scholarly journals Modeling the combined impact of future climate and land use changes on streamflow of Xinjiang Basin, China

2015 ◽  
Vol 47 (2) ◽  
pp. 356-372 ◽  
Author(s):  
Renhua Yan ◽  
Jiacong Huang ◽  
Yan Wang ◽  
Junfeng Gao ◽  
Lingyan Qi
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Planning ◽  
Scientific Information ◽  
Land Use Changes ◽  
Coupled Model ◽  
Climate Scenario ◽  
Future Climate ◽  
Climate Change Scenarios ◽  
Future Evolution

The response of hydrologic circulation to climate and land use changes is important in studying the historical, present, and future evolution of aquatic ecosystems. In this study, the Coupled Model Inter-comparison Project Phase 5 multi-model ensemble and a raster-based Xin'anjiang model were applied to simulate future streamflows under three climate change scenarios and two land use/cover change conditions in the Xinjiang Basin, China, and to investigate the combined effect of future climate and land use/cover changes on streamflow. Simulation results indicated that future climate and land use/cover changes affect not only the seasonal distributions of streamflow, but also the annual amounts of streamflow. For each climate scenario, the average monthly streamflows increase by more than 4% in autumn and early winter, while decreasing by more than −26% in spring and summer for the 21st century. The annual streamflows present a clear decreasing trend of −27%. Compared with land use/cover change, climate change affects streamflow change more. Land use/cover change can mitigate the climate change effect from January to August and enhance it in other months. These results can provide scientific information for regional water resources management and land use planning in the future.

Modelling the impacts of climate change and land-use change on the hydrology of Vietnam’s river basins

2020 ◽  
Author(s):  
Francesca Moschini ◽  
Iacopo Federico Ferrario ◽  
Barbara Hofmann
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Change ◽  
Land Use Planning ◽  
Weighted Average ◽  
Surface Fluxes ◽  
Base Flow ◽  
Balance Model ◽  
Climate Change Scenarios ◽  
Hydrological Fluxes

<p>Quantifying how land-use change affects hydrological components is a challenge in hydrological science. It is not yet clear how changes in land use relate to runoff extremes and why some catchments are more sensitive to land-use change than others. Identifying which areas are hydrologically more sensitive to land-use change can lead to better land-use planning, reduction of the impacts of extreme rainfall events and extended dry periods. In this study we aim to quantify how land-use change and climate change are affecting the hydrological response of  Vietnam’s basins. Over the past decades the country’s land use has shifted from forest to agriculture, with very high production of rice, coffee, tea, pepper and sugar cane.</p><p>We combine the historical, the Intergovernmental Panel on Climate Change’s (IPCC) Representative Concentration Pathway (RCP) RCP4.5 and RCP8.5 climate change scenarios developed for Vietnam, with two different land cover maps (from the years 1992 and 2017). The combined and separate effect of land use and climate change are assessed and the most sensitive to change areas are identified. The Variable infiltration Capacity (VIC) surface water and energy balance model applied here is a grid-based model that calculates evapotranspiration, runoff, base flow, soil moisture and other hydrological fluxes. Surface heterogeneity within VIC is represented by a tiled approach, whereby the surface of each grid-box comprises fractions of the different surface types. For each surface type of the grid-box, the energy and water balances are solved, and a weighted average is calculated from the individual surface fluxes for each grid-box. Hydrological fluxes were compared for each grid cell and basin to analyse the degree of difference between the scenarios.</p><p>Significant changes in future hydrologic fluxes arise under both climate change scenarios pointing towards a severe increase in hydrological extremes. The changes in all the examined hydrological components are greater in the combined land-use and climate change experiments.</p>

The energy budget of the tropical band in future climate 

2021 ◽  
Author(s):  
David Ferreira ◽  
Roberta D'Agostino
Keyword(s):  
Climate Change ◽  
Coupled Model ◽  
Lower Troposphere ◽  
Hadley Circulation ◽  
Climate Scenario ◽  
Future Climate ◽  
Unperturbed System ◽  
Net Energy ◽  
Mean Flow ◽  
Wave Trapping

