29 July 2009

the climate of health

One of the consequences of climate change is the impact it has on human health. According to an IPCC report, there are six health outcomes which are likely to be affected by climate change : respiratory diseases, vector-borne diseases (malaria and dengue), water-borne diseases (diarrohea and cholera), malnutrition, injuries and psychosocial stress. Urgent action is needed to strengthen the existing health systems to deal with the potential increase in health risks due to climate change.

CO2 emissions stimulate ragweed, some pollen-bearing trees and fungi, extending allergy and asthma seasons inducing respiratory disorders. Due to rise in temperatures, diseases that are of tropical origin are predicted to move into temperate zones. Geographic and environmental boundaries that once protected us from widespread disease outbreaks will not exist anymore - this is not only due to rise in temperatures but also increase in air travel and other factors. Viruses and bacteria long confined to living in a single species, or in one part of the world, can now quickly be moved to new areas and thrive in environments, animals or people unprepared for their arrival.

Changes in climatic conditions can also increase the frequency and severity of zoonotic diseases. Healthy animals depend on a healthy environment and when this is degraded, animal health both wild and domestic is compromised which affects humans adversely. Appreciation of the scale and type of influence on human health requires a new perspective which focuses on ecosystems. It also brings an appreciation of the complexity of the systems upon which we depend.

According to a WHO report, climate change will affect the pattern of deaths from exposure to high or low temperatures. In 2030 the estimated risk of diarrhoea will be up to 10% higher in some regions than if no climate change occurred. Estimated effects on malnutrition vary markedly among regions. By 2030, the relative risks for unmitigated emissions, relative to no climate change, vary from a significant increase in the South- East Asia region to a small decrease in the Western Pacific.

Proportional changes in the numbers of people killed or injured in coastal floods are large, although they refer to low absolute burdens. Impacts of inland floods are predicted to increase by a similar proportion, and would generally cause a greater acute rise in disease burden. While these proportional increases are similar in developed and developing regions, the baseline rates are much higher in developing countries. Changes in various vector-borne infectious diseases are predicted. This is particularly so for malaria in regions bordering current endemic zones. Smaller changes would occur in currently endemic areas. Already malaria slows economic growth in Africa by up to 1.3% each year. Since sub-Saharan Africa's GDP is around $300 billion, the short-term benefits of malaria control can reasonably be estimated at between $3 billion.

If the trend is to continue, similar costs are going to affect global economy predicted in the Stern review and can cost global economy huge amounts of money. Any monetary effort put into prevention and/or finding cures for diseases is money well-spent especially in the light of shifting temperatures.

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