The Taklimakan Desert,located in the heart of central Asia,covers approximately 330000 km^(2),making it China's largest desert and the world's second-largest shifting desert(Dong et al.,2024).With an average a...The Taklimakan Desert,located in the heart of central Asia,covers approximately 330000 km^(2),making it China's largest desert and the world's second-largest shifting desert(Dong et al.,2024).With an average annual precipitation of less than 100 mm and evaporation rates ranging from 2000 to 3000 mm(Yang et al.,2020),it is recognized as one of the driest regions on Earth,often referred to as the“sea of death”.展开更多
The migration speed of a typical barchan on the border of Minqin oasis,Gansu Province,northwestern China,was estimated by means of two methods.One is on the basis of a simple physical model and short-term field measur...The migration speed of a typical barchan on the border of Minqin oasis,Gansu Province,northwestern China,was estimated by means of two methods.One is on the basis of a simple physical model and short-term field measurements.The other comes from the combination of the barchan internal structure detected by ground-penetrating radar and optical/radiocarbon dating techniques.The upper limit of migration speed given by conventional C-14 dating is 3.42 m/yr.The optically stimulated luminescence dating indicates that the time-average migration speed of the studied barchan was 1.78 m/yr in 28 years prior to 2007.The physical estimation further suggests that the annual migration speed has increased in recent years.展开更多
The domestication of livestock from their wild progenitors was essential in the process of the Neolithic Revolution.Aurochs(Bos primigenius)are considered to be the ancestors of modern cattle(B.taurus).They were once ...The domestication of livestock from their wild progenitors was essential in the process of the Neolithic Revolution.Aurochs(Bos primigenius)are considered to be the ancestors of modern cattle(B.taurus).They were once widespread across Eurasia and North Africa but became extinct approximately 400 years ago[1].展开更多
Reliable climate modeling of the Tibetan Plateau(TP)is essential for understanding the variability of the Asian monsoon,water resources,and associated energy and water cycles.However,accurately simulating the region’...Reliable climate modeling of the Tibetan Plateau(TP)is essential for understanding the variability of the Asian monsoon,water resources,and associated energy and water cycles.However,accurately simulating the region’s complex climate remains challenging for existing models,which often significantly overestimate precipitation and underestimate cold-season air temperatures.In this study,we introduce the Tibetan Plateau Climate System Model(TPCSM),also referred to as TP-WRF,developed from the Weather Research and Forecasting(WRF)model.We have enhanced or incorporated key physical processes related to terrain,land,lakes,snow,and clouds that are often poorly represented or missing in standard climate models.These refinements lead to a significant improvement in simulation accuracy.The wet bias in summer precipitation,averaged across weather stations,is reduced from 2.0 to 0.5 mm/d,primarily due to the implementation of a turbulent orographic form drag scheme and a probability cloud fraction scheme.Similarly,the cold bias in air temperature from winter to spring is nearly eliminated(from−1.8℃to 0.1℃),largely attributable to improved parameterizations for shallow-snow albedo and the representation of complex terrain effects on snow cover.The TPCSM has contributed to two international model intercomparison projects and has been used to develop high-resolution meteorological datasets,thereby advancing our understanding of the TP’s water and energy cycles.The development of TPCSM marks a significant step forward in regional climate modeling for complex terrain,with implications for improving water resource management,hazard forecasting,and climate change impact assessment across the Third Pole region.展开更多
Proxy-based reconstructions and climate model simulations of Holocene global annual mean temperatures exhibit divergent trends,leading to the well-known“Holocene temperature conundrum(HTC)”.This discrepancy is most ...Proxy-based reconstructions and climate model simulations of Holocene global annual mean temperatures exhibit divergent trends,leading to the well-known“Holocene temperature conundrum(HTC)”.This discrepancy is most pronounced in the mid-to-high latitudes of the Northern Hemisphere(NH)and has been attributed to either proxy seasonal bias or deficiencies in climate models.Paleoclimate data assimilation(PDA),which integrates proxy records with climate model simulations,provides an advanced method for generating global seasonal temperature reanalysis datasets for the mid-Holocene(MH).Assimilated results indicate that MH Eurasian temperatures are largely independent of the choice of model priors and exhibit significant spatial heterogeneity.Compared to the pre-industrial(PI)period,the MH is characterized by winter and annual mean warming in Europe and high-latitude Eurasia,while the rest of Eurasia experiences cooling.However,this spatial heterogeneity is not well represented in model simulations due to a pronounced winter cooling bias at high latitudes,likely resulting from inadequate representations of vegetation and sea ice feedback mechanisms.As Eurasian proxy records are predominantly concentrated in Europe,this regional imbalance introduces a warm bias in reconstructed winter and annual temperatures intended to represent broader Eurasian temperature changes.These results suggest that the HTC may stem from both the uneven spatial distribution of proxy records and the incomplete representation of internal climate feedbacks in current models.展开更多
Peatlands are important carbon reservoirs,yet the mechanisms governing their long-term carbon dynamics remain poorly understood,particularly under combined climatic and anthropogenic pressures.Here,we present comprehe...Peatlands are important carbon reservoirs,yet the mechanisms governing their long-term carbon dynamics remain poorly understood,particularly under combined climatic and anthropogenic pressures.Here,we present comprehensive Holocene records of net carbon balance(NCB)and accumulation rates(AR)from peatlands across the mainland of China,encompassing alpine,subalpine,and lowland ecosystems.Our results reveal distinct regional trajectories shaped by the interplay of climatic variability and human activity.During the early Holocene(~11.5–8 kyr BP),peatlands across China exhibited uniform declines in NCB and AR,primarily driven by rapid climatic warming,intensified peat decomposition,and hydrological disturbances.Since the mid-Holocene,carbon dynamics have diverged markedly between regions:alpine peatlands on the Tibetan Plateau and Altai Mountains(TPA)experienced sustained declines in NCB due to continued warming and drying,while intensified human activity became the dominant driver in subtropical South China(SSC)and Northeast China(NEC)peatlands.Specifically,human-induced erosion in SSC subalpine peatlands increased AR but caused significant carbon dilution in peat deposits,thereby reducing NCB.In contrast,lowland peatlands in NEC received substantial inputs of TOC-enriched soils due to agricultural expansion and permafrost thaw,resulting in concurrent increases in AR and stable to rising NCB.These findings highlight the critical role of regional geomorphology,climatic conditions,soil properties,and both the type and intensity of human disturbances in mediating peatland responses to environmental change.Our study has significant implications for global climate mitigation efforts,as it underscores the need for region-specific peatland management strategies to preserve these vital carbon sinks.展开更多
