scholarly journals Modelling the impact of prescribed global warming on runoff from headwater catchments of the Irrawaddy River and their implications for the water level regime of Loktak Lake, northeast India

2010 ◽  
Vol 14 (9) ◽  
pp. 1745-1765 ◽  
Author(s):  
C. R. Singh ◽  
J. R. Thompson ◽  
J. R. French ◽  
D. G. Kingston ◽  
A. W. Mackay

Abstract. Climate change is likely to have major implications for wetland ecosystems, which will include altered water level regimes due to modifications in local and catchment hydrology. However, substantial uncertainty exists in the precise impacts of climate change on wetlands due in part to uncertainty in GCM projections. This paper explores the impacts of climate change upon river discharge within three sub-catchments of Loktak Lake, an internationally important wetland in northeast India. This is achieved by running pattern-scaled GCM output through distributed hydrological models (developed using MIKE SHE) of each sub-catchment. The impacts of climate change upon water levels within Loktak Lake are subsequently investigated using a water balance model. Two groups of climate change scenarios are investigated. Group 1 uses results from seven different GCMs for an increase in global mean temperature of 2 °C, the purported threshold of ''dangerous'' climate change, whilst Group 2 is based on results from the HadCM3 GCM for increases in global mean temperature between 1 °C and 6 °C. Results from the Group 1 scenarios show varying responses between the three sub-catchments. The majority of scenario-sub-catchment combinations (13 out of 21) indicate increases in discharge which vary from <1% to 42% although, in some cases, discharge decreases by as much as 20%. Six of the GCMs suggest overall increases in river flow to Loktak Lake (2–27%) whilst the other results in a modest (6%) decline. In contrast, the Group 2 scenarios lead to an almost linear increase in total river flow to Loktak Lake with increasing temperature (up to 27% for 6 °C), although two sub-catchments experience reductions in mean discharge for the smallest temperature increases. In all but one Group 1 scenario, and all the Group 2 scenarios, Loktak Lake water levels are higher, regularly reaching the top of a downstream hydropower barrage that impounds the lake and necessitating the release of water for barrage structural stability. Although elevated water levels may permit enhanced abstraction for irrigation and domestic uses, future increases in hydropower generation are limited by existing infrastructure. The higher water levels are likely to exacerbate existing ecological deterioration within the lake as well as enhancing problems of flooding of lakeside communities.

2010 ◽  
Vol 7 (3) ◽  
pp. 2781-2828 ◽  
Author(s):  
C. R. Singh ◽  
J. R. Thompson ◽  
J. R. French ◽  
D. G. Kingston ◽  
A. W. Mackay

Abstract. Climate change is likely to have major implications for wetland ecosystems, which will include altered water level regimes due to modifications in local and catchment hydrology. However, substantial uncertainty exists in the precise impacts of climate change on wetlands due in part due to uncertainty in GCM projections. This paper explores the impacts of climate change upon river discharge within three sub-catchments of Loktak Lake, an internationally important wetland in northeast India. This is achieved by running pattern-scaled GCM output through distributed hydrological models (developed using MIKE SHE) of each sub-catchment. The impacts of climate change upon water levels within Loktak Lake are subsequently investigated using a water balance model. Two groups of climate change scenarios are investigated. Group 1 uses results from seven different GCMs for an increase in global mean temperature of 2 °C, the purported threshold of "dangerous" climate change, whilst Group 2 is based on results from the HadCM3 GCM for increases in global mean temperature between 1 °C and 6 °C. Results from the Group 1 scenarios show varying responses between the three sub-catchments. The majority of scenario-sub-catchment combinations (13 out of 21) indicate increases in discharge which vary from <1% to 42% although, in some cases, discharge decreases by as much as 20%. Six of the GCMs suggest overall increases in river flow to Loktak Lake (2–27%) whilst the other results in a modest (6%) decline. In contrast, the Group 2 scenarios lead to an almost linear increase in total river flow to Loktak Lake with increasing temperature (up to 27% for 6 °C), although two sub-catchments experience reductions in mean discharge for the smallest temperature increases. In all but one Group 1 scenario, and all the Group 2 scenarios, Loktak Lake water levels are higher, regularly reaching the top of a downstream hydropower barrage that impounds the lake and necessitating the release of water for barrage structural stability. Although elevated water levels may permit enhanced abstraction for irrigation and domestic uses, future increases in hydropower generation are limited by existing infrastructure. The higher water levels are likely to exacerbate existing ecological deterioration within the lake as well as enhancing problems of flooding of lakeside communities.


2010 ◽  
Vol 106 (2) ◽  
pp. 141-177 ◽  
Author(s):  
Rachel Warren ◽  
Jeff Price ◽  
Andreas Fischlin ◽  
Santiago de la Nava Santos ◽  
Guy Midgley

2019 ◽  
Author(s):  
Champak Bhakat

In order to decide the optimum time of grazing for camels during hot summer months, 10 growing camel calveswere divided into 2 equal groups. First group was sent for grazing during 10:00 h to 16:00 h daily and second groupallowed for grazing during thermo neutral period. The climatic variables were recorded daily (April 2012 to March2013). The average daily gain and total body weight gain in calves sent for grazing during relatively cool parts ofday (group 2) was significantly higher as compared to group 1 calves sent as per routine farm schedule. Theaverage intake of fodder and water from manger was higher in group 1 calves. The average DMI from manger forgroup 1 calves was higher as compared to group 2 calves. The comparative biometrics of camel calves in differentgrazing management practices revealed that body length, heart girth, height at wither, neck length were significantly(P&lt;0.01) higher in group 2 calves as compared to group 1 calves. After 180 days of experimentation, humpcircumference vertical and hind leg length were significantly (P&lt;0.05) increased in group 2 as compared to group1. Analysis of recorded data of climatic parameters revealed that average maximum temperature was higher duringJune 2012. The values of THI also were higher in monsoon and post monsoon months hence the practice of sendingcamel calves during relatively comfortable part of hot and hot humid months was successful in getting good growth.The relative humidity was significantly higher during morning as compared to evening period for all months. TheTHI was significantly lower during morning as compared to evening hours for all months in different climate forwhole year. Economic analysis reveals that the cost of feed per kg body weight gain was quite less in group 2 ascompared to group 1. So the practice of grazing of camel calves during cool hours of day remain profitable forfarmers by looking at the body weight gain and better body conformation in climate change condition.


