1957—2006年塔里木河流域气候变化和人类活动对水资源和生态环境的影响

塔里木河是我国最大的内陆河,历史上是环塔里木盆地九大水系144条河流的总称,目前呈"四源一干"格局.依据1957—2006年近50a气象及水文监测资料,分析了气候变化和人类活动对塔里木河流域水资源的影响.虽然近50a来塔里木河流域山区与平原整体呈现气温升高、降水量增加特征,出山口径流量也呈增加趋势,然而在2000年前塔里木河流域生态环境急剧退化.其成因主要为:1)从20世纪50年代起到近2006年,四条源流入塔里木河水量50a减少了15.4×108m3;2)塔里木河上、中、下游耗水量比例的失调及区域水资源分配发生变化,造成塔里木河下游生态环境恶化;3)实施塔里木河综合治理后,即使进入塔里木河的下游的水量增加,中游段耗水量下降,但是上游耗水迅速增加且数量巨大,还是对塔里木河水资源综合利用、改善的下游生态环境产生负面影响.

塔里木河流域适应气候变化和人类活动的应对措施

自2001年开始实施塔里木河流域近期综合治理工程,提出了以强化流域水资源统一管理和调度为核心,以源流区节水改造和干流河道治理为重点进行综合治理,积极稳妥地进行经济结构调整,实施退耕封育保护,有效保护好现有天然林草植被.通过向塔里木河下游生态输水,干涸近30a的台特玛湖于2001年11月16日开始有水,使塔里木河下游绿色走廊得到初步复苏等,流域生态环境得到极大的恢复.然而,自2007年以来,塔里木河向下游输水已大为减少,仅能输水到中游,特别是2009年水文干旱,塔里木河干流断流达1 100km多,使下游绿色走廊再度陷入生态危机.为此,需要重新审视塔里木河流域的综合治理,从加强源流治理开始,来巩固干流治理成果.认真总结10a来治理经验与教训,针对人类活动和气候变化对源流与干流造成的影响程度,积极采取应对措施.

气候变化和人类活动对水库面源污染负荷影响

文章应用SWAT模型定量分析气候和人类活动共同影响下水库面源污染的时空响应,并对两者的贡献率进行定量分离。结果表明:气候变化对库区面源污染负荷贡献率均值为36%,而人类活动贡献率均值为64%,在气温每上升3℃及退耕还林面积超过10%条件下,库区面源污染负荷削减明显,削减率在18. 9%～27. 6%之间,而在降水每增加10%及城镇用地面积增加5%条件下,区域面源污染负荷呈现显著上升趋势。研究成果对于评估环境变化对水库面源污染负荷变化影响提供方法参考。

清姜河流域年径流变化趋势及气候与人类活动对径流的影响分析

以清姜河流域为研究区域,基于益门镇水文站1956-2020年水文监测数据资料,采用滑动平均、线性回归、曼—肯德尔、SCRAQ法分析清姜河流域年径流量变化趋势、突变情况及气候变化与人类活动因子对年径流变化的影响程度。分析结果表明;自1956年以来,清姜河流域年径流量波动变化剧烈、年际变化差异性大、减少趋势明显,其减少率为-0.010 9亿m^(3)/a,在1971年、1977年、1988年和2002年间发生突变现象;在气候变化与人类活动共同作用的影响下,清姜河流域年径流量的减少趋势十分明显,其中主要因素是人类活动,次要因素是气候变化。

全球气候变化背景下雄安新区建设水资源安全风险与治理对策

雄安新区气候暖干化趋势将导致地表径流集聚减少,同时加之新区快速城镇化建设必然面临水安全问题挑战。文章秉承雄安新区建设的"生态优先、绿色发展、绿色宜居"理念,从气候变化与人类活动双重角度,系统分析了雄安新区气候变化特征和人类活动对水安全问题的影响。进一步分析了雄安新区未来建设中可能面临的自然、生态和经济灾害风险。从而提出了相应的战略对策,以期保障美丽雄安新区建设。

