scholarly journals Soybean photosynthetic and biomass responses to carbon dioxide concentrations ranging from pre-industrial to the distant future

2020 ◽  
Vol 71 (12) ◽  
pp. 3690-3700
Author(s):  
David W Drag ◽  
Rebecca Slattery ◽  
Matthew Siebers ◽  
Evan H DeLucia ◽  
Donald R Ort ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Climate Models ◽  
Positive Impact ◽  
Carbon Dioxide Concentration ◽  
C3 Plants ◽  
Carbon Gain ◽  
Case Scenario ◽  
Worst Case ◽  
C3 Plant ◽  
Co2 Levels

Abstract Increasing atmospheric carbon dioxide concentration ([CO2]) directly impacts C3 plant photosynthesis and productivity, and the rate at which [CO2] is increasing is greater than initially predicted by worst-case scenario climate models. Thus, it is increasingly important to assess the physiological responses of C3 plants, especially those that serve as important crops, to [CO2] beyond the mid-range levels used in traditional experiments. Here, we grew the C3 crop soybean (Glycine max) at eight different [CO2] levels spanning subambient (340 ppm) to the highest level thought plausible (~2000 ppm) in chambers for 5 weeks. Physiological development was delayed and plant height and total leaf area increased at [CO2] levels higher than ambient conditions, with very little difference in these parameters among the elevated [CO2] treatments >900 ppm. Daily photosynthesis initially increased with rising [CO2] but began to level off at ~1000 ppm CO2. Similar results occurred in biomass accumulation. Thus, as [CO2] continues to match or exceed the worst-case emission scenarios, these results indicate that carbon gain, growth, and potentially yield increases will diminish, thereby ultimately constraining the positive impact that continuing increases in atmospheric [CO2] could have on crop productivity and global terrestrial carbon sinks.

scholarly journals Effect of Carbon Dioxide Concentration on Cereal Yield in Sudan

2019 ◽  
Vol 5 ◽  
pp. 1
Author(s):  
Ibrahim A. Onour ◽  
Keyword(s):  
Carbon Dioxide ◽  
Positive Impact ◽  
Carbon Dioxide Concentration ◽  
Cointegration Analysis ◽  
Short Term ◽  
Time Duration ◽  
Yield Increase ◽  
Research Findings ◽  
Bound Test

To estimate the long-term effect of carbon dioxide (CO2) emission on cereal yield in Sudan, we employed an autoregressive distributed lagged (ARDL) bound test for cointegration analysis. The ARDL results reveal evidence of cointegration between the dependent variable (cereals yield) and two independent variables (CO2 emission) and agricultural GDP. The estimation results of the error correction model indicate that change in CO2 has a positive and significant impact on the cereal yield in the long and short terms, as 1% increase in CO2 leads to a cereal yield increase by 3% in the short term and by 0.7% in the long term. This result adds two important findings to the existing literature: First, the positive impact of CO2 on cereal yield in Sudan supports previous research findings in other countries of warm and arid climates. Second, the effect of CO2 on cereal yield differs from short to long term, as our finding indicates that CO2 has a greater positive effect in the short term compared to that in the long term, implying that the effect of CO2 on cereal yields is not linear, as commonly perceived, but it decreases as time duration extends to longer periods. This may be due to the CO2 effect on global warming that emanates from cumulative CO2 concentration, which leaves a disproportionate impact on crops over time.

scholarly journals Impact of Climate Change on the Hydrology of the Forested Watershed That Drains to Lake Erken in Sweden: An Analysis Using SWAT+ and CMIP6 Scenarios

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1803
Author(s):  
Inmaculada C. Jiménez-Navarro ◽  
Patricia Jimeno-Sáez ◽  
Adrián López-Ballesteros ◽  
Julio Pérez-Sánchez ◽  
Javier Senent-Aparicio
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Snow Water Equivalent ◽  
Hydrological Cycle ◽  
Global Climate ◽  
Water Discharge ◽  
Global Climate Models ◽  
Climate Change Scenarios ◽  
Case Scenario ◽  
Worst Case

