Due to the uplift of Qinghai-Tibet Plateau （QTP）, the cryosphere gradually developed on the higher mountain summits after the Neocene, becoming widespread during the Late Quaternary. During this time, permafrost on ...Due to the uplift of Qinghai-Tibet Plateau （QTP）, the cryosphere gradually developed on the higher mountain summits after the Neocene, becoming widespread during the Late Quaternary. During this time, permafrost on the QTP experienced repeated expansion and degradation. Based on the remains and cross-correlation with other proxy records such as those from glacial landforms, ice-core and paleogeography, the evolution and changes of permafrost and environmental changes on the QTP during the past 150,000 years were deduced and are presented in this paper.At least four obvious cycles of the extensive and intensive development, expansion and decay of permafrost occurred during the periods of 150-130, 80-50, 30-14 and after 10.8 ka B.P.. Ehiring the Holocene, fluctuating climatic environ-ments affected the permafrost on the QTP, and the peripheral mountains experienced six periods of discernible permafrost changes： （1） Stable development of permafrost in the early Holocene （10.8 to 8.5-7.0 ka B.P.）; （2） Intensive permafrost degradation during the Holocene Megathermal Period （HMP, from 8.5-7.0 to 4.0-3.0 ka B.P.）; （3） Permafrost expansion during the early Neoglacial period （ca. 4,000-3,000 to 1,000 a B.P.）; （4） Relative degradation during the Medieval Warm Period （MWP,from 1,000 to 500 a B.R）; （5） Expansion of permafrost during the Little Ice Age （LIA,from 500 to 10.a B.P.）; （6） Observed and predicted degradation of permafrost during the 20th and 21st century. Each period differed greatly in paleoclimate, paleoenvironment, and permafrost distribution, thickness, areal extent, and ground temperatures, as well as in the development of periglacial phenomena. Statistically, closer dating of the onset permafrost formation, more identi-fication of permafrost remains with richer proxy information about paleoenvironment, and more dating information enable higher resolution for paleo-permafrost reconstruction. Based on the scenarios of persistent climate warming of 2 2 -2 .6 °C in the next 50 years, and in combination of the monitored trends of climate and permafrost changes, and model predictions suggest an accelerated regional degradation of plateau pemafrost. Therefore,during the first half of the 21st century, profound changes in the stability of alpine ecosystems and hydro（geo）logical environments in the source regions of the Yangtze and Yellow rivers may occur. The foundation stability of key engineering infrastructures and sustainable eco-nomic development in cold regions on the QTP may be affected.展开更多
基金supported by the Subproject No.XDA05120302(Permafrost Extent in China during the Last Glaciation Maximum and Megathermal)Strategic Pilot Science and Technology Program of the Chinese Academy of Sciences(Identification of Carbon Budgets for Adaptation to Changing Climate and the Associated Issues)(Grant No.XDA05000000)+1 种基金Open Fund of State Key Laboratory of Frozen Soil Engineering(Grant No.SKLFSE201505)under the auspices of the International Permafrost Association(IPA)Working Group on"Last Permafrost Maximum and Minimum(LPMM)on the Eurasian Continent."
文摘Due to the uplift of Qinghai-Tibet Plateau （QTP）, the cryosphere gradually developed on the higher mountain summits after the Neocene, becoming widespread during the Late Quaternary. During this time, permafrost on the QTP experienced repeated expansion and degradation. Based on the remains and cross-correlation with other proxy records such as those from glacial landforms, ice-core and paleogeography, the evolution and changes of permafrost and environmental changes on the QTP during the past 150,000 years were deduced and are presented in this paper.At least four obvious cycles of the extensive and intensive development, expansion and decay of permafrost occurred during the periods of 150-130, 80-50, 30-14 and after 10.8 ka B.P.. Ehiring the Holocene, fluctuating climatic environ-ments affected the permafrost on the QTP, and the peripheral mountains experienced six periods of discernible permafrost changes： （1） Stable development of permafrost in the early Holocene （10.8 to 8.5-7.0 ka B.P.）; （2） Intensive permafrost degradation during the Holocene Megathermal Period （HMP, from 8.5-7.0 to 4.0-3.0 ka B.P.）; （3） Permafrost expansion during the early Neoglacial period （ca. 4,000-3,000 to 1,000 a B.P.）; （4） Relative degradation during the Medieval Warm Period （MWP,from 1,000 to 500 a B.R）; （5） Expansion of permafrost during the Little Ice Age （LIA,from 500 to 10.a B.P.）; （6） Observed and predicted degradation of permafrost during the 20th and 21st century. Each period differed greatly in paleoclimate, paleoenvironment, and permafrost distribution, thickness, areal extent, and ground temperatures, as well as in the development of periglacial phenomena. Statistically, closer dating of the onset permafrost formation, more identi-fication of permafrost remains with richer proxy information about paleoenvironment, and more dating information enable higher resolution for paleo-permafrost reconstruction. Based on the scenarios of persistent climate warming of 2 2 -2 .6 °C in the next 50 years, and in combination of the monitored trends of climate and permafrost changes, and model predictions suggest an accelerated regional degradation of plateau pemafrost. Therefore,during the first half of the 21st century, profound changes in the stability of alpine ecosystems and hydro（geo）logical environments in the source regions of the Yangtze and Yellow rivers may occur. The foundation stability of key engineering infrastructures and sustainable eco-nomic development in cold regions on the QTP may be affected.
