Global warming may also increase the risk of some infectious diseases, particularly those diseases that only appear in warm areas. Some scientists believe that algal blooms could occur more frequently as temperatures warm - particularly in areas with polluted waters - in which case diseases such a cholera that tend to accompany algal blooms could become more frequent Concentrations have increased mainly because of the use of fossil fuels, deforestation and other human activities, spurred on by economic and population growth. Greenhouse gases stop energy escaping from the Earth's surface and atmosphere. If levels rise too high, excessive warming can distort natural patterns of climate, researchers say. Of people around the world throughout the world, the prevalence of particular diseases and other threats to human health depend largely on local climate. Extreme temperatures can directly cause the loss of life. Moreover, several serious diseases only appear in warm areas. Finally, warm temperatures can increase air and water pollution, which in turn harm human health. The most direct effect of climate change would be the impacts of hotter temperatures themselves. Extremely hot temperatures increase the number of people who die on a given day for many reasons: People with heart problems are vulnerable because one’s cardiovascular system must work harder to keep the body cool during hot weather. Heat exhaustion and some respiratory problems increase. Global warming may also increase the risk of some infectious diseases, particularly those diseases that only appear in warm areas. Diseases that are spread by mosquitoes and other insects could become more prevalent if warmer temperatures enabled those insects to become established farther north; such "vector-borne" diseases include malaria, dengue fever, yellow fever, and encephalitis. Some scientists believe that algal blooms could occur more frequently as temperatures warm — particularly in areas with polluted waters — in which case diseases such a cholera that tend to accompany algal blooms could become more frequent. This paper will bring out the impact of global warming on global health and the precautionary steps to be taken by people to protect their heal. © IAEME Publication.