Precipitation and temperature around the world are expected to be altered by climate change. This will cause regional alterations to the hydrological cycle. For proper water management, anticipating these changes is necessary. In this study, the basin of Lake Erken (Sweden) was simulated with the recently released software SWAT+ to study such alterations in a short (2026–2050), medium (2051–2075) and long (2076–2100) period, under two different climate change scenarios (SSP2-45 and SSP5-85). Seven global climate models from the latest projections of future climates that are available (CIMP 6) were compared and ensembled. A bias-correction of the models’ data was performed with five different methods to select the most appropriate one. Results showed that the temperature is expected to increase in the future from 2 to 4 °C, and precipitation from 6% to 20%, depending on the scenario. As a result, water discharge would also increase by about 18% in the best-case scenario and by 50% in the worst-case scenario, and the surface runoff would increase between 5% and 30%. The floods and torrential precipitations would also increase in the basin. This trend could lead to soil impoverishment and reduced water availability in the basin, which could damage the watershed’s forests. In addition, rising temperatures would result in a 65% reduction in the snow water equivalent at best and 92% at worst.

scholarly journals Predicting the diversion length of capillary barriers using steady state and transient state numerical modeling: case study of the Saint-Tite-des-Caps landfill final cover

2015 ◽  
Vol 52 (12) ◽  
pp. 2141-2148 ◽  
Author(s):  
Benoit Lacroix Vachon ◽  
Amir M. Abdolahzadeh ◽  
Alexandre R. Cabral
Keyword(s):  
Steady State ◽  
Numerical Simulations ◽  
Positive Impact ◽  
Protective Layer ◽  
Transient State ◽  
Capillary Barrier ◽  
Case Scenario ◽  
Worst Case ◽  
Seepage Rate ◽  
Final Covers

Covers with capillary barrier effect (CCBE) have already been proposed to meet regulatory requirements for landfill final covers. Modeling of CCBE can be a relatively complex and time-consuming task. Simpler, albeit conservative, design tools — such as steady state numerical analyses — can, in certain cases, be justified and have a positive impact in practice. In this study, numerical simulations were performed of the experimental CCBE constructed on the Saint-Tite-des-Caps landfill (Quebec). The CCBE consists of a capillary barrier, composed of sand and gravel, on top of which a layer of deinking by-products (DBP) was installed as a protective layer (also to control seepage). The addition of a protective layer over the infiltration control layer (such as a capillary barrier) is required in most jurisdictions. In many European countries, such as Germany and the Netherlands, a thick “recultivation” layer is required. The results of numerical simulations were compared with the in situ behaviour of the Saint-Tite CCBE as well as with analytical solutions. The effectiveness of the capillary barrier was assessed by quantifying the diversion length (DL), which reflects the lateral drainage capacity of the CCBE, i.e., the capacity to drain water laterally. Collection of the water that has drained laterally prevents seepage into the waste mass. This study shows that when the seepage rate reaching the top layer of the capillary barrier is controlled, it is possible to predict the worst-case scenario in terms of seepage (and therefore predict the shortest DL) using steady state numerical simulations. These simpler-to-perform numerical simulations could be adopted in practice, at least in a pre-feasibility study for cases with a similar profile as the one at the Saint-Tite-des-Caps experimental CCBE.

scholarly journals Impact of climate change on wintertime European atmospheric blocking

2021 ◽  
Author(s):  
Sara Bacer ◽  
Fatima Jomaa ◽  
Julien Beaumet ◽  
Hubert Gallée ◽  
Enzo Le Bouëdec ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Coupled Model ◽  
Atmospheric Blocking ◽  
Case Scenario ◽  
Worst Case ◽  
Impact Of Climate Change ◽  
Intercomparison Project ◽  
The Impact ◽  
Type Decomposition

Abstract. We study the impact of climate change on wintertime atmospheric blocking over Europe focusing on the frequency, duration, and extension of blocking events. These events are identified via the weather type decomposition (WTD) methodology applied on the output of climate models of the Coupled Model Intercomparison Project phase 6 (CMIP6). Historical simulations as well as two future scenarios, SSP2-4.5 and SSP5-8.5, are considered. The models are evaluated against the reanalysis and only a subset of climate models, which better represent the blocking weather regime in the recent-past climate, is considered for the analysis. We find that frequency and duration of blocking events remain relatively stationary over the 21st century. In order to quantify the extension of blocking events, we define a new methodology which relies on the WTD to identify blocking events. We show that the results are in agreement with previous studies that define blocking events with blocking indexes. We find that blocking extension will increase, especially in the worst-case scenario, due to a pressure increase driven by a thermodynamical warming during blocking events rather than atmospheric circulation changes.

scholarly journals The vulnerability of lakes to climate change along an altitudinal gradient

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Love Råman Vinnå ◽  
Iselin Medhaug ◽  
Martin Schmid ◽  
Damien Bouffard
Keyword(s):  
Altitudinal Gradient ◽  
Climate Models ◽  
Future Scenarios ◽  
Case Scenario ◽  
Worst Case ◽  
Lake Model ◽  
Atmospheric Phenomena ◽  
The Impact ◽  
Substantial Change ◽  
Mean Annual Air Temperature