The southeastern Tibetan Plateau(SETP)is the preeminent summer heavy precipitation region within the Tibetan Plateau(TP).However,the large-scale circulation types and dynamics driving summer heavy precipitation in the...The southeastern Tibetan Plateau(SETP)is the preeminent summer heavy precipitation region within the Tibetan Plateau(TP).However,the large-scale circulation types and dynamics driving summer heavy precipitation in the SETP remain inadequately elucidated.Using the hierarchical clustering method,two distinctive atmospheric circulation patterns associated with heavy precipitation were identified:the Tibetan Plateau vortex type(TPVT,constituting 56.6%of the events)and the mid-latitude trough type(MLTT,43.4%).A comprehensive examination of the two atmospheric circulation patterns reveals a clear nexus between the occurrences of summer heavy precipitation and positive vorticity anomalies,moisture convergence,as well as the southeastward displacement of the westerly jet core.Specifically,TPVT events are characterized by the eastward and dry-to-wet potential vorticity progression processes,while MLTT events are linked to the intrusion of a deep extratropical trough into the SETP.This study advances our understanding of the complex mechanisms governing the summer heavy precipitation in the SETP,shedding light on critical meteorological processes in the region.展开更多
Central Asia(CA)faces a severe water crisis exemplified by the shrinking Aral Sea.However,little is known about the entire region,particularly the numerous small water bodies that are vulnerable to climate change yet ...Central Asia(CA)faces a severe water crisis exemplified by the shrinking Aral Sea.However,little is known about the entire region,particularly the numerous small water bodies that are vulnerable to climate change yet vital for regional sustainability.We examined water bodies as small as 0.0045 km^(2)across CA from 1992 to 2020,identifying 66,215 water bodies in 2020,82.2%of which were previously unstudied.In contrast to the well-documented decline of the Aral Sea,other water bodies have expanded by 10.7%(8714.3 km^(2)),with a net gain of 15,831 lakes since 1992.These findings challenge the perception of a drying CA and provide evidence of a warm-wet climate trend,which is redistributing water resources and creating opportunities for transforming water management to address the long-standing water crisis in CA.展开更多
The intensification of millet agriculture facilitated the development of ancient civilization in northern China.In Inner Mongolia and the Central Plains,the intensification of millet farming was relatively continuous....The intensification of millet agriculture facilitated the development of ancient civilization in northern China.In Inner Mongolia and the Central Plains,the intensification of millet farming was relatively continuous.However,prior evidence from the western Loess Plateau(WLP)has suggested an indistinct sequence of millet cultivation and a time lag between the initial intensification of millet agriculture and subsequent expansion of millet farming.We report on new stable isotopic data and radiocarbon dates from the Gedachuan site which challenge that interpretation.Our results indicate a gradual intensification and expansion of millet agriculture across the whole WLP.They attest to intensive broomcorn millet-based farming underpinning the emergence and development of the agrarian society in the WLP during the early-middle Yangshao period(∼6300-5500 BP),and to an intensification of the higher-yielding foxtail millet-based farming leading to the rapid growth of population in the WLP and expansion of millet cultivation after 5300 BP.展开更多
Inland lakes in arid Central Asia are particularly susceptible to the impact of climate change and human activities.Ebinur Lake,the largest salt inland lake in Xinjiang,Northwest China,has experienced rapid shrinkage,...Inland lakes in arid Central Asia are particularly susceptible to the impact of climate change and human activities.Ebinur Lake,the largest salt inland lake in Xinjiang,Northwest China,has experienced rapid shrinkage,with human activities identified as the primary influencing factor.However,it remains unclear how human water use in different sectors,such as irrigation,husbandry,and industry,is responsible for the long-term change and seasonal variability of the lake area under changing climate.This study aims to address this knowledge gap by developing an integrated hydrological-socioeconomic-lake model that simulates the changes in the Ebinur Lake area during the period of 1950–2020.The simulated lake area changes under different model experiments were then compared with separate the impacts of climate change and human water use of different sectors.The results indicate that climate change,irrigation,husbandry,and industry water uses have contributed+5%,-79%,-25%,and-1%of the long-term change in the lake area,respectively.Despite climate change alone increasing the lake area,the increase in human water use has resulted in the persistent decline of Ebinur Lake.Notably,husbandry water use emerges as a significant contributor to lake shrinkage,accounting for approximately one-third of the impact of irrigation.Furthermore,irrigation water use has contributed to the enhanced seasonal variability,as indicated by the difference between the maximum and minimum monthly lake area in a year.This difference has increased from 120 km2in the 1950s to 183 km2in the 2010s.展开更多
The spheres of the Earth—specifically the lithosphere,hydrosphere,atmosphere,and biosphere—are intricately connected and interact through the fluxes of matter and energy,forming a complex and ever-evolving Earth sys...The spheres of the Earth—specifically the lithosphere,hydrosphere,atmosphere,and biosphere—are intricately connected and interact through the fluxes of matter and energy,forming a complex and ever-evolving Earth system.Understanding the dynamic linkages between these spheres during different types of forcings or events is essential for predicting changes and securing a sustainable future for living organisms,particularly humans.However,uncovering these linkages is challenging due to the need for suitable proxies that can demonstrate how these systems or spheres change across diverse temporal and spatial scales.展开更多
