Critically evaluate the possible effects of the phenomenon known as global warming and suggest possible responses to them (40 marks)
Global warming is the gradual increase in the temperature of the earth's atmosphere and oceans, mostly caused by the greenhouse effect. The greenhouse effect is where incoming short-wave solar radiation from the sun can pass through the earth’s atmosphere to reach the surface; some of this radiation is then reflected back into space at a longer wavelength. Greenhouse gases in the atmosphere absorb some of this long wave radiation and re-radiate it back to the earth’s surface, trapping heat in our atmosphere. There have always been natural fluctuations in the earth’s temperature, for the last 2.5 million years earth has shifted between cold glacial periods, and warmer interglacial periods. We are currently in an interglacial period, where the temperatures have been warm, with very small fluctuations for the last 10,000 years. Over the last century global temperatures have increased rapidly, there was a sharp rise in temperature between 1900 and 2000 of 0.7oC. Most scientists agree that this sharp increase was caused by human activities (anthropogenic). This continued increase in temperatures could have many major impacts worldwide, both positively and negatively. The most well-known effect of global warming is that the rise in temperature could cause ice caps, glaciers and sea ice to melt. Since the 1950’s arctic sea ice has reduced by 10-15%, and the Jakobshavn glacier in Greenland retreated by 10km between 1997 and 2007, both of which are evidence that the recent increases in temperature are causing ice to melt. This melting of ice, along with thermal expansion of water, caused by increased temperatures will lead to rise in sea levels; average global sea levels could rise almost 1m between 1990 and 2100. A rise in sea levels could have devastating social impacts on low lying coastal areas; a 1m rise in sea levels could flood...
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