<p>The atmospheric circulation is expected to change in response to anthropogenic CO<sub>2</sub> emissions. Both theory and model simulations of future climate suggest that the tropical overturning will weaken, with a weaker Hadley Circulation ascent, while the stratification of moist static energy (MSE) will strengthen. These two changes have opposite effects on the energy balance of the deep tropics. In the unperturbed system, the equatorward convergence of the mean flow in the lower troposphere (i.e. at low MSE) is compensated by a divergence in the upper troposphere (i.e. at high MSE), resulting in a net lateral export of MSE out of the region of ascent.</p><p>The weakening of the circulation in a future warmer climate would weaken the export of MSE while the strengthening of the stratification -- an increase of the MSE contrast between the upper and lower branches -- would reinforce it. However, previous studies suggest that these two effects do not exactly cancel out. A neglected element in this picture is the primary driver of these changes: due to the long-wave trapping by higher CO<sub>2 </sub>concentration, the tropical atmosphere will also receive more energy at the top and bottom (an increased Net Energy Input, NEI).</p><p>In this study, we attempt to reconcile changes in the circulation, stratification and NEI under climate change. Specifically, we investigate 1) to which extent the effects of circulation and stratification changes on the MSE budget compensate and 2) if inclusion of the NEI changes brings the MSE budget closer to equilibrium.</p><p>To address these questions, we compute the Gross Moist Stability in a series of simulations from the Coupled Model Intercomparison Project 5 archive. To test our understanding of the MSE budget, we consider both a future climate scenario (RCP8.5) and the mid-Holocene (6000 A.D). For the future climate, we show that, although there is a rough balance by the circulation and stratification effects, inclusion of the NEI term significantly improves the closure of the MSE budget in the deep tropics. The mid-Holocene case is, however, fundamentally different as both stratification and circulation weaken, reinforcing their effects on the MSE export. In this case, inclusion of the NEI term is critical to establish the MSE balance of the deep tropics.</p><p>Both cases underline that a three-term balance (between changes in circulation, MSE stratification and NEI) provides a robust description of the deep tropics MSE budget under climate change.</p>

scholarly journals Land-use change may exacerbate climate change impacts on water resources in the Ganges basin

2018 ◽  
Vol 22 (2) ◽  
pp. 1411-1435 ◽  
Author(s):  
Gina Tsarouchi ◽  
Wouter Buytaert
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Water Resources ◽  
Land Use Change ◽  
Land Surface ◽  
Land Surface Model ◽  
Coupled Model ◽  
Surface Model ◽  
Climate Change Scenarios ◽  
Ganges River

Abstract. Quantifying how land-use change and climate change affect water resources is a challenge in hydrological science. This work aims to quantify how future projections of land-use and climate change might affect the hydrological response of the Upper Ganges river basin in northern India, which experiences monsoon flooding almost every year. Three different sets of modelling experiments were run using the Joint UK Land Environment Simulator (JULES) land surface model (LSM) and covering the period 2000–2035: in the first set, only climate change is taken into account, and JULES was driven by the CMIP5 (Coupled Model Intercomparison Project Phase 5) outputs of 21 models, under two representative concentration pathways (RCP4.5 and RCP8.5), whilst land use was held fixed at the year 2010. In the second set, only land-use change is taken into account, and JULES was driven by a time series of 15 future land-use pathways, based on Landsat satellite imagery and the Markov chain simulation, whilst the meteorological boundary conditions were held fixed at years 2000–2005. In the third set, both climate change and land-use change were taken into consideration, as the CMIP5 model outputs were used in conjunction with the 15 future land-use pathways to force JULES. Variations in hydrological variables (stream flow, evapotranspiration and soil moisture) are calculated during the simulation period. Significant changes in the near-future (years 2030–2035) hydrologic fluxes arise under future land-cover and climate change scenarios pointing towards a severe increase in high extremes of flow: the multi-model mean of the 95th percentile of streamflow (Q5) is projected to increase by 63 % under the combined land-use and climate change high emissions scenario (RCP8.5). The changes in all examined hydrological components are greater in the combined land-use and climate change experiment. Results are further presented in a water resources context, aiming to address potential implications of climate change and land-use change from a water demand perspective. We conclude that future water demands in the Upper Ganges region for winter months may not be met.

scholarly journals Agricultural and Forestry Land and Labor Use under Long-Term Climate Change in Chile

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 305
Author(s):  
Oscar Melo ◽  
William Foster
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Climate Changes ◽  
Land Use Changes ◽  
Climate Change Scenarios ◽  
Income Generation ◽  
Net Income ◽  
Average Output ◽  
Allocation Model ◽  
Municipal Level

The appropriate design of land-use and rural employment policies depends upon the anticipated performance of the farm sector in the context of expected climate changes, especially with respect to land allocations to potential activities. Concerns over the possible net benefits of land-use changes are particularly acute in lower- and middle-income countries, where agriculture tends to be important in employment, income generation and foreign-exchange earnings. This paper presents an analysis of the expected impacts on land use in Chile of projected climate-change scenarios in 2040 and 2070. We developed a farmland allocation model with associated labor employment at the municipal level driven by expected relative net incomes per hectare, constructed from local average per-hectare yields, regional average output prices and per-hectare production cost estimates. The sensitivities of cropland allocations to relative net-income changes were estimated using historical land allocations at the municipal level derived from the last two Chilean Agricultural Censuses. The results show that the impacts of climate changes will be mitigated by land-use adaptation, the main export-earning crops tending to move south; in aggregate, agricultural employment will decrease in all the climate-change scenarios; forestry and agriculture would likely suffer a loss in net-income generation under severe climate-change scenarios.

