Analysis on impacts of hydro-climatic changes and human activities on available water changes in Central Asia

2020 ◽  
Vol 737 ◽  
pp. 139779
Author(s):  
Hui Chen ◽  
Hailong Liu ◽  
Xi Chen ◽  
Yina Qiao
Keyword(s):  
Central Asia ◽  
Human Activities ◽  
Climatic Changes ◽  
Available Water

Assessing extreme climatic changes on a monthly scale and their implications for vegetation in Central Asia

2020 ◽  
Vol 271 ◽  
pp. 122396
Author(s):  
Min Luo ◽  
Chula Sa ◽  
Fanhao Meng ◽  
Yongchao Duan ◽  
Tie Liu ◽  
...  
Keyword(s):  
Central Asia ◽  
Climatic Changes ◽  
Monthly Scale

scholarly journals Anthropogenic Influences on Environmental Changes of Lake Bosten, the Largest Inland Freshwater Lake in China

2020 ◽  
Vol 12 (2) ◽  
pp. 711 ◽  
Author(s):  
Wen Liu ◽  
Long Ma ◽  
Jilili Abuduwaili
Keyword(s):  
Central Asia ◽  
Lake Sediments ◽  
Human Activities ◽  
Environmental Changes ◽  
Living Environment ◽  
Water Levels ◽  
Aral Sea ◽  
Anthropogenic Factors ◽  
Large Spatial Scale ◽  
The 1960S

A short lacustrine sediment core (41 cm) from Lake Bosten in arid central Asia was used to investigate the environmental changes that occurred in the past ≈150 years based on the superposition of climate and anthropogenic factors. Geochemical elements, total organic carbon (TOC) and nitrogen (TN), and stable isotope data (δ13Corg and δ15N) were used to identify abnormal environmental changes. The average C/N ratio in the sediments of Lake Bosten suggested that the organic matter in lake sediments was mainly from aquatic plants. The δ13Corg and δ15N in the lake sediments mainly reflect changes in the structure of the lake’s ecosystem. Before the 1960s, the primary productivity of the lake was relatively low with a relatively stable lake water environment. From the 1960s to the mid-1980s, the lake’s ecosystem was closely related to a significant decline in water levels caused by human activities and an increase in salinity. From the late 1980s to ≈2000, the aquatic plant structure of Lake Bosten did not change significantly. After 2000, the upper part of the sedimentary record suggested enhanced productivity due to urban and industrial development in the catchment area. However, sedimentary perspectives of the responses of different environmental proxies in sediments to human activities were anisochronous, and the increasing heavy metal (Pb and Cu) and P accumulations appeared in 1970, reflecting heightened human impacts. Through the comparison between the Aral Sea and Lake Bosten, it was inferred that, under the intervention of human activities, the lake experienced a completely different evolution trend. Humans, as geological agents, should protect our living environment while satisfying social development. The results will provide an important supplement to a large spatial scale study of the influences of human activities on the environment in Central Asia, which also has some significant implications for the protection of the ecological environment and the realization of sustainable development in arid regions.

scholarly journals Environmental variability and human activity over the past 140 years documented by sediments of Ebinur Lake in arid central Asia

2017 ◽  
Author(s):  
Wen Liu ◽  
Long Ma ◽  
Jinglu Wu ◽  
Jilili Abuduwaili
Keyword(s):  
Heavy Metal ◽  
Magnetic Susceptibility ◽  
Organic Matter ◽  
Central Asia ◽  
Human Activities ◽  
Arid Central Asia ◽  
Ebinur Lake ◽  
Metal Contents ◽  
The 1960S ◽  
Environmental Proxies

<p>A short (50-cm-long) sediment core from Ebinur Lake in arid central Asia has been analyzed for various environmental proxies, including organic matter content, δ<sup>13</sup>C in organic matter, magnetic susceptibility, heavy metal contents, and stable isotopic compositions of bulk carbonate (δ<sup>18</sup>O and δ<sup>13</sup>C). The results reveal that the evolutionary stages inferred from environmental indicators have an asynchronous nature. If the asynchrony of periodic changes in multi-environmental proxies is ignored, important information may be lost, especially regarding anthropogenic influences. On the basis of magnetic susceptibility and heavy metal contents, human activities appear to have resulted in increases in surface erosion and measurable heavy-metal accumulation from the mid-1960s, whereas the organic matter contents, which display an obvious shift in the late 1930s, correlate with regional climate. However, the changes in the stable isotopes of bulk carbonate are mainly controlled by the isotopic composition of the host water which is generally consistent with the lake level. From the late 1870s to the 1960s, the lake was in a natural evolutionary state. From the 1960s to the mid-2000s, the runoff feeding Ebinur Lake dropped rapidly, in association with a sharp increase in agricultural development. Finally, beginning in the early twenty-first century, the climate became wetter than during the earlier two stages, and as agricultural water demand decreased, surface runoff once again increased. It is noted that, although the different proxies respond differently to climate changes and human activities, any analysis of environmental evolution should consider them each individually, in order to fully understand the complex interactions between climate and human influence. </p>

