Đang tải... (xem toàn văn)
As we all know, greenhouse gas emissions generated by human activity will change Earth’s climate. The recent globally averaged warming by 0.5ºC is partly attributable to such anthropogenic emissions. Unfortunately, climate change may impact adverse affects on human health through a range of pathways. For instance, we normally consider the increased frequency and intensity of heat waves, polluted air, increased floods and droughts, changed in the distribution of vectorborne diseases and the risk of extreme disasters and malnutrition. Finally, prevent is nearly better than cure, therefore we can mitigate the impact of climate change by reducing the use of fossil fuels and increasing the use of a number of renewable energy technologies should improve health in the near term by reducing exposure to air pollution.
Vu Tuan Tai K55TTKHMT 10000792 Report Climate Change and Human Health Abstract: As we all know, greenhouse gas emissions generated by human activity will change Earth’s climate The recent globally averaged warming by 0.5ºC is partly attributable to such anthropogenic emissions Unfortunately, climate change may impact adverse affects on human health through a range of pathways For instance, we normally consider the increased frequency and intensity of heat waves, polluted air, increased floods and droughts, changed in the distribution of vector-borne diseases and the risk of extreme disasters and malnutrition Finally, prevent is nearly better than cure, therefore we can mitigate the impact of climate change by reducing the use of fossil fuels and increasing the use of a number of renewable energy technologies should improve health in the near term by reducing exposure to air pollution Introduction According to The Intergovernmental Panel on Climate Change (IPCC 2001), drawing on the published results of leading modeling groups around the world, the scientists forecast an increase in global average temperature by 2100 within the range 1.4 – 5.8ºC The increase will be greater at higher latitudes and over land Global average annual rainfall will increase, although many mid latitude and lower latitude land regions will become drier, whereas elsewhere precipitation events and flooding could become more and more severe Climate variability is expected to increase in a warmer world today A fundamental global environmental change, affecting physical systems and ecosystems, will affect human health in many ways However, many details are debated What health effects will occur for human? Climate change impact on human health There are several mechanisms by which climate change can affect human health Extremes of temperature and rainfall - e.g heat waves, floods, and droughts have direct immediate effects on mortality as well as longer-term effects Moreover, populations that have experienced flooding may suffer from sustained increases in common mental disorders In addition, climate change is also likely to affect biodiversity and the ecosystem goods and services that we rely on for human health Changes in temperature and rainfall may also affect the distribution of disease vectors—e.g those of malaria and dengue—and the incidence of diarrhoeal diseases 2.1 Extreme heat and cold Extreme weather events such as heat waves and cold spells lead to mortality ratios 10% or higher than for average temperatures (Huynen et al 2001) Typically, weather stress does not kill directly; instead, it is a “last straw” of additional stress for people with other conditions such as heart or lung disease The elderly and infirm are therefore at greater risk, as are those individuals exposed to thermal stress via their occupation (e.g outdoor laborers) Much of the excess mortality from heat waves is related to cardiovascular, cerebrovascular, and respiratory causes and is most concentrated in elderly people Extreme heating, and therefore its negative effects, are exacerbated by the “urban heat island” This term describes the well-known climatic effects of urbanization that lead to cities being warmer than the surrounding areas, especially overnight (Comrie 2000) Daily minimum temperatures can be 5°C or more warmer, meaning fewer winter frosts, an earlier thermal springtime , and of course higher overnight minimum temperatures in summer Depending on the city and humidity levels, the latter can reduce the relief from daytime high temperatures and increase weather stress Climate model projections of overnight lows for the next century show the warmest night of the year increasing by 10°C (Christidis et al 2005), before accounting for the additional urban heat island effect in cities While local conditions may modulate these projections higher or lower, the overall potential for increases in heat deaths is high Location (date) England, Wales (Aug 4-13) Italy (Jun 1-Aug 5) France (Aug1-20) Portugal (Aug) Spain (Jun-Aug) Switzerland (Jun-Sept) Excess mortality (%increase) 2091 deaths (17%) 3134 (15%) 14802 (60%) 1854 (40%) 4151(11%) 975 (6.9%) References Johnson et al Conti