Is human activity bringing about alarming global warming scenarios and related catastrophes? Or is such thinking a myth brought about by flawed or incomplete science? Finding the answers to these questions has turned global warming into a highly politicized and contentious issue.
Until about 1960, most scientists thought it implausible that humans could actually affect average global temperatures. (Refer to NOW's “History of Global Warming” at http://www.pbs.org/now/science/climatechange.html)
Today, most scientists agree that Earth's temperature has risen over the past century and that carbon dioxide is one of the primary greenhouse gases that contribute to global warming. Disagreement persists, however, over whether or not global climate change is a normal environmental variation and over how big of a problem global warming could become for the planet.
Amidst such controversy, world leaders have met and outlined legal rules, known as the Kyoto Protocol, to limit the emissions of greenhouse gases. One hundred forty countries that collectively represent 61.6% of greenhouse gas emissions worldwide have ratified the Kyoto Protocol.
The United States does not support the Kyoto Protocol and disagrees with a number of its provisions. Instead, the U.S. is funding additional scientific research on the causes and effects of global warming, encouraging climate change technology research and development efforts, looking at how its own federal and state laws can regulate greenhouse gas emissions in the U.S., backing the research and development of renewable energy sources, and pursuing other strategies that it believes will address global climate change without major upsets to the U.S. economy.