Projecting thermal stratification and hypolimnetic oxygen conditions by coupling paleolimnological and 1D lake model approaches

2021 ◽  
Author(s):  
Jean-Philippe Jenny ◽  
Olivia Itier ◽  
Victor Frossard ◽  
David Etienne ◽  
Jean Guillard
Keyword(s):  
Climate Change ◽  
Thermal Regime ◽  
Thermal Stratification ◽  
Climatic Factors ◽  
Climate Data ◽  
The Past ◽  
Lake Model ◽  
Hypolimnetic Oxygen ◽  
The Future ◽  
Oxygen Conditions

<p>Climate change raises many questions about the future of lakes’ thermal regime and hypolimnetic oxygen conditions. One dimensional models have been widely implemented over that last years <sup>1–3</sup>, but most of these models are calibrated against very few years of limnological records, potentially limiting the robustness in long-term reconstructions and preventing inclusion of future scenarios. To analysis the variability and the effects of climate change on thermal regime and oxygen conditions of deep hard-water lakes, we relayed on paleolimnological records and 1D thermal lake model calibrated against time series of limnological data collected by the French Observatoire des LAcs (OLA). Continuous sediment records on four peri-alpine lakes (Lake Geneva, Lake Annecy, Lake Bourget and Lake Aiguebelette) were analysed using micro-XRF Mn-Fe ratio as proxy to infer near-annual trends of oxygen conditions for the past 300 years<sup>4</sup>. Past hypoxia dynamics were further inferred from varved records preserved in sediment cores<sup>5</sup>. General Lake Model (GLM), i.e. a 1-D modelling tool, has been constrained by climate data derived from meteorological observations and CMIP6 simulations in order to reconstruct and forcast stratification regims for the next century. Our paleolimnological results show that fluctuations in hypoxic volumes since the 1950s were great and that these fluctuations were essentially driven by climatic factors, legitimating the use of thermal model approaches for future projections of hypolimnetic oxygen conditions. In this line, thermal regime simulations based on GLM forecast an intensification in thermal stratification and an increase in volumes of water warmer than 9°C over the period 1850-2100 with potential consequence for hypolimnetic oxygen conditions and ecological habitats. Coupling model and paleolimnological approaches seem a promising way to examine the evolution of lakes in the past, and to realistically anticipate the future of lakes for the next decades.</p>

scholarly journals Artificial Neural Network to Estimate the Paddy Yield Prediction Using Climatic Data

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Vinushi Amaratunga ◽  
Lasini Wickramasinghe ◽  
Anushka Perera ◽  
Jeevani Jayasinghe ◽  
Upaka Rathnayake
Keyword(s):  
Neural Network ◽  
Climate Change ◽  
Climatic Factors ◽  
Computational Time ◽  
Training Algorithm ◽  
Climate Data ◽  
Nonlinear Relationships ◽  
The Future ◽  
Artificial Neural ◽  
Paddy Yield

Paddy harvest is extremely vulnerable to climate change and climate variations. It is a well-known fact that climate change has been accelerated over the past decades due to various human induced activities. In addition, demand for the food is increasing day-by-day due to the rapid growth of population. Therefore, understanding the relationships between climatic factors and paddy production has become crucial for the sustainability of the agriculture sector. However, these relationships are usually complex nonlinear relationships. Artificial Neural Networks (ANNs) are extensively used in obtaining these complex, nonlinear relationships. However, these relationships are not yet obtained in the context of Sri Lanka; a country where its staple food is rice. Therefore, this research presents an attempt in obtaining the relationships between the paddy yield and climatic parameters for several paddy grown areas (Ampara, Batticaloa, Badulla, Bandarawela, Hambantota, Trincomalee, Kurunegala, and Puttalam) with available data. Three training algorithms (Levenberg–Marquardt (LM), Bayesian Regularization (BR), and Scaled Conjugated Gradient (SCG)) are used to train the developed neural network model, and they are compared against each other to find the better training algorithm. Correlation coefficient (R) and Mean Squared Error (MSE) were used as the performance indicators to evaluate the performance of the developed ANN models. The results obtained from this study reveal that LM training algorithm has outperformed the other two algorithms in determining the relationships between climatic factors and paddy yield with less computational time. In addition, in the absence of seasonal climate data, annual prediction process is understood as an efficient prediction process. However, the results reveal that there is an error threshold in the prediction. Nevertheless, the obtained results are stable and acceptable under the highly unpredicted climate scenarios. The ANN relationships developed can be used to predict the future paddy yields in corresponding areas with the future climate data from various climate models.

scholarly journals Warm climates of the past—a lesson for the future?