scholarly journals Scenario-based impacts of land use and climate changes on the hydrology of a lowland rainforest catchment in Ghana, West Africa

2017 ◽  
Author(s):  
Michael S. Aduah ◽  
Graham P. W. Jewitt ◽  
Michele L. W. Toucher
Keyword(s):  
Climate Change ◽  
Land Use ◽  
West Africa ◽  
Spatial Variability ◽  
Climate Changes ◽  
Land Use Changes ◽  
Control Period ◽  
Mitigation Strategies ◽  
Climate Change Scenarios ◽  
Land Use Scenarios

Abstract. This study analysed the separate and the combined impacts of climate and land use changes on hydrology on the Bonsa catchment in Ghana, West Africa, using the ACRU hydrological model. The study used five RCP8.5 climate change scenarios (wet, 25th percentile, 75th percentile, dry and a multi-model median of nine GCMs) from the CMIP5 AR5 models for near (2020–2039) and far (2060–2079) future time slices. Change factors were used to downscale the GCM scenarios to the local scale, using observed climate data for the control period of 1990 to 2009. The land use of 1991 and 2011 were used as the baseline and current land use as well as three future land use scenarios (BAU, EG, EGR) for two time slices (2030 and 2070) were used. The study showed that under all separate climate change scenarios, overall flows reduced, but under combined climate and land use changes, streamflows increased. Under the combined scenarios, streamflow responses due to the different future land use scenarios were not substantially different. Also, land use is the dominant controlling factor in streamflow changes in the Bonsa catchment under a dry climate change, but under a wet climate change, climate controls streamflow changes. The spatial variability of catchment streamflow changes under combined land use and climate changes were greater than the spatial variability of streamflow changes under climate change. The range of plausible future streamflows changes derived in this study provides natural resources and environmental managers of the Bonsa catchment, the first ever and the most current information to develop suitable adaptation and mitigation strategies, to prepare adequately for climate and land use changes.

scholarly journals Estimation of Watershed Hydrochemical Responses to Future Climate Changes Based on CMIP6 Scenarios in the Tianhe River (China)

2021 ◽  
Vol 13 (18) ◽  
pp. 10102
Author(s):  
Jian Sha ◽  
Xue Li ◽  
Jingjing Yang
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Climate Changes ◽  
Coupled Model ◽  
General Circulation Models ◽  
Future Climate ◽  
Research Station ◽  
Climate Change Scenarios ◽  
Climate Scenarios ◽  
Hydrochemical Processes

The impacts of future climate changes on watershed hydrochemical processes were assessed based on the newest Shared Socioeconomic Pathways (SSP) scenarios in Coupled Model Intercomparison Project Phase 6 (CMIP6) in the Tianhe River in the middle area of China. The monthly spatial downscaled outputs of General Circulation Models (GCMs) were used, and a new Python procedure was developed to batch pick up site-scale climate change information. A combined modeling approach was proposed to estimate the responses of the streamflow and Total Dissolved Nitrogen (TDN) fluxes to four climate change scenarios during four future periods. The Long Ashton Research Station Weather Generator (LARS-WG) was used to generate synthetic daily weather series, which were further used in the Regional Nutrient Management (ReNuMa) model for scenario analyses of watershed hydrochemical process responses. The results showed that there would be 2–3% decreases in annual streamflow by the end of this century for most scenarios except SSP 1-26. More streamflow is expected in the summer months, responding to most climate change scenarios. The annual TDN fluxes would continue to increase in the future under the uncontrolled climate scenarios, with more non-point source contributions during the high-flow periods in the summer. The intensities of the TDN flux increasing under the emission-controlled climate scenarios would be relatively moderate, with a turning point around the 2070s, indicating that positive climate policies could be effective for mitigating the impacts of future climate changes on watershed hydrochemical processes.

