What you need to know:

Greenhouse gas emissions have shown a steady increase in recent decades, and are one of the main contributors to climate change. In the United States, greenhouse gases are largely caused by the burning of fossil fuels for transportation, heat, and electricity. These gases act as a blanket, trapping heat above the earth’s surface which leads to increased temperatures, altered precipitation patterns, higher sea levels with flooding, and severe weather events.

Global climate change has many negative health consequences for humans that may result in disease and injury. Negative cardiovascular effects from climate change, including stroke and heart disease, will be the result of elevated surface temperatures and air pollution. Natural disasters, such as intense storms, flooding, and forced evacuation may further exacerbate cardiovascular disease and lead to depression and post-traumatic stress disorder in many victims.

Malaria and Dengue fever are expected to rise secondary to hotter temperatures and higher levels of precipitation. Mosquito breeding in standing surface water will increase as the result of higher precipitation levels. Elevated temperatures will correlate with increased mosquito bites, increased parasite reproductive cycles, and increased survival potential of mosquito vectors in regions where colder temperatures were previously unable to sustain them. Higher temperatures and greater larval development will speed up the development of Aedes mosquitoes, which causes Dengue fever.

Rising temperatures have allowed the tick vector for Lyme disease, Ixodes scaularis to survive and expand in the cold climate of Canada. Arboviruses, such as Zika virus, chikungunya virus disease, eastern equine encephalitis, and West Nile virus disease are also expected to spread because of climate change. Warmer temperatures correlate with increased proliferation of the Vibrio species, which increases risk for Vibrio infection. Vibriosis is caused by exposing a wound to seawater or by consuming raw or under-cooked seafood.

Excessive rainfall often causes waterborne disease, usually through contaminated drinking water. Combined sewer systems where sanitary wastewater and storm water are transported together in the same pipe to water treatment facilities often overflow with untreated sewage into freshwater following heavy precipitation. These overflow situations frequently result in excretion of heavy metals, chemicals, and pathogens. Persons exposed to sewer overflow are at risk of developing Hepatitis A, E. coli, and cryptosporidial.

Read more about the health effects of climate change:

Harrison’s Principles of Internal Medicine, 20e: Chapter 120. Climate Change and Infectious Disease

Hurst’s the Heart, 14e: Chapter 110. Environment and Heart Disease

Understanding Global Health, 2e: Chapter 1. Global Health: Past, Present, and Future

World Health Organization: Climate Change and Human Health