2013 ◽  
Vol 371 (2001) ◽  
pp. 20130146 ◽  
Author(s):  
D. J. Lunt ◽  
H. Elderfield ◽  
R. Pancost ◽  
A. Ridgwell ◽  
G. L. Foster ◽  
...  
Keyword(s):  
Climate Change ◽  
Numerical Models ◽  
Future Climate ◽  
Future Climate Change ◽  
Climate Data ◽  
Comprehensive Overview ◽  
Past Climate ◽  
The Past ◽  
The Future ◽  
Warm Climates

This Discussion Meeting Issue of the Philosophical Transactions A had its genesis in a Discussion Meeting of the Royal Society which took place on 10–11 October 2011. The Discussion Meeting, entitled ‘Warm climates of the past: a lesson for the future?’, brought together 16 eminent international speakers from the field of palaeoclimate, and was attended by over 280 scientists and members of the public. Many of the speakers have contributed to the papers compiled in this Discussion Meeting Issue. The papers summarize the talks at the meeting, and present further or related work. This Discussion Meeting Issue asks to what extent information gleaned from the study of past climates can aid our understanding of future climate change. Climate change is currently an issue at the forefront of environmental science, and also has important sociological and political implications. Most future predictions are carried out by complex numerical models; however, these models cannot be rigorously tested for scenarios outside of the modern, without making use of past climate data. Furthermore, past climate data can inform our understanding of how the Earth system operates, and can provide important contextual information related to environmental change. All past time periods can be useful in this context; here, we focus on past climates that were warmer than the modern climate, as these are likely to be the most similar to the future. This introductory paper is not meant as a comprehensive overview of all work in this field. Instead, it gives an introduction to the important issues therein, using the papers in this Discussion Meeting Issue, and other works from all the Discussion Meeting speakers, as exemplars of the various ways in which past climates can inform projections of future climate. Furthermore, we present new work that uses a palaeo constraint to quantitatively inform projections of future equilibrium ice sheet change.

scholarly journals Application of SWAT in Hydrological Simulation of Complex Mountainous River Basin (Part II: Climate Change Impact Assessment)

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1548
Author(s):  
Suresh Marahatta ◽  
Deepak Aryal ◽  
Laxmi Prasad Devkota ◽  
Utsav Bhattarai ◽  
Dibesh Shrestha
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Climate Models ◽  
Assessment Tool ◽  
Swat Model ◽  
Global Climate Models ◽  
Climate Data ◽  
The Future ◽  
The Impact ◽  
Mountainous River

This study aims at analysing the impact of climate change (CC) on the river hydrology of a complex mountainous river basin—the Budhigandaki River Basin (BRB)—using the Soil and Water Assessment Tool (SWAT) hydrological model that was calibrated and validated in Part I of this research. A relatively new approach of selecting global climate models (GCMs) for each of the two selected RCPs, 4.5 (stabilization scenario) and 8.5 (high emission scenario), representing four extreme cases (warm-wet, cold-wet, warm-dry, and cold-dry conditions), was applied. Future climate data was bias corrected using a quantile mapping method. The bias-corrected GCM data were forced into the SWAT model one at a time to simulate the future flows of BRB for three 30-year time windows: Immediate Future (2021–2050), Mid Future (2046–2075), and Far Future (2070–2099). The projected flows were compared with the corresponding monthly, seasonal, annual, and fractional differences of extreme flows of the simulated baseline period (1983–2012). The results showed that future long-term average annual flows are expected to increase in all climatic conditions for both RCPs compared to the baseline. The range of predicted changes in future monthly, seasonal, and annual flows shows high uncertainty. The comparative frequency analysis of the annual one-day-maximum and -minimum flows shows increased high flows and decreased low flows in the future. These results imply the necessity for design modifications in hydraulic structures as well as the preference of storage over run-of-river water resources development projects in the study basin from the perspective of climate resilience.

scholarly journals Impact of climate change and human activity on the runoff in the upper reaches of the Shiyang River, Northwest China

2014 ◽  
Author(s):  
Peng Li ◽  
Jianhua Xu ◽  
Zhongsheng Chen ◽  
Benfu Zhao
Keyword(s):  
Climate Change ◽  
Human Activity ◽  
Climatic Factors ◽  
Meteorological Data ◽  
Northwest China ◽  
Potential Evaporation ◽  
The Past ◽  
Shiyang River Basin ◽  
Runoff Change ◽  
Increasing Trend

Based on the hydrological and meteorological data of the upper reaches of Shiyang River basin in Northwest China from 1960 to 2009, this paper analyzed the change in runoff and its related climatic factors, and estimated the contribution of climate change and human activity to runoff change by using the moving T test, cumulative analysis of anomalies and multiple regression analysis. The results showed that temperature revealed a significant increasing trend, and potential evaporation capacity decreased significantly, while precipitation increased insignificantly in the past recent 50 years. Although there were three mutations in 1975, 1990 and 2002 respectively, runoff presented a slight decreasing trend in the whole period. The contributions of climate change and human activity to runoff change during the period of 1976-2009 were 45% and 55% respectively.

