Ramin et al. (2009) studied the considerable effects climate change will continue to have on homeless people. The homeless are the most vulnerable group in developed countries and they have the highest rates of poorly controlled chronic disease, respiratory conditions, and mental illness, which the authors suggest are exacerbated by climate change. Few people have begun to address this issue and more research is required. These scientists are the first to examine the impact on the health of the homeless of increased heat waves, worsening air pollution, intensified severity of floods and storms, and the expanding distribution of West Nile Virus. Due to these changes, the homeless are highly susceptible to higher morbidity and mortality. — Leah Kahn
Ramin, B., Svoboda, T. 2009. Health of the Homeless and Climate Change. Journal of Urban Health: Bulletin of the New York Academy of Medicine 86, 654–663.
Approximately five to eight million Americans experienced homelessness within the last five years and their health suffers. Chronic disease severity is typically worse in homeless people because of extreme poverty, delays and limitations in seeking care, non-adherence to therapy, substance abuse, and cognitive impairment. Heat waves negatively affect the health of the homeless as the globe experiences higher minimum and maximum temperatures as well as greater frequency and intensity of heat waves. For example, 2005 was the hottest year on record in North America and in 2003, Europe experienced the hottest summer since 1500, causing 35,000 deaths. Models project a doubling to tripling of mortality in urban areas across the United States. Homeless are at risk because pre-existing psychiatric conditions triple the risk of death due to extreme heat, as do cardiovascular disease, pulmonary disease, advanced age, living alone, being socially isolated, not having air conditioning, alcoholism, using tranquilizers, and cognitive impairment. The heat island effect exacerbates these health problems since a high majority of the homeless live in urban areas.
Air pollution is also severe in urban areas. Ground-level ozone (O3), acid aerosols, particulate matter, and carbon monoxide aggravate chronic lung disease and asthma. O3 is formed by volatile organic compounds (VOCs) and nitrogen oxide (NOx) in sunlight so it peaks in warmer conditions. It is projected that O3 levels will increase by 2–4% with a 2°C temperature rise and 5–10% with a 5°C temperature rise. Air pollution disproportionately impacts people with cardio-respiratory conditions, asthma, and peripheral vascular disease. The homeless have high levels of exposure to outdoor air pollution and are therefore susceptible to climate change-related increases in air pollution.
With rising temperatures and air pollution comes more severe weather including floods and storms. Floods were the most frequent natural disaster over the past 10 years, killing over 100,000 people. Models predict more floods due to extreme precipitation, and hurricanes are predicted to escalate in size and severity, putting millions of people at risk of drowning, infectious disease outbreaks, and increased incidence of anxiety and depression. Homeless people occupy marginal areas that are more vulnerable to natural disasters but are not included in most disaster planning.
As precipitation heavily increases, so do water-dependent diseases like West Nile Virus that have mosquitos need water as a vector. The virus came to the United States in 1999 and with spring arriving earlier each year, there is an amplification cycle, an influx of human infection. Mosquitoes are most active at night and people sleeping outdoors are the most vulnerable to the Culex species. People with chronic illnesses such as alcoholism and heart disease—which is prevalent in the homeless—have a higher chance of developing meningoencephalitis when infected with West Nile Virus.