More and more people will fall victim to serious illnesses and a host of deadly diseases
The health impacts of climate change are difficult to calculate since most human health problems have multiple factors. Demographics, environmental degradation and socioeconomic conditions are major factors in illness and disease.
l Climate related shortages in natural resources like fresh water will exacerbate health problems.
l According to the World Heatlh Organisation (who) , there will be a drop in deaths and illnesses related to cold, but those caused by heat will intensify. The number of people dying during heat waves will increase . In urban areas, this will be exacerbated by air pollution.
l Climate change will add to the numbers suffering from infectious diseases. Temperature and rainfall affect the distribution of disease vectors and disease-organisms, as well as the vulnerability of populations to these diseases. An example of this can be seen in the case of mosquitoes. Various species of mosquitoes carry malaria, dengue fever, yellow fever, and several types of encephalitis. Cold is usually the limiting factor in mosquito survival, so any increase in minimum winter temperatures is likely to extend mosquito ranges into cooler climes or higher altitudes.
l According to the World Resources Institute (wri) , Washington dc , higher temperatures also speed up the life cycles of both the mosquito and the disease organisms they harbour and make adult mosquitoes bite more often. At 30 c , the dengue virus takes 12 days to incubate in the Aedes aegypti mosquito, but only seven days at 32 c . The shorter incubation period translates to a potential threefold higher transmission rate of the disease. Higher temperatures also produce smaller adult mosquitoes that must feed more often to develop an egg batch, which, in turn, increases the chances of disease transmission. Some models suggest that the rise in incidences of malaria globally will be as high as 10 to 20 per cent.
l Prey-predator relationships like that of frogs and mosquitoes, which control disease-bearing organisms, may break down leading to an increase in vector numbers.
l Water-borne diseases including cholera and diarrhoeal diseases caused by organisms such as giardia and salmonella could also be affected as rainfall patterns change, along with human access to water supplies and sanitation.
l According to who, global warming will increase the incidence of respiratory and cardiovascular diseases in arid and semi-arid parts of India.
l Global warming and increased ultraviolet (uv) radiation will both accelerate the photochemical reaction rates among chemical pollutants and increase ozone concentration in urban areas. Ozone and other photochemical oxidants are associated with many respiratory diseases and cancer.
l Incidences of cataracts and skin cancer will increase due to an increase in uv radiation.
l It is estimated that the average number of tropical disturbance days (with storms or cyclones) may jump twofold causing illnesses, disease, injuries and loss of lives . In the North Indian Ocean, the average number of tropical disturbance days will increase from 17 to 29 days per year under conditions of doubled carbon dioxide concentration. Cyclone storms approach the 7,000 km long Indian coast from both the Bay of Bengal and the Arabian Sea.
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