scholarly journals Impact of future climate change on water supply and irrigation demand in a small mediterranean catchment. Case study: Nebhana dam system, Tunisia

2019 ◽  
Vol 11 (4) ◽  
pp. 1724-1747 ◽  
Author(s):  
M. Allani ◽  
R. Mezzi ◽  
A. Zouabi ◽  
R. Béji ◽  
F. Joumade-Mansouri ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Supply ◽  
General Circulation ◽  
General Circulation Models ◽  
Future Climate ◽  
Annual Rainfall ◽  
Future Climate Change ◽  
Cycle Duration ◽  
Climate Change Scenarios ◽  
Time Periods

Abstract This study evaluates the impacts of climate change on water supply and demand of the Nebhana dam system. Future climate change scenarios were obtained from five general circulation models (GCMs) of CMIP5 under RCP 4.5 and 8.5 emission scenarios for the time periods, 2021–2040, 2041–2060 and 2061–2080. Statistical downscaling was applied using LARS-WG. The GR2M hydrological model was calibrated, validated and used as input to the WEAP model to assess future water availability. Expected crop growth cycle lengths were estimated using a growing degree days model. By means of the WEAP-MABIA method, projected crop and irrigation water requirements were estimated. Results show an average increase in annual ETo of 6.1% and a decrease in annual rainfall of 11.4%, leading to a 24% decrease in inflow. Also, crops' growing cycles will decrease from 5.4% for wheat to 31% for citrus trees. The same tendency is observed for ETc. Concerning irrigation requirement, variations are more moderated depending on RCPs and time periods, and is explained by rainfall and crop cycle duration variations. As for demand and supply, results currently show that supply does not meet the system demand. Climate change could worsen the situation unless better planning of water surface use is done.

scholarly journals Impact of Climate Change on Water Balance Components and Droughts in the Guajoyo River Basin (El Salvador)

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2360 ◽  
Author(s):  
Pablo Blanco-Gómez ◽  
Patricia Jimeno-Sáez ◽  
Javier Senent-Aparicio ◽  
Julio Pérez-Sánchez
Keyword(s):  
Climate Change ◽  
El Salvador ◽  
River Basin ◽  
General Circulation ◽  
Goodness Of Fit ◽  
General Circulation Models ◽  
Future Climate ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Historical Series

This study assessed how changes in terms of temperature and precipitation might translate into changes in water availability and droughts in an area in a developing country with environmental interest. The hydrological model Soil and Water Assessment Tool (SWAT) was applied to analyze the impacts of climate change on water resources of the Guajoyo River Basin in El Salvador. El Salvador is in one of the most vulnerable regions in Latin America to the effects of climate change. The predicted future climate change by two climate change scenarios (RCP 4.5 and RCP 8.5) and five general circulation models (GCMs) were considered. A statistical analysis was performed to identify which GCM was better in terms of goodness of fit to variation in means and standard deviations of the historical series. A significant decreasing trend in precipitation and a significant increase in annual average temperatures were projected by the middle and the end of the twenty–first century. The results indicated a decreasing trend of the amount of water available and more severe droughts for future climate scenarios with respect to the base period (1975–2004). These findings will provide local water management authorities useful information in the face of climate change to help decision making.

Climate Change Scenarios for New Zealand Rainfall

2007 ◽  
Vol 46 (5) ◽  
pp. 573-590 ◽  
Author(s):  
John Sansom ◽  
James A. Renwick
Keyword(s):  
Climate Change ◽  
New Zealand ◽  
General Circulation ◽  
General Circulation Models ◽  
Future Climate ◽  
Future Climate Change ◽  
Rainfall Time Series ◽  
Climate Change Scenarios ◽  
Extreme Rainfall Events ◽  
Rainfall Events

Abstract In terms of the effects of future climate change upon society, some of the most important parameters to estimate are associated with changing risks of extreme rainfall events, both floods and droughts. However, such aspects of the climate system are hard to estimate well using general circulation models (GCMs)—in particular, for a small mountainous landmass such as New Zealand. This paper describes a downscaling technique using broad-scale changes simulated by GCMs to select past analogs of future climate. The analog samples are assumed to represent an unbiased sample of future rainfall and are used to develop detailed descriptions of rainfall statistics using hidden semi-Markov models of rainfall breakpoint information. Such models are used to simulate long synthetic rainfall time series for comparison with the historical record. Results for three New Zealand sites show overall increases in rainfall with climate change, brought about largely by an increased frequency of rainfall events rather than an increase in rainfall intensity. There was little evidence for significant increases in high-intensity short-duration rainfalls at any site. Such results suggest that, although regional increases of rainfall are consistent with expected future climate changes, it may be that circulation changes, rather than temperature (and vapor pressure) changes, will be the more important determinant of future rainfall distributions, at least for the coming few decades.

