Global Warming and its Dermatologic Implications

By Haw-Yueh Thong, M.D., MS, & Howard I. Maibach, M.D.

Published in Int Dermatol 2008, 47;5:522–4

Scientists have claimed that atmospheric accumulations of carbon dioxide, methane, chlorofluorocarbons, (CFCs), and nitrous oxide, namely the “greenhouse gases,” stemming primarily from fossil fuel combustion, could increase global surface temperature by 5-4ºC. Such warming could produce extreme weather events, including tropical cyclones, drought, and heat waves. Global warming has the potential to develop into the greatest environmental challenge of the 21st century. We believe that global warming/climate change will bring new dermatologic challenges.

By contrast, with the extensive research and publications on ozone depletion, ultraviolet (UV) radiation exposure, photocarcinogenesis, and the epidemiology of skin cancer, a search on Pub Med from 1975 to 2007 on global warming and skin diseases revealed a rather scant literature.

Although stratospheric ozone depletion has traditionally been held responsible for the changes in terrestrial UV radiation, climate changes may also modify ambient UV through influences on other variables such as clouds and aerosols.

Although climatologic factors may determine the levels of UV radiation at the Earth’s surface, it is the behavior of individuals outdoors that has a greater impact on personal UV exposure, e.g., the growth in outdoor leisure activities with consequent increases in sunlight exposure. In fact, one scientist believes that behavior associated with climate change rather than ozone depletion may be the largest determinant of sun exposure, with a consequent impact on skin cancer, in the UK population.

The disease profile as a result of natural disasters may be quite different from our daily encounter. Following the occurrence of Hurricane Katrina and subsequent flooding, there was concern amongst experts that the prolonged flooding and exposure to contaminated water would lead to an outbreak of skin infections and other health problems. One month later, the Centers for Disease Control and Prevention (CDC) reported wound infections with methicillin-resistant Styphylococcus aureus (MRSA), Vibrio vulnificus, and Vibrio parahaemolyticus in evacuees of Hurricane Katrina, and tinea corporis, folliculitis, miliaria, and arthropod bites amongst rescue workers.

Global warming and climate change are challenging collective action problems. Without proactive measures to fight global warming, more than one million animal and plant species could face extinction by 2050 under various predications. Given the superior adaptive capacity of mankind, it is likely that we will be able to survive global warming. Nevertheless, the skin diseases we encounter may change, and we should be well prepared to face the challenges that lie ahead.

Reprint requests: Dr. Howard I. Maibach, Department of Dermatology, University of California School of Medicine, Box 0989, San Francisco, CA 94143.