scholarly journals Evaluation of the Impact of Climate Change on Runoff Generation in an Andean Glacier Watershed

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3547
Author(s):  
Rossana Escanilla-Minchel ◽  
Hernán Alcayaga ◽  
Marco Soto-Alvarez ◽  
Christophe Kinnard ◽  
Roberto Urrutia

Excluding Antarctica and Greenland, 3.8% of the world’s glacier area is concentrated in Chile. The country has been strongly affected by the mega drought, which affects the south-central area and has produced an increase in dependence on water resources from snow and glacier melting in dry periods. Recent climate change has led to an elevation of the zero-degree isotherm, a decrease in solid-state precipitation amounts and an accelerated loss of glacier and snow storage in the Chilean Andes. This situation calls for a better understanding of future water discharge in Andean headwater catchments in order to improve water resources management in glacier-fed populated areas. The present study uses hydrological modeling to characterize the hydrological processes occurring in a glacio-nival watershed of the central Andes and to examine the impact of different climate change scenarios on discharge. The study site is the upper sub-watershed of the Tinguiririca River (area: 141 km2), of which nearly 20% is covered by Universidad Glacier. The semi-distributed Snowmelt Runoff Model + Glacier (SRM+G) was forced with local meteorological data to simulate catchment runoff. The model was calibrated on even years and validated on odd years during the 2008–2014 period and found to correctly reproduce daily runoff. The model was then forced with downscaled ensemble projected precipitation and temperature series under the RCP 4.5 and RCP 8.5 scenarios, and the glacier adjusted using a volume-area scaling relationship. The results obtained for 2050 indicate a decrease in mean annual discharge (MAD) of 18.1% for the lowest emission scenario and 43.3% for the most pessimistic emission scenario, while for 2100 the MAD decreases by 31.4 and 54.2%, respectively, for each emission scenario. Results show that decreasing precipitation lead to reduced rainfall and snowmelt contributions to discharge. Glacier melt thus partly buffers the drying climate trend, but our results show that the peak water occurs near 2040, after which glacier depletion leads to reducing discharge, threatening the long-term water resource availability in this region.

2020 ◽  
Author(s):  
Kristian Näschen ◽  
Bernd Diekkrüger ◽  
Mariele Evers ◽  
Britta Höllermann ◽  
Larisa S. Seregina ◽  
...  

<p>The Kilombero catchment is a meso-scale catchment of 40,240 km² in south central Tanzania and is characterized by overall data scarcity like many other African catchments. The catchment consists of a highly dynamic floodplain system at its centre which is sustained by water from the surrounding uplands. It also contains a Ramsar site giving evidence to its valuable ecosystem and importance concerning biodiversity conservation. However, in the last decades land use and land cover changes (LULCC) accelerated drastically towards an agriculturally-shaped landscape, especially at the fringes of the wetland. The wetland system provides fertile soils, water as well as other water-related ecosystem services. Nevertheless, the increasing pressure on natural resources jeopardizes the sustainability of the socio-ecological system, especially in the face of climate change.</p><p> </p><p>In this study, methods of hydrology, meteorology and remote sensing were used to overcome data-scarcity and gather a sound representation of natural processes in the catchment. The Soil and Water Assessment Tool (SWAT) was applied to represent the hydrological processes in the catchment. We utilized Landsat images from several decades to simulate the impact of LULCC from the 1970s until today. Furthermore, we applied the Land Change Modeller (LCM) to simulate potential LULCC until 2030 and their impact on water resources. To account for climatic changes, a regional climate model ensemble of the Coordinated Regional Downscaling Experiment (CORDEX) Africa project was analysed and bias-corrected to investigate changes in climatic patterns until 2060, according to the RCP4.5 (representative concentration pathways) and RCP8.5 scenarios.</p><p> </p><p>The climate change signal indicates rising temperatures, especially in the hot dry season, which reinforces the special features of this season. However, the changes in precipitation signals among the analysed RCMs vary between -8.3% and +22.5% of the annual mean values. The results of the hydrological modelling also show heterogeneous spatial patterns within the catchment area. LULCC simulation results show a 6-8% decrease in low flows for the LULCC scenarios, while high flows increase by up to 84% for combined LULCC and climate change scenarios. The effect of climate change is more pronounced compared to the effect of LULCC, but also contains higher uncertainties. This study exemplarily quantifies the impact of LULCC and climate change in a data-scarce catchment and therefore contributes to the sustainable management of the investigated catchment, as it shows the impact of environmental change on hydrological extremes and determines hot spots, which are crucial for more detailed analyses like hydrodynamic modelling. The information from this study are an essential part to assist local stakeholders protecting the wetlands integrity on the one hand and to ensure sustainable agricultural practices in order to guarantee food security on the other hand in a catchment that has already changed tremendously and is still target to manifold future plans.</p>


2019 ◽  
Vol 11 (8) ◽  
pp. 2450 ◽  
Author(s):  
Noora Veijalainen ◽  
Lauri Ahopelto ◽  
Mika Marttunen ◽  
Jaakko Jääskeläinen ◽  
Ritva Britschgi ◽  
...  