China announced its national goal to reach the peak of carbon emission by 2030 and achieve carbon neutrality by 2060,during the General Assembly of the United Nations in September 2020.In this context,the potential of...China announced its national goal to reach the peak of carbon emission by 2030 and achieve carbon neutrality by 2060,during the General Assembly of the United Nations in September 2020.In this context,the potential of the carbon sink in China’s terrestrial ecosystems to mitigate anthropogenic carbon emissions has attracted unprecedented attention from scientific communities,policy makers and the public.Here,we reviewed the assessments on China’s terrestrial ecosystem carbon sink,with focus on the principles,frameworks and methods of terrestrial ecosystem carbon sink estimates,as well as the recent progress and existing problems.Looking forward,we identified critical issues for improving the accuracy and precision of China’s terrestrial ecosystem carbon sink,in order to serve the more realistic policy making in pathways to achieve carbon neutrality for China.展开更多
The natural environment provides material essentials for human survival and development. The characteristics,processes, regional differentiation and forcing mechanisms of the elements of the natural environment(e.g. g...The natural environment provides material essentials for human survival and development. The characteristics,processes, regional differentiation and forcing mechanisms of the elements of the natural environment(e.g. geomorphology,climate, hydrology, soil, etc.) are the main objects of research in physical geography. China has a complex natural environment and huge regional differentiation and therefore it provides outstanding reserach opportunities in physical geography. This review summarizes the most important developments and the main contributions of research in the physical geography and human living environment in China during the past 70 years. The major topics addressed are the uplift of the Tibetan Plateau and the evolution of its cryosphere, the development of fluvial systems, the acidification of the vast arid region of the Asian interior, variations in the monsoon and westerly climate systems on multiple timescales, the development of lakes and wetlands, the watershed system model, soil erosion, past human-environment interactions, biogeography, and physical geographic zonality. After briefly introducing international research developments, we review the history of research in physical geography in China, focusing on the major achievements and major academic debates, and finally we summarize the status of current research and the future prospects. We propose that in the context of the national demand for the construction of an ecological civilization, we should make full use of the research findings of physical geography, and determine the patterns and mechanisms of natural environmental processes in order to continue to promote the continued contribution of physical geography to national development strategies, and to further contribute to the theory of physical geography from a global perspective.展开更多
The Tibetan Plateau,the world's "Third Pole",has an average elevation above 4,000 masl (meters above sea level)and an area of over 500×10^4km^2,It is the highest and largest plateau on earth and is ...The Tibetan Plateau,the world's "Third Pole",has an average elevation above 4,000 masl (meters above sea level)and an area of over 500×10^4km^2,It is the highest and largest plateau on earth and is very sensitive to global climate change [1,2].The cold,dry and hypoxic high-altitude environment of the plateau presents a major challenge to human survival.Therefore,the history and mechanisms of prehistoric human history on the Tibetan Plateau-from brief hunting expeditions to seasonal hunting-gathering and finally to permanent settlements-has attracted both general interest and substantial scientific debates [3-6].Archaeological studies indicate that humans probably first explored the plateau at the end of the late Pleistocene.They practiced intensive seasonal hunting-gathering from 15 ka BP [6],and permanently settled regions above 3,000 masl after 3.6 ka BP,which was facilitated by the development of an agropastoral economy [3].However, the early part of the human history of the Tibetan Plateau is still poorly documented,due to the lack of well-preserved archaeological sites and reliable dating results (Fig.la).展开更多
The origins and spread of agriculture was one of the milestones in human history.When and how prehistoric agriculture spread to mainland Southeast Asia is highly concerned,which contributed to the formation of modern ...The origins and spread of agriculture was one of the milestones in human history.When and how prehistoric agriculture spread to mainland Southeast Asia is highly concerned,which contributed to the formation of modern Austroasiatic in this region.Previous studies mainly focused on the time and route of rice agriculture’s introduction into Southeast Asia while millet agriculture was not paid proper attention.Here we analyze 31214C dating data yielded from charred seeds of rice(Oryza sativa),foxtail millet(Setaria italica)and broomcorn millet(Panicum miliaceum)from 128 archaeological sites in China and mainland Southeast Asia.The result shows that millet farming was introduced to mainland Southeast Asia in the late third millennium BC and rice farming was in the late second millennium BC.The agriculture of mainland Southeast Asia might originate from three areas,Southwest China,Guangxi-West Guangdong and coastal Fujian.The spread route of ancient agriculture in Southwest China is close to the“Southwest Silk Road”recorded in literature,which implies there was possibly a channel of cultural exchanges on the eastern margin of Tibetan Plateau already in the late Neolithic period,laying the foundation for the Southwest Silk Road later.展开更多
