scholarly journals A 100-year record of climate change and human activities inferred from the geochemical composition of sediments in Chaiwopu Lake, arid northwest China

2016 ◽  
Author(s):  
Wen Liu ◽  
Jinglu Wu ◽  
Xiangliang Pan
Keyword(s):  
Climate Change ◽  
Human Activities ◽  
Chemical Weathering ◽  
Northwest China ◽  
Past Century ◽  
Surface Erosion ◽  
Geochemical Composition ◽  
The Past ◽  
Element Concentrations ◽  
Arid Northwest China

An 81-cm sediment core from Chaiwopu Lake in arid northwest China was analyzed for <sup>137</sup>Cs activity and concentrations of major and trace elements. We used these data to discriminate between the influence of climate change and human activities on the geochemical change of the lake sediments over the past century. Elements Al, K, Ba, Ti, V, Fe, Ni, Mn, Li, and Be were mainly from detrital. Ca, Sr, and Mg concentrations were controlled by chemical weathering processes. Na came mainly from salt precipitation caused by a decline in water level. Enrichment factors for Pb and P in recent deposits are large, indicating they were influenced by human activies. Geochemical conditions during the past century can be divided into three stages: i) From ca. 1900 to the1950s element concentrations varied widely and frequently. In general, concentrations of typical mobile elements Ca, Sr, and Mg stay relatively high whereas values for other elements remained relatively low. This was interpreted to reflect variable climate under conditions of weak surface erosion intensity. ii) From the 1950s to the early 2000s, element concentrations display less variability. The Al, K, Ba, Ti, P, Cr, V, Fe, Ni, Mn, Co, Cu, Li, Zn, Be, Pb, and Na contents were generally higher, whereas contents of Ca, Sr, and Mg were on average lower. This indicates that the regional environment was conducive to surface erosion. Enrichment of trace metals and major elements in the sediment reflects enhanced human activities. iii) In the last decade, Pb and P exhibited a great increase, possibly associated with the input from fossil fuel combustion, sewage discharge and non-point-source pollution in the watershed. The lake volume decreased substantially because of groundwater extraction for municipal water, which resulted in a marked increase in salinity and enhanced Na precipitation.

scholarly journals Impact of climate change and human activity on the runoff in the upper reaches of the Shiyang River, Northwest China

2014 ◽  
Author(s):  
Peng Li ◽  
Jianhua Xu ◽  
Zhongsheng Chen ◽  
Benfu Zhao
Keyword(s):  
Climate Change ◽  
Human Activity ◽  
Climatic Factors ◽  
Meteorological Data ◽  
Northwest China ◽  
Potential Evaporation ◽  
The Past ◽  
Shiyang River Basin ◽  
Runoff Change ◽  
Increasing Trend

Based on the hydrological and meteorological data of the upper reaches of Shiyang River basin in Northwest China from 1960 to 2009, this paper analyzed the change in runoff and its related climatic factors, and estimated the contribution of climate change and human activity to runoff change by using the moving T test, cumulative analysis of anomalies and multiple regression analysis. The results showed that temperature revealed a significant increasing trend, and potential evaporation capacity decreased significantly, while precipitation increased insignificantly in the past recent 50 years. Although there were three mutations in 1975, 1990 and 2002 respectively, runoff presented a slight decreasing trend in the whole period. The contributions of climate change and human activity to runoff change during the period of 1976-2009 were 45% and 55% respectively.

Effects of human activities and climate change on the reduction of visibility in Beijing over the past 36 years

2018 ◽  
Vol 116 ◽  
pp. 92-100 ◽  
Author(s):  
Xuwu Chen ◽  
Xiaodong Li ◽  
Xingzhong Yuan ◽  
Guangming Zeng ◽  
Jie Liang ◽  
...  
Keyword(s):  
Climate Change ◽  
Human Activities ◽  
The Past

The impact of climate change and human activities on the Aral Sea Basin over the past 50 years

2020 ◽  
Vol 245 ◽  
pp. 105125 ◽  
Author(s):  
Xuanxuan Wang ◽  
Yaning Chen ◽  
Zhi Li ◽  
Gonghuan Fang ◽  
Fei Wang ◽  
...  
Keyword(s):  
Climate Change ◽  
Human Activities ◽  
Aral Sea ◽  
Aral Sea Basin ◽  
Impact Of Climate Change ◽  
The Past ◽  
The Impact

scholarly journals Assessment of Anthropogenic Impact versus Climate Change on the Succession of the Diatom Community in Lugu Lake (Yunnan-Guizhou Plateau, China) Using the Sedimentary Record of Geochemical Elements

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 655 ◽  
Author(s):  
Yi Liu ◽  
Chuanhong Chen ◽  
Shao Yang
Keyword(s):  
Climate Change ◽  
Human Impact ◽  
Human Activities ◽  
Anthropogenic Sources ◽  
Diatom Community ◽  
The Third ◽  
The Past ◽  
Third Stage ◽  
Lugu Lake ◽  
Guizhou Plateau

