Potential impacts of climate change on grazing capacity of native grasslands in the Canadian prairies

2008 ◽  
Vol 88 (4) ◽  
pp. 595-609 ◽  
Author(s):  
J. Thorpe ◽  
S A Wolfe ◽  
B. Houston
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Warm Season ◽  
Actual Evapotranspiration ◽  
Canadian Prairies ◽  
Geographic Patterns ◽  
Key Words Climate Change ◽  
Grassland Production ◽  
Grazing Capacity ◽  
Impacts Of Climate Change

Relationships between climate and native grassland production in the Canadian prairies were modelled and used to estimate the potential impacts of climate change on grazing capacity. Field measurements of production were related to climate variables and water balance estimates using regression analysis. Historical time series showed that year-to-year production is most closely correlated with annual actual evapotranspiration, whereas geographic patterns revealed that average production is most closely related to the annual water deficit. Climate and production estimates from the US Great Plains represent potential analogues for the Canadian prairies in the 2050s. Analysis of geographic patterns using Canadian and US data showed that production can be related to actual evapotranspiration (Model 1) or the ratio of actual to potential evapotranspiration (Model 2). The proportion of warm-season (C4) grasses has a significant effect on production in these models. A third independent model (Model 3) using US production data was used for comparison. Five general circulation model (GCM) scenarios covering a range of predictions simulated warmer climates of the 2050s. The production models were used to estimate changes in grassland production. On loamy soils, Model 1 predicts increases in production whereas Models 2 and 3 predict decreases. However, all predicted changes are modest, indicating that Canadian grasslands will probably remain productive over the next 50 yr. In addition, warm-season grasses could increase, particularly on sandy soils, thus benefiting productivity. Key words: Climate change, grazing capacity, grasslands, prairies

Impact of climate change scenarios on the agroclimate of the Canadian prairies

2003 ◽  
Vol 83 (5) ◽  
pp. 623-630 ◽  
Author(s):  
S. M. McGinn ◽  
A. Shepherd
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
Soil Water ◽  
Water Deficit ◽  
General Circulation ◽  
Weather Data ◽  
Climate Change Scenarios ◽  
Soil Water Deficit ◽  
Canadian Prairies ◽  
Key Words Climate Change

Regional climate change scenarios for the Canadian prairies were generated using historic weather data and daily data from two Canadian Climate Centre general circulation models (GCM). Model CGCM1-A was a recent version release while its predecessor was model GCMII. The GCM data were combined with historic values to generate two additional scenarios. All scenarios were used to drive the modified Versatile Soil Moisture Budget model that assessed soil moisture, aridity and other agroclimatic indices. The modelled results for all scenarios were compared to those using the historic climate data. The model predicted earlier seeding dates for spring wheat between 18 and 26 d. Early seeding and harvest was shown to be an appropriate adaptive strategy that avoided more arid conditions in the late summer. The soil water deficit was lower under GCMII than historic values by 46 mm. For CGCM1-A, the soil water deficit was decreased by 8 mm across the Prairie Provinces compared to historic values. GCM scenarios predicted unchanged or increased soil water in the top 120 cm soil across the Canadian prairies compared to the historic scenario. There were some regions such as south eastern Saskatchewan and southern Manitoba where reductions in summer rainfall (for CGCM1-A) were large. These regions experienced the greatest benefit of earlier seeding dates. Key words: Climate change, agriculture, aridity, growing degree-days, soil moisture, seeding date, harvest date

scholarly journals Quantifying the Impacts of Climate Change and Vegetation Variation on Actual Evapotranspiration Based on the Budyko Hypothesis in North and South Panjiang Basin, China

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 508 ◽  
Author(s):  
Tiansheng Li ◽  
Jun Xia ◽  
Dunxian She ◽  
Lei Cheng ◽  
Lei Zou ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Surface ◽  
Climatic Factors ◽  
Actual Evapotranspiration ◽  
Maximum Temperature ◽  
Linear Regression Method ◽  
North And South ◽  
Average Contribution ◽  
Vegetation Variation ◽  
Impacts Of Climate Change