Severe droughts cause substantial damage to different socio-economic sectors, and even Finland, which has abundant water resources, is not immune to their impacts. To assess the implications of a severe drought in Finland, we carried out a national scale drought impact analysis. Firstly, we simulated water levels and discharges during the severe drought of 1939–1942 (the reference drought) in present-day Finland with a hydrological model. Secondly, we estimated how climate change would alter droughts. Thirdly, we assessed the impact of drought on key water use sectors, with a focus on hydropower and water supply. The results indicate that the long-lasting reference drought caused the discharges to decrease at most by 80% compared to the average annual minimum discharges. The water levels generally fell to the lowest levels in the largest lakes in Central and South-Eastern Finland. Climate change scenarios project on average a small decrease in the lowest water levels during droughts. Severe drought would have a significant impact on water-related sectors, reducing water supply and hydropower production. In this way drought is a risk multiplier for the water–energy–food security nexus. We suggest that the resilience to droughts could be improved with region-specific drought management plans and by including droughts in existing regional preparedness exercises.


2019 ◽  
Vol 11 (24) ◽  
pp. 7083 ◽  
Author(s):  
Kristian Näschen ◽  
Bernd Diekkrüger ◽  
Mariele Evers ◽  
Britta Höllermann ◽  
Stefanie Steinbach ◽  
...  

Many parts of sub-Saharan Africa (SSA) are prone to land use and land cover change (LULCC). In many cases, natural systems are converted into agricultural land to feed the growing population. However, despite climate change being a major focus nowadays, the impacts of these conversions on water resources, which are essential for agricultural production, is still often neglected, jeopardizing the sustainability of the socio-ecological system. This study investigates historic land use/land cover (LULC) patterns as well as potential future LULCC and its effect on water quantities in a complex tropical catchment in Tanzania. It then compares the results using two climate change scenarios. The Land Change Modeler (LCM) is used to analyze and to project LULC patterns until 2030 and the Soil and Water Assessment Tool (SWAT) is utilized to simulate the water balance under various LULC conditions. Results show decreasing low flows by 6–8% for the LULC scenarios, whereas high flows increase by up to 84% for the combined LULC and climate change scenarios. The effect of climate change is stronger compared to the effect of LULCC, but also contains higher uncertainties. The effects of LULCC are more distinct, although crop specific effects show diverging effects on water balance components. This study develops a methodology for quantifying the impact of land use and climate change and therefore contributes to the sustainable management of the investigated catchment, as it shows the impact of environmental change on hydrological extremes (low flow and floods) and determines hot spots, which are critical for environmental development.


2021 ◽  
Vol 13 (24) ◽  
pp. 14025
Author(s):  
Fazlullah Akhtar ◽  
Usman Khalid Awan ◽  
Christian Borgemeister ◽  
Bernhard Tischbein

The Kabul River Basin (KRB) in Afghanistan is densely inhabited and heterogenic. The basin’s water resources are limited, and climate change is anticipated to worsen this problem. Unfortunately, there is a scarcity of data to measure the impacts of climate change on the KRB’s current water resources. The objective of the current study is to introduce a methodology that couples remote sensing and the Soil and Water Assessment Tool (SWAT) for simulating the impact of climate change on the existing water resources of the KRB. Most of the biophysical parameters required for the SWAT model were derived from remote sensing-based algorithms. The SUFI-2 technique was used for calibrating and validating the SWAT model with streamflow data. The stream-gauge stations for monitoring the streamflow are not only sparse, but the streamflow data are also scarce and limited. Therefore, we selected only the stations that are properly being monitored. During the calibration period, the coefficient of determination (R2) and Nash–Sutcliffe Efficiency (NSE) were 0.75–0.86 and 0.62–0.81, respectively. During the validation period (2011–2013), the NSE and R2 values were 0.52–0.73 and 0.65–0.86, respectively. The validated SWAT model was then used to evaluate the potential impacts of climate change on streamflow. Regional Climate Model (RegCM4-4) was used to extract the data for the climate change scenarios (RCP 4.5 and 8.5) from the CORDEX domain. The results show that streamflow in most tributaries of the KRB would decrease by a maximum of 5% and 8.5% under the RCP 4.5 and 8.5 scenarios, respectively. However, streamflow for the Nawabad tributary would increase by 2.4% and 3.3% under the RCP 4.5 and 8.5 scenarios, respectively. To mitigate the impact of climate change on reduced/increased surface water availability, the SWAT model, when combined with remote sensing data, can be an effective tool to support the sustainable management and strategic planning of water resources. Furthermore, the methodological approach used in this study can be applied in any of the data-scarce regions around the world.