Asian dust storms have long been a major environmental concern in China,affecting the lives of about one billion people.However,it is unclear whether the mechanisms responsible for Asian dust storms during the Holocen...Asian dust storms have long been a major environmental concern in China,affecting the lives of about one billion people.However,it is unclear whether the mechanisms responsible for Asian dust storms during the Holocene varied on different timescales,and thus it is unclear whether there was a shift from a natural forcing to an anthropogenic forcing of dust storms.We reconstructed a high-resolution Holocene record of dust storms from the sediments of an undisturbed alpine lake on the Chinese Loess Plateau.We found that Asian dust storm activity generally increased during the Holocene,with the largest fluctuations occurring during the past 2000 years.The increase in dust storm activity was in contrast to the decrease in East Asian winter monsoon(EAWM)intensity during the Holocene,indicating that the EAWM played a limited role in modulating dust storms.By contrast,the increase in dust storms corresponded to a decrease in East Asian summer monsoon(EASM)precipitation.This demonstrates that EASM precipitation was the dominant control of dust storm activity on a millennial timescale,because decreased EASM precipitation expanded the desert area and thus increased the dust storm activity.The increasing intensity of human activity in the region since the Bronze Age resulted in an acceleration of dust storm activity against the background of decreased EASM precipitation.As human disturbance continued to intensify,beginning at least at~2 cal ka BP,increased dust storms were closely linked to increasing human populations in the dust source regions,and there is a strong temporal coherence between increased dust storms and higher EASM precipitation.This was completely different from when natural processes are dominant.During that period,fewer dust storms occurred during periods of a strengthened EASM.Therefore,there was a shift from a natural forcing to an anthropogenic forcing of dust storms on a multi-decadal to centennial timescale,and was a mode in which‘‘human activity overtook the EASM as the dominant control of the Earth surface system”.展开更多
Arid Central Asia(ACA), with its diverse landscapes of high mountains, oases, and deserts, hosted the central routes of the Silk Roads that linked trade centers from East Asia to the eastern Mediterranean.Ecological p...Arid Central Asia(ACA), with its diverse landscapes of high mountains, oases, and deserts, hosted the central routes of the Silk Roads that linked trade centers from East Asia to the eastern Mediterranean.Ecological pockets and ecoclines in ACA are largely determined by local precipitation. However, little research has gone into the effects of hydroclimatic changes on trans-Eurasian cultural exchange. Here,we reconstruct precipitation changes in ACA, covering the mid-late Holocene with a U-Th dated, ~3 a resolution, multi-proxy time series of replicated stalagmites from the southeastern Fergana Valley,Kyrgyzstan. Our data reveal a 640-a megadrought between 5820 and 5180 a BP, which likely impacted cultural development in ACA and impeded the expansion of cultural traits along oasis routes. Instead,it may have diverted the earliest transcontinental exchange along the Eurasian steppe during the 5 th millennium BP. With gradually increasing precipitation after the megadrought, settlement of peoples in the oases and river valleys may have facilitated the opening of the oasis routes, ‘‘prehistoric Silk Roads", of trans-Eurasian exchange. By the 4 th millennium BP, this process may have reshaped cultures across the two continents, laying the foundation for the organized Silk Roads.展开更多
The Tibetan Plateau(TP),as the world’s highest plateau,has almost all the key elements of the entire Earth system,including interconnected lithosphere,atmosphere,cryosphere,biosphere and anthroposphere[1-3].This comp...The Tibetan Plateau(TP),as the world’s highest plateau,has almost all the key elements of the entire Earth system,including interconnected lithosphere,atmosphere,cryosphere,biosphere and anthroposphere[1-3].This completeness makes the TP an ideal natural laboratory for studying multispheric interactions within the Earth system,and for cultivating key breakthroughs in geoscience of the 21st century[2,3].展开更多
Since Shi et al.proposed that the climate in the drylands of Northwest China experienced a significant transition from a“warming and drying”trend to a“warming and wetting”trend in the 1980s,researchers have conduc...Since Shi et al.proposed that the climate in the drylands of Northwest China experienced a significant transition from a“warming and drying”trend to a“warming and wetting”trend in the 1980s,researchers have conducted numerous studies on the variations in precipitation and humidity in the region and even in arid Central Asia.In particular,the process of the“warming and wetting”trend by using obtained measurement data received much attention.However,there remain uncertainties about whether the“warming and wetting”trend has paused and what its future variations may be.In this study,we examined the spatiotemporal variations in temperature,precipitation,the aridity index(AI),vegetation,and runoff during 1950-2019.The results showed that the climate in the drylands of Northwest China and the northern Tibetan Plateau is persistently warming and wetting since the 1980s,with an acceleration since the 1990s.The precipitation/humidity variations in North China,which are mainly influenced by summer monsoon,are generally opposite to those in the drylands of Northwest China.This reverse change is mainly controlled by an anomalous anticyclone over Mongolia,which leads to an anomalous easterly wind,reduced water vapor output,and increased precipitation in the drylands of Northwest China.While it also causes an anomalous descending motion,increased water vapor divergence,and decreased precipitation in North China.Precipitation is the primary controlling factor of humidity,which ultimately forms the spatiotemporal pattern of the“westerlies-dominated climatic regime”of antiphase precipitation/humidity variations between the drylands of Northwest China and monsoonal region of North China.The primary reasons behind the debate of the“warming and wetting”trend in Northwest China were due to the use of different time series lengths,regional ranges,and humidity indices in previous analyses.Since the EC-Earth3 has a good performance for simulating precipitation and humidity in Northwest and North China.By using its simulated results,we found a wetting trend in the drylands of Northwest China under low emission scenarios,but the climate will gradually transition to a“warming and drying”trend as emissions increase.This study suggests that moderate warming can be beneficial for improving the ecological environment in the drylands of Northwest China,while precipitation and humidity in monsoon-dominated North China will persistently increase under scenarios of increased emissions.展开更多
基金supported by the National Natural Science Foundation of China(No.42072211)the National Natural Science Foundation of China(No.42401048)the Third Xinjiang Scientific Expedition and Research Program(No.2021xjkk0302)。
文摘The Taklimakan Desert,located in the heart of central Asia,covers approximately 330000 km^(2),making it China's largest desert and the world's second-largest shifting desert(Dong et al.,2024).With an average annual precipitation of less than 100 mm and evaporation rates ranging from 2000 to 3000 mm(Yang et al.,2020),it is recognized as one of the driest regions on Earth,often referred to as the“sea of death”.