The Expanding Sahara

1974 ◽  
Vol 1 (1) ◽  
pp. 5-13 ◽  
Author(s):  
J. L. Cloudsley-Thompson
Keyword(s):  
Human Activities ◽  
Shifting Cultivation ◽  
Human Population ◽  
Arid Regions ◽  
Climatic Changes ◽  
The South

The belts of savanna lying to the south of the Sahara are described. Evidence is then presented which suggests that these have been created from forest by shifting cultivation and the use of fire: they have probably developed contemporaneously with the evolution of Man and increase in human population. The effect of climatic changes in creating desert are discussed, and the conclusion is reached that present conditions in much of the Sahara have been engendered almost entirely by human activities. These include felling of trees for firewood and charcoal, or to make their leaves accessible to stock in times of drought and, even more important, overgrazing—especially by goats. Finally, it is suggested that, in the long term, agriculture may not be the most promising way of developing arid regions. Overstocking the savanna and desert must inevitably lead to disaster.

scholarly journals Biodiversity Generation and Loss

2018 ◽  
Author(s):  
T.H. Oliver
Keyword(s):  
Genetic Diversity ◽  
Species Diversity ◽  
Human Activities ◽  
Native Species ◽  
Large Scale ◽  
Volcanic Eruptions ◽  
Biodiversity Loss ◽  
Climatic Changes ◽  
Anthropogenic Drivers ◽  
Species Biodiversity

Human activities in the Anthropocene are influencing the twin processes of biodiversity generation and loss in complex ways that threaten the maintenance of biodiversity levels that underpin human well-being. Yet many scientists and practitioners still present a simplistic view of biodiversity as a static stock rather than one determined by a dynamic interplay of feedback processes that are affected by anthropogenic drivers. Biodiversity describes the variety of life on Earth, from the genes within an organism to the ecosystem level. However, this article focuses on variation among living organisms, both within and between species. Within species, biodiversity is reflected in genetic, and consequent phenotypic, variations among individuals. Genetic diversity is generated by germ line mutations, genetic recombination during sexual reproduction, and immigration of new genotypes into populations. Across species, biodiversity is reflected in the number of different species present and also, by some metrics, in the evenness of their relative abundance. At this level, biodiversity is generated by processes of speciation and immigration of new species into an area. Anthropogenic drivers affect all these biodiversity generation processes, while the levels of genetic diversity can feed back and affect the level of species diversity, and vice versa. Therefore, biodiversity maintenance is a complex balance of processes and the biodiversity levels at any point in time may not be at equilibrium. A major concern for humans is that our activities are driving rapid losses of biodiversity, which outweigh by orders of magnitude the processes of biodiversity generation. A wide range of species and genetic diversity could be necessary for the provision of ecosystem functions and services (e.g., in maintaining the nutrient cycling, plant productivity, pollination, and pest control that underpin crop production). The importance of biodiversity becomes particularly marked over longer time periods, and especially under varying environmental conditions. In terms of biodiversity losses, there are natural processes that cause roughly continuous, low-level losses, but there is also strong evidence from fossil records for transient events in which exceptionally large loss of biodiversity has occurred. These major extinction episodes are thought to have been caused by various large-scale environmental perturbations, such as volcanic eruptions, sea-level falls, climatic changes, and asteroid impacts. From all these events, biodiversity has shown recovery over subsequent calmer periods, although the composition of higher-level evolutionary taxa can be significantly altered. In the modern era, biodiversity appears to be undergoing another mass extinction event, driven by large-scale human impacts. The primary mechanisms of biodiversity loss caused by humans vary over time and by geographic region, but they include overexploitation, habitat loss, climate change, pollution (e.g., nitrogen deposition), and the introduction of non-native species. It is worth noting that human activities may also lead to increases in biodiversity in some areas through species introductions and climatic changes, although these overall increases in species richness may come at the cost of loss of native species, and with uncertain effects on ecosystem service delivery. Genetic diversity is also affected by human activities, with many examples of erosion of diversity through crop and livestock breeding or through the decline in abundance of wild species populations. Significant future challenges are to develop better ways to monitor the drivers of biodiversity loss and biodiversity levels themselves, making use of new technologies, and improving coverage across geographic regions and taxonomic scope. Rather than treating biodiversity as a simple stock at equilibrium, developing a deeper understanding of the complex interactions—both between environmental drivers and between genetic and species diversity—is essential to manage and maintain the benefits that biodiversity delivers to humans, as well as to safeguard the intrinsic value of the Earth’s biodiversity for future generations.

scholarly journals Tradition Formation of Water Civilization in Uzbekistan

2021 ◽  
Vol 58 (1) ◽  
pp. 2024-2030
Author(s):  
Khatamova Ra’no
Keyword(s):  
Central Asia ◽  
20Th Century ◽  
Human Activities ◽  
Land Reclamation ◽  
Agricultural Mechanization ◽  
Irrigation Agriculture

This article summarizes issues related to water civilization, irrigation thinking and centuries-old traditions of our people on irrigation, agriculture and land reclamation as the basis for the formation of the Tashkent Institute of Irrigation and Agricultural Mechanization Engineers at the beginning of the 20th century. It is known that the natural foundations of the water civilization of our region are inextricably linked with the history and development of the largest rivers in Central Asia, the Syrdarya and Amudarya, life in their basins, human activities and society in this region.

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