Word: carbonation
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Dates: during 1990-1999
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...artifacts from Monte Verde have now been subjected to dozens of radiocarbon analyses -- a standard archaeological dating technique in which the amount of radioactive carbon in an organic specimen is used to calculate its age. Dillehay says he is "very confident" that he has found remnants of a culture that existed some 125 centuries...
That kind of derision doesn't faze the feisty Guidon. On the charcoal deposits, she argues, "If they had been left by forest fires, carbon deposits would have been found scattered across a wide area." They are not. In many cases, the charcoal is ringed by stones, says Guidon, which is strong supporting evidence that these were man-made hearths, not natural formations. Besides, the area was a humid, tropical rain forest 30,000 years ago, and natural fires would have had a hard time getting started...
...year's Earth Summit in Rio, Clinton declared that the U.S. would sign an international treaty to protect the diversity of living species. And the President followed through on a pledge that briefly seemed in jeopardy: he committed the U.S. to a specific timetable for curbing the release of carbon dioxide and other so-called greenhouse gases believed to be causing a long- term rise in temperatures around the globe...
That will not be easy. America was built on cheap and seemingly unlimited supplies of carbon-based fuels -- wood, coal, oil and natural gas. With only 5% of the world's population, the U.S. today produces nearly 25% of global carbon emissions. If nothing is done, the country will be pouring 100 million more tons into the atmosphere by the turn of the century...
...world, accounting for as much as 15% of U.S. sales. There is also the undeniable fact that Americans, particularly in the more polluted and congested urban areas, are driving themselves to death. As much as 80% of all urban smog and a quarter of the nation's total carbon dioxide are caused by engines burning fossil fuels...