scholarly journals Simulating Long-Term Development of Greenhouse Gas Emissions, Plant Biomass, and Soil Moisture of a Temperate Grassland Ecosystem under Elevated Atmospheric CO2

Agronomy ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 50
Author(s):  
Ralf Liebermann ◽  
Lutz Breuer ◽  
Tobias Houska ◽  
David Kraus ◽  
Gerald Moser ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Elevated Co2 ◽  
Biomass Production ◽  
Atmospheric Co2 ◽  
N2o Emissions ◽  
Gas Emissions ◽  
Co2 Concentrations

The rising atmospheric CO2 concentrations have effects on the worldwide ecosystems such as an increase in biomass production as well as changing soil processes and conditions. Since this affects the ecosystem’s net balance of greenhouse gas emissions, reliable projections about the CO2 impact are required. Deterministic models can capture the interrelated biological, hydrological, and biogeochemical processes under changing CO2 concentrations if long-term observations for model testing are provided. We used 13 years of data on above-ground biomass production, soil moisture, and emissions of CO2 and N2O from the Free Air Carbon dioxide Enrichment (FACE) grassland experiment in Giessen, Germany. Then, the LandscapeDNDC ecosystem model was calibrated with data measured under current CO2 concentrations and validated under elevated CO2. Depending on the hydrological conditions, different CO2 effects were observed and captured well for all ecosystem variables but N2O emissions. Confidence intervals of ensemble simulations covered up to 96% of measured biomass and CO2 emission values, while soil water content was well simulated in terms of annual cycle and location-specific CO2 effects. N2O emissions under elevated CO2 could not be reproduced, presumably due to a rarely considered mineralization process of organic nitrogen, which is not yet included in LandscapeDNDC.

scholarly journals Ecosystem feedbacks from subarctic wetlands: vegetative and atmospheric CO<sub>2</sub> controls on greenhouse gas emissions

2016 ◽  
Author(s):  
Matthew J. Bridgman ◽  
Barry H. Lomax ◽  
Sofie Sjogersten
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Elevated Co2 ◽  
Atmospheric Co2 ◽  
Carbon Substrate ◽  
Total Biomass ◽  
Growth Responses ◽  
Gas Emissions ◽  
Ch4 Emissions ◽  
Species Specific

Abstract. Wetland vegetation provide strong controls on greenhouse gas fluxes but impacts of elevated atmospheric carbon dioxide (CO2) levels on greenhouse gas emissions from wetlands are poorly understood. This study aims to investigate if elevated atmospheric CO2 enhance methane (CH4) emissions from subarctic wetlands and to determine if responses are comparable or species specific within the Cyperaceae, an important group of artic wetland plants. To achieve this we carried out a combined field and laboratory investigation to measure of CO2 and CH4 fluxes. The wetland was a CH4 source with comparable fluxes from areas with and without vegetation and across the different sedge communities. In contrast, the net ecosystem exchange of CO2 differed with sedge species. Within the laboratory experiment plants grown at double ambient (800 ppm) CO2, total biomass of Eriophorum vaginatum and Carex brunnescens increased, whereas the total biomass of E. angustifolium and C. acuta decreased, compared to the control (400 ppm CO2). These changes in biomass were associated with corresponding changes in CH4 flux. E. vaginatum and C. brunnescens mesocosms produced more CH4 when grown in 800 ppm atmospheric CO2 when compared to 400 ppm CO2 with E. angustifolium and C. acuta producing less. Additionally, redox potential and carbon substrate availability in the pore water differed among the plant treatments and in response to the elevated CO2 treatment. Together, this suggests species specific controls of CH4 emissions in response to elevated CO2, which facilitate differential plant growth responses and modification of the rhizosphere environments. Our study highlights species composition as an important control of greenhouse gas feedbacks in a CO2 rich future, which need to be considered in models aiming to predict how ecosystems respond to climate change.

scholarly journals Agricultural Greenhouse Gas Emissions in a Data-Scarce Region Using a Scenario-Based Modeling Approach: A Case Study in Southeastern USA