The lake ecosystems on the Yunnan-Guizhou Plateau in China have degraded in recent decades under the effects of anthropogenic activities and climate change. The human impact on the oligotrophic Lugu Lake aquatic ecosystem was evaluated using the sediment records of metals, nitrogen isotopes (δ15N) and magnetic susceptibility over the past 200 years. Three periods were identified based on the trace metal and δ15N records. During the first stage (1816–1976 AD), the concentrations of metals, δ15N and magnetic susceptibility were low with small variations. The anthropogenic contributions to the inputs were also small, except for Ni, reflecting minor human activities in the watershed, and no significant change was observed in the sediment record of the diatom assemblage. During the second stage (1976–2001 AD), the concentrations of Zn and δ15N increased, as well as the anthropogenic contribution of Zn. However, no significant change was detected in the anthropogenic sources of the other metals. These results reflect the low-level use of chemical fertilizers. The major shift in the sediment diatom assemblage during this stage was mainly attributed to regional climate change. During the third stage (2001–2010 AD), the concentrations of the sedimentary metals (Ni, Cr, Mn, Cu, Hg and Al) increased rapidly, with the exception of As and Zn, and a similar increasing trend was observed in the changes by anthropogenic sources of Ni, Cr, Mn and Cu. RDA (Redundancy Analysis) and variance partitioning analysis showed that the human impact and climate proxies independently explained 31.59% and 4.26% of the change of diatom community, respectively, and the interaction between climate change and human impact accounted for 18.61% of the change of diatom community. Tourism-dominated human activities, which were reflected in the metals profiles, facilitated the dominance of eutrophic species and reduced that of oligotrophic species. The development of tourism was likely the main driving force for the succession of diatom assemblages in the third stage. In summary, the anthropogenic input of trace metals in Lugu Lake is still at a low level. However, the significant growth trend in metals over the past decade is significantly related to the change in the lake ecosystem. Therefore, the effects of human activities, especially tourism, on the watershed should be controlled for the protection of the oligotrophic Lugu Lake.

Impacts of climate change and irrigation on lakes in arid northwest China

2018 ◽  
Vol 154 ◽  
pp. 34-39 ◽  
Author(s):  
Leqi Fang ◽  
Shengli Tao ◽  
Jiangling Zhu ◽  
Yu Liu
Keyword(s):  
Climate Change ◽  
Northwest China ◽  
Impacts Of Climate Change ◽  
Arid Northwest China

Coastal dune mobility over the past century: A global review

2020 ◽  
Vol 44 (6) ◽  
pp. 814-836 ◽  
Author(s):  
Jinjuan Gao ◽  
David M Kennedy ◽  
Teresa M Konlechner
Keyword(s):  
Human Activities ◽  
Vegetation Cover ◽  
Dominant Role ◽  
Coastal Dunes ◽  
Mediterranean Area ◽  
Global Scale ◽  
Coastal Dune ◽  
Sediment Supply ◽  
Past Century ◽  
The Past

The mobility of coastal dunes is characterised by bio-geomorphological responses related to change in boundary conditions, particularly sediment supply, wind and vegetation cover, as well as human activities. There remains uncertainty regarding the relative importance of these drivers on dune mobility at a global scale. In this study, trends and dominant drivers of coastal dune mobility are synthesised through the literature review focusing on shifts in dune mobility over the last century (1870–2018). In total, 176 individual dunes, with 55 dunes from the Europe-Mediterranean area, 23 from Africa, 30 from North America, 23 from South America, 20 from Oceania and 23 from Asia, are reviewed in this work. The results show that there is a worldwide trend of dune stabilisation, with 93% (164 out of 176) of the reviewed sites showing a loss of bare sand area due to an increase in vegetation cover and urbanisation expansion. Multiple factors have contributed to the stabilisation process, including (a) land-use change such as the change of traditional farming practises, coastal urbanisation and tourism development; (b) dune stabilisation projects; (c) sediment decline caused by the riverine and coastal constructions; and (d) change in climate (i.e. the decrease in windiness, and the increase in temperature and rainfall) and storms. Our results suggest human intervention played a dominant role in altering dune mobility for most dunes during the past century, while climate and storms are also important drivers, especially for dune sites with limited human activities.

Climate Change-Driven Shifts in Elevation and Ecophysiological Traits of Himalayan Plants during the Past Century

2017 ◽  
Vol 112 (03) ◽  
pp. 595 ◽  
Author(s):  
Priyanka Agnihotri ◽  
Tariq Husain ◽  
Pramod Arvind Shirke ◽  
Om Prakash Sidhu ◽  
Harsh Singh ◽  
...  
Keyword(s):  
Climate Change ◽  
Past Century ◽  
The Past ◽  
Ecophysiological Traits

Recent Record Growth in Atmospheric CO2 Levels

2005 ◽  
Vol 2 (1) ◽  
pp. 3 ◽  
Author(s):  
Roger J. Francey
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Greenhouse Effect ◽  
Fossil Fuels ◽  
Trace Gases ◽  
Atmospheric Co2 ◽  
Past Century ◽  
The Past ◽  
Rate Of Growth ◽  
Co2 Levels

Environmental Context.Excessive levels of carbon dioxide are accumulating in the atmosphere, principally from burning fossil fuels. The gas is linked to the enhanced greenhouse effect and climate change, and is thus monitored carefully, along with other trace gases that reflect human activity.The rate of growth of carbon dioxide has increased gradually over the past century, and more rapidly in the last decade. Teasing out fossil emissions from changes due to wildfires and to natural exchange with plants and oceans guide global attempts in reducing emissions.

Sign in / Sign up

Export Citation Format

Share Document