The climate changes expected from increased atmospheric concentrations of greenhouse gases are likely to have widespread effects, many of them negative, on ecological systems, human health, and socioeconomic sectors. In general, people in developing countries are more vulnerable to climate change because of limited infrastructure and capital and greater dependence on natural resources. Beyond such concentrations, impacts appear to worsen, but uncertainty about what will happen increases. Worsening Health Effects - Climate change will impact human health in a variety of ways.
Warmer temperatures increase the risk of mortality from heat stress.
Today, such events occur about once every 150 years. By 2100, they could become six times more frequent. The potential increases in the heat index, a calculation combining temperature and humidity, illustrate the magnitude of this threat. Because children and the elderly are the most vulnerable populations, they are likely to suffer disproportionately with both warmer temperatures and poorer air quality. Diseases that thrive in warmer climates, such as malaria, dengue and yellow fevers, encephalitis, and cholera, are likely to spread due to the expansion of the ranges of mosquitos and other disease-carrying organisms and increased rates of transmission.