人类活动与气候变化影响慕士塔格冰芯细菌群落百年变化

冰芯高保真地提供了高分辨率的历史气候和人类活动的长时间记录.已有的冰芯气候环境变化记录主要基于离子、同位素、粉尘等物理化学指标,而生物指标则鲜有涉及.本文对钻取自青藏高原慕士塔格冰川74m冰芯中的细菌群落进行了研究,以建立生物指标与过去气候环境变化和人类活动的联系.通过分析冰芯中1907~1991年间的微生物及其与环境指标的关系,发现冰芯中细菌丰富度随时间增加,并与指示农业发展的NH4+含量的升高有关;冰芯细菌群落组成受源自人类活动和自然生态系统的物质输入及气温的共同影响,在20世纪50年代后,人类活动的影响尤为显著.此外,我们还发现源自动物肠道的细菌科Aerococcaceae、Nocardiaceae、Muribaculaceae和Lachnospiraceae的相对丰度与中亚地区养殖牲畜数量的变化相关,它们对牲畜数量变化的解释量达59.8%.这项研究定量化揭示了细菌多样性和群落组成与过去气候和人类活动之间的关系,突显了微生物在冰芯气候变化研究中的潜力.

末次盛冰期以来气候变化和人类活动对我国沙漠和沙地环境的影响

末次盛冰期以来,我国沙漠和沙地经历了气候由冷干向暖湿的变化以及全新世以来人类活动的急剧增强,地表沉积和环境也随之发生了很大的变化。在"全球变化研究"国家重大科学研究计划的支持下,我们对最近21ka以来中国沙漠和沙地环境演化的特征、影响机制以及自然与人为因素的作用等进行了研究,发现在末次盛冰期,中国沙漠和沙地的流沙面积扩张了10%—270%;在全新世暖期,中国西部沙漠的流沙面积缩小了5%—20%,中部-东部沙地基本被植被覆盖、流沙固定。全新世以来,人类活动对沙地地区的影响急剧增强,证据显示,现代的流沙活动受到自然气候和人类活动的双重影响,进一步的分析有望定量区分人类活动和气候变化对沙漠化变化的贡献。在未来的研究工作中,要加强高分辨率气候变化的定量重建、气候-环境-人类活动相互作用的机制、沙漠和沙地对气候变率响应的敏感性以及粉尘释放的定量评估等研究工作。

基于大样本^(14)C测年资料的华北平原沉积速率研究

华北平原是我国研究程度较高的地区,历年来积累了大量的14C测年资料。从这些资料中尽可能地提取沉积速率的信息,并进而研究华北平原沉积速率的变化及其与流域自然和人文环境变化之间的关系,是一个有重要意义的问题。利用华北平原456个地点的14C年龄与样品埋深资料,计算出了各个样品所在层位沉积以来的平均沉积速率(RT),以此来近似反映各地点的平原沉积速率,并据此建立了RT随时间的变化关系。从古至今,RT有明显的增大趋势。以点群的上包线反映各时代的平原最大沉积速率,该指标可以反映华北平原的主体即黄河下游冲积平原的沉积速率。发现了最大平均沉积速率随时间变化过程中的4个突变点,分别为10000aB.P.,5000aB.P.,3000aB.P.和1400aB.P.。4个突变点将上包线分成5条折线,由此可以将近4万年以来的变化分成5个阶段。从古至今,5条折线的斜率增大,反映了平原沉积的加速过程;并对4个突变点的成因进行了解释。阶段1,阶段2和阶段3沉积速率的加速是由自然原因造成的;阶段4和阶段5沉积速率的加速则是由自然和人为原因共同造成的。从456个地点的14C年龄与样品埋深资料中提取了距今4万年以来华北平原的平均沉积速率的信息,计算出平均沉积速率为0.9mm/a。按此求出,近4万年以来华北平原的沉积总厚度为36m。

Shrinking and Drying up of Baiyangdian Lake Wetland:A Natural or Human Cause?

The shrinking and drying up of wetlands in arid and semiarid areas of China have been widely observed in the recent years, but there has been no consensus on whether the aggravation is caused by human activities or by global climate warming. For a better understanding of the cause, this study investigates the dynamic changes of Baiyangdian Lake wetland over the last 40 years. It is shown that since the 1980s, Baiyangdian Lake has suffered from an insufficient water input and shrunk considerably. By using SPSS 11.0, this study urines a detailed Analysis on the signifficance of the effects of the possible driving factors for the degradation. It is identified that the North China Plain has been warrnin~ up significantly in recent years, which causes a significant reduction in the precipitation and inflow to the lake. Although human disturbances such as the irrigation and storage of water in reservoirs do not play a decisive role, they accelerate the degradation and their effects should be minimized.