at al Anon Botelho et al Simon et al Grize et al Table 1: Excess mortality attributed to the 2003 heat wave in Europe 2.2 Air pollution Connections between air quality and health have been known for a long period of time , although the precise effects of specific pollutants are still actively researched (Pope et al 2002) Health effects were self-evident from the thousands of deaths in the infamous London smog of the 1950s (about 4000 were estimated for the December 1952 smog), when smoke concentrations were tens and even hundreds of times higher than today (Harrison 2006) Higher temperatures increase ground-level ozone pollution (Patz et al 2001), because the chemical reactions that produce ozone from its precursor pollutants proceed faster under warmer conditions If cloud-free conditions increase, then more available solar radiation will further increase ozone levels Ozone health effects include breathing problems, airway inflammation, and reduced resistance to infections Climate change projections indicate the likelihood for a longer , more severe, and more widespread high-ozone season each year (Fiore et al 2002; Hogrefe et al 2004) 2.3 Floods, storms and droughts Natural disasters have a variety of human health impacts, ranging from immediate effects of physical injury and morbidity and mortality through to potentially long-lasting effects on mental health In 1997, river floods in central Europe left over 200,000 people homeless, and more than 100 people were killed Following floods, increases in diarrhoeal and respiratory diseases are reported in both high-income and low-income countries; transmission is increased where there is crowding of displaced populations In industrialised countries, although infections are much less of a problem, the impact on the local economy may still be severe and increases in common mental disorders such as anxiety and depression are common These increases are probably related to damage to the home environment and economic losses and may persist for more than a year after flooding In US history, over 1800 deaths, approximately 2000 injuries and more than million displaced people resulted from Hurricane Katrina on August 2005, which is now one of the most expensive and deadliest natural disasters (Zimmermann 2012) Droughts may have wide ranging effects on health including on nutrition, infectious diseases, and on forest fires causing air pollution, particularly in low-income countries The number of people worldwide affected by drought is influenced strongly by the El Niño cycle 2.4 Infectious diseases Transmission of many infectious disease agents is sensitive to weather conditions, particularly those spending part of their life cycle outside the human body Pathogens that are carried by insects are exposed to ambient weather Vector-borne diseases typically exhibit seasonal patterns in which the role of temperature and rainfall is well documented Some vector-borne diseases, such as malaria, also display considerable year-to-year variation in some regions that can also be partly explained by climatic factors such as temperature, humidity, sea level rise Vector Mosquitoes Sandflies Triatomines Ixodes ticks Blackflies Major diseases Malaria, yellow fever Leish maniasis Chagas disease Lyme disease Onchocerciasis Table 2: Examples of vector-borne diseases likely to be sensitive to climate change Precipitation and temperature fluctuations can directly impact pathogens and diseases in water and food Natural flood events cause increases in fecal bacteria (Escherichia coli) as water levels rise and debris is washed into the stream Higher mean temperatures lead to more monthly Salmonellacases (WHO 2003), most likely resulting from improper refrigeration and exacerbation of food contamination Water-borne pathogens are numerous and widespread; some examples include cholera, cryptosporidium, rotaviruses, Coxsackie viruses, hepatitis A and E viruses Health risks range from wound infections to diarrhea and organ failure (Rose et al 2001) 2.5 Malnutrition Attribution of current and future climate-change-related malnutrition burdens is problematic because the determinants of malnutrition are complex Due to the very large number of people that may be affected, malnutrition linked to extreme climatic events may be one of the most important consequences of climate change (IPCC 2007) For example, climate change is projected to increase the percentage of the Malian population at risk of hunger from 34% to between 64% and 72% by the 2050s, although this could be substantially reduced by the effective implementation of a range of adaptive strategies (Butt et al., 2005) Climate change models project that those likely to be adversely affected are the regions already most vulnerable to food insecurity, notably Africa, which may lose substantial agricultural land Overall, climate change is projected to increase the number of people at risk of hunger Adverse health effects Heat-related illnesses and deaths Changes in intermediate factors Natural and human