2021 ◽  
Vol 25 (2) ◽  
pp. 637-651
Author(s):  
Michel Le Page ◽  
Younes Fakir ◽  
Lionel Jarlan ◽  
Aaron Boone ◽  
Brahim Berjamy ◽  
...  

Abstract. In the context of major changes (climate, demography, economy, etc.), the southern Mediterranean area faces serious challenges with intrinsically low, irregular, and continuously decreasing water resources. In some regions, the proper growth both in terms of cropping density and surface area of irrigated areas is so significant that it needs to be included in future scenarios. A method for estimating the future evolution of irrigation water requirements is proposed and tested in the Tensift watershed, Morocco. Monthly synthetic crop coefficients (Kc) of the different irrigated areas were obtained from a time series of remote sensing observations. An empirical model using the synthetic Kc and rainfall was developed and fitted to the actual data for each of the different irrigated areas within the study area. The model consists of a system of equations that takes into account the monthly trend of Kc, the impact of yearly rainfall, and the saturation of Kc due to the presence of tree crops. The impact of precipitation change is included in the Kc estimate and the water budget. The anthropogenic impact is included in the equations for Kc. The impact of temperature change is only included in the reference evapotranspiration, with no impact on the Kc cycle. The model appears to be reliable with an average r2 of 0.69 for the observation period (2000–2016). However, different subsampling tests of the number of calibration years showed that the performance is degraded when the size of the training dataset is reduced. When subsampling the training dataset to one-third of the 16 available years, r2 was reduced to 0.45. This score has been interpreted as the level of reliability that could be expected for two time periods after the full training years (thus near to 2050). The model has been used to reinterpret a local water management plan and to incorporate two downscaled climate change scenarios (RCP4.5 and RCP8.5). The examination of irrigation water requirements until 2050 revealed that the difference between the two climate scenarios was very small (< 2 %), while the two agricultural scenarios were strongly contrasted both spatially and in terms of their impact on water resources. The approach is generic and can be refined by incorporating irrigation efficiencies.


2016 ◽  
Vol 8 (1) ◽  
pp. 10-21
Author(s):  
Narayan P Gautam ◽  
Manohar Arora ◽  
N.K. Goel ◽  
A.R.S. Kumar

Climate change has been emerging as one of the challenges in the global environment. Information of predicted climatic changes in basin scale is highly useful to know the future climatic condition in the basin that ultimately becomes helpful to carry out planning and management of the water resources available in the basin. Climatic scenario is a plausible and often simplified representation of the future climate, based on an internally consistent set of climatological relationships that has been constructed for explicit use in investigating the potential consequences of anthropogenic climate change. This study based on statistical downscaling, provide good example focusing on predicting the rainfall and runoff patterns, using the coarse general circulation model (GCM) outputs. The outputs of the GCMs are utilized to study the impact of climate change on water resources. The present study has been taken up to identify the climate change scenarios for Satluj river basin, India.Journal of Hydrology and Meteorology, Vol. 8(1) p.10-21


2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
L Velez Lapão

Abstract Background Climate change is modifying weather patterns, producing far-reaching effects on the environment, the economy and society as a whole, endangering global livelihoods, health, food and energy security, and water resources. Europe, and the Mediterranean will not escape the effects of climate change, which will aggravate risks and threats to human security (mainly public health) and regional stability. Actual cooperation and appropriate instruments are needed to address these threats. In this context, higher temperatures and extreme weather phenomena, such as severe droughts and heat waves will inevitably cause water scarcity in these regions and significant health issues. The degradation of the environment will foreseeably create security and health crisis scenarios, arising from energy shortages, air quality, water stress and food supply problems. Methods A scenario analysis was designed to address the relation between security, healthcare, energy and climate change, which contains multiple dimensions. We did a review of the literature and use it to feed the scenario analysis development, to better describe a phenomenon that is complex, with many possible paths and outcomes. Results Among the possible scenarios, two were considered: one based on collaboration and the other, on conflict. Several dimensions were examined to address both cooperation instruments and the consequences of non-cooperation: Energy production (e.g., conventional versus renewable) and use; water resources and food security; the environment (air quality) and the impact on health; Population and migration flow. Conclusions Climate change is a serious threat. To achieve and implement cooperation, there must be multilateral collaboration between the EU and the other Mediterranean countries, including stronger investment flows from north to south, in conjunction with the promotion of both energy efficiency policies and better healthcare system in the south.