Cultivated floodplains of the Cambodian Mekong delta: understanding the changing balance between the flow regime and the agricultural practices

2021 ◽  
Author(s):  
Christina Anna Orieschnig ◽  
Gilles Belaud ◽  
Jean-Philippe Venot ◽  
Sylvain Massuel
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Changes ◽  
Local Population ◽  
Agricultural Productivity ◽  
Mekong Delta ◽  
Agricultural Practices ◽  
Fruit Trees ◽  
Climate Change Scenarios ◽  
Crop Water

<p>On the floodplains of the Cambodian Mekong Delta, rainfed and irrigated dry-season agriculture is a crucial source of revenue for the local population. Traditional rice production is being progressively complemented by the cultivation of higher-value crops like maize, fruit trees and vegetables. Fundamentally, the annual monsoon regime and the resulting flood dynamics determine the framework for these agricultural practices, with a wet season lasting from June to November and a peak high flow reached in September. Rice is cultivated after flood recession in lower-lying areas. On higher terrain, fruit trees and vegetables are widely irrigated by farmers using individual pumps to lift water from large-scale communal channels.</p><p><br>However, in recent years, various drivers of change have impacted these long-established dynamics. Climate change is causing shifting precipitation patterns and a modification of annual flow regimes in the Mekong river and its deltaic distributaries. In addition, the irrigation channel infrastructure is being largely rehabilitated by both local initiatives and international development agencies. These measures are rapidly changing the conveyance network for inundation, drainage, and irrigation on the floodplains, with proportions and consequences which are yet unknown. Finally, land use changes driven by market forces - such as the shift to cash crops like mango trees - are modifying the crop water demand in the area. </p><p><br>In this context, the present study aims to provide a thorough understanding and quantification of the effects of these changes with regard to crop water requirements, irrigation efficiency, and agricultural productivity. Extensive fieldwork was carried out on a 44-km² area to gather knowledge of agricultural practices (especially irrigation) and to identify the main local hydrological objects and drivers. The land use and seasonal inundation extents were characterized through remote sensing analyses, using optical Sentinel-2 and synthetic aperture radar (SAR) Sentinel-1 images. On that basis, an eco-hydrological model is being developed on the generic software platform OpenFLUID, explicitly representing the hydraulic connections and irrigation decisions. This tool will be used to highlight possible salient control factors for hydrological processes, and to simulate the direct and indirect effects of climate change scenarios, irrigation and water power infrastructure development, and land use changes on local hydrology, irrigation, and agricultural productivity. </p>

scholarly journals Major United States Land Use as Influenced by an Altering Climate: A Spatial Econometric Approach

Land ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 546
Author(s):  
Sung-Ju Cho ◽  
Bruce McCarl
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Land Use Changes ◽  
Climate Change Scenarios ◽  
Spatial Effects ◽  
Pasture Grass ◽  
Temperature And Precipitation ◽  
Econometric Approach ◽  
Business As Usual ◽  
The U.S

Climate and socioeconomic and policy factors are found to stimulate land use changes along with changes in greenhouse gas emissions and adaption behaviors. Most of the studies investigating land use changes in the U.S. have not considered potential spatial effects explicitly. We used a two-step linearized multinomial logit to examine the impacts of various factors on conterminous U.S. land use changes including spatial lag coefficients. The estimation results show that the spatial dependences have existed for cropland, pastureland, and grasslands with a negative dependence on forests but weakened in most of the land uses except for croplands. Temperature and precipitation were found to have nonlinear impacts on the land use shares in the succeeding years by exerting opposite effects on crop versus pasture/grass shares. We also predicted land use changes under different climate change scenarios. The simulation results imply that the southern regions of the U.S. would lose cropland shares with further severity under the business-as-usual climate scenarios, while the land use shares for pasture/grass and forest would increase in those regions. As land use plays an important role in the climate system and vice versa, the results from this study may help policymakers tackle climate-driven land use changes and farmers adapt to climate change.

Hydrologic impacts of climate change and urbanization in the Las Vegas Wash Watershed, Nevada

2016 ◽  
Vol 7 (3) ◽  
pp. 598-620 ◽  
Author(s):  
Susanna T. Y. Tong ◽  
Heng Yang ◽  
Heyin Chen ◽  
Jeffrey Y. Yang
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Urban Development ◽  
Las Vegas ◽  
Land Use Changes ◽  
Climate Scenario ◽  
Balance Model ◽  
Climate Projections ◽  
Intergovernmental Panel ◽  
The Future

A cell-based model for the Las Vegas Wash Watershed in Clark County, Nevada, USA, was developed by combining the Thornthwaite water balance model and the Soil Conservation Survey's Curve Number method with pixel-based computing technology. After the model was validated, it was used to predict the 2030 and 2050 hydrologic conditions under future scenarios of climate and land-use changes. The future climate projections were based on the Intergovernmental Panel on Climate Change (IPCC) B1 climate scenario, and the land-use scenarios were derived from a CA-Markov land-use model. Results indicate that under these hypothetical conditions, the future surface runoff in the watershed will significantly decrease in winters but increase in summers. Climate change will be the primary controlling factor over runoff. Urban development is projected to increase runoff and may contribute 1.1–18.7% of the changes. This finding may be useful in devising future urban development plans and water management policies.

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