Author(s):  
Annalisa Savaresi

This chapter discusses how international law has responded to climate change, focusing on the challenges that have faced implementation of existing climate treaties, and on the suitability of the Paris Agreement to address these. Expectations of this new treaty could scarcely be greater: the Paris Agreement is meant to provide a framework to improve international cooperation on climate change, and to keep the world within the global mean temperature-change goal identified by scientists as safe. Yet, whether and how this important objective will be reached largely depends, on the one hand, on the supporting political will and, on the other, on the redesign of the international architecture for climate governance. This chapter specifically reflects on international law-making and on the approach to climate change governance embedded in the Paris Agreement, drawing inferences from the past, to make predictions on what the future may hold for international climate change law.


Science ◽  
2007 ◽  
Vol 318 (5850) ◽  
pp. 629-632 ◽  
Author(s):  
Gerard H. Roe ◽  
Marcia B. Baker

Uncertainties in projections of future climate change have not lessened substantially in past decades. Both models and observations yield broad probability distributions for long-term increases in global mean temperature expected from the doubling of atmospheric carbon dioxide, with small but finite probabilities of very large increases. We show that the shape of these probability distributions is an inevitable and general consequence of the nature of the climate system, and we derive a simple analytic form for the shape that fits recent published distributions very well. We show that the breadth of the distribution and, in particular, the probability of large temperature increases are relatively insensitive to decreases in uncertainties associated with the underlying climate processes.


2020 ◽  
Vol 12 (9) ◽  
pp. 3737
Author(s):  
Osamu Nishiura ◽  
Makoto Tamura ◽  
Shinichiro Fujimori ◽  
Kiyoshi Takahashi ◽  
Junya Takakura ◽  
...  

Coastal areas provide important services and functions for social and economic activities. Damage due to sea level rise (SLR) is one of the serious problems anticipated and caused by climate change. In this study, we assess the global economic impact of inundation due to SLR by using a computable general equilibrium (CGE) model that incorporates detailed coastal damage information. The scenario analysis considers multiple general circulation models, socioeconomic assumptions, and stringency of climate change mitigation measures. We found that the global household consumption loss proportion will be 0.045%, with a range of 0.027−0.066%, in 2100. Socioeconomic assumptions cause a difference in the loss proportion of up to 0.035% without greenhouse gas (GHG) emissions mitigation, the so-called baseline scenarios. The range of the loss proportion among GHG emission scenarios is smaller than the differences among the socioeconomic assumptions. We also observed large regional variations and, in particular, the consumption losses in low-income countries are, relatively speaking, larger than those in high-income countries. These results indicate that, even if we succeed in stabilizing the global mean temperature increase below 2 °C, economic losses caused by SLR will inevitably happen to some extent, which may imply that keeping the global mean temperature increase below 1.5 °C would be worthwhile to consider.


2019 ◽  
Author(s):  
Inne Vanderkelen ◽  
Jakob Zschleischler ◽  
Lukas Gudmundsson ◽  
Klaus Keuler ◽  
Francois Rineau ◽  
...  

Abstract. Ecotron facilities allow accurate control of many environmental variables coupled with extensive monitoring of ecosystem processes. They therefore require multivariate perturbation of climate variables, close to what is observed in the field and projections for the future, preserving the co-variances between variables and the projected changes in variability. Here we present a new experimental design for studying climate change impacts on terrestrial ecosystems and apply it to the UHasselt Ecotron Experiment. The new methodology consists of generating climate forcing along a gradient representative of increasingly high global mean temperature anomalies and uses data derived from the best available regional climate model (RCM) projection. We first identified the best performing regional climate model (RCM) simulation for the ecotron site from the Coordinated Regional Downscaling Experiment in the European Domain (EURO-CORDEX) ensemble with a 0.11° (12.5 km) resolution based on two criteria: (i) highest skill of the simulations compared to observations from a nearby weather station and (ii) representativeness of the multi-model mean in future projections. Our results reveal that no single RCM simulation has the best score for all possible combinations of the four meteorological variables and evaluation metrics considered. Out of the six best performing simulations, we selected the simulation with the lowest bias for precipitation (CCLM4-8-17/EC-EARTH), as this variable is key to ecosystem functioning and model simulations deviated the most for this variable, with values ranging up to double the observed values. The time window is subsequently selected from the RCM projection for each ecotron unit based on the global mean temperature of the driving Global Climate Model (GCM). The ecotron units are forced with 3-hourly output from the RCM projections of the five-year period spanning the year in which the global mean temperature crosses the predefined values. With the new approach, Ecotron facilities become able to assess ecosystem responses on changing climatic conditions, while accounting for the co-variation between climatic variables and their projection in variability, well representing possible compound events. The gradient approach will allow to identify possible threshold and tipping points.


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