基金supported by 973 project No. 2000048700NSFC projects No. 40601053 and 40872108Ministry of Science and Technology of China project No. 2006FY110800
文摘The migration speed of a typical barchan on the border of Minqin oasis,Gansu Province,northwestern China,was estimated by means of two methods.One is on the basis of a simple physical model and short-term field measurements.The other comes from the combination of the barchan internal structure detected by ground-penetrating radar and optical/radiocarbon dating techniques.The upper limit of migration speed given by conventional C-14 dating is 3.42 m/yr.The optically stimulated luminescence dating indicates that the time-average migration speed of the studied barchan was 1.78 m/yr in 28 years prior to 2007.The physical estimation further suggests that the annual migration speed has increased in recent years.
基金supported by the National Natural Science Foundation of China Basic Science Center for Tibetan Plateau Earth System(41988101).
文摘The domestication of livestock from their wild progenitors was essential in the process of the Neolithic Revolution.Aurochs(Bos primigenius)are considered to be the ancestors of modern cattle(B.taurus).They were once widespread across Eurasia and North Africa but became extinct approximately 400 years ago[1].
基金supported by the National Natural Science Foundation of China(42588201)China Huaneng Group Co.Ltd.(HNKJ24-H166).
文摘Reliable climate modeling of the Tibetan Plateau(TP)is essential for understanding the variability of the Asian monsoon,water resources,and associated energy and water cycles.However,accurately simulating the region’s complex climate remains challenging for existing models,which often significantly overestimate precipitation and underestimate cold-season air temperatures.In this study,we introduce the Tibetan Plateau Climate System Model(TPCSM),also referred to as TP-WRF,developed from the Weather Research and Forecasting(WRF)model.We have enhanced or incorporated key physical processes related to terrain,land,lakes,snow,and clouds that are often poorly represented or missing in standard climate models.These refinements lead to a significant improvement in simulation accuracy.The wet bias in summer precipitation,averaged across weather stations,is reduced from 2.0 to 0.5 mm/d,primarily due to the implementation of a turbulent orographic form drag scheme and a probability cloud fraction scheme.Similarly,the cold bias in air temperature from winter to spring is nearly eliminated(from−1.8℃to 0.1℃),largely attributable to improved parameterizations for shallow-snow albedo and the representation of complex terrain effects on snow cover.The TPCSM has contributed to two international model intercomparison projects and has been used to develop high-resolution meteorological datasets,thereby advancing our understanding of the TP’s water and energy cycles.The development of TPCSM marks a significant step forward in regional climate modeling for complex terrain,with implications for improving water resource management,hazard forecasting,and climate change impact assessment across the Third Pole region.
基金supported by the Basic Science Center for Tibetan Plateau Earth System(BSCTPES,41988101)the National Key Research and Development Program of China(2023YFF0805200)the National Natural Science Foundation of China(42101148)。
文摘Proxy-based reconstructions and climate model simulations of Holocene global annual mean temperatures exhibit divergent trends,leading to the well-known“Holocene temperature conundrum(HTC)”.This discrepancy is most pronounced in the mid-to-high latitudes of the Northern Hemisphere(NH)and has been attributed to either proxy seasonal bias or deficiencies in climate models.Paleoclimate data assimilation(PDA),which integrates proxy records with climate model simulations,provides an advanced method for generating global seasonal temperature reanalysis datasets for the mid-Holocene(MH).Assimilated results indicate that MH Eurasian temperatures are largely independent of the choice of model priors and exhibit significant spatial heterogeneity.Compared to the pre-industrial(PI)period,the MH is characterized by winter and annual mean warming in Europe and high-latitude Eurasia,while the rest of Eurasia experiences cooling.However,this spatial heterogeneity is not well represented in model simulations due to a pronounced winter cooling bias at high latitudes,likely resulting from inadequate representations of vegetation and sea ice feedback mechanisms.As Eurasian proxy records are predominantly concentrated in Europe,this regional imbalance introduces a warm bias in reconstructed winter and annual temperatures intended to represent broader Eurasian temperature changes.These results suggest that the HTC may stem from both the uneven spatial distribution of proxy records and the incomplete representation of internal climate feedbacks in current models.
基金supported by the National Natural Science Foundation of China(Grant Nos.42571186,42171156&42371164)the Aid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Provincethe Postgraduate Research Innovation Project of Hunan Province(Grant No.LXBZZ2024083)。
文摘Peatlands are important carbon reservoirs,yet the mechanisms governing their long-term carbon dynamics remain poorly understood,particularly under combined climatic and anthropogenic pressures.Here,we present comprehensive Holocene records of net carbon balance(NCB)and accumulation rates(AR)from peatlands across the mainland of China,encompassing alpine,subalpine,and lowland ecosystems.Our results reveal distinct regional trajectories shaped by the interplay of climatic variability and human activity.During the early Holocene(~11.5–8 kyr BP),peatlands across China exhibited uniform declines in NCB and AR,primarily driven by rapid climatic warming,intensified peat decomposition,and hydrological disturbances.Since the mid-Holocene,carbon dynamics have diverged markedly between regions:alpine peatlands on the Tibetan Plateau and Altai Mountains(TPA)experienced sustained declines in NCB due to continued warming and drying,while intensified human activity became the dominant driver in subtropical South China(SSC)and Northeast China(NEC)peatlands.Specifically,human-induced erosion in SSC subalpine peatlands increased AR but caused significant carbon dilution in peat deposits,thereby reducing NCB.In contrast,lowland peatlands in NEC received substantial inputs of TOC-enriched soils due to agricultural expansion and permafrost thaw,resulting in concurrent increases in AR and stable to rising NCB.These findings highlight the critical role of regional geomorphology,climatic conditions,soil properties,and both the type and intensity of human disturbances in mediating peatland responses to environmental change.Our study has significant implications for global climate mitigation efforts,as it underscores the need for region-specific peatland management strategies to preserve these vital carbon sinks.
