Paleo-environmental changes in the Yangtze Delta during past8000 years

The Yangtze Delta is one of the economically most developed areas in China. It is located in the eastern China monsoon region. Archaeological excavations and environment-archaeology studies over many years in this region provide exceptional information about climate changes, development of human civilization and also human-environment interactions. Archaeological excavations made in the study region reveal that the development of Neolithic cultures is not continuous, which may be a result of extreme climatic events. The analysis of 14 C-dated buried paleotrees, peat and shell ridges show the rise and fall of human civilization in the study area. The research results presented in this paper confirm that human civilization collapsed six times in the Yangtze Delta, matching six high sea level epoches, peat accumulation and buried paleotrees formation periods respectively. This indicates that human activities in the Yangtze Delta are controlled by local climate changes and changing hydrological conditions. The collapse of the Liangzhu culture (5000 aBP-3800 aBP) in about 4000 aBP, after a tremendous flooding event, followed by a relatively backward Maqiao culture (3800 aBP-3200 aBP) confused researchers and aroused their great interest. The research results in this paper show that the collapse of the Liangzhu culture is a result of several factors, for example war and food shortage, but the flooding event occurred in the late Liangzhu culture epoch is the main factor therein.

Variation Trends of Hydrology and Water Resources in Yangtze River Delta Region,China and Its Responses to Climate Change

Global warming has become one of important environmental issues, and will alter the spatial distribution of hydrology and water re- sources through accelerating atmospheric and hydrological cycles. Yangtze River Delta region, an economic center in China, has experienced a re- gional temperature increase since the 1960s, forming a heat island, and the warming rate has improved since the 1990s. The characteristics of hy- drology and water resources changed under regional climate warming. Here, the impacts of climate change on hydrology and water resources were discussed from the aspects of precipitation change, sea level rise, seawater invasion and water pollution in Yangtze River Delta region, China.

Potential control of climatic changes on flood events in the Yangtze Delta during1100-2002

Wide collection on the historic records of the climatic changes and flood events is performed in the Yangtze Delta. Man-Kendall (MK) method is applied to explore the changing trends of the time series of the flood discharge and the maximum high summer temperature. The research results indicate that the flood magnitudes increased during the transition from the medieval warm interval into the early Little Ice Age. Fluctuating climate changes of the Little Ice Age characterized by arid climate events followed by the humid and cold climate conditions give rise to the frequent flood hazards. Low-lying terrain made the study region prone to the flood hazards, storm tide and typhoon. MK analysis reveals that the jumping point of the time series of the flood discharge changes occurred in the mid-1960s, that of the maximum summer temperature changes in the mid-1990s, and the exact jump point in 1993. The flood discharge changes are on negative trend before the 1990s, they are on positive tendency after the 1990s; the maximum high summer temperature changes are on negative trend before the 1990s and on positive tendency after the 1990s. These results indicate that the trend of flood discharge matches that of the maximum high summer temperature in the Yangtze Delta. The occurrence probability of the maximum high summer temperature will be increasing under the climatic warming scenario and which will in turn increase the occurrence probability of the flood events. More active solar action epochs and the higher sea surface temperature index (SST index) of the south Pacific Ocean area lying between 4 o N-4 o S and 150 o W-90 o W correspond to increased annual precipitation, flood discharge and occurrence frequency of floods in the Yangtze Delta. This is partly because the intensified solar activities and the higher SST index give rise to accelerated hydrological circulation from ocean surface to the continent, resulting in increased precipitation on the continent.

Perception-Based Analysis (PBA) of Climate Change Impacts on the Forest and Agricultural Ecosystem of Shropshire, United Kingdom

Agriculture and forestry are vital sectors providing services, food and other environmental benefits that could be most affected by the impact of climate change (CC). This study analysed the impact of CC on forestry and agriculture in a typical UK rural environment. The study interrogates this complex question using the Perception Based Analysis (PBA) methodological approach. Data analysis utilized chi square test and one-way analysis of variance (Anova) in comparing the impact of climate change and human factors on forest and agricultural ecosystems, (significance level α = 5%), calculated ρ = 0.36 > 0.05. This non-significant ρ value suggests that the null hypothesis Ho “climate change is responsible for the changes in forest and agricultural ecosystem in the case study area” could be true.

