Climate change effects on denitrification and associated avoidance costs in three Baltic river basin - coastal sea systems

2017 ◽  
Vol 21 (4) ◽  
pp. 561-569 ◽  
Author(s):  
Alexander Allin ◽  
Gerald Schernewski ◽  
Rene Friedland ◽  
Thomas Neumann ◽  
Hagen Radtke
2018 ◽  
Vol 22 (12) ◽  
pp. 6473-6491 ◽  
Author(s):  
Francisco Pellicer-Martínez ◽  
José Miguel Martínez-Paz

Abstract. Currently, climate change is a major concern around the world, especially because of the uncertainty associated with its possible consequences for society. Among them, fluvial alterations can be highlighted in basins whose flows depend on groundwater discharges and snowmelt. This is the case of the headwaters of the Tagus River basin, whose water resources, besides being essential for water uses within this basin, are susceptible to being transferred to the Segura River basin (both basins are in the Iberian Peninsula). This work studies the possible effects that the latest climate change scenarios may have on this transfer, one of the most important ones in southern Europe. In the first place, the possible alterations of the water cycle of the donor basin were estimated. To do this, a hydrological model was calibrated. Then, with this model, three climatic scenarios were simulated, one without climate change and two projections under climate change (Representative Concentration Pathways 4.5 (RCP 4.5) and 8.5 (RCP 8.5)). The results of these three hydrological modelling scenarios were used to determine the possible flows that could be transferred from the Tagus River basin to the Segura River basin, by simulating the water resource exploitation system of the Tagus headwaters. The calibrated hydrological model predicts, for the simulated climate change scenarios, important reductions in the snowfalls and snow covers, the recharge of aquifers, and the available water resources. So, the headwaters of the Tagus River basin would lose part of its natural capacity for regulation. These changes in the water cycle for the climate change scenarios used would imply a reduction of around 70 %–79 % in the possible flows that could be transferred to the Segura basin, with respect to a scenario without climate change. The loss of water resources for the Segura River basin would mean, if no alternative measures were taken, an economic loss of EUR 380–425 million per year, due principally to decreased agricultural production.


2020 ◽  
Vol 2 (1) ◽  
pp. 93-105 ◽  
Author(s):  
Ghanashyam Khanal

Background: Climate change is an emerging challenge that the global society will have to deal with over the coming decades. The task is particularly daunting to developing societies as they are considered more susceptible to climate change because of their exposures and sensitivities to climate-related extremes, and especially because of their restricted adaptive capabilities to deal with the effects of hazardous events. Objectives: This research attempts to seek evidence of adaptation undertaken as a result of climate change-induced impacts and analyze the factors affecting the capability and strategies of climate change adaptation by small scale farmers in Nepal. Methods: A descriptive cum correlational research design was employed in the study following a quantitative approach. Using a convenience sampling method, primary data for each variable was collected from 67 small scale farmers of Tinau River Basin located in the Western region of Nepal. 5-Point Likert Scale questions were prepared and pilot testing was conducted to collect the responses. Descriptive statistics, Kendall Rank Correlation and Cronbach’s Alpha (α) Test were used while analyzing the data and testing the hypotheses. The inferences were made at 5% and 1% level of significance. Results: The findings indicate that the small scale farmers in the Tinau River Basin are experiencing the varied level of changes in climate. It revealed the existence of some barring factors for adaptation, further, insisting that farmers are prone to suffer from capability losses due to climate change. Conclusion: The study concludes that small scale farmers are prone to suffer from capability losses due to climate change. Climate change effects are hampering their ability to cultivate the land, increasingly damaging their production, and causing lower yields of harvests. Implications:  This study suggests that such influencing factors should be taken into prime consideration (while developing additional intervention) to enhance farmers’ capabilities to better cope with climate change effects; thus improving their adaptation measures for maintaining a flourishing relationship with the changing climate.


