GGRB28 Ch9 notes

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University of Toronto Scarborough
Talar Sahsuvaroglu

GGRB28 Chapter 9 Notes Health impacts of global environmental change IntroductionCommon areas of research of environmental epidemiologists include air and water quality radiation contaminated food and noiseThis chapter focuses on broader processes of environmental and ecological change those with consequences for health are in direct but also indirect Many of these processes are global in their scale and the health impact will be widespreadIn this chapter two broad environmental changes will be considered o The health consequences from ozone losses from the upper atmosphere o Impacts of climate changeto the extent to which climate warming is likely to have negative consequences for human healthThere is still some uncertainty that is attached to the predicted health consequences The risk provided by researchers are therefore inevitably wideThe earths poor population will be among those who are greatly impactedThe impact of greenhouse gases on global climate change have resulted in reduced rainfall in sudanFor example Lake Chad o Has shrunk to one twentieth of its former size With lake shrinkage temperatures have increased fish have disappeared and agricultural production has collapsedo Millions of human have been displaced due to the intense droughtStratospheric Ozone depletionUV radiation from the sun is usually divided into 3 classes depending on the wavelengtho Longwave radiation UVA occupies the range 315 400 nanometerso UVB and UVC radiation occupy lower ranges at 280 315 and 100 280 respectively The ozone layer in the upper atmosphere ensures that none of the short wave UVC radiation that can damage genetic material reaches eartho The stratosphere further absorbs much of the UVB radiation that also harms living thingsIn 1985 research showed the beginning of the depletion within the ozone layer commonly known as the hole o Because there is little harm to humans within this area there was not that much attention given to the situation o Instead researchers focussed on depletion of ozone at lower latitudesResearch has found that there has been 6 ozone loss at levels of 45 degrees in both hemispheres o During the winter months the losses are higherStratospheric ozone depletion is caused by chlorofluorocarbons CFCs halocarbonsand aerosol propellants o As they reach the stratosphere they form very reactive chemicals likereactive chemicals such as chlorine monoxide which react ozone to convert it back to oxygen Chlorine loading of the atmosphere will continue at high levels and the recovery of the ozone layer will not occur for at least another 50 years Of the radiation that does get through to the earths surface there is evidence that it can cause skin cancers and eye disease cataractsOzone depletion and skin cancer
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