Climate change will also harm people while it harms the environment. More frequent and severe floods and heat waves, for example, as well as increased air pollution and expanded ranges for disease-carrying insects, could raise the numbers of the ill or injured. But many local public health directors feel ill prepared to safeguard their communities, according to the Environmental Defense Fund, which collaborated with the National Association of County and City Health Officials and George Mason University to survey local health departments. Nearly 70% of public health directors reported having perceived local climate change in the last two decades and 78% expect it in the next two, but only 19% of respondents felt their organization was "highly prepared" to deal with a climate-related emergency. The World Health Organization made climate change the theme of last year's World Health Day (held April 4) and launched a Web site dedicated to the issue at http://www.who.int/topics/climate/en.

Figure. Water and food scarcity can dramatically affect the health of already vulnerable communities. Severe drought conditions in places like Niger (above), in Africa, result from the higher temperatures and variable precipitation caused by climate change. Photo credit: WHO/Marko Kokic