OENO One ◽  
2018 ◽  
Vol 52 (1) ◽  
Author(s):  
Maria Concepción Ramos ◽  
Gregory V Jones ◽  
Jesús Yuste

Aim: This research examined relationships between grapevine phenology and climate in the Ribera del Duero DO (Spain). The observed varieties included Tempranillo, the main variety planted in the region, and Cabernet-Sauvignon.Methods and Results: Phenological events for stages C (budbreak), I (bloom), M (véraison) and N (maturity) were analyzed for 2004-2015. Dormant period chilling and late winter heating requirements to initiate growth were evaluated and accumulated temperature (growing degree days-GDD) prior to each phenological event and in between events were examined for the role they play in influencing growth timing. The results were then used to examine future phenological changes due to climate change using eight models integrated in the Coupled Model Intercomparison Project (CMIP5) and for two Representative Concentration Pathways (RCP) scenarios – RCP4.5 and RCP8.5 – for 2030, 2050, and 2070. Accumulated temperatures after March 20th become important for initiating phenology and are strongly correlated to all growth events. The influence of water availability between budbreak and bloom and between bloom and véraison on phenological timing was also confirmed.Conclusions: The projections showed that for the RCP4.5 emission scenario, budbreak is predicted earlier by approximately 2 days for 2030, 3 days for 2050 and 5 days for 2070, while bloom is predicted to be 3 to 8 days earlier and véraison 6 to 19 days earlier for the same time periods. For the RCP8.5 emission scenario, budbreak is modeled to take place about 3 days, 5 days and 9 days earlier, respectively for 2030, 2050 and 2070. Bloom is predicted to occur about 5, 10 and 16 days earlier; véraison is predicted earlier by 10 days for 2030, 19 days for 2050, and 28 days for 2070. Maturity and the timing of harvest could be up to 23 days earlier under the RCP4.5 emission scenario and up to 35 days earlier under the RCP8.5 emission scenario. Compared to Cabernet-Sauvignon, Tempranillo exhibited greater phenological sensitivity to temperature changes in the observed time period that is likely to continue into the future with greater changes to earlier growth events projected. This sensitivity could be problematic for the region due to the variety’s historic importance and points to the need to examine adaptive measures that can help growers to respond to projected changes in climate.Significance and impact of the study: The projected climate changes in the future indicate the potential for significant changes in the phenology of Tempranillo in the Ribera del Duero DO, Spain. Given that this variety has the largest contribution and importance in this region, these changes could have impacts on wine quality, indicating the need of establishing strategies to reduce or mitigate the impact from future changes in climate.


2022 ◽  
Author(s):  
Babar Zahoor ◽  
Xuehua Liu ◽  
Melissa Songer

Abstract Global temperatures are predicted to rise from between 1.4 to 5.8°C by 21st century, which could result in a 20 to 30% extinction of species. The negative impacts of climate change on the northern highlands of Pakistan (NHP) could change the species composition. Range shifts and range reduction in the forested landscapes will dramatically affect the distribution of forest dwelling species, including the Galliformes (ground birds). Three Galliformes (e.g., Lophophorus impejanus, Pucrasia macrolopha and Tragopan melanocephalus) are indicator species of the environment and currently distributed in NHP. For this study, we used Maximum Entropy Model (MaxEnt) to simulate the current and future (in 2050 and 2070) distributions of the species using three General Circulation Models (GCMs) and two climate change scenarios, i.e., RCP4.5 (moderate carbon emission scenario) and RCP8.5 (peak carbon emission scenario). Our results indicated that (i) all the three species would be negatively affected by the climate change in 2050 and in 2070. (ii) Under all three climate scenarios, species distribution was predicted to both reduce and shift towards higher altitudes. (iii) Across the provinces in the NHP, the species were predicted to lose over one quarter in 2050 and one-third by 2070 of the current suitable habitat. (iv) The maximum area of climate refugia was projected between the altitudinal range of 2000 m to 4000 m and predicted to shift towards higher altitudes primarily >3000 m in the future. The proposed implications such as establishment and upgradation of the protected areas, ban on hunting, timber mafia and temporary settlements of the local people in the forested landscapes should be under special consideration to mitigate the impact of climate change.


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