Actual evapotranspiration (Ea) plays a key role in the global water and energy cycles. The accurate quantification of the impacts of different factors on Ea change can help us better understand the driving mechanisms of Ea in a changing environment. Climate change and vegetation variations are well known as two main factors that have significant impacts on Ea change. Our study used three differential Budyko-type equations to quantify the contributions of climate change and vegetation variations to Ea change. First, in order to establish the relationship between the parameter n, which usually presents the land surface characteristics in the Budyko-type equations, with basic climatic variables and the Normalized Difference Vegetation Index (NDVI), the stepwise linear regression method has been used. Then, elasticity and contribution analyses were performed to quantify the contributions of different numbers of climatic factors and NDVI to Ea change. The North and South Panjiang basin in China was selected to investigate the efficiency of the modified Budyko-type equations and quantify the impacts of climate change and vegetation variations on Ea change. The empirical formal of the parameter n established in this study can be used to simulate the parameter n and Ea for the study area. The results of the elasticity and contribution analyses suggest that climate change contributed (whose average contribution is 149.6%) more to Ea change than vegetation variation (whose average contribution is −49.4%). Precipitation, NDVI and the maximum temperature are the major drivers of Ea change, while the minimum temperature and wind speed contribute the least to Ea change.

Impact of warm summers on the actual evapotranspiration from spring wheat grown on the eastern Canadian prairies

1998 ◽  
Vol 78 (1) ◽  
pp. 171-179 ◽  
Author(s):  
R. L. Raddatz ◽  
C. F. Shaykewich
Keyword(s):  
Climate Warming ◽  
Spring Wheat ◽  
Current Trend ◽  
Wheat Yield ◽  
Warm Season ◽  
Growth Period ◽  
Crop Growth ◽  
Actual Evapotranspiration ◽  
Canadian Prairies ◽  
Summer Temperatures

How do warm summers (June–July–August) influence the actual evapotranspiration totals from cropped land sown to spring wheat on the eastern Canadian Prairies? The eastern Prairies is a semi-arid region where over 60% of the land is cultivated. Over a third of the cropped land is usually sown to spring wheat. A comparison of mean summer temperatures and modelled evapotranspiration, for the years 1988 to 1996, demonstrated that with the current environmental conditions and farming practices, warm summers have lower actual evapotranspiration totals from spring wheat than cool summers. The average daily actual evapotranspiration rate is generally higher in years with higher mean summer temperatures; however, the crop growth-period is shorter. The net effect is lower total actual evapotranspiration from spring wheat. This suggests that climate warming on the eastern Canadian Prairies, if the current trend continues and all other factors remain equal, will reduce, on average, the total actual evapotranspiration from spring wheat. A reduction in the growth-period actual evapotranspiration from lands sown to spring wheat will likely decrease the total actual evapotranspiration for the entire warm season as growth-period evapotranspiration currently makes up about three-quarters of the seasonal total. However, the magnitude and timing of the reduction is far from certain. The consequence for agriculture may be a reduction in the average spring wheat yield because yield is positively correlated with the actual evapotranspiration total from the crop. Key words: Modelling, crop growth-period, yield, climate warming

scholarly journals Simulation and analysis of the impact of projected climate change on the spatially distributed waterbalance in Thuringia, Germany

2009 ◽  
Vol 21 ◽  
pp. 33-48 ◽  
Author(s):  
P. Krause ◽  
S. Hanisch
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
Hydrological Model ◽  
Actual Evapotranspiration ◽  
Climate Data ◽  
Runoff Generation ◽  
Entire Area ◽  
Spatially Distributed ◽  
The Impact ◽  
Conceptual Hydrological Model