The Impact of Climate Change on Ground Water Supplies Affecting Rural Livelihood in Developing Countries

Climate change is becoming a serious issue nowadays.There are profound environmental,economic and political implications of global warming. Ecosystems,from mountains to oceans and from the poles to the tropics,are undergoing rapid change.The cost will be borne by all,but especially by the

Climatic evolution in the Yangtze Delta region in the late Holocene epoch

Neolithic site sections, natural sections and other proxy indicators like paleotrees and peat are collected for further understanding the environmental changes during the past 10,000 years in the Yangtze Delta region. The results indicate that cultural interruption in the Yangtze Delta was the result of water expansion induced by climatic changes like more precipitation. For fi＇agile human mitigation to the natural hazards in the Neolithic cultural period, environmental changes usually exerted tremendous influences on human activities, havocking the human civilization, which is meaningful for human mitigation to natural hazards under the present global warming. At the same time, some uncertainties in reconstruction ofoaleo-environmental changes were discussed in the text.

Possible effect of climate changes on the coastal zone of the Yangtze River Delta

A coastal historical evolution of the Yangtze River Delta was discussed in this paper on the basis of the historical data of the coastal zone and an estimation was made for the future change of the coast The emphasis was put on the future climate change that will have influence on the sea wall, coastal navigation and freshwater resources in the Delta It was also pointed out that the global warming and precipitation increase in the Yangtze River Valley may exert more impact on the zone In addition, some measures describing how to adapt to the climate change and reduce its impact were put forward

CALCULATION AND ANALYSIS ON CHANGE OFAGRICULTURAL WATER CONSUMPTIONIN THE CHANGJIANG DELTA

ABSTRACT: The potential evapotranspiration of specific crops in the Changjiang Delta is calculated by using Pen-man-Monteith method, and an agricultural water consumption model in the area is developed on the basis of agricultural production situation. This model has higher precision compared with actual data and can reflect the actual status of agriculture water need. Considering the meteorological, hydrological, economical development situation of the Changjiang Delta, this paper calculates and analyzes the volumes of agricultural water consumption in 2000, 2010, 2030 and 2050 under different climate change conditions and different development speeds of urbanization in future. The result shows agriculture water demand increases with temperature rising and decreases obviously with cultivated area reducing. For the Changjiang Delta, the volume of agricultural water consumption in the future will less than that of present.

Evaluation of the water conservation function in the Ili River Delta of Central Asia based on the InVEST model

The Ili River Delta(IRD)is an ecological security barrier for the Lake Balkhash and an important water conservation area in Central Asia.In this study,we selected the IRD as a typical research area,and simulated the water yield and water conservation from 1975 to 2020 using the water yield module of the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model.We further analyzed the temporal and spatial variations in the water yield and water conservation in the IRD from 1975 to 2020,and investigated the main driving factors(precipitation,potential evapotranspiration,land use/land cover change,and inflow from the Ili River)of the water conservation variation based on the linear regression,piecewise linear regression,and Pearson's correlation coefficient analyses.The results indicated that from 1975 to 2020,the water yield and water conservation in the IRD showed a decreasing trend,and the spatial distribution pattern was"high in the east and low in the west";overall,the water conservation of all land use types decreased slightly.The water conservation volume of grassland was the most reduced,although the area of grassland increased owing to the increased inflow from the Ili River.At the same time,the increased inflow has led to the expansion of wetland areas,the improvement of vegetation growth,and the increase of regional evapotranspiration,thus resulting in an overall reduction in the water conservation.The water conservation depth and precipitation had similar spatial distribution patterns;the change in climate factors was the main reason for the decline in the water conservation function in the delta.The reservoir in the upper reaches of the IRD regulated runoff into the Lake Balkhash,promoted vegetation restoration,and had a positive effect on the water conservation;however,this positive effect cannot offset the negative effect of enhanced evapotranspiration.These results provide a reference for the rational allocation of water resources and ecosystem protection in the IRD.

Carbon sink response of terrestrial vegetation ecosystems in the Yangtze River Delta and its driving mechanism

The carbon cycle of terrestrial ecosystems is influenced by global climate change and human activities.Using remote sensing data and land cover products,the spatio-temporal variation characteristics and trends of NEP in the Yangtze River Delta from 2000 to 2020 were analyzed based on the soil respiration model.The driving influences of ecosystem structure evolution,temperature,rainfall,and human activities on NEP were studied.The results show that the NEP shows an overall distribution pattern of high in the southeast and low in the northwest.The area of carbon sinks is larger than that of the carbon sources.NEP spatial heterogeneity is significant.NEP change trend is basically unchanged or significantly better.The future change trend in most areas will be continuous decrease.Compared with temperature,NEP are more sensitive to precipitation.The positive influence of human activities on NEP is mainly observed in north-central Anhui and northern Jiangsu coastal areas,while the negative influence is mainly found in highly urbanized areas.In the process of ecosystem structure,the contribution of unchanged areas to NEP change is greater than that of changed areas.