Estimation of hydrological response to future climate change in a cold watershed

2018 ◽  
Vol 10 (1) ◽  
pp. 78-88 ◽  
Author(s):  
Jian Sha ◽  
Zhong-Liang Wang ◽  
Yue Zhao ◽  
Yan-Xue Xu ◽  
Xue Li
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Water System ◽  
Coupled Model ◽  
Weather Conditions ◽  
General Circulation Models ◽  
Future Climate ◽  
Future Climate Change ◽  
Research Station ◽  
Hydrological Process

Abstract The vulnerability of the natural water system in cold areas to future climate change is of great concern. A coupled model approach was applied in the headwater watershed area of Yalu River in the northeastern part of China to estimate the response of hydrological processes to future climate change with moderate data. The stochastic Long Ashton Research Station Weather Generator was used to downscale the results of general circulation models to generate synthetic daily weather series in the 2050s and 2080s under various projected scenarios, which were applied as input data of the Generalized Watershed Loading Functions hydrological model for future hydrological process estimations. The results showed that future wetter and hotter weather conditions would have positive impacts on the watershed runoff yields but negative impacts on the watershed groundwater flow yields. The freezing period in winter would be shortened with earlier snowmelt peaks in spring. These would result in less snow cover in winter and shift the monthly allocations of streamflow with more yields in March but less in April and May, which should be of great concern for future local management. The proposed approach of the coupled model application is effective and can be used in other similar areas.

scholarly journals Hydrological responses to climate change conditioned by historic alterations of land-use and water-use

2011 ◽  
Vol 8 (4) ◽  
pp. 7595-7620 ◽  
Author(s):  
J. Jarsjö ◽  
S. M. Asokan ◽  
C. Prieto ◽  
A. Bring ◽  
G. Destouni
Keyword(s):  
Climate Change ◽  
Water Loss ◽  
Land Surface ◽  
General Circulation ◽  
General Circulation Models ◽  
Future Climate ◽  
Aral Sea ◽  
Future Climate Change ◽  
Hydrological Responses ◽  
Irrigation Practices

Abstract. This paper quantifies and conditions expected hydrological responses in the Aral Sea Drainage Basin (ASDB; occupying 1.3 % of the earth's land surface), Central Asia, to multi-model projections of climate change in the region from 20 general circulation models (GCMs). The aim is to investigate how uncertainties of future climate change interact with the effects of historic human re-distributions of water for land irrigation to influence future water fluxes and water resources. So far, historic irrigation changes have greatly amplified water losses by evapotranspiration (ET) in the ASDB, whereas the 20th century climate change has not much affected the regional net water loss to the atmosphere. Projected future climate change (for the period 2010–2039) however is here calculated to considerably increase the net water loss to the atmosphere. Furthermore, the ET response strength to any future temperature change will be further increased by maintained (or increased) irrigation practices. With such irrigation practices, the river runoff is likely to decrease to near-total depletion, with risk for cascading ecological regime shifts in aquatic ecosystems downstream of irrigated land areas. Without irrigation, the agricultural areas of the principal Syr Darya river basin could sustain a 50 % higher temperature increase (of 2.3 °C instead of the projected 1.5 °C until 2010–2039) before yielding the same consumptive ET increase and associated R decrease as with the present irrigation practices.

