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Earth is approaching "tipping points of the system with the potential for irreversible deleterious effects," said James Hansen, director of the NASA Goddard Institute for Space Studies. "Human health is already being affected," testified Camille Parmesan, an associate professor of integrative biology at UT-Austin. "Just as we're seeing birds and butterflies coming up from Mexico, human parasites and their wild animal vectors are likely to be shifting northward as well."
Republicans on the committee scoffed at the "gloom and doom" scenarios.
"The title of today's hearing sounds a little like a scary movie: 'Dangerous Climate Change!' " said Rep. James Sensenbrenner, R-Wis. "We've seen this film before. It stars industrialized society, a character who improves the livelihood of billions of humans by providing them with vital jobs and services. But in this movie, industry is actually the villain, with an evil plan to destroy the Earth with invisible, odorless gases."
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The Earth's temperature rose more than 1.25 degrees Fahrenheit in the 20th century, and more than half of all plant and animal species showed a measurable response, Parmesan said. "We're seeing many tropical species moving into the Gulf Coast states; former migrants like the rufous hummingbird and the Mexican green jay have become year-around residents in Alabama and Texas, respectively," she testified. "Florida has five new species of tropical dragonfly. Many tropical butterflies that are normally confined to Mexico are starting to breed as far north as Austin, Texas."
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http://www.statesman.com/news/content/news/stories/nation/04/27/27climate.html