GEOGRAPHY AND HISTORY

  The ozone layer or ozone shield refers to a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet (UV) radiation. It contains high concentrations of ozone (O3) relative to other parts of the atmosphere, although still very small relative to other gases in the stratosphere. Reductions in stratospheric ozone levels will lead to higher levels of UVB reaching the Earth's surface. The sun's output of UVB does not change; rather, less ozone means less protection, and hence more UVB reaches the Earth. Studies have shown that in the Antarctic, the amount of UVB measured at the surface can double during the annual ozone hole. Another study confirmed the relationship between reduced ozone and increased UVB levels in Canada during the past several years. The following are effects of depletion of ozone layer Effects on Human Health Laboratory and epidemiological studies demonstrate that UVB causes nonmelanoma skin cancer and plays a major role in malignant mel...

  Mining is the extraction of natural resources from the earth's crust for economic use The following Environmental problems caused by mining Mining also leads to destruction of land which could have been used for agriculture e.g. by depositing rock debris after rock blasts. Mining also leads to swamp reclamation hence destructing the water cycle e.g. quarrying of clay and sand. Mining also leads to silting of river valleys which causes floods. It leads to destruction of natural beauty by leaving behind large pits. It has led to loss of property through displacement of people near mining areas. Mining is risky it has involved suffocation of miners underground or burying them underground. It has led to neglect of agriculture which leads to outbreak of famine. It leads to soil erosion especially in highland areas where trees are cleared leading to soil infertility. Mining also leads to landslides in highland regions which destroy human property and life. It leads to air pollutio...