AbstractStudies of future 21st century climate warming in lakes along altitudinal gradients have been partially obscured by local atmospheric phenomena unresolved in climate models. Here we forced the physical lake model Simstrat with locally downscaled climate models under three future scenarios to investigate the impact on 29 Swiss lakes, varying in size along an altitudinal gradient. Results from the worst-case scenario project substantial change at the end of the century in duration of ice-cover at mid to high altitude (−2 to −107 days), stratification duration (winter −17 to −84 days, summer −2 to 73 days), while lower and especially mid altitude (present day mean annual air temperature from 9 °C to 3 °C) dimictic lakes risk shift to monomictic regimes (seven out of the eight lakes). Analysis further indicates that for many lakes shifts in mixing regime can be avoided by adhering to the most stringent scenario.

scholarly journals Heavy Daily Precipitation Events in the CMIP6 Worst-Case Scenario: Projected Twenty-First-Century Changes

2020 ◽  
Vol 33 (17) ◽  
pp. 7631-7642 ◽  
Author(s):  
Enrico Scoccimarro ◽  
Silvio Gualdi
Keyword(s):  
Extreme Precipitation ◽  
Climate Models ◽  
Daily Precipitation ◽  
Case Scenario ◽  
Worst Case ◽  
Precipitation Distribution ◽  
Daily Precipitation Data ◽  
The Right ◽  
The Tropics ◽  
Emissions Scenario

AbstractHeavy precipitation is often the trigger for flooding and landslides, leading to significant societal and economic impacts, ranging from fatalities to damage to infrastructure to loss of crops and livestock. Therefore, it is critical that we have a better understanding of how it may be changing in the future. Based on model projections from phases 3 and 5 of the Coupled Model Intercomparison Project (CMIP3 and CMIP5), future daily precipitation is likely to increase in intensity. The main goal of this study is to examine possible improvements in the representation of intense and extreme precipitation by a new set of climate models contributing to phase 6 of CMIP effort (CMIP6) and to quantify its projected changes under the highest emissions scenario by the end of the current century [i.e., Shared Socioeconomic Pathway (SSP) SSP5-8.5]. Daily precipitation data from six CMIP6 models were analyzed that have a nominal horizontal grid spacing around 100 km and provide data for the highest emissions scenario SSP5-8.5. Two of the six CMIP6 models overestimate the extreme precipitation (defined as the 99th percentile of the precipitation distribution) in the tropics, leading to large biases in the right tail of the daily precipitation over the tropics. Consistent with the CMIP5 results, the CMIP6 models projected increased heavy daily precipitation and increased width of the right tail of the precipitation distribution associated with increased water vapor content.

scholarly journals Responses of the diatom <i>Asterionellopsis glacialis</i> to increasing sea water CO<sub>2</sub> concentrations and the effect of turbulence

2016 ◽  
Author(s):  
Francesca Gallo ◽  
Kai G. Schulz ◽  
Eduardo B. Azevedo ◽  
João Madruga ◽  
Joana Barcelos e Ramos
Keyword(s):  
Carbon Dioxide ◽  
Ocean Acidification ◽  
Growth Rates ◽  
Sea Water ◽  
Carbon Dioxide Concentration ◽  
Marine Phytoplankton ◽  
Surface Ocean ◽  
Phytoplankton Communities ◽  
Co2 Levels ◽  
Asterionellopsis Glacialis

Abstract. Emissions of greenhouse gases, such as carbon dioxide (CO2), are lead to increasing global and surface ocean temperatures. At the same time, as CO2 equilibrates between the atmosphere and the surface ocean, it decreases sea water pH. As a result, the changes in physical and chemical properties of the ocean can affect marine primary producers in various ways. A number of researches have addressed the effects of ocean acidification on marine phytoplankton. However, phytoplankton responses to combined effects are still poorly understood. Here, we chose monospecific cultures of the cosmopolitan chain forming diatom Asterionellopsis glacialis (A. glacialis), grown semi-continuously under controlled laboratory conditions, to assess the combined effect of ocean acidification (~ 420 to 2800 µatm) and turbulence. At current CO2 levels, growth rates of A. glacialis increased under enhanced turbulence. This was the result of an optimum shift towards lower CO2 concentrations and accompanied by a prevalence of longer chains (more than 6 cells). For increasing CO2 levels (up to ~ 2800 µatm) and decreased pH values, enhanced turbulence significantly decreased growth rates, chain length and organic matter production of A. glacialis. Thus, our study suggests that, even though A. glacialis benefited from enhanced turbulence, at present carbon dioxide concentration, at higher CO2 levels, turbulence magnified the stress by acidification. If in the future, the ocean surface layer will be more frequently exposed to storm and wind events, then phytoplankton communities might be more sensitive to lower pH, with potential consequences for community composition and productivity.

