Many scientists regard anthropogenic global cliate change to be the most inportant anvironmental issue of our time. carbon dioxide and certain other trace gases inluding methane, nithrous oxide and chlorofluorocarbons are accumulating in the atmosphere as a result of human activities. carbon dioxide is by far the most impartant cause of anthropogenic alimate change. Burning carbon-containing fossil fuels------coal, iol, and natural gas-------accountsfor most human-made carbon dioxide. carbon dioxide is also releades when forests are burned.The concentration of atmospheric carbon dioxide has increased from about 280 parts par million (ppm) before the industrial Revolution began in 1760, to about 38 oppm now. scientists estimate that by the end of the twenty-first century, theconcentration ofatmospheric carbon bioxide will be about 500ppm. since preindustrial times atmospheric concentrations of carbon dioxide, methane and nitrous oxide haveclimbod by over 31%, 151%, and17% respectively. Throughout Earth,s history the climare has varied, sometimes considerably. Recent warming, however, is due to human industrialization processes.
"some scientists think that the planet is already on an irrevarsisible journey to dangerous warming. A few climate-change sceptics think the problem will right itself. Either may be correct. prediction about a mechanism as complex as the climate cannot be made with any certainty. But the broad scientific consensus is that serious climate change is a danger''. THE Economist, December,2009.
global warming occurs as a cansequence ofgreenhouse effect. There is little doubt that our planet is warming. over the last century the average global temperaturehas elimbed about 0.6c. The five warmest year on record, in order (warmest first) are 2005, 1998, 2002, 2003, and 2004. According to the world Meteorological organizattion (WMO), the 1990s was the warmest decade. The 1900s was the warmest century buring the last 1,000 years.
Currently, 80 parcent of our energy comes from fossil fuels. According to the international Energy Institute, this conld increase to 90 parcent by 2020. And the amount of energy people use is increasing too, not least because developing countries such as China are becoming more affuent.