基金Second Tibetan Plateau Scientific Expedition,Research(STEP)Programme(2019QZKK0105)National Natural Science Foundation of China(U2442213,42122033,42475002 and 42075006).
文摘The southeastern Tibetan Plateau(SETP)is the preeminent summer heavy precipitation region within the Tibetan Plateau(TP).However,the large-scale circulation types and dynamics driving summer heavy precipitation in the SETP remain inadequately elucidated.Using the hierarchical clustering method,two distinctive atmospheric circulation patterns associated with heavy precipitation were identified:the Tibetan Plateau vortex type(TPVT,constituting 56.6%of the events)and the mid-latitude trough type(MLTT,43.4%).A comprehensive examination of the two atmospheric circulation patterns reveals a clear nexus between the occurrences of summer heavy precipitation and positive vorticity anomalies,moisture convergence,as well as the southeastward displacement of the westerly jet core.Specifically,TPVT events are characterized by the eastward and dry-to-wet potential vorticity progression processes,while MLTT events are linked to the intrusion of a deep extratropical trough into the SETP.This study advances our understanding of the complex mechanisms governing the summer heavy precipitation in the SETP,shedding light on critical meteorological processes in the region.
基金supported by the Excellent Research GroupProgram for Tibetan Plateau Earth System(42588201)the National Key Research and Development Program of China(2018YFA0606404)+2 种基金the State Key Laboratory of Tibetan PlateauEarth System,Environment and Resources(TPESER)Youth Innovation Key Program(TPESER-QNCX2022ZD-04)the National NaturalScience Foundation of China(42401048)the China Postdoctoral Innovation Program(GZC20241804).
文摘Central Asia(CA)faces a severe water crisis exemplified by the shrinking Aral Sea.However,little is known about the entire region,particularly the numerous small water bodies that are vulnerable to climate change yet vital for regional sustainability.We examined water bodies as small as 0.0045 km^(2)across CA from 1992 to 2020,identifying 66,215 water bodies in 2020,82.2%of which were previously unstudied.In contrast to the well-documented decline of the Aral Sea,other water bodies have expanded by 10.7%(8714.3 km^(2)),with a net gain of 15,831 lakes since 1992.These findings challenge the perception of a drying CA and provide evidence of a warm-wet climate trend,which is redistributing water resources and creating opportunities for transforming water management to address the long-standing water crisis in CA.
基金supported by the National Natural Science Foundation of China(41825001)the National Key R&D Program of China(2018YFA0606402)+2 种基金Fundamental Research Funds for the Central Universities(lzujbky-2021-77 and lzujbky-2021-ct03)National Social Science Fund of China(21CKG011)National Natural Science Foundation of China(42001073)and Academician and Expert Workstation of Yunnan Province(202305AF150183).
文摘The intensification of millet agriculture facilitated the development of ancient civilization in northern China.In Inner Mongolia and the Central Plains,the intensification of millet farming was relatively continuous.However,prior evidence from the western Loess Plateau(WLP)has suggested an indistinct sequence of millet cultivation and a time lag between the initial intensification of millet agriculture and subsequent expansion of millet farming.We report on new stable isotopic data and radiocarbon dates from the Gedachuan site which challenge that interpretation.Our results indicate a gradual intensification and expansion of millet agriculture across the whole WLP.They attest to intensive broomcorn millet-based farming underpinning the emergence and development of the agrarian society in the WLP during the early-middle Yangshao period(∼6300-5500 BP),and to an intensification of the higher-yielding foxtail millet-based farming leading to the rapid growth of population in the WLP and expansion of millet cultivation after 5300 BP.
基金supported by the Third Xinjiang Scientific Expedition and Research(Grant No.2021xjkk0805)the National Natural Science Foundation of China(Grant No.41790424)NSFC-DFG Mobility(Grant No.M0468)。
文摘Inland lakes in arid Central Asia are particularly susceptible to the impact of climate change and human activities.Ebinur Lake,the largest salt inland lake in Xinjiang,Northwest China,has experienced rapid shrinkage,with human activities identified as the primary influencing factor.However,it remains unclear how human water use in different sectors,such as irrigation,husbandry,and industry,is responsible for the long-term change and seasonal variability of the lake area under changing climate.This study aims to address this knowledge gap by developing an integrated hydrological-socioeconomic-lake model that simulates the changes in the Ebinur Lake area during the period of 1950–2020.The simulated lake area changes under different model experiments were then compared with separate the impacts of climate change and human water use of different sectors.The results indicate that climate change,irrigation,husbandry,and industry water uses have contributed+5%,-79%,-25%,and-1%of the long-term change in the lake area,respectively.Despite climate change alone increasing the lake area,the increase in human water use has resulted in the persistent decline of Ebinur Lake.Notably,husbandry water use emerges as a significant contributor to lake shrinkage,accounting for approximately one-third of the impact of irrigation.Furthermore,irrigation water use has contributed to the enhanced seasonal variability,as indicated by the difference between the maximum and minimum monthly lake area in a year.This difference has increased from 120 km2in the 1950s to 183 km2in the 2010s.