The past and future of human rights

2021 ◽  
pp. 183-224
Author(s):  
Gráinne de Búrca
Keyword(s):  
Climate Change ◽  
Social Support ◽  
Human Rights ◽  
Social Movements ◽  
The Past ◽  
Human Rights Movement ◽  
The Future ◽  
Human Rights Advocacy ◽  
Advocacy Campaigns

This chapter reflects on the lessons to be derived from the advocacy campaigns in Pakistan, Argentina, and Ireland discussed in earlier chapters. Insights drawn from those campaigns are used to refine the experimentalist account of human rights advanced in Chapter 2, particularly as regards the importance of social movements and of building broad social support for human rights campaigns. The remainder of the chapter describes five major challenges of the current era—illiberalism, climate change, digitalization, pandemics, and inequality—and considers the difficulties they pose for the experimentalist account of human rights advocacy. It argues that the experimentalist practice of human rights advocacy is reasonably resilient and adaptive, and that internal contestation from within the human rights movement as well as external critiques have already helped to catalyze reform and to push activists and advocates to think more innovatively about the changes needed to strengthen the ability of the movement to engage with these major challenges in the future. It concludes that in a turbulent era, rather than abandon human rights, we should redouble our efforts to bolster, renew, and reinvigorate a movement that has galvanized constituencies and communities around the globe to mobilize for a better world.

Epilogue

2016 ◽  
pp. 119-122
Author(s):  
Christian W. McMillen
Keyword(s):  
Public Health ◽  
Climate Change ◽  
Lessons Learned ◽  
The Past ◽  
Public Health Infrastructure ◽  
Health Infrastructure ◽  
The World ◽  
The Future ◽  
The Face ◽  
New Challenges

There will be more pandemics. A pandemic might come from an old, familiar foe such as influenza or might emerge from a new source—a zoonosis that makes its way into humans, perhaps. The epilogue asks how the world will confront pandemics in the future. It is likely that patterns established long ago will re-emerge. But how will new challenges, like climate change, affect future pandemics and our ability to respond? Will lessons learned from the past help with plans for the future? One thing is clear: in the face of a serious pandemic much of the developing world’s public health infrastructure will be woefully overburdened. This must be addressed.

Indigenous science (fiction) for the Anthropocene: Ancestral dystopias and fantasies of climate change crises

2018 ◽  
Vol 1 (1-2) ◽  
pp. 224-242 ◽  
Author(s):  
Kyle P. Whyte
Keyword(s):  
Climate Change ◽  
Science Fiction ◽  
Indigenous Peoples ◽  
Viewing Time ◽  
The Past ◽  
The Future ◽  
Parallel Universes ◽  
Indigenous Perspectives ◽  
Colonial Violence ◽  
Climate Crisis

Portrayals of the Anthropocene period are often dystopian or post-apocalyptic narratives of climate crises that will leave humans in horrific science-fiction scenarios. Such narratives can erase certain populations, such as Indigenous peoples, who approach climate change having already been through transformations of their societies induced by colonial violence. This essay discusses how some Indigenous perspectives on climate change can situate the present time as already dystopian. Instead of dread of an impending crisis, Indigenous approaches to climate change are motivated through dialogic narratives with descendants and ancestors. In some cases, these narratives are like science fiction in which Indigenous peoples work to empower their own protagonists to address contemporary challenges. Yet within literature on climate change and the Anthropocene, Indigenous peoples often get placed in historical categories designed by nonIndigenous persons, such as the Holocene. In some cases, these categories serve as the backdrop for allies' narratives that privilege themselves as the protagonists who will save Indigenous peoples from colonial violence and the climate crisis. I speculate that this tendency among allies could possibly be related to their sometimes denying that they are living in times their ancestors would have likely fantasized about. I will show how this denial threatens allies' capacities to build coalitions with Indigenous peoples. Inuit culture is based on the ice, the snow and the cold…. It is the speed and intensity in which change has occurred and continues to occur that is a big factor why we are having trouble with adapting to certain situations. Climate change is yet another rapid assault on our way of life. It cannot be separated from the first waves of changes and assaults at the very core of the human spirit that have come our way. Just as we are recognizing and understanding the first waves of change … our environment and climate now gets threatened. Sheila Watt-Cloutier, interviewed by the Ottawa Citizen. (Robb, 2015) In North America many Indigenous traditions tell us that reality is more than just facts and figures collected so that humankind might widely use resources. Rather, to know “it”—reality—requires respect for the relationships and relatives that constitute the complex web of life. I call this Indigenous realism, and it entails that we, members of humankind, accept our inalienable responsibilities as members of the planet's complex life system, as well as our inalienable rights. ( Wildcat, 2009 , xi) Within Māori ontological and cosmological paradigms it is impossible to conceive of the present and the future as separate and distinct from the past, for the past is constitutive of the present and, as such, is inherently reconstituted within the future. (Stewart-Harawira, 2005, 42) In fact, incorporating time travel, alternate realities, parallel universes and multiverses, and alternative histories is a hallmark of Native storytelling tradition, while viewing time as pasts, presents, and futures that flow together like currents in a navigable stream is central to Native epistemologies. ( Dillon, 2016a , 345)

