According to the Intergovernmental Panel on Climate Change (IPCC) 4th Assessment Report, climate change can affect human health in many ways, including:

• An increase in the frequency or intensity of heatwaves will increase the risk of mortality and morbidity, principally in older age groups and among the urban poor.
• Increases in storms, floods, cyclones or droughts associated with climate change would cause deaths and injuries, population displacement, and adverse effects on food production, freshwater availability and quality, and would increase the risks of infectious disease, particularly in low-income countries.
• In some settings, the impacts of climate change may cause social disruption, economic decline, and displacement of populations. The health impacts associated with such socio-economic dislocation and population displacement are substantial.
• Changes in climate, including changes in climate variability, would affect many vector-borne infections. Populations at the margins of the current distribution of diseases might be particularly affected.
• Climate change represents an additional pressure on the world’s food supply system and is expected to increase yields at higher latitudes and decrease yields at lower latitudes. This would increase the number of undernourished people in the low-income world, unless there was a major redistribution of food around the world.
• Assuming that current emission levels continue, air quality in many large urban areas will deteriorate. Increases in exposure to ozone and other air pollutants (e.g., particulates) could increase morbidity and mortality.

Source: IPCC. <http://www.ipcc.ch/publications_and_data/ar4/wg2/en/ch8.html>.