27 September, 2008

What is Climate Change ?????


Earth’s climate is changing. Greenhouse gases are accumulating. Human activities are the cause.

The build-up of greenhouse gases (GHGs) threatens to set the Earth inexorably on the path to a unpredictably different climate. The Intergovernmental Panel on Climate Change (IPCC) says many parts of the planet will be warmer. Droughts, floods and other forms of extreme weather will become more frequent, threatening food supplies. Plants and animals which cannot adjust will die out. Sea levels are rising and will continue to do so, forcing hundreds of thousands of people in coastal zones to migrate.


One of the main GHGs which humans are adding to the atmosphere, carbon dioxide (CO2), is increasing rapidly. Around 1750, about the start of the Industrial Revolution in Europe, there were 280 parts per million (ppm) of CO2 in the atmosphere. Today the overall amount of GHGs has topped 390 ppm CO2e (parts per million of carbon dioxide equivalent – all GHGs expressed as a common metric in relation to their warming potential) and the figure is rising by 1.5–2 ppm annually. Reputable scientists believe the Earth’s average temperature should not rise by more than 2°C over pre-industrial levels. Among others, the European Union indicated that this is essential to minimize the risk of what the UN Framework Convention on Climate Change (UNFCCC) calls dangerous climate change and keep the costs of adapting to a warmer world bearable.


Scientists say there is a 50 per cent chance of keeping to 2°C if the total GHG concentration remains below 450 ppm.
(Source: UNEP)

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