Abstract. The impact of projected climate change on the long-term hydrological balance and seasonal variability in the federal German state of Thuringia was assessed and analysed. For this study projected climate data for the scenarios A2 and B1 were used in conjunction with a conceptual hydrological model. The downscaled climate data are based on outputs of the general circulation model ECHAM5 and provide synthetic climate time series for a large number of precipitation and climate stations in Germany for the time period of 1971 to 2100. These data were used to compute the spatially distributed hydrological quantities, i.e. precipitation, actual evapotranspiration and runoff generation with a conceptual hydrological model. This paper discusses briefly the statistical downscaling method and its validation in Thuringia and includes an overview of the hydrological model. The achieved results show that the projected climate conditions in Thuringia follow the general European climate trends – increased temperature, wetter winters, drier summers. But, in terms of the spatial distribution and interannual variability regional differences occur. The analysis showed that the general increase of the winter precipitation is more distinct in the mid-mountain region and less pronounced in the lowland whereas the decrease of summer precipitation is higher in the lowland and less distinct in the mid-mountains. The actual evapotranspiration showed a statewide increase due to higher temperatures which is largest in the summer period. The resulting runoff generation in winter was found to increase in the mid-mountains and to slightly decrease in the lowland region. In summer and fall a decrease in runoff generation was estimated for the entire area due to lower precipitation and higher evapotranspiration rates. These spatially differentiated results emphasize the need of high resolution climate input data and distributed modelling for regional impact analyses.

scholarly journals Future changes in Mekong River hydrology: impact of climate change and reservoir operation on discharge

2012 ◽  
Vol 9 (5) ◽  
pp. 6569-6614 ◽  
Author(s):  
H. Lauri ◽  
H. de Moel ◽  
P. J. Ward ◽  
T. A. Räsänen ◽  
M. Keskinen ◽  
...  
Keyword(s):  
Climate Change ◽  
Reservoir Operation ◽  
General Circulation ◽  
General Circulation Models ◽  
Dry Season ◽  
Mekong River ◽  
Cumulative Impacts ◽  
Cumulative Impact ◽  
Impacts Of Climate Change ◽  
Hydropower Reservoirs

Abstract. The transboundary Mekong River is facing two on-going changes that are estimated to significantly impact its hydrology and the characteristics of its exceptional flood pulse. The rapid economic development of the riparian countries has led to massive plans for hydropower construction, and the projected climate change is expected to alter the monsoon patterns and increase temperature in the basin. The aim of this study is to assess the cumulative impact of these factors on the hydrology of the Mekong within next 20–30 yr. We downscaled output of five General Circulation Models (GCMs) that were found to perform well in the Mekong region. For the simulation of reservoir operation, we used an optimisation approach to estimate the operation of multiple reservoirs, including both existing and planned hydropower reservoirs. For hydrological assessment, we used a distributed hydrological model, VMod, with a grid resolution of 5 km × 5 km. In terms of climate change's impact to hydrology, we found a high variation in the discharge results depending on which of the GCMs is used as input. The simulated change in discharge at Kratie (Cambodia) between the baseline (1982–1992) and projected time period (2032–2042) ranges from −11% to +15% for the wet season and −10% to +13% for the dry season. Our analysis also shows that the changes in discharge due to planned reservoir operations are clearly larger than those simulated due to climate change: 25–160% higher dry season flows and 5–24% lower flood peaks in Kratie. The projected cumulative impacts follow rather closely the reservoir operation impacts, with an envelope around them induced by the different GCMs. Our results thus indicate that within the coming 20–30 yr, the operation of planned hydropower reservoirs is likely to have a larger impact on the Mekong hydrograph than the impacts of climate change, particularly during the dry season. On the other hand, climate change will increase the uncertainty of the estimated hydropower impacts. Consequently, both dam planners and dam operators should pay better attention to the cumulative impacts of climate change and reservoir operation to the aquatic ecosystems, including the multibillion-dollar Mekong fisheries.

scholarly journals The impacts of climate change on water diversion strategies for a water deficit reservoir

2013 ◽  
Vol 16 (4) ◽  
pp. 872-889 ◽  
Author(s):  
Chi Zhang ◽  
Xueping Zhu ◽  
Guangtao Fu ◽  
Huicheng Zhou ◽  
Hao Wang
Keyword(s):  
Climate Change ◽  
General Circulation ◽  
General Circulation Models ◽  
Water Transfer ◽  
Water Levels ◽  
Water Diversion ◽  
Optimal Solutions ◽  
Nsga Ii ◽  
Conflicting Objectives ◽  
Impacts Of Climate Change

