Global Warming

New environmental legislation could require energy companies to generate 15 percent of their power out-put to be harvested from renewable forms of energy, such as wind.

Soeren Bidstrup / AFP / Getty

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The heat-trapping effects of the earth's atmosphere originally created the temperatures necessary for life. But now-with some help from post-Industrial Revolution humanity-the system could threaten ecosystems around the world. While some debate still exists as to whether global warming is a measurable phenomenon, most environmental scientists now agree that by releasing large amounts of so-called "greenhouse gases" into the atmosphere—through auto exhaust, industrial pollution and other forms of modern human activity—we have accelerated the heat-trapping process, contributing to a global temperature increase of 1.1 degrees Fahrenheit in the last century. This warming threatens to change agricultural patterns and wildlife habitats and could cause sea levels to rise by as much as 23 inches by the end of the 21st century. Former U.S. Vice President Al Gore has been leading the fight against global warming with lobbying and notably, the 2006 film An Inconvenient Truth, which earned an Oscar and contributed to his shared Nobel Prize with the U.N.'s Intergovernmental Panel on Climate Change. A report released by the panel in February 2007, in which hundreds of international scientists agreed that the warming trend was definitive, and that humans were the likely cause for temperature increases, galvanized an already substantial environmental movement. Growing concerns and awareness of global warming have become a major issue of the 2008 U.S. presidential election, and have also given rise to a rapidly expanding grassroots movement, as more and more people try to limit their dependence on fossil fuels and reduce their carbon output.

—By Tiffany Sharples