据高分辨率的青海都兰树轮年表,将过去2000年的气候变化划分为230’S以前的高温期,240’S～800’S冷暖波动强烈的低温期,810’S～1070’S显著高温期,即中世纪暖期,1080’S～1880’S的低温期,其中包括1420’S～1870’S的小冰期,以及1890’S后的升温期。统计发现11次极端高温或低温事件,以及几次大的突变事件全部出现于中世纪之前,指示150’S～1100’S期间气候运行的高度不稳定性。和中国东部、古里雅冰芯和青藏高原南部温度代用资料比较后发现,公元初至3世纪前期的东汉暖期,3世纪后期至7世纪初的魏晋南北朝冷期(期间约380’S～460’S暖),中世纪暖期以及小冰期等几次重大的气候事件在中国东部、都兰和青藏高原南部序列中均存在。古里雅冰芯仅记录了前两次重要事件,中世纪暖期以及小冰期在该序列中表现微弱。20世纪的升温在古里雅冰芯最显著,都兰、中国东部次之,而高原南部似乎不明显。

Based on hig resolution tree ring data from Dulan area of Qinghai Province, five spells have been divided: the warm period before 230’s A.D., the cold period between 240’s A.D.and 800’s A.D., the significantly warm period between 810’s A.D.and 1070’s, i.e. "Medieval Warm Period", the cold period including the "Little Ice Age" 1420’s-1870’s and the warming period since 1880’s.All the eleven coldest or warmest decades and several great abrupt changes took place before the Middle Ages, indicating that climatic system operated in great instability during the period 150’-1100’s A.D..Comparison of the tree ring data with other temperature proxy data from East China, Guliya ice core as well as the south of Qinghai Tibet Plateau shows that such great climatic events as Eastern Han warm period between the beginning of the 1st century and the previous fifty years of the third century, the cold period covering the span of Wei, Jin and the Southern and Northern Dynasties, the well known "Medieval Warm Period" as well as the "Little Ice Age" appeared in such series as East China and Dulan area.Only the first two climatic events were recorded conspicuously in Guliya ice core while the "Medieval Warm Period" and "Little Ice Age" is far weaker.Also, the well defined "Medieval Warm Period" didn’t occur in the south of Qinghai Tibet Plateau.The warming since the 20th century is the warmest in the last 200 years in Guliya ice core, the second in Dulan area and East China, but it scarcely seems pronounced in the eastern part of Qinghai Tibet Plateau.