Earth Hour

Background:

             For over the past 200 years, the burning of fossil fuels, such as coal and oil (for the generation of electricity), and deforestation have caused the concentrations of heat-trapping "greenhouse gases" to increase significantly in our atmosphere. These gases prevent heat from escaping to space, somewhat like the glass panels of a conventional greenhouse. Greenhouse gases are necessary to life as we know it, because they keep the planet's surface warmer than it otherwise would be. But, as the concentrations of these gases continue to increase in the atmosphere, the Earth's temperature is climbing above past levels on a global scale. This results in a phenomenon known as 'Global warming'.

            Global warming affects people, plants, and animals. Scientists are working to better understand future changes and how the effects will vary by region and over time but some damaging changes are already occurring. Observed effects include sea level rise, shrinking glaciers, changes in the range and distribution of plants and animals, trees blooming earlier, lengthening of growing seasons, ice on rivers and lakes freezing later and breaking up earlier, and thawing of permafrost. Another key area of concern is how societies and the Earth's environment will adapt and cope.

            Most scientists agree that something needs to be done urgently to reduce greenhouse gases. Thus the need for projects such as Earth Hour.