Impact of Climate Change on Human Health

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The Pacific-based El Niño Southern Oscillation (ENSO), an approximately semi-decadal cycle, influences much of the world’s regional weather patterns. Climate change is increasing the frequency and/or amplitude of El Niño. It defined well how climatic extremes events can effect on human health. The two important categories of climatic extremes are first is simple extremes of climatic statistical ranges, such as very low or very high temperatures and second is complex events i.e. droughts, floods. Insect vectors of the vector-borne infectious disease have important influences due to the temperature and surface water. Their good example is Mosquito species act as a vector of different viral and bacterial diseases such as malaria, yellow and Dengue fever. Mosquitoes need access to stagnant water for breeding and humid conditions for surviving of an adult. Warmer temperatures reduce the pathogen’s maturation period within the vector organism and increase vector breeding. However, very hot and dry conditions can demote mosquito survival. The disease’s sensitivity to climate is demonstrated by desert and highland brim areas where higher temperatures and/or rainfall companion with El Niño may rise the transmission of malaria. In areas of unstable malaria in poor countries, populations lack protective immunity and are likely to epidemics when weather conditions promote the transmission. Malaria is mostly occupied by tropical and subtropical regions. The other example is Dengue. It is the most tectonic arboviral disease of humans, occurring in tropical and subtropical regions, particularly in urban locations. Temperate regions following mild wet winters, act as a source for various diseases.

Due to the climate variability (flooding), help for spreading of certain rodent-borne diseases including leptospirosis, tularemia, viral hemorrhagic and many other diseases associated with rodents and ticks i.e tick-borne encephalitis, Lyme disease and hantavirus pulmonary syndrome. In the tropical areas, diarrheal diseases typically high during in rainy seasons because they vary seasonally sensitivity to climate. The risk of diarrheal diseases increased by flooding and drought condition. Heavy rain falls and contaminated water causes the risk of diarrhea and many other diseases just like cholera, cryptosporidium, E. coli infection, giardia, typhoid, and hepatitis.

Global climate change will be increased frequency and intensity of heat waves as well as warmer summers and milder winters. The extent of winter-associated mortality directly attributable to stressful weather is less easy to determine. In temperate countries undergoing climate change, a reduction in winter deaths may outnumber the increase in summer deaths. Due to heat waves 514 deaths (12 per 100,000 population) and 3300 excess emergency admissions. The death rates during the winter season are higher than the summer season. The death rate is 10-25% in the winter seasons. In July 1995, in Chicago, the US, most of the excess deaths with preexisting disease, especially cardiovascular and respiratory disease. In terms of the amount of life lost, the mortality impact of an acute event such as a heat wave is uncertain because an unknown proportion of deaths are in susceptible persons who would have died in the very near future. El Niño events influence the annual toll of persons affected by natural disasters. An analysis by the reinsurance company Munich found a tripling in the number of natural catastrophes in the last ten years, compared to the 1960s. Globally, natural disaster impacts have been increasing. The effects of weather disasters (droughts, floods, storms, and bushfires) on health are difficult to quantify because secondary and delayed consequences are poorly reported. This reflects global trends in population vulnerability more than an increased frequency of extreme climatic events. Developing countries are poorly equipped to deal with weather extremes, even as the population concentration increases in high-risk areas (coastal zones and cities). Hence, the number of people killed, injured or made homeless by natural disasters has been increasing rapidly.

Remarkably, human-induced depletion of stratospheric ozone has recently begun after 8,000 generations of Homo sapiens. Stratospheric ozone absorbs much of the incoming solar ultraviolet radiation (UVR), especially the biologically more damaging, shorter-wavelength, UVR. We know that various industrial halogenated chemicals such as the chlorofluorocarbons (CFCs – Cleaning solvent, foaming agent and refrigeration) and methyl bromide is a colorless, odorless and is an ozone depletion chemical (methyl bromide) produced from industrially and biologically. While inert at ambient Earth-surface temperatures, react with ozone in the extremely cold polar stratosphere. This destruction of ozone occurs especially in late winter and early spring.

During the 1980s and 1990s at northern mid-latitudes (such as Europe), the average year-round ozone concentration declined by around 4% per decade: over the southern regions of Australia, New Zealand, Argentina and South Africa, the figure approximated 6-7%. Estimating the resultant changes in actual ground-level ultraviolet radiation remains technically complex. However, exposures at northern mid-latitudes, for example, are likely to peak around 2020, with an estimated 10% increase in effective ultraviolet radiation relative to 1980s levels. In the mid-1980s, governments recognized the emerging hazard from ozone depletion. The Montreal Protocol of 1987 was adopted, widely ratified and the phasing out of major ozone destroying gases began. The protocol was tightened in the 1990s. Scientists anticipate a slow but near-complete recovery of stratospheric ozone by the middle of the twenty-first century. The range of certain or possible health impacts of stratospheric ozone depletion become the cause of evaluation of the evidence implicating UVR in their causation. Many epidemiological studies have implicated solar radiation as a cause of skin cancer (melanoma and other types) in fair-skinned humans. Climate change causing a disease stress for the human.

This article is jointly authored by Rao M. Sajjad sharif – Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad, Dr. Zahoor Ahmad – Cholistan Institute of Desert Studies, The Islamia University of Bahawalpur, and Waseem Abbas – Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad.


Published in: Volume 08 Issue 28

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