between geographic locations based on biological, social, and economic vulnerabilities as well as the nature of the climate hazard." The series, which can be accessed here, contains much interesting information.