Extreme Weather and Air Pollution
Source: IPCC, Climate Change 2001 - Synthesis Report 2-1 http://www.ipcc.ch/present/graphics.htm |
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At the core of the change that is occurring is pollution. The table at the top of the page from the IPCC presents the startling “hockey stick” image of which greenhouse gasses are being produced. These gases then retain long wave radiation in the atmosphere resulting in a warming system. With increased temperature, respiratory-related morbidity is growing. Not only is smog and other particulate matter an issue, but the presence of ozone is becoming a bigger issue as larger quantities are being measured in the troposphere. When ground temperature in summer months is measured over 32°C, the number of days where ozone levels are above the suggested standard also increased (Patz and Olson 2006). Greater ozone levels lead to lung damage because of the formation of radicals, OH-. Further, ozone can increase cases of asthma in children and the sensitivity of those who do have asthma to other allergens (Patz and Kovats 2002). In the United States alone there has been a quadrupling in asthma cases over the last two decades (Epstein 2005). Other regions suffer for different reasons, for example in the Caribbean there is an increased incidence of respiratory issues due to dust clouds blown across the Atlantic Ocean by trade winds (Epstein 2005).
El Niño and warm episodes in December-February (a) and in June-August (b) Source: Patz and Kovats, 2002 |
Source: McMichael et al. 2006 |
A very direct and clear threat to human life comes in the form of extreme weather events whether it is a heat wave, flood, hurricane, or blizzard. In 2003 one of the most severe heat waves in Europe was observed, in no more than two weeks 45,000 had died with the mean temperature merely being 3.5°C over the seasonal average (Patz and Olson 2006). This isn’t the only instance; there are increased numbers of heat related deaths in 28 United States cities (McMichael et al. 2006). By 2050, 1,400-2,000 (over an average of 10 cities) deaths will be attributable to extreme heat or cold, but the majority will be related to heat (Campbell-Lendrum and Woodruff 2006). Looking to the third figure on this page which displays the number of deaths based on temperature, the trend observed is that there will be a continued increase in heat related deaths. Populations in temperate areas are more prone to heat deaths, while populations in tropical regions are more prone to cold deaths (McMichael et al. 2006). One factor proposed for these periods of heat is the “urban heat island effect”, which establishes that heat in urban centers is usually higher than rural areas because of land use and infrastructure. Land use plays a sizeable factor because different materials and land cover (trees, lakes, cropland) absorb and reflects heat differently. In urban centers asphalt will be more prevalent than forest, which result in more radiation storage because asphalt does not reflect radiation as well as plants do. The pollution in these areas is usually higher because of the compact population, creating a miniature greenhouse effect further holding radiation in the area. Wind currents cannot reduce most of this smog because of the mass amount being produced daily. In some instances the differences between urban and rural temperatures can be between 5-11° C (Patz et al 2005). As with most disease the subgroups of the population most affected, are the elderly, children, or individuals with pre-existing conditions (McMichael et al. 2006).
With the majority of warming occurring in the artic and boreal regions, the artic ice cap and major glaciers, in the case of Greenland, are rapidly melting. Sea level rise will become a serious problem with an expectation of 40cm of hydrologic ascension. This will place 75 to 200 million people at risk either through disruption of freshwater aquifers or other water disposal or purification systems (Patz and Olson 2006). Countries that do not have solidified infrastructure will be at even greater risk. It is also unknown what the effect that water level rise will have on flooding. Flooding is the most frequent natural disaster and has been estimated to kill 1 to 2 billion people over the course of a decade (McMichael et al. 2006). Flood frequencies are expected to increase and are very dependent on ENSO (McMichael et al. 2006).While not only causing direct deaths, flooding leads to morbidity and mortality related to water-borne diseases which are described in another section. Blizzards should also be viewed as a hazard not for their effect on transportation, but for their relationship with increased numbers of heart attacks (Ebi et al. 2006).