influences on climate Climate variability and change Regional and local weather change Mitigation policies Change in sea level Extreme weather-related health effects Air pollution concentration and distribution Air pollution-related health effects Pollen production Allergic diseases Microbial contamination and transmission Infectious diseases Water-borne and food-borne diseases Vector-borne and rodentborne diseases Crop yield Malnutrition Coastal flooding Coastal aquifer salinity Storm surge-related drowning and injuries Health problems of displaced populations Modulating influences and adaptation measures Diagram 1: Summary the potential health effects of climate change (reproduced from Haines A, Patz J “Health effects of climate change” JAMA2004; 291:99–103) Conclusion Prevention is nearly always better than cure There is an urgent need to develop improved methods and tools of climate impact assessment (such as the use of probabilities and Bayesian analysis) within a precautionary framework The effects of climate change on health are likely to be predominately negative and impact most heavily on low-income countries where capacity to adapt is weakest, but also on the most vulnerable groups in developed countries Adaptation strategies should blunt some of the adverse impacts but will pose difficulties of implementation, particularly in low-income countries With climate change already underway, there is a need to assess vulnerabilities and identify cost-effective intervention/adaptation options in the health sector and in other sectors that have direct links to human health Early planning can help reduce future adverse health impacts and mitigation strategies such as using a number of renewable energy sources can improve health by reducing air pollution as well as addressing climate change References IPCC Climate change 2001: the scientific basis Contribution of working group I to the third assessment report of the Intergovernmental Panel on Climate Change Cambridge: Cambridge University Press, 2001 World Health Organization (WHO 2003) Climate change and human health-risks and responses Huynen, M.M T E., et al (2001) The impact of heat waves and cold spells on mortality rates in the Dutch population Environment Health Perspectives109, pp 463–470 Comrie, A C (2000) Mapping a wind-modified urban heat island in Tucson, Arizona (with comments on integrating research and undergraduate learning) Bulletin of the American Meteorological Society81, pp 2417–2431 Christidis, N., et al (2005) Detection of changes in temperature extremes during the second half of the 20th century Geophysical Research Letters 32, L20716 Johnson H, Kovats RS, McGregor G, et al The impact of the 2003 heat wave on mortality and hospital admissions in England Conti S, Meli P, Minelli G, et al Epidemiologic study of mortality during the summer 2003 heat wave in Italy Environ Res2005; 98:390–99 Anon Impact sanitaire de la vague de chaleur en France survenue en août 2003 Paris: Institut de Veille Sanitaire, 2003 Botelho J, Caterino J, Calado R, Nogueira PJ, Paixao E, Falcao JM Onda de calor de Agosto de 2003 Os seus efeitos sobre a mortalidade da populacao portuguesa Lisbon: Instituto Nacional de Saude Dr Ricardo Jorge, 2005 10 Simon F, Lopez-Abente G, Ballester E, Martinez F Mortality in Spain during the heat waves of summer 2003 Euro Surveill 2005; 10:156–60 11 Grize L, Hussa A, Thommena O, Schindlera C, BraunFahrlandera C Heat wave 2003 and mortality in Switzerland Swiss Med Wkly2005; 135:200–05 12 Pope, C A., et al (2002) Lung cancer, cardiopulmonary mortality , and long-term exposure to fine particulate air pollution Journal of the American Medical Association 287, pp 1132–1141 13 Harrison, R.G (2006) Urban smoke concentrations at Kew, London, 1898–2004 Atmospheric Environment40, pp 3327–3332 14 Patz, J A et al (2001) Potential consequences of climate variability and change for human health in the United States Chapter 15 in National Assessment Synthesis Team, Foundation document of Climate change impacts on the United States Washington, DC: US Global Change Research Program, pp 437–458 15 Kim Ann Zimmermann, LiveScience contributor Hurricane Katrina: Facts, Damage and Aftermath 2012 16 Fiore, A M., et al (2002) Linking ozone pollution with climate change: the case for controlling methane Geophysical Research Letters 29, 1919 17 Hogrefe, C., et al (2004) Simulating regional-scale ozone climatology over the eastern United States: model evaluation results Atmospheric Environment38, pp 2627–2638 18 Rose, J B., et al (2001) Climate variability and change in the United States: potential impacts on water-and food-borne diseases caused by microbiologic agents Environment Health Perspectives 109(Suppl 2), pp 211–221 19 Butt, T., B McCarl, J Angerer, P Dyke and J Stuth, 2005: The economic and flood security implications of climate change in Mali Climatic Change,68, 355-378 20 Haines A, Patz J “Health effects of climate change” JAMA2004; 291:99–103 21 IPCC 2007 Volume 2: Impacts, adaptation and vulnerability