2018 ◽  
Author(s):  
Francisco Pellicer-Martínez ◽  
José Miguel Martínez-Paz

Abstract. Currently, climate change is a major concern around the world, especially because of the uncertainty associated with its possible consequences for society. Among these can be highlighted the fluvial alterations in basins whose flows depend on groundwater discharges and snow melt. This is the case of the headwaters of the Tagus River Basin, whose water resources, besides being essential for water uses within this basin, are susceptible to being transferred to the Segura River Basin (both basins are in the Iberian Peninsula). This work studies the possible effects that the latest climate change scenarios may have on this transfer, one of the most important in southern Europe. In the first place, the possible alterations of the water cycle of the donor basin were estimated. To do this, a hydrological model was calibrated. Then, with this model, three climatic scenarios were simulated, one without climate change and two projections under climate change (Representative Concentration Representative 4.5 (RCP 4.5) and RCP 8.5). The results of these three hydrological modelling scenarios were used to determine the possible flows that could be transferred from the Tagus River Basin to the Segura River Basin, by simulating the water resource exploitation system of the Tagus headwaters. These hydrological modelling predict, for the simulated climate change scenarios, important reductions in the snowfalls and snow covers, the recharge of aquifers and the available water resources. So, the headwaters of the Tagus River Basin would be the loss of part of its natural capacity for regulation. These changes in the water cycle for the climate change scenarios used would imply a reduction of around 80 % in the possible flows that could be transferred to the Segura Basin, with respect to a scenario without climate change. The loss of water resources for the Segura River Basin would mean, if no alternative measures were taken, an economic loss of 330–380 million euro per year, due principally to decreased agricultural production.


Author(s):  
Ryosuke ARAI ◽  
Yasushi TOYODA ◽  
Masamichi OHBA ◽  
Takahiro SATO ◽  
So KAZAMA

Author(s):  
Camila Billerbeck ◽  
Ligia Monteiro da Silva ◽  
Silvana Susko Marcellini ◽  
Arisvaldo Méllo Junior

Abstract Regional climate models (RCM) are the main tools for climate change impacts assessment in hydrological studies. These models, however, often show biases when compared to historical observations. Bias Correction (BC) are useful techniques to improve climate projection outputs. This study presents a multi-criteria decision analysis (MCDA) framework to compare combinations of RCM with selected BC methods. The comparison was based on the modified Kling-Gupta efficiency (KGE’). The criteria evaluated the general capability of models in reproducing the observed data main statistics. Other criteria evaluated were the relevant aspects for hydrological studies, such as seasonality, dry and wet periods. We applied four BC methods in four RCM monthly rainfall outputs from 1961 to 2005 in the Piracicaba river basin. The Linear Scaling (LS) method showed higher improvements in the general performance of the models. The RCM Eta-HadGEM2-ES, corrected with Standardized Reconstruction (SdRc) method, achieved the best results when compared to the observed precipitation. The bias corrected projected monthly precipitation (2006-2098) preserved the main signal of climate change effects when compared to the original outputs regarding annual rainfall. However, SdRc produced significant decrease in monthly average rainfall, higher than 45% for July, August and September for RCP4.5 and RCP8.5 scenarios.


Author(s):  
J. Y. G. Santos ◽  
R. M. Silva ◽  
J. G. Carvalho Neto ◽  
S. M. G. L. Montenegro ◽  
C. A. G. Santos ◽  
...  

Abstract. This study assesses the impact of the land use and climate changes between 1967–2008 on the streamflow and sediment yield in Tapacurá River basin (Brazil) using the Soil and Water Assessment Tool (SWAT) model. The model was calibrated and validated by comparing simulated mean monthly streamflow with observed long-term mean monthly streamflow. The obtained R2 and Nash–Sutcliffe efficiency values to streamflow data were respectively 0.82 and 0.71 for 1967–1974, and 0.84 and 0.82 for 1995–2008. The results show that the land cover and climate change affected the basin hydrology, decreasing the streamflow and sediment yield (227.39 mm and 18.21 t ha−1 yr−1 for 1967–1974 and 182.86 mm and 7.67 t ha−1 yr−1 for 1995–2008). The process changes are arising mainly due to the land cover/use variability, but, mainly due to the decreasing in the rainfall rates during 1995–2008 when compared with the first period analysed, which in turn decreased the streamflow and sediments during the wet seasons and reduced the base flow during the dry seasons.


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