scholarly journals Analysis on Water use Efficiency of Populus Euphratica Forest Ecosystem in Arid Area

2021 ◽  
Author(s):  
Xue Lianqing ◽  
Fu Fangbing ◽  
Chen Xinfang ◽  
Liu Yuanhong ◽  
Han Qiang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Water Use Efficiency ◽  
Water Use ◽  
Forest Ecosystem ◽  
Populus Euphratica ◽  
Carbon Dioxide Concentration ◽  
Arid Area ◽  
Carbon Gain ◽  
Energy Fluxes ◽  
Use Efficiency

Abstract Water use efficiency (WUE, the ratio of gross primary productivity (GPP) to evapotranspiration (ET)) reflects the coupled relationship between water loss and carbon gain in the process of plant photosynthetic carbon assimilation. As a dominant tree species in arid area, Populus euphratica plays an important ecological role in slowing desertification. Here, continuous observations of carbon, water and energy fluxes were carried out in Populus euphratica forest with eddy covariance (EC) technique in 2018. We systematically explained the variation characteristics of energy fluxes and WUE at different time scales, and explored the main controlling factors of WUE in drought-stressed environment based on the synchronous meteorological data. Results showed that the carbon exchange of the Populus euphratica forest ecosystem occurred mainly during the growing seasons (April–October). During this period, the entire ecosystem appeared as a carbon sink with the potential to sequester atmospheric carbon dioxide. The average daily WUE was 2.2 g C/kg H2O, which was lower than other temperate forests (2.57–6.07 g C/kg H2O) but higher than grassland, wetland and cropland. We also concluded that an increase in carbon dioxide concentration (CCO2) and air relative humidity (RH) could promote the increase of WUE. Nevertheless, WUE was negatively correlated with air temperature (Ta), photosynthetically active radiation (PAR), and normalized difference vegetation index (NDVI). Additionally, WUE increased under moderate soil water content (SWC), but decreased due to the continuously rising SWC. WUE was more strongly affected by factors affecting water consumption than carbon uptake. Under the conditions of high temperature, strong radiation and low humidity in the summer, the growth rate of ET was much larger than that of GPP. This study not only contributes to our understanding of the carbon, water and energy dynamics of the Populus euphratica forest ecosystem but also provides an important reference for ecological conservation and ecological restoration in arid regions.

Reducing Probabilistic Weather Forecasts to the Worst Case Scenario: Anchoring Effects

2008 ◽  
Author(s):  
Sonia Savelli ◽  
Susan Joslyn ◽  
Limor Nadav-Greenberg ◽  
Queena Chen
Keyword(s):  
Case Scenario ◽  
Worst Case ◽  
Weather Forecasts ◽  
Worst Case Scenario ◽  
Anchoring Effects

Communication: Photoinduced Carbon Dioxide Binding with Surface-Functionalized Silicon Quantum Dots

2018 ◽  
Author(s):  
Oscar A. Douglas-Gallardo ◽  
Cristián Gabriel Sánchez ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Carbon Dioxide ◽  
Quantum Dots ◽  
Atmospheric Carbon Dioxide ◽  
Density Functional ◽  
Tight Binding ◽  
Carbon Dioxide Concentration ◽  
Research Area ◽  
Silicon Quantum Dots ◽  
Dependent Model ◽  
Photoinduced Charge

<div> <div> <div> <p>Nowadays, the search of efficient methods able to reduce the high atmospheric carbon dioxide concentration has turned into a very dynamic research area. Several environmental problems have been closely associated with the high atmospheric level of this greenhouse gas. Here, a novel system based on the use of surface-functionalized silicon quantum dots (sf -SiQDs) is theoretically proposed as a versatile device to bind carbon dioxide. Within this approach, carbon dioxide trapping is modulated by a photoinduced charge redistribution between the capping molecule and the silicon quantum dots (SiQDs). Chemical and electronic properties of the proposed SiQDs have been studied with Density Functional Theory (DFT) and Density Functional Tight-Binding (DFTB) approach along with a Time-Dependent model based on the DFTB (TD-DFTB) framework. To the best of our knowledge, this is the first report that proposes and explores the potential application of a versatile and friendly device based on the use of sf -SiQDs for photochemically activated carbon dioxide fixation. </p> </div> </div> </div>

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