全球变化背景下古气候学的研究越来越受到关注。利用多年来的文献记载和自然证据,对青藏高原东北部气候变化进行重建。并以若尔盖湿地为例,梳理了区域5000 a来气候变化对湿地植被类型、泥炭沼泽发育和文化发展产生的影响,探讨了气候变化、文化发展、沼泽发育三者之间可能具有的相互关系。指出青藏高原东北部5000-3000 a B.P.之间气候较为暖湿,其平均温度要高出现在2℃左右;3000 a B.P.至今为气候干冷期,其中1000 a B.P.左右是过去5000 a中最寒冷时期,近1000 a来气温呈缓慢回升趋势。区域的气候变化决定了植被类型,对泥炭沼泽的形成和发育发挥了重要作用,对文明进程的影响主要体现在气候变化通过影响沼泽的演替,从而改变人类活动的范围与早期文明的形成,同时人类的过度活动也在一定程度上影响了沼泽的分布格局及动态。但气候变化、沼泽发育和文化发展三者之间的关系有赖于多因素耦合,其具体机理有待更深入的研究。
英文摘要:
Paleoclimatology is attached more and more importance by climate and ecological scientists. As the strengthening of the monsoon activity, the middle Holocene (6.0-5.0ka B.P.) became an important reference era of Paleoclimate Modeling Intercomparison Project (PMIP). In addition, the northeastern Qinghai-Tibetan Plateau was focused by its climatic sensibility and ecological vulnerability. In this paper, we used the data from Qinghai Lake, Zoige plateau and the source area of Yellow River to present the trends of 5000-year climate change on northeastern Qinghai-Tibetan Plateau. Then taking Zoige wetlands as an example, we reviewed studies about the impact of climate change on vegetation types, peat development and civilization evolution, and discussed the possible interaction among them. According to our analyses, the climate on the northeastern Qinghai-Tibetan Plateau was warm and humid from 5.0 to 3.0 ka B. P., with an average temperature 2°C higher than the present. In this period, the dominant macrophanerophyte was mainly coniferous tree and the major herbage type was sedge. Moreover, thick peat accumulation was found due to the warm and humid climate. However, the climate turned into dry and cold since then to 1.0 ka B.P., with an extremely cold event around 1ka B.P.. The coniferous forest had been shrinking from highland to lowland because of fading Indian monsoon, wetlands developed very slowly and the civilization was also influenced. Meanwhile, human activities also slightly limited the development of wetlands due to the increasing population of Di-Qiang ancient people. We deduced that there existed a roughly synchronous resonance between climate change and the phenomenon of nomad migrated southward or eastward periodically. It is worth mentioning that Medieval Warm Period was observed in this era, following the prosperity of The tea-horse trade and the appearance of agricultural production by Uigur in Gansu Corridor. In recent 1000 years, due to the relatively warming climate, though not very steady, the coniferous forest and the wetland developed slightly again. In recent 100 years, the abrupt warming was introduced by increasing GHGs, the precipitation was decreased relatively. The area of Zoige wetlands decreased by a half due to drainage from 60s to the early 80s, then the shrinkage of wetlands was mainly due to climate warming, especially the abrupt warming of recent ten years. In short, the regional climate change determined vegetation types and affected the formation and development of wetlands. Climate change also impacted civilization, which altered the scope of human activity and early establishment of civilization. Meanwhile, human activities also affected the distribution and dynamics of wetlands. The interaction among climate change, wetland development and civilization course, however, depend on coupling of different factors. Furthermore, it is urgent to carry out researches about integrated adaptation and related technology on alpine's ecosystem to mitigate the climate change, as well as establishing a sustainable management system of Qinghai-Tibetan Plateau.