Stratospheric ozone destruction essentially a separate process to greenhouse gas accumulation. However, greenhouse gas warming of the troposphere appears to be linked to cooling of the stratosphere (Houghton et al., 2001). Further, peoples, solar exposure behavior may change as climatic conditions change, appreciated only recently, is that lower temperatures in the stratosphere may accelerate the destruction of ozone by chlorofluorocarbons (CFCs). Although emissions of ozone-depleting chemicals such as CFCs have fallen significantly because of international agreements, global climate change may delay recovery of the stratospheric ozone. High levels of solar ultraviolet (UV) radiation will continue to pass through to Earth’s surface for longer than would occur without climate change.
The effects of UV radiation on skin cancer, skin ageing, and cataracts of the eye are important public health issues in Australia, which has one of the highest skin cancer rates in the world (Marks et al., 1989). These high rates cannot be attributed to relatively recent phenomena such as ozone depletion or climate change because of the relatively long incubation time of serious skin cancer forms such as melanoma. Much of the risk is likely to be due to a predominantly pale-skinned population living in an environment with relatively low air pollution, plentiful sunlight and an outdoors-oriented lifestyle (Armstrong, 1994). In a warmer world, patterns of exposure to solar radiation can be expected to change (such as an increase in swimming and other outdoor activities, or conversely a retreat indoors to air conditioning).
These behaviors do signal a high degree of vulnerability to prolonged elevated levels of UV radiation (McKenzie and Elwood, 1990). The present levels of UV radiation have been increasing for the past 20 years (Mckenzie et al., 1999), and it is expected that the incidence of melanomas and other skin cancers will increase as a result of increasing UV radiation (Longstreth et al., 1998). Preliminary evidence also suggests that higher environmental temperatures enhance UV carcinogenesis. If this were true, the effect of rising temperatures on skin cancer incidence may soon be greater than that of ozone depletion (Len and Gruijl 2002). While recognizing the adverse effects of increased exposure to ultraviolet radiation, Lucas and Ponsonby (2002) also point out that some exposure to ultraviolet radiation is needed to maintain healthy levels of vitamin D.
10 Tips On How To Lower Cholesterol
Ayurveda is the only Natural Way to Health and Happiness
How to avoid Constipation-Simple Tips To Avoid Constipation
Deficiency Diseases due to Malmutrition
No comments:
Post a Comment