Interlinking climate change with waterenergy-food nexus and related ecosystem processes in California case studies

Global climate change creates critical challenges with increasing temperature,reducing snowpack,and changing precipitation for water,energy,and food,as well as ecosystem processes at regional scales.Ecosystem services provide life support,goods,and natural resources from water,energy,and food,as well as the environments.There are knowledge gaps from the lack of conceptual framework and practices to interlink major climate change drivers of water resources with water-energy-food nexus and related ecosystem processes.This paper provided an overview of research background,developed a conceptual framework to bridge these knowledge gaps,summarized California case studies for practices in cross sector ecosystem services,and identified future research needs.In this conceptual framework,climate change drivers of changing temperature,snowpack,and precipitation are interlinked with life cycles in water,energy,food,and related key elements in ecosystem processes.Case studies in California indicated climate change affected variation in increasing temperature and changing hydrology at the regional scales.A large variation in average energy intensity values was also estimated from ground water and federal,state,and local water supplies both within each hydrological region and among the ten hydrological regions in California.The increased regional temperature,changes in snowpack and precipitation,and increased water stresses from drought can reduce ecosystem services and affect the water and energy nexus and agricultural food production,as well as fish and wildlife habitats in the Sacramento-San Joaquin Delta(Delta)and Central Valley watersheds.Regional decisions and practices in integrated management of water,energy,food,and related ecosystem processes are essential to adapt and mitigate global climate change impacts at the regional scales.Science and policy support for interdisciplinary research are critical to develop the database and tools for comprehensive analysis to fill knowledge gaps and address ecosystem service complexity,the related natural resource investment,and integrated planning needs.

Finding Food Security through Changing the Agricultural Model to Sustain Insect Biodiversity

Worldwide biodiversity is being threatened by human activities to a greater level wherein the natural ecosystems are reaching the verge of collapsing. We are faced with four major interrelated challenges namely a changing climate, biodiversity loss, human population growth and food production for this growing population. Agricultural intensification contributes significantly to biodiversity loss. The agricultural model for our current food production systems is mainly based on the Green Revolution, which promoted the cultivation of crops in extensive monoculture fields and intensified external inputs of agrochemicals. This model resulted in biodiversity loss, particularly in insect populations. A model based on ecological intensification as an alternative to agricultural intensification with minimized use of agro-inputs may slow the rate of biodiversity loss resulting in more sustainable agricultural ecosystems.

Future wet grasslands:ecological implications of climate change

Wet grasslands are threatened by future climate change,yet these are vital ecosystems for both conservation and agriculture,providing livelihoods for millions of people.These biologically diverse,transitional wetlands are defined by an abundance of grasses and periodic flooding,and maintained by regular disturbances such as grazing or cutting.This study summarizes relevant climate change scenarios projected by the Intergovernmental Panel on Climate Change and identifies implications for wet grasslands globally and regionally.Climate change is predicted to alter wet grassland hydrology,especially through warming,seasonal precipitation variability,and the severity of extreme events such as droughts and floods.Changes in the diversity,composition,and productivity of vegetation will affect functional and competitive relations between species.Extreme storm or flood events will favor ruderal plant species able to respond rapidly to environmental change.In some regions,wet grasslands may dry out during heatwaves and drought.C4 grasses and invasive species could benefit from warming scenarios,the latter facilitated by disturbances such as droughts,floods,and possibly wildfires.Agriculture will be affected as forage available for livestock will likely become less reliable,necessitating adaptations to cutting and grazing regimes by farmers and conservation managers,and possibly leading to land abandonment.It is recommended that agri-environment schemes,and other policies and practices,are adapted to mitigate climate change,with greater emphasis on water maintenance,flexible management,monitoring,and restoration of resilient wet grasslands.

气候变化背景下赣江流域复合高温干旱事件时空演变特征

【目的】在气候变化背景下,全球多区域复合高温干旱事件频率与强度呈现增加趋势。系统揭示赣江流域复合高温干旱事件的时空演变特征,为灾害风险防范提供参考。【方法】采用1961—2021年的日最高温度和表层土壤含水量数据,评估赣江流域热浪、农业干旱和复合高温干旱事件的时空变化趋势,对比分析复合高温干旱事件与单独极端事件的特征差异。【结果】结果表明:赣江流域农业干旱事件频次呈下降趋势(-0.027场/10 a),热浪事件及复合高温干旱事件的频次呈上升趋势(0.084场/10 a、0.013场/10 a)。与1961—2000年相比,2001—2021年赣江流域农业干旱的发生频率在北部大部分区域有所下降,南部地区大部分区域有所增加;热浪事件的发生频率在全流域均呈增加趋势;复合高温干旱的发生频率在东北部有所下降,南部显著上升。与单独热浪事件和单独农业干旱事件相比,复合高温干旱下的热浪事件历时和烈度分别增加16.87%和26.25%,农业干旱事件历时和烈度分别增加10.65%和26.86%。【结论】赣江流域南部地区复合高温干旱事件发生频率显著增加;相比于单独的极端事件,复合高温干旱事件的危险性有所增强,未来应加强该区域的复合高温干旱风险防范能力。