HISTORICAL DESERTIFICATION PROCESS IN HEXI CORRIDOR,CHINA

Over the last 2000 years, approximately 38 ancient cities were abandoned through desertification in Hexi Corridor, Northwest China. Among them, 21.05% were abandoned during the Northern and Southern Dynasties, 21.05% during the end of the Tang Dynasty and the Five Dynasties, and 57.9% during the Ming and Qing dynasties. At the same time, main lakes were shrinking rapidly from the 5th Century to the 6th Century and the end of the Qing Dynasty. The climate in these periods was relatively arid and cold with frequent dusts. The phase of these changes indicated that there were three periods of desertification enlargement in the northern China. They were Northern and Southern Dynasties, the end of Tang Dynasty and Five Dynasties, the Ming and Qing dynasties. The macro-process of desertification in the study area was controlled mainly by the climatic changes. But from the facts that the population density in the middle of Qing Dynasty had exceeded the critical index of population pressure in arid area and the usage rate of water resources had exceeded 40% in Hexi Corridor, this paper also suggests that human activities have played an important role in desertification processes of the study area mainly during the recent 300 years.

Influence of the Pacific Decadal Oscillation on regional sea level rise in the Pacific Ocean from 1993 to 2012

The rate of regional sea level rise （SLR） provides important information about the impact of human activities on climate change. However, accurate estimation of regional SLR can be severely affected by sea surface height （SSH） change caused by the Pacific Decadal Oscillation （PDO-SSH）. Here, the PDO- SSH signal is extracted from satellite altimeter data by multi-variable linear regression, and regional SLR in the altimeter era is calculated, before and after removing that signal. The results show that PDO-SSH trends are rising in the western Pacific and falling in the eastern Pacific, with the strongest signal confined to the tropical and North Pacific. Over the past 20 years, the PDO-SSH accounts for about 30%/-400% of altimeter-observed SLR in the regions 8° 15°N, 130°-160°E and 30°-40°N, 170°-220°E. Along the coast ＆North America, the PDO-SSH signal dramatically offsets the coastal SLR, as the sea level trends change sign from falling to rising.

Land Use Changes in Northeast China Driven by Human Activities and Climatic Variation

Human-induced land use/cover change (LUCC) forms an important component of global environmental change. Therefore, it is important to study land use/cover and its change at local, regional and global scales. In this paper we conducted the study of land use change in Northeast China, one of the most important agricultural zones of the nation. From 1986 to 2000, according to the study results obtained from Landsat images, widespread changes in land use/cover took place in the study area. Grassland, marsh, water body and woodland decreased by 9864, 3973, 1367 and 10,052km2, respectively. By comparison, paddy field, dry farmland, and built-up land expanded by 7339, 17193 and 700km2, respectively. Those changes bore an interactive relationship with the environment, especially climate change. On the one hand, climate warming created a potential environment for grassland and marsh to be changed to farmland as more crops could thrive in the warmer climate, and for dry farmland to paddy field. On the other hand, the changed surface cover modified the local climate. Those changes, in turn, have adversely influenced the local environment by accelerating land degradation. In terms of socio-economic driving forces, population augment, regional economic development, and national and provincial policies were confirmed as main driving factors for land use change.

Spatio-temporal Pattern of Net Primary Productivity in Hengduan Mountains area, China： Impacts of Climate Change and Human Activities

Net primary productivity(NPP), a metric used to define and identify changes in plant communities, is greatly affected by climate change, human activities and other factors. Here, we used the Carnegie-Ames-Stanford Approach(CASA) model to estimate the NPP of plant communities in Hengduan Mountains area of China, and to explore the relationship between NPP and altitude in this region. We examined the mechanisms underlying vegetation growth responses to climate change and quantitatively assessed the effects of ecological protection measures by partitioning the contributions of climate change and human activities to NPP changes. The results demonstrated that: 1) the average total and annual NPP values over the years were 209.15 Tg C and 468.06 g C/(m2·yr), respectively. Their trend increasingly fluctuated, with spatial distribution strongly linked to altitude(i.e., lower and higher NPP in high altitude and low altitude areas, respectively) and 2400 m represented the marginal altitude for vegetation differentiation; 2) areas where climate was the main factor affecting NPP accounted for 18.2% of the total research area, whereas human activities were the primary factor influencing NPP in 81.8% of the total research area, which indicated that human activity was the main force driving changes in NPP. Areas where climatic factors(i.e., temperature and precipitation) were the main driving factors occupied 13.6%(temperature) and 6.0%(precipitation) of the total research area, respectively. Therefore, the effect of temperature on NPP changes was stronger than that of precipitation; and 3) the majority of NPP residuals from 2001 to 2014 were positive, with human activities playing an active role in determining regional vegetation growth, possibly due to the return of farmland back to forest and natural forest protection. However, this positive trend is decreasing. This clearly shows the periodical nature of ecological projects and a lack of long-term effectiveness.