This paper presents an assessment framework that analyses the impacts of climate change on the water diversion strategies of a water transfer project in China. A water diversion strategy consists of high and low water levels as well as related diversion flows in four operating periods: pre-flood, flood, post-flood and non-flood periods. The optimal water diversion problem is defined as a multi-objective problem with two conflicting objectives: minimising human and ecological water supply shortages, and solved by the popular non-dominated sorting genetic algorithm II (NSGA-II). The derived Pareto-optimal solutions are then evaluated using the predicted runoffs based on an ensemble of three general circulation models under three climate scenarios. Results obtained from the study catchment show that intra-annual distribution of future runoff changes. The optimal solutions on the Pareto front have greatly varying performance under a climate scenario. It is critical to reveal the different impacts of climate change on the water shortages over the four operating periods, in particular when an increase of water shortage in one period is masked by a reduction in one or more periods. This study illustrates that the framework can be used to identify resilient water diversion strategies to mitigate the potential impacts of climate change on the operation of a water transfer project.

scholarly journals Climate change and agricultural productivity in Brazil: future perspectives

2016 ◽  
Vol 21 (5) ◽  
pp. 581-602 ◽  
Author(s):  
Juliano Assunção ◽  
Flávia Chein
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
General Circulation ◽  
Agricultural Productivity ◽  
General Circulation Models ◽  
Future Perspectives ◽  
Intergovernmental Panel ◽  
Cross Sectional ◽  
The Impact ◽  
Impacts Of Climate Change

AbstractThis paper evaluates the impact of climate change on agricultural productivity. Cross-sectional variation in climate among Brazilian municipalities is used to estimate an equation in which geographical attributes determine agricultural productivity. The Intergovernmental Panel on Climate Change (IPCC) predictions based on atmosphere–ocean, coupled with general circulation models (for 2030–2049), are used to simulate the impacts of climate change. Our estimates suggest that global warming under the current technological standards is expected to decrease the agricultural output per hectare in Brazil by 18 per cent, with the effects on municipalities ranging from−40 to+15 per cent.

scholarly journals Development of a SWAT Hydropower Operation Routine and Its Application to Assessing Hydrological Alterations in the Mekong

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2193
Author(s):  
Jayandra P. Shrestha ◽  
Markus Pahlow ◽  
Thomas A. Cochrane
Keyword(s):  
Climate Change ◽  
Reservoir Operation ◽  
General Circulation ◽  
Hydrological Model ◽  
Circulation Model ◽  
Climate Change Scenarios ◽  
Reservoir Operations ◽  
Reservoir Systems ◽  
Hydropower Operation ◽  
Impacts Of Climate Change

Reservoir operations and climate change can alter natural river flow regimes. To assess impacts of climate and hydropower operations on downstream flows and energy generation, an integrated hydropower operations and catchment hydrological model is needed. The widely used hydrological model Soil and Water Assessment Tool (SWAT) is ideal for catchment hydrology, but provides only limited reservoir operation functions. A hydropower reservoir operation routine (HydROR) was thus developed for SWAT to analyze complex reservoir systems under different policies. The Hydrologic Engineering Center’s Reservoir System Simulation (HEC-ResSim) model, a well-established reservoir simulation model, was used to indirectly evaluate functionality of the HydROR. A comparison between HydROR and HEC-ResSim under a range of operation rule curves resulted in R2 values exceeding 0.99. The HydROR was then applied to assess hydrological alterations due to combined impacts of climate change and reservoir operations of 38 hydropower dams in the 3S basin of the Mekong River. Hydropower production under climate change varied from −1.6% to 2.3%, depending on the general circulation model chosen. Changing the hydropower operation policy from maximizing energy production to maintaining ecological flows resulted in a production change of 13%. The calculation of hydrological alteration indices at the outlet of the 3S basin revealed that over 113% alteration in the natural river outflow regime occurred from the combined impacts of climate change and reservoir operations. Furthermore, seasonal flows and extreme water conditions changed by 154% and 104%, respectively. Alterations were also significant within the basin, and, as expected, were larger for high-head and small-river reservoirs. These alterations will adversely affect ecological dynamics, in particular, habitat availability. HydROR proved to be a valuable addition to SWAT for the analyses of complex reservoir systems under different policies and climate change scenarios.

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