Plant Breeding for Harmony between Modern Agriculture Production and the Environment

The world population is estimated to be 9.2 billion in 2050. To sufficiently feed these people, the total food production will have to increase 60% - 70%. Climate models predict that warmer tem-peratures and increases in the frequency and duration of drought during the present century will have negative impact on agricultural productivity. These new global challenges require a more complex integrated agricultural and breeding agenda that focuses on livelihood improvement coupled with agro-ecosystem resilience, eco-efficiency and sustainability rather than just on crop productivity gains. Intensifying sustainability agro-ecosystems by producing more food with lower inputs, adapting agriculture to climate change, conserving agro-biodiversity through its use, and making markets to work for the small farmers are needed to address the main issues of our time. Plant breeding has played a vital role in the successful development of modern agriculture. Development of new cultivars will be required while reducing the impact of agriculture on the environment and maintaining sufficient production. Conventional plant breeding will remain the backbone of crop improvement strategies. Genetic engineering has the potential to address some of the most challenging biotic constraints faced by farmers, which are not easily addressed through conventional plant breeding alone. Protective measures and laws, especially patenting, must be moderated to eliminate coverage so broad that it stifles innovation. They must be made less restrictive to encourage research and free flow of materials and information. Small farmers have an important role in conserving and using crop biodiversity. Public sector breeding must remain vigorous, especially in areas where the private sector does not function. This will often require benevolent public/private partnerships as well as government support. Active and positive connections between the private and public breeding sectors and large-scale gene banks are required to avoid a possible conflict involving breeders’ rights, gene preservation and erosion. Plant breeding can be a powerful tool to bring “harmony” between agriculture and the environment, but partnerships and cooperation are needed to make this a reality.

2022年4月长三角区域臭氧污染特征与影响因素分析

近年来,臭氧污染已经成为中国中东部影响环境空气的重要因素,臭氧在大气中的作用复杂,局地气象条件、臭氧前体物以及臭氧浓度的时空变化都会对其产生重要的影响。本研究将开展青浦区大气中臭氧及其重要前体物的时空分布规律研究,以分析长三角区域环境空气中臭氧浓度水平与其前体物之间的相互关系,探明青浦区大气臭氧污染形成的关键组分、分布规律。通过与松江区和嘉定区各监测站点臭氧浓度对比,其变化趋势基本一致,与吴江、嘉善监测站点臭氧浓度的对比表明,臭氧污染为区域性污染问题,青浦区臭氧污染受到长三角地区臭氧区域性污染的影响。本次研究表明长时间的日照因素为近地层臭氧浓度升高提供了必要的气象条件;由于疫情封控和气象条件的变化以及外部传输等原因,青浦、吴江、嘉善地区臭氧前体物浓度皆有不同降幅,前体物减排比例受到影响,进而臭氧浓度随之上升。

Detection of the Hazards That Threaten Some Coastal Areas, and Ecosystem-Based Solution to Strengthen the Natural Defenses

The coastal strip of the Nile delta has been vulnerable to environmental hazards. Field surveys, interpretation of Landsat enhanced thematic mapper imageries (ETM), and hydrochemistry analysis of the water samples was used as methods and materials to detect the hazards associated with climate change which threaten some natural protection coastal areas of the central part of the Nile Delta and assess its magnitude. The invasion of seawaters is the main hazard due to the impacts of global warming phenomena. Elimination of the coastal dunes which act as natural defenses has been accelerating the negative impacts that have been appearing clearly on low-lying lands. Planting that protected areas of the coastal strip are considered the most suitable ecosystem-based and most beneficial solution should be authorized and adopted by the local administration to preserve those areas and adapt to these disasters.