Quantitative Estimation on Contributions of Climate Changes and Human Activities to Decreasing Runoff in Weihe River Basin, China

Human activities and climate changes are deemed to be two primary driving factors influencing the changes of hydrological processes, and quantitatively separating their influences on runoff changes will be of great significance to regional water resources planning and management. In this study, the impact of climate changes and human activities was initially qualitatively distinguished through a coupled water and energy budgets analysis, and then this effect was further separated by means of a quantitative estimation based on hydrological sensitivity analysis. The results show that: 1) precipitation, wind speed, potential evapotranspiration and runoff have a significantly decreasing trend, while temperature has a remarkably increasing tendency in the Weihe River Basin, China; 2) the major driving factor on runoff decrease in the 1970 s and 1990 s in the basin is climate changes compared with that in the baseline 1960 s, while that in the 1980 s and 2000 s is human activities. Compared with the results based on Variable Infiltration Capacity(VIC) model, the contributions calculated in this study have certain reliability. The results are of great significance to local water resources planning and management.

Change of Flood Patterns in China under the Influences of Climate Change and Human Activities

Based on the flood affected area （FA） data of the provinces in China from 1950 to 2005, the article discusses the change of the flood patterns in China, and investigates its relationship with climate change and human activities. The flood center shifted from North China and the Yangtze-Huaihe basin in the 1950s towards the south, north and west of China, and located in the south of the Yangtze River and South China after the 1990s. The FA in the western provinces was continuously on the rise since the 1950s. There are two characteristics for the future flood pattem in China. The pattern of ＂flood in the south and drought in the north＂ depends on the north-south shift of the maximum rainfall region in eastern China. The flood intensification to the west of Hu Huanyong＇s line mainly results from the increase of rainfall, extreme precipitation and the melting of glaciers under the background of human activity magnification.

Climate Change and Environmental Impact Caused by Anthropogenic

For the last two decades the world has undergone a population explosion which has been accompanied by a speeding up of urbanization and land use for industrial and agricultural products. These involve a vast increase in the discharge of pollutants into very different receiving water bodies, and have had adverse effects on the various components of the environment. For a long time, human has concerned a little of the natural environment. It is obvious that this variation in surface temperature of the earth increases the level of sea due to snowmelt. So climate change is manifested by many phenomena： floods, droughts, fires, tornadoes, cyclones, earthquakes, volcanic eruptions, diseases etc.. The statement today is dramatic. Entire regions were devastated and many rivers and lakes have become polluted around the world. Pollution has it nature which is hard to be absorbed. Where did the different pollutants come from？ What are the risks to the aquatic environment？ To prevent and combat the general decline of these ecosystems, it is important to distinguish and determine the effects of different sources of pollution and any changes that may suffer the physical environment. The climate depends primarily on changes in earth orbit parameters, which affect the solar radiation received by the earth surface. Therefore, human participates strongly to these changes, for example, pollution is the main reason to argue the greenhouse effect, an increase of anthropogenic carbon dioxide （CO2） into the atmosphere, which promotes global warming to the planet. These modifications are already applied in order to ensure durable development in water resources by controlling discharges into streams to preserve water resources for future generations and to ensure reconciliation between man-climate and environment.

Exploring seven hundred years of transhumance, climate dynamic, fire and human activity through a historical mountain pass in central Spain

A high-altitude peat sequence from the heart of the Spanish Central System(Gredos range) was analysed through a multi-proxy approach to determine the sensitivity of high-mountain habitats to climate, fire and land use changes during the last seven hundred years, providing valuable insight into our understanding of the vegetation history and environmental changes in a mountain pass close to a traditional route of transhumance. The pollen data indicate that the vegetation was dominated by shrublands and grasslands with scattered pines in high-mountain areas, while in the valleys cereals, chestnut and olive trees were cultivated. Strong declines of high-mountain pines percentages are recorded at 1540, 1675, 1765, 1835 and 1925 cal AD, which may be related to increasing grazing activities and/or the occurrence of anthropogenic fires. The practice of mountain summer farming and transhumance deeply changed and redesigned the landscape of the high altitudes in central Spain(Gredos range) since the Middle Ages, although its dynamics was influenced in some way by climate variability of the past seven centuries.