Predictions of future climate change in the caribbean region using global general circulation models

2007 ◽  
Vol 27 (5) ◽  
pp. 555-569 ◽  
Author(s):  
Moises E. Angeles ◽  
Jorge E. Gonzalez ◽  
David J. Erickson ◽  
José L. Hernández
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
General Circulation Models ◽  
Future Climate ◽  
Future Climate Change ◽  
Caribbean Region ◽  
The Caribbean

scholarly journals Potential Climate Change Impacts on Water Resources in Egypt

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1715
Author(s):  
Soha M. Mostafa ◽  
Osama Wahed ◽  
Walaa Y. El-Nashar ◽  
Samia M. El-Marsafawy ◽  
Martina Zeleňáková ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Irrigation Water ◽  
General Circulation ◽  
General Circulation Models ◽  
Future Climate ◽  
Future Climate Change ◽  
Impact Of Climate Change ◽  
Water Demands ◽  
The Impact

This paper presents a comprehensive study to assess the impact of climate change on Egypt’s water resources, focusing on irrigation water for agricultural crops, considering that the agriculture sector is the largest consumer of water in Egypt. The study aims to estimate future climate conditions using general circulation models (GCMs), to assess the impact of climate change and temperature increase on water demands for irrigation using the CROPWAT 8 model, and to determine the suitable irrigation type to adapt with future climate change. A case study was selected in the Middle part of Egypt. The study area includes Giza, Bani-Sweif, Al-Fayoum, and Minya governorates. The irrigation water requirements for major crops under current weather conditions and future climatic changes were estimated. Under the conditions of the four selected models CCSM-30, GFDLCM20, GFDLCM21, and GISS-EH, as well as the chosen scenario of A1BAIM, climate model (MAGICC/ScenGen) was applied in 2050 and 2100 to estimate the potential rise in the annual mean temperature in Middle Egypt. The results of the MAGICC/SceGen model indicated that the potential rise in temperature in the study area will be 2.12 °C in 2050, and 3.96 °C in 2100. The percentage of increase in irrigation water demands for winter crops under study ranged from 6.1 to 7.3% in 2050, and from 11.7 to 13.2% in 2100. At the same time, the increase in irrigation water demands for summer crops ranged from 4.9 to 5.8% in 2050, and from 9.3 to 10.9% in 2100. For Nili crops, the increase ranged from 5.0 to 5.1% in 2050, and from 9.6 to 9.9% in 2100. The increase in water demands due to climate change will affect the water security in Egypt, as the available water resources are limited, and population growth is another challenge which requires a proper management of water resources.

scholarly journals Climate change scenarios and its impact on water resources of Langtang Khola Basin, Nepal

2014 ◽  
Vol 364 ◽  
pp. 9-13
Author(s):  
T. Raj Adhikari ◽  
L. Prasad Devkota ◽  
A. Bhakta Shrestha
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Local Level ◽  
General Circulation Models ◽  
Temperature Data ◽  
Future Climate ◽  
Optimization Approach ◽  
Climate Change Scenarios ◽  
The Future ◽  
Precipitation And Temperature

Abstract. General Circulation Models (GCMs) successfully simulate future climate variability and climate change on a global scale; however, poor spatial resolution constrains their application for impact studies at a regional or a local level. The dynamically downscaled precipitation and temperature data were used for the future climate scenarios prediction for the period 2000–2050s, under the Special Report on Emissions Scenarios (SRES) A2 and A1B scenarios. In addition, rating equation was developed from measured discharge and gauge (stage) height data. The generated precipitation and temperature data from downscale and rating equation was used to run the HBV-Light 3.0 conceptual rainfall–runoff model for the calibration and validation of the model, gauge height was taken in the reference period (1988–2009). In the HBV-Light 3.0, a GAP optimization approach was used to calibrate the observed streamflow. From the precipitation scenarios with SRES A2 and A1B emissions at Kyanging, an increase of precipitation during summer and spring and a decrease during winter and autumn seasons was shown. The model projected annual precipitation for the 2050s of both the A2 and A1B scenarios are 716.4 mm and 703.6 mm, respectively. Such precipitation projections indicate the future increase of precipitation in all seasons except the summer. By the end of the 2050s simulation projects an increase maximum (minimum) discharge of 37.8 m3/s (13.9 m3/s) for A1B scenario and 36.2 m3/s (14.3 m3/s) for A2 scenario. A maximum projected discharge will increase for all seasons except for spring, whereas the minimum will decrease in summer.

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.