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1323
Author(s):  
Mahnaz Afroz ◽  
Runwei Li ◽  
Gang Chen ◽  
Aavudai Anandhi
Keyword(s):  
Climate Change ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Atmospheric Co2 ◽  
Similar Data ◽  
Validation Data ◽  
Gas Emissions ◽  
Southeastern Usa ◽  
Co2 Concentrations ◽  
Atmospheric Co2 Concentrations

Climate change may impact agricultural greenhouse gas emissions (GHGs) and yields under higher temperatures, higher atmospheric CO2 concentrations, and variable precipitations. This calls for adaptation strategies to optimize agricultural productions with minimal GHGs. This study aimed to identify these optimum agricultural managements in response to current and projected climatic scenarios for the Choctawhatchee Basin in Southeastern USA, an experimentally unexplored data-scarce region lacking validation data. This scenario-based modeling study analyzed a total of 1344 scenarios consisting of four major crops, eight managements (varying tillage, manuring, and residue), and forty climatic combinations under current as wells as two representative concentration pathways with process-based Denitrification and Decomposition (DNDC) model. The results indicated that the region’s GHGs and yields were most affected by higher temperatures (≥+3 °C) and extreme precipitation changes (≥±40%), while high atmospheric CO2 concentrations exerted positive fertilization effects. The manure-related and higher residue incorporation scenarios were found to be better options in varying climates with minimal present global warming potentials (GWP) of 0.23 k to −29.1 k MT equivalent CO2. As such, the study presented climate change impacts and potential mitigation options in the study region while presenting a framework to design GHG mitigation in similar data-scarce regions.

scholarly journals Modelling dynamics of emission of greenhouse gases (CO2, N2O) from soils in agroecosystems

2021 ◽  
Keyword(s):  
Soil Moisture ◽  
Greenhouse Gases ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
N2o Emission ◽  
Integrated Model ◽  
N2o Emissions ◽  
Gas Emissions ◽  
Co2 Flow ◽  
Emission Of Greenhouse Gases

Problem formulation. One of the main factors affecting climate change is the greenhouse effect conditioned by adding greenhouse gases to the atmosphere, among which CO2, CH4 and N2O are the most dangerous heat-trapping gases. In addition to anthropogenic activities, the source of greenhouse gases is emissions from natural ecosystems and agroecosystems. Carbon dioxide (CO2) accounts for the largest share of greenhouse gas emissions, nitrous oxide (N2O) also has large global warming potential, being nearly 300 times higher than CO2 on a weight basis. The purpose of the study is to create the integrated model of greenhouse gas emissions from soils in the agroecosystems on the basis of studies concerning modelling carbon dioxide emissions from mineral soils, quantitatively describing nitrous oxide emissions and modelling agroecosystem productivity. Methods. Mathematical modelling of environmental processes, the synthesis of quantitative approaches to their description. Results. The results of modelling greenhouse gas emissions from soils in agro-ecosystems during 2017-2019 obtained by means of the integrated model developed showed that there is an interseasonal and interannual variability of CO2 and N2O fluxes. The higher CO2 flow rate was observed in 2017, in 2018 the lower CO2 emission intensity was discovered and in 2019 the CO2 flow rate was even lower. The emission of greenhouse gases varies depending on soil temperature, moisture and humus level of the soil. The equally low level of CO2 fluxes was observed at sufficiently low (from 1 to 6°C) soil temperatures. It was 0.072 – 0.401 g C-CO2/m2/day. The highest level of CO2 emission was observed in 2017 with a combination of high soil temperature (24-27°C) and sufficient soil moisture, and varies between 1,058 to 1,307 g С- CO2/m2/day. It was revealed that the most intense emission of N2O was observed during periods of high soil moisture when anaerobic conditions were established in the soil. The denitrification process was particularly intense in the spring of 2019, when the seasonal precipitation sum was 226 mm, and water-filled pore space (WFPS) reached more than 0.8 relative units. The average emission level of N2O was 15.592 g N-N2O/m2/day over this period, and the total N2O emission was the highest (1.134 kg of N-N2O/ha). The N2O emission intensity varied depending on the meteorological seasons. In the spring of 2017 and spring of 2018, the total N2O emission was 0.153–0.173 kg N-N2O/ha. The N2O emissions reached to 0.202-0.503 kg N-N2O/ha in the summer season and 0.192-0.660 kg N-N2O/ha in the autumn. The highest emission levels were observed in the spring seasons (2018 and 2019) and in the autumn months (2017 and 2018), an increase in soil moisture worsened soil aeration, which led to an intensive denitrification process. In total, for the three meteorological seasons the highest emission was in 2019 (1.567 kg N- N2O/ha). The emission level was lower in 2018 (1.323 kg N-N2O/ha) and even lower in 2017 (0.569 kg N-N2O/ha). Conclusions. Based on the synthesis of approaches to modelling CO2, N2O emissions and agroecosystem productivity, an integrated model of greenhouse gas emissions from soils in agro-ecosystems has been developed (plant-agrosoil-GHG-model). The interseasonal and interannual variability of CO2 and N2O fluxes and their dependence on weather conditions and humus level of the soil have been obtained.