Climate change, cocoa migrations and deforestation in West Africa: What does the past tell us about the future?

2014 ◽  
Vol 10 (1) ◽  
pp. 101-111 ◽  
Author(s):  
François Ruf ◽  
Götz Schroth ◽  
Kone Doffangui
Keyword(s):  
Climate Change ◽  
West Africa ◽  
The Past ◽  
The Future

scholarly journals Dynamics of Vegetation Greenness and Its Response to Climate Change in Xinjiang over the Past Two Decades

2021 ◽  
Vol 13 (20) ◽  
pp. 4063
Author(s):  
Jie Xue ◽  
Yanyu Wang ◽  
Hongfen Teng ◽  
Nan Wang ◽  
Danlu Li ◽  
...  
Keyword(s):  
Climate Change ◽  
Vegetation Change ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Dynamic Change ◽  
Google Earth ◽  
Arid Areas ◽  
Climate Data ◽  
Northern Margin ◽  
The Past

Climate change has proven to have a profound impact on the growth of vegetation from various points of view. Understanding how vegetation changes and its response to climatic shift is of vital importance for describing their mutual relationships and projecting future land–climate interactions. Arid areas are considered to be regions that respond most strongly to climate change. Xinjiang, as a typical dryland in China, has received great attention lately for its unique ecological environment. However, comprehensive studies examining vegetation change and its driving factors across Xinjiang are rare. Here, we used the remote sensing datasets (MOD13A2 and TerraClimate) and data of meteorological stations to investigate the trends in the dynamic change in the Normalized Difference Vegetation Index (NDVI) and its response to climate change from 2000 to 2019 across Xinjiang based on the Google Earth platform. We found that the increment rates of growth-season mean and maximum NDVI were 0.0011 per year and 0.0013 per year, respectively, by averaging all of the pixels from the region. The results also showed that, compared with other land use types, cropland had the fastest greening rate, which was mainly distributed among the northern Tianshan Mountains and Southern Junggar Basin and the northern margin of the Tarim Basin. The vegetation browning areas primarily spread over the Ili River Valley where most grasslands were distributed. Moreover, there was a trend of warming and wetting across Xinjiang over the past 20 years; this was determined by analyzing the climate data. Through correlation analysis, we found that the contribution of precipitation to NDVI (R2 = 0.48) was greater than that of temperature to NDVI (R2 = 0.42) throughout Xinjiang. The Standardized Precipitation and Evapotranspiration Index (SPEI) was also computed to better investigate the correlation between climate change and vegetation growth in arid areas. Our results could improve the local management of dryland ecosystems and provide insights into the complex interaction between vegetation and climate change.

scholarly journals Temperature and rainfall estimates for past 18 000 years in Owens Valley, California with a coupled catchment–lake model

2015 ◽  
Vol 12 (7) ◽  
pp. 6505-6539 ◽  
Author(s):  
Z. Yu ◽  
W. Dong ◽  
P. Jiang
Keyword(s):  
General Circulation ◽  
Regional Climate ◽  
Circulation Model ◽  
Climate Data ◽  
Owens Valley ◽  
Climatic Fluctuations ◽  
Closed Basin ◽  
The Past ◽  
Lake Model ◽  
Physically Based

Abstract. Closed-basin lakes are intricately linked to the hydrological systems and are very sensitive recorders of local hydro-climatic fluctuations. Lake records in closed-basins are usually used to investigate the paleoclimate condition which is critical for understanding the past and predicting the future. In this study, a physically based catchment–lake model was developed to extract quantitative paleoclimate information including temperature and rainfall over the past 18 000 years (ka) from lake records in a hydrologically closed basin in the Owens River Valley, California, US. The initial model inputs were prepared based on current regional climate data, boundary conditions from the General Circulation Model, and fossil proxy data. The inputs subsequently were systematically varied in order to produce the observed lake levels. In this way, a large number of possible paleoclimatic combinations can quickly narrow the possible range of paleoclimatic combinations that could have produced the paleolake level and extension. Finally, a quantitative time-series of paleoclimate information for those key times was obtained.

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