Simulating Future Distributions of Northern Permafrost Peatlands

2021 ◽  
Author(s):  
Richard Fewster ◽  
Paul Morris ◽  
Ruza Ivanovic ◽  
Graeme Swindles ◽  
Anna Peregon ◽  
...  
Keyword(s):  
Climate Change ◽  
Northern Hemisphere ◽  
General Circulation ◽  
General Circulation Models ◽  
Future Climate ◽  
Future Climate Change ◽  
Organic Soils ◽  
Climate Projections ◽  
Cold Temperatures ◽  
Peat Plateaus

<p>Northern permafrost peatlands represent one of Earth’s largest terrestrial carbon stores and are highly sensitive to climate change. Whilst frozen, peatland carbon fluxes are restricted by cold temperatures, but once permafrost thaws and saturated surficial conditions develop, emissions of carbon dioxide (CO<sub>2</sub>) and methane (CH<sub>4</sub>) substantially increase. This positive feedback mechanism threatens to accelerate future climate change globally. Whilst future permafrost distributions in mineral soils have been modelled extensively, the insulating properties of organic soils mean that peatland permafrost responses are highly uncertain. Peatland permafrost is commonly evidenced by frost mounds, termed palsas/peat plateaus, or by polygonal patterning in more northerly regions. Although the distribution of palsas in northern Fennoscandia is well-studied, the extent of palsas/peat plateaus and polygon mires elsewhere remains poorly constrained, which currently restricts predictions of their future persistence under climate change.  </p><p>Here, we present the first pan-Arctic analyses of the modern climate envelopes and future distributions of permafrost peatland landforms in North America, Fennoscandia, and Western Siberia. We relate a novel hemispheric-scale catalogue of palsas/peat plateaus and polygon mires (>2,100<strong> </strong>individual sites) to modern climate data using one-vs-all (OVA) binary logistic regression. We predict future distributions of permafrost peatland landforms across the northern hemisphere under four Shared Socioeconomic Pathway (SSP) scenarios, using future climate projections from an ensemble of 12 general circulation models included in the Coupled Model Intercomparison Project 6 (CMIP6). We then combine our simulations with recent soil organic carbon maps to estimate how northern peatland carbon stocks may be affected by future permafrost redistribution. These novel analyses will improve our understanding of future peatland trajectories across the northern hemisphere and assist predictions of climate feedbacks resulting from peatland permafrost thaw. </p>

scholarly journals Assessment of Ecological and Hydro-Geomorphological Alterations under Climate Change Using SWAT and IAHRIS in the Eo River in Northern Spain

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1745
Author(s):  
Julio Pérez-Sánchez ◽  
Javier Senent-Aparicio ◽  
Carolina Martínez Santa-María ◽  
Adrián López-Ballesteros
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Assessment Tool ◽  
Swat Model ◽  
General Circulation Models ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Efficiency Coefficient ◽  
Northern Spain

Magnitude and temporal variability of streamflow is essential for natural biodiversity and the stability of aquatic environments. In this study, a comparative analysis between historical data (1971–2013) and future climate change scenarios (2010–2039, 2040–2069 and 2070–2099) of the hydrological regime in the Eo river, in the north of Spain, is carried out in order to assess the ecological and hydro-geomorphological risks over the short-, medium- and long-term. The Soil and Water Assessment Tool (SWAT) model was applied on a daily basis to assess climate-induced hydrological changes in the river under five general circulation models and two representative concentration pathways. Statistical results, both in calibration (Nash-Sutcliffe efficiency coefficient (NSE): 0.73, percent bias (PBIAS): 3.52, R2: 0.74) and validation (NSE: 0.62, PBIAS: 6.62, R2: 0.65), are indicative of the SWAT model’s good performance. The ten climate scenarios pointed out a reduction in rainfall (up to −22%) and an increase in temperatures, both maximum (from +1 to +7 °C) and minimum ones (from +1 to +4 °C). Predicted flow rates resulted in an incrementally greater decrease the longer the term is, varying between −5% (in short-term) and −53% (in long-term). The free software IAHRIS (Indicators of Hydrologic Alteration in Rivers) determined that alteration for usual values remains between excellent and good status and from good to moderate in drought values, but flood values showed a deficient regime in most scenarios, which implies an instability of river morphology, a progressive reduction in the section of the river and an advance of aging of riparian habitat, endangering the renewal of the species.

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