Low-Carbon Russia: Prospects after the Crisis

2009 ◽  
pp. 107-120 ◽  
Author(s):  
I. Bashmakov
Keyword(s):  
Economic Growth ◽  
Potential Energy ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Low Carbon ◽  
Modeling Tools ◽  
Gas Emissions ◽  
Scenario Approach

On the eve of the worldwide negotiations of a new climate agreement in December 2009 in Copenhagen it is important to clearly understand what Russia can do to mitigate energy-related greenhouse gas emissions in the medium (until 2020) and in the long term (until 2050). The paper investigates this issue using modeling tools and scenario approach. It concludes that transition to the "Low-Carbon Russia" scenarios must be accomplished in 2020—2030 or sooner, not only to mitigate emissions, but to block potential energy shortages and its costliness which can hinder economic growth.

scholarly journals Long-term greenhouse gas emissions from hydroelectric reservoirs in tropical forest regions

1999 ◽  
Vol 13 (2) ◽  
pp. 503-517 ◽  
Author(s):  
Corinne Galy-Lacaux ◽  
Robert Delmas ◽  
Georges Kouadio ◽  
Sandrine Richard ◽  
Philippe Gosse
Keyword(s):  
Tropical Forest ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Gas Emissions ◽  
Hydroelectric Reservoirs ◽  
Forest Regions

scholarly journals Verification of greenhouse gas emission reductions: the prospect of atmospheric monitoring in polluted areas

2011 ◽  
Vol 369 (1943) ◽  
pp. 1906-1924 ◽  
Author(s):  
Ingeborg Levin ◽  
Samuel Hammer ◽  
Elke Eichelmann ◽  
Felix R. Vogel
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Catchment Area ◽  
Greenhouse Gas Emission ◽  
Atmospheric Transport ◽  
Atmospheric Measurements ◽  
Transport Modelling ◽  
Gas Emissions ◽  
Atmospheric Transport Modelling

Independent verification of greenhouse gas emissions reporting is a legal requirement of the Kyoto Protocol, which has not yet been fully accomplished. Here, we show that dedicated long-term atmospheric measurements of greenhouse gases, such as carbon dioxide (CO 2 ) and methane (CH 4 ), continuously conducted at polluted sites can provide the necessary tool for this undertaking. From our measurements at the semi-polluted Heidelberg site in the upper Rhine Valley, we find that in the catchment area CH 4 emissions decreased on average by 32±6% from the second half of the 1990s until the first half of the 2000s, but the observed long-term trend of emissions is considerably smaller than that previously reported for southwest Germany. In contrast, regional fossil fuel CO 2 levels, estimated from high-precision 14 CO 2 observations, do not show any significant decreasing trend since 1986, in agreement with the reported emissions for this region. In order to provide accurate verification, these regional measurements would best be accompanied by adequate atmospheric transport modelling as required to precisely determine the relevant catchment area of the measurements. Furthermore, reliable reconciliation of reported emissions will only be possible if these are known at high spatial resolution in the catchment area of the observations. This information should principally be available in all countries that regularly report their greenhouse gas emissions to the United Nations Framework Convention on