农业适应气候变化研究进展回顾与展望

气候变化对农业生产产生了广泛而深刻的影响。本文基于气候系统和农业生态系统、经济社会系统的相互作用关系,梳理气候变化的农业影响和适应的逻辑层次。影响的逻辑层次可以归结为:气候平均状态变化的影响、极端天气气候事件加剧的影响、气候变化引起的生态后果和经济社会后果等4个方面;与气候变化影响的逻辑层次相应,适应气候变化的逻辑层次可以分解为:气候变暖条件下农业气候资源的高效利用;根据气候变暖背景下农业气象灾害发生新特征,系统调整农业防灾减灾工作思路与技术路线;加强农业生物多样性保护,优化农业生态系统的结构与功能,充分发挥农业生态系统服务增强农业气候韧性;以及农业经济社会系统整体的优化转型。在对气候变化影响评估和已采取的适应措施系统总结回顾基础上,分析了农业适应气候变化面临的挑战,即:气候胁迫不断加大、农业系统对于气候变化的脆弱性不断加大、粮食安全保障体系还很不完善、适应能力薄弱等。最后提出农业适应气候变化需要加强研究的关键科学问题:扩展气候变化农业影响评估研究领域、科学辨识农业之于气候变化的脆弱性和风险、揭示农业适应气候变化的科学机理、构建农业适应气候变化技术体系、加强农业适应气候变化的决策能力研究、加强农业适应行动实施的保障能力研究等。

1978—2012年长江三角洲城市群极端小时降水时空变化特征

【目的】全球气候变暖和快速城镇化背景下极端降水事件频发,严重影响社会经济可持续发展,特别是城市群或都市圈面临更大挑战。为准确评估长江三角洲城市群极端降水演变规律,【方法】利用135个气象站点1978—2012年小时降水资料,选取最大1小时降水量(Rx1hr)、超过95%和99%阈值小时降水量(R95pw1hr和R99pw1hr)、超过10 mm和20 mm小时降水频次(R1hr10 mm和R1hr20 mm)五个极端小时降水指标,采用滑动平均法、EOF分解法分析极端小时降水时空变化特征。【结果】结果表明:(1)除R1hr10 mm外,极端小时降水指标总体呈显著上升趋势;(2)空间上主要表现为东南多,西北少,且显著增加站点主要在江苏南部;(3)极端小时降水峰值主要集中在12—18时,占比68.1%~79.3%;(4)极端小时降水主要表现为区域一致型、正负反向型和中心型,其中第一模态以区域一致型为主,且表现出明显增长趋势。【结论】结果证实1978—2012年长江三角洲城市群极端小时降水呈现明显增加趋势,其空间格局受地形特征、城市化发展影响明显,且城市化对极端小时降水有一定促进作用。该研究有助于科学认识城市群极端降水演变,为城市群防灾减灾与合理规划提供参考。

气候变化和土地利用变化对长江中下游地区植被NPP变化相对贡献分析

基于MODIS数据、气象数据和土地利用类型数据,利用Theil-Sen Median趋势分析、Mann-Kendall显著性检验和重标极差(R/S)分析,揭示长江中下游地区植被生态系统NPP时空演变特征和未来变化趋势;并基于情景设置的相对贡献分析,在区域和格网尺度上定量厘定气候变化和土地利用变化对长江中下游地区植被生态系统NPP变化的相对贡献.结果表明,时间上,2000~2021年长江中下游地区植被NPP整体呈波动上升趋势,上升速率为6.99g/(m^(2)·a).林地、草地和耕地生态系统NPP均呈上升趋势,林地生态系统NPP上升速率最高,为9.79g/(m^(2)·a),草地生态系统NPP上升速率次之,为8.84g/(m^(2)·a),耕地生态系统NPP上升速率最低,为2.34g/(m^(2)·a).空间上,长江中下游地区植被NPP变化斜率呈现“南高北低”的空间分布格局.长江中下游地区整体及各植被生态系统NPP呈上升趋势的面积占比均大于呈下降趋势的面积占比,其中,林地和草地生态系统NPP呈上升趋势的面积占比分别为91.43%和91.48%.长江中下游地区植被NPP未来呈上升趋势的面积占比小于呈下降趋势的面积占比.由相对贡献分析结果可知,区域尺度上,气候变化和土地利用变化对长江中下游地区植被生态系统NPP变化的相对贡献分别为85.60%和10.85%.气候变化主导林地和草地生态系统NPP变化,而土地利用变化主导耕地生态系统NPP变化.格网尺度上,长江中下游地区耕地和草地生态系统NPP变化由土地利用变化主导的面积占比最大,分别为54.99%和56.91%.林地生态系统NPP变化由气候变化主导的面积占比最大,为71.96%.剩余因素对耕地生态系统NPP变化的相对贡献高于林地和草地生态系统.