評論
打印
Scientists believe the Sahara desert is twice as old as we previously thought. Science books generally say the Sahara is around three million years old. However, a new study from a centre for climate research in Norway says it could be around seven million years old. Researchers used computers to try and calculate when large parts of North Africa became desert. Their tests showed that global warming seven million years ago dried a lot of the land in what is today the African nation of Chad. A sea called the Tethys Sea started shrinking. This made the African summer monsoons less frequent, which helped form sand dunes in Chad. The scientists say this is how the Sahara first started.
科學家認為撒哈拉沙漠比以前認為的存在時間要長兩倍。科學書籍一般都寫著撒哈拉沙漠存在的時間約為300萬年。然而，挪威一所氣候研究中心的一項新的研究表明，撒哈拉沙漠存在的時間可能是700萬年。研究人員用電腦試著計算北非變成沙漠的時間。他們的實驗表明，700萬年以前的全球變暖造成許多土地變干，形成了現在的乍得國。特提斯海開始縮小。這使得非洲的夏季風頻率變小。從而形成了乍得國的沙丘。科學家稱，這就是撒哈拉沙漠最開始形成的狀況。
The Sahara is one of the world's best-known and largest deserts. It covers about 10 per cent of the whole African continent and forms large parts of Algeria, Chad, Egypt, Sudan and other nations. The sands stretch from the Atlantic Ocean in the west to the Red Sea in the east. Not everyone agrees that the Sahara is as old as the Norway research says it is. Stefan Kröpelin, a geologist in Germany, says real geological evidence is needed to be sure. He said the Norway research is based on numbers and not evidence, saying: "Nothing you can find in the Sahara is older than 500,000 years old". He added that our knowledge of the Saharan climate is only from 10,000 years ago and that our knowledge is "full of gaps".
撒哈拉沙漠是世界上一片著名的最大的沙漠之一。撒哈拉沙漠面積約為非洲大陸的10%。而且覆蓋了阿爾及利亞，乍得，埃及，蘇丹和其他國家的大部分地區。沙漠從大西洋西部一直延伸至紅海的東部。并不是所有人都認同挪威研究中心對撒哈拉沙漠存在時間的研究結果。德國地理學家斯特芬說，真正的地理證據需要核實。他說，挪威的研究并不是依據證據，而是依據數字。他說，在撒哈拉沙漠找到的任何東西的存在時間都小于50萬年。他還說，我們所知道的關于撒哈拉沙漠地區的氣候知識是在1萬年以前，并且我們的知識有許多漏洞。
譯文屬可可英語原創，未經允許，不得轉載。
