Yet more evidence has come in about the extreme and growing effects of human-generated climate change. Associated Press Science writer Seth Borenstein reports that data published in the journal Science documents a recent study showing global temperature had been slowly cooling until it dramatically reversed in the last 100 years. See his summary article here. If you're really geeky you can see the abstract in Science with a link to the entire published study here.
Researchers studied the fossils of small temperature-sensitive marine organisms to extend temperature records back 11,300 years. What they found was a gradual warming until 6,000 years ago, and gradual cooling until about 1910. The decade ending in 1910 was one of the coolest recorded. That abruptly reversed and continues to accelerate at a pace much faster than the temperature changes that ended the Ice Age. Lead researcher Shaun Marcott of Oregon State University said, "We've never seen something this rapid. Even in the Ice Age the global temperature never changed this quickly."
It appears that we may have been slowly heading back into an ice age period based on very long term changes in the earth's orbit that take it farther away from the sun and tilt the axis more steeply so that solar radiation falls less directly on the planet's surface. But these natural cooling factors have been massively overridden by an atmosphere that now contains 395 parts per million of carbon dioxide, up from about 280 ppm before the Industrial Revolution began a little over 200 years ago.
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