Greenhouse effect occurred 5,000 years ago: archaeologists www.chinaview.cn 2005-10-31 19:10:24 JINAN, Oct. 31 (Xinhuanet) -- It is common sense nowadays that excessive carbon dioxide in the air caused by excessive lumbering leads to global greenhouse effects. But a team of archaeologists from China and the United States is saying that the greenhouse effect started about 5,000 years ago, much earlier than people might expect. This is the conclusion reached by a group of Chinese and US archaeologists based on research on the relics excavated from the ruins of a Neolithic site in Rizhao City, east China's Shandong Province, over the...