半干旱草原型流域径流变化特征及其影响因子定量分析

研究引起径流变化的主要驱动因子对流域水文水资源与生态相关研究具有重要的指导意义。以典型草原型流域-锡林河流域1970-2014年径流及气象数据为基础,采用Mann-Kendall法、弹性系数法定量分析了气候变化及人类活动对径流变化的贡献程度。结果表明:近45a来锡林河流域年径流量呈显著下降的趋势,在1979、1986和1998年发生突变。1980-1986年人类活动对径流减少的贡献率为46.57%;1987-1998年人类活动对径流增加的贡献率高达91.46%,气候变化的贡献率仅为8.54%;1999-2014年人类活动对径流减少的贡献率为66.16%。整体而言,人类活动是锡林河流域径流变化的主要驱动力。

The Impacts of Climate Change and Human Activities on Cropland Net Primary Productivity in Bangladesh,India and Myanmar

Under global change and climate variations,determining the impacts of climate change and human activities on cropland net primary productivity(NPP)in Bangladesh,India and Myanmar(BIM)is of great significance for identifying yield-limiting factors,making adaptive agricultural management plans,and improving yields.Based on the GLOPEM-CEVSA model,through an integration of remote sensing data and LAI simulation,we investigated the impacts and spatiotemporal changes of water and human activities on BIM from 1982 to 2015.Three types of cropland NPPs were considered:actual NPP(NPPA),NPP affected by temperature and water(NPPWT),and NPP only affected by temperature(NPPT).Our analysis revealed that the water factor plays a predominant role in determining the NPP level in the BIM.Temperature variability was found to be conducive to NPPT,exhibiting an increasing trend of 10.66 g C m^(-2) yr^(-1).However,this trend was partially offset by precipitation variability,resulting in a net increase of 0.96 g C m^(-2) yr^(-1).In comparing temperature-driven NPP to temperature and water-driven NPP,water stress caused NPPT to decrease by 65.46% compared to NPPWT for the entire region.Cropland NPP in northwestern India and the central Deccan Plateau were significantly affected by water stress.Moreover,the influence of water on NPP in the BIM exhibited a substantial upward trend from 1982 to 2015,with Myanmar experiencing the most significant increase.The gap between NPPWT and NPPA in BIM demonstrated a notable decreasing trend during the same period,underscoring the positive impact of human activities on NPP.Inferences drawn from our findings suggest that with the implementation of rational and efficient crop management practices,there is a 36.80% potential improvement in NPPA compared to NPPWT in the BIM region,with India and Myanmar showing potential increases of 39.20% and 38.29%,respectively.These insights provide guidance for practical measures aimed at water resource management to enhance cropland productivity in the BIM,and they present a methodology for quantifying the effects of climatic changes and human activities at a regional scale.

Impacts of Climate Change and Human Activities on Water Suitability in the Upper and Middle Reaches of the Tao'er River Area

Due to the impact of climate change and human activities, the upper and middle reaches of the Tao＇er River have become an ecologically sensitive area in Northeast China. It is important to evaluate the contributions of climate change and human activities to water suitability in the Tao＇er River area. From the perspective of water and heat balance, the water suitability index （Cr） was used to analyze the water suitability of the upper and middle reaches of the river. The nonparametric Mann-Kendall, moving t-test and cumulative anomaly methods were used to detect abrupt changes in Taonan station runoff from 1961 to 2012. Three inflexion years were detected. Thus, the entire time period was divided into four periods： 1961-1974, 1975-1983, 1984-1998, and 1999-2012. In order to estimate the impacts of climate change and human activities on runoff, the slope change ratio of cumulative quan- tity （SCRCQ） was adopted. Finally, the contribution of climate change and human activity to Cr was transformed from the contribution of climate change and human activity to runoff by the sensitivity coefficient method and SCIRCQ method. The results showed that the water suitability index （cr） had a decreasing trend 1961-2012. Fac- tors influencing cr, such as net radiation and runoff, also exhibited a decreasing trend, while precipitation exhibited an increasing trend over the past 52 years. The trends of Cr, net radiation and runoff were obvious, which passed the Mann-kendall test of significance at a=0.05. Human activities were the main factors that affected runoff, al- though the degree of impact was different at different times. During the past 52 years, the biggest contributor to the change in Cr was precipitation.