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History 1301
Global Warming
The term “global warming” refers to the warming of earth surface in recent years and its projected continuation and implies human influence. The united nation framework convention on climate change uses the term climate change for human caused change and climate variability for other changes. The average global air temperature near the earth surface increased 0.74-0.18C during hundred years ending 2005. Scientist James Hansen indicates the 0.75 degree rise in average global temperature in last 100 years is due to green house gases other than carbon dioxide. On earth there are different concentrations of green house gases like water vapor which causes about 36-70% of the greenhouse effect carbon dioxide which causes 9-26%, methane which causes 4-9% and ozone which causes 3-7%. The increased in global average temperature is due to emission of man-made greenhouse gases concentrations. There have already been a warning by the natural phenomena like the volcanoes from pre-industrial revolution. Intergovernmental panel on climate change concludes that there will be further rise in global surface temperature of about 1.1 to 6.4C by the twenty first century. Studies focuses that even if the green house gas emission is stabilized warming and sea level rise will still continue for more thousand years.
The increased global temperature will cause sea level rise, increase in intensity of extreme weather, changes in agriculture yields, trade routes, glacier retreat, species extinctions. There have been some steps taken to reduce green house...