基金supported by the National Natural Science Foundation of China(41988101)the International Partnership Program of Chinese Academy of Sciences for Future Network Project(162GJHZ2023053FN).
文摘The spheres of the Earth—specifically the lithosphere,hydrosphere,atmosphere,and biosphere—are intricately connected and interact through the fluxes of matter and energy,forming a complex and ever-evolving Earth system.Understanding the dynamic linkages between these spheres during different types of forcings or events is essential for predicting changes and securing a sustainable future for living organisms,particularly humans.However,uncovering these linkages is challenging due to the need for suitable proxies that can demonstrate how these systems or spheres change across diverse temporal and spatial scales.
基金supported by the National Natural Science Foundation of China(Grant No.41988101)National Key R&D Program of China(Grant No.2019YFA0607304)。
文摘China announced its national goal to reach the peak of carbon emission by 2030 and achieve carbon neutrality by 2060,during the General Assembly of the United Nations in September 2020.In this context,the potential of the carbon sink in China’s terrestrial ecosystems to mitigate anthropogenic carbon emissions has attracted unprecedented attention from scientific communities,policy makers and the public.Here,we reviewed the assessments on China’s terrestrial ecosystem carbon sink,with focus on the principles,frameworks and methods of terrestrial ecosystem carbon sink estimates,as well as the recent progress and existing problems.Looking forward,we identified critical issues for improving the accuracy and precision of China’s terrestrial ecosystem carbon sink,in order to serve the more realistic policy making in pathways to achieve carbon neutrality for China.
基金supported by the National Natural Science Foundation of China (Grant No. 41842050)
文摘The natural environment provides material essentials for human survival and development. The characteristics,processes, regional differentiation and forcing mechanisms of the elements of the natural environment(e.g. geomorphology,climate, hydrology, soil, etc.) are the main objects of research in physical geography. China has a complex natural environment and huge regional differentiation and therefore it provides outstanding reserach opportunities in physical geography. This review summarizes the most important developments and the main contributions of research in the physical geography and human living environment in China during the past 70 years. The major topics addressed are the uplift of the Tibetan Plateau and the evolution of its cryosphere, the development of fluvial systems, the acidification of the vast arid region of the Asian interior, variations in the monsoon and westerly climate systems on multiple timescales, the development of lakes and wetlands, the watershed system model, soil erosion, past human-environment interactions, biogeography, and physical geographic zonality. After briefly introducing international research developments, we review the history of research in physical geography in China, focusing on the major achievements and major academic debates, and finally we summarize the status of current research and the future prospects. We propose that in the context of the national demand for the construction of an ecological civilization, we should make full use of the research findings of physical geography, and determine the patterns and mechanisms of natural environmental processes in order to continue to promote the continued contribution of physical geography to national development strategies, and to further contribute to the theory of physical geography from a global perspective.
基金supported by the National Natural Science Foundation of China (41771225 and 41620104007)the Fundamental Research Funds for the Central Universities (lzujbky-2018-146)
文摘The Tibetan Plateau,the world's "Third Pole",has an average elevation above 4,000 masl (meters above sea level)and an area of over 500×10^4km^2,It is the highest and largest plateau on earth and is very sensitive to global climate change [1,2].The cold,dry and hypoxic high-altitude environment of the plateau presents a major challenge to human survival.Therefore,the history and mechanisms of prehistoric human history on the Tibetan Plateau-from brief hunting expeditions to seasonal hunting-gathering and finally to permanent settlements-has attracted both general interest and substantial scientific debates [3-6].Archaeological studies indicate that humans probably first explored the plateau at the end of the late Pleistocene.They practiced intensive seasonal hunting-gathering from 15 ka BP [6],and permanently settled regions above 3,000 masl after 3.6 ka BP,which was facilitated by the development of an agropastoral economy [3].However, the early part of the human history of the Tibetan Plateau is still poorly documented,due to the lack of well-preserved archaeological sites and reliable dating results (Fig.la).
基金supported by the National Natural Science Foundation of China(Grant Nos.41901108&41930323)the Second Tibetan Plateau Scientific Expedition(Grant No.2019QZKK0601)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA2004010103).
文摘The origins and spread of agriculture was one of the milestones in human history.When and how prehistoric agriculture spread to mainland Southeast Asia is highly concerned,which contributed to the formation of modern Austroasiatic in this region.Previous studies mainly focused on the time and route of rice agriculture’s introduction into Southeast Asia while millet agriculture was not paid proper attention.Here we analyze 31214C dating data yielded from charred seeds of rice(Oryza sativa),foxtail millet(Setaria italica)and broomcorn millet(Panicum miliaceum)from 128 archaeological sites in China and mainland Southeast Asia.The result shows that millet farming was introduced to mainland Southeast Asia in the late third millennium BC and rice farming was in the late second millennium BC.The agriculture of mainland Southeast Asia might originate from three areas,Southwest China,Guangxi-West Guangdong and coastal Fujian.The spread route of ancient agriculture in Southwest China is close to the“Southwest Silk Road”recorded in literature,which implies there was possibly a channel of cultural exchanges on the eastern margin of Tibetan Plateau already in the late Neolithic period,laying the foundation for the Southwest Silk Road later.
基金supported by the National Natural Science Foundation of China(41790421,41722105,41988101)。
文摘Asian dust storms have long been a major environmental concern in China,affecting the lives of about one billion people.However,it is unclear whether the mechanisms responsible for Asian dust storms during the Holocene varied on different timescales,and thus it is unclear whether there was a shift from a natural forcing to an anthropogenic forcing of dust storms.We reconstructed a high-resolution Holocene record of dust storms from the sediments of an undisturbed alpine lake on the Chinese Loess Plateau.We found that Asian dust storm activity generally increased during the Holocene,with the largest fluctuations occurring during the past 2000 years.The increase in dust storm activity was in contrast to the decrease in East Asian winter monsoon(EAWM)intensity during the Holocene,indicating that the EAWM played a limited role in modulating dust storms.By contrast,the increase in dust storms corresponded to a decrease in East Asian summer monsoon(EASM)precipitation.This demonstrates that EASM precipitation was the dominant control of dust storm activity on a millennial timescale,because decreased EASM precipitation expanded the desert area and thus increased the dust storm activity.The increasing intensity of human activity in the region since the Bronze Age resulted in an acceleration of dust storm activity against the background of decreased EASM precipitation.As human disturbance continued to intensify,beginning at least at~2 cal ka BP,increased dust storms were closely linked to increasing human populations in the dust source regions,and there is a strong temporal coherence between increased dust storms and higher EASM precipitation.This was completely different from when natural processes are dominant.During that period,fewer dust storms occurred during periods of a strengthened EASM.Therefore,there was a shift from a natural forcing to an anthropogenic forcing of dust storms on a multi-decadal to centennial timescale,and was a mode in which‘‘human activity overtook the EASM as the dominant control of the Earth surface system”.
基金supported by the National Key Research and Development Program of China (2018YFA0606400)he Strategic Priority Research Program of Chinese Academy of Sciences (XDB40000000)+5 种基金the 2nd Tibetan Plateau Scientific Expedition and Research (2019QZKK0101)the Youth Innovation Promotion Association of Chinese Academy of Sciences (Y201681)partly supported by the National Natural Science Foundation of China (41888101)the National Social Science Foundation of China (18ZDA172)the National Science Foundation of United States (NSF 1702816, EAR-0908792, and EAR-1211299)a part of the ‘‘Belt & Road” Project of the Institute of Earth Environment, Chinese Academy of Sciences (IEECAS)。
文摘Arid Central Asia(ACA), with its diverse landscapes of high mountains, oases, and deserts, hosted the central routes of the Silk Roads that linked trade centers from East Asia to the eastern Mediterranean.Ecological pockets and ecoclines in ACA are largely determined by local precipitation. However, little research has gone into the effects of hydroclimatic changes on trans-Eurasian cultural exchange. Here,we reconstruct precipitation changes in ACA, covering the mid-late Holocene with a U-Th dated, ~3 a resolution, multi-proxy time series of replicated stalagmites from the southeastern Fergana Valley,Kyrgyzstan. Our data reveal a 640-a megadrought between 5820 and 5180 a BP, which likely impacted cultural development in ACA and impeded the expansion of cultural traits along oasis routes. Instead,it may have diverted the earliest transcontinental exchange along the Eurasian steppe during the 5 th millennium BP. With gradually increasing precipitation after the megadrought, settlement of peoples in the oases and river valleys may have facilitated the opening of the oasis routes, ‘‘prehistoric Silk Roads", of trans-Eurasian exchange. By the 4 th millennium BP, this process may have reshaped cultures across the two continents, laying the foundation for the organized Silk Roads.
基金This work was supported by the National Natural Science Foundation of China(41988101).
文摘The Tibetan Plateau(TP),as the world’s highest plateau,has almost all the key elements of the entire Earth system,including interconnected lithosphere,atmosphere,cryosphere,biosphere and anthroposphere[1-3].This completeness makes the TP an ideal natural laboratory for studying multispheric interactions within the Earth system,and for cultivating key breakthroughs in geoscience of the 21st century[2,3].
基金supported by the National Natural Science Foundation of China(Grant Nos.41988101&42101149)the National Key Research and Development Program of China(Grant No.2018YFA0606404).
文摘Since Shi et al.proposed that the climate in the drylands of Northwest China experienced a significant transition from a“warming and drying”trend to a“warming and wetting”trend in the 1980s,researchers have conducted numerous studies on the variations in precipitation and humidity in the region and even in arid Central Asia.In particular,the process of the“warming and wetting”trend by using obtained measurement data received much attention.However,there remain uncertainties about whether the“warming and wetting”trend has paused and what its future variations may be.In this study,we examined the spatiotemporal variations in temperature,precipitation,the aridity index(AI),vegetation,and runoff during 1950-2019.The results showed that the climate in the drylands of Northwest China and the northern Tibetan Plateau is persistently warming and wetting since the 1980s,with an acceleration since the 1990s.The precipitation/humidity variations in North China,which are mainly influenced by summer monsoon,are generally opposite to those in the drylands of Northwest China.This reverse change is mainly controlled by an anomalous anticyclone over Mongolia,which leads to an anomalous easterly wind,reduced water vapor output,and increased precipitation in the drylands of Northwest China.While it also causes an anomalous descending motion,increased water vapor divergence,and decreased precipitation in North China.Precipitation is the primary controlling factor of humidity,which ultimately forms the spatiotemporal pattern of the“westerlies-dominated climatic regime”of antiphase precipitation/humidity variations between the drylands of Northwest China and monsoonal region of North China.The primary reasons behind the debate of the“warming and wetting”trend in Northwest China were due to the use of different time series lengths,regional ranges,and humidity indices in previous analyses.Since the EC-Earth3 has a good performance for simulating precipitation and humidity in Northwest and North China.By using its simulated results,we found a wetting trend in the drylands of Northwest China under low emission scenarios,but the climate will gradually transition to a“warming and drying”trend as emissions increase.This study suggests that moderate warming can be beneficial for improving the ecological environment in the drylands of Northwest China,while precipitation and humidity in monsoon-dominated North China will persistently increase under scenarios of increased emissions.
