Word: carbons
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Dates: during 1970-1979
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Using radioactive dating methods based on the decay of the isotope carbon 14, scientists have estimated the seeds to be as much as 11,700 years old; the same tests on ancient grain samples found in the Middle East or Latin America show that none are more than 9,500 years old. Thus, says the director of the University of Hawaii expedition. Anthropologist Wilhelm G. Solheim II. Thailand's ancient inhabitants may well have been the world's first farmers...
Early Rice. Other scientists suggest that agriculture developed more or less simultaneously in widely separated regions of the world. Carbon-14 dating techniques, they note, can easily be off by as much as 1,000 years. But Solheim's claim is at least indirectly supported by other evidence of Southeast Asia's prehistoric culture. At the historic Thai village of Non Nok Tha, another University of Hawaii archaeological team has discovered a 3,500-year-old metal ax with a socket for a handle. The unusual implement may show that Thailand's ancient people were able...
...nation's 83 million cars cause 60% of the air pollution in cities. Fully aware of the pressure to reform, Detroit will introduce 1971 models that exhale only 37% as much carbon monoxide as did 1960 models. To achieve this, however, requires increased engine heat, which in turn will increase the nitrogen oxide emissions. And nitrogen oxides are particularly dangerous: under sunlight, they react with waste hydrocarbons from gasoline to form PAN (per-oxyacl nitrate), along with ozone the most toxic element in smog...
Some environment experts visualize future dramas of disaster that seem to border on science fiction. A few scientists feel that the outpouring of carbon dioxide, mainly from industry, is forming an invisible global filter in the atmosphere. This filter may act like a greenhouse: transparent to sunlight but opaque to heat radiation bouncing off the earth. In theory, the planet will warm up. The icecaps will melt; the oceans will rise by 60 ft., drowning the world's coastal cities...
Other scientists argue the exact opposite: they point out that the earth's average temperature has dropped by .2° C. since 1945, though the carbon dioxide content of the air keeps increasing every year. To explain this phenomenon, many ecologists think that various particles in the atmosphere are reflecting sunlight away from the earth, thus cooling the planet. Since about 31% of the world's surface is covered by low clouds, increasing this cover to 36% through pollution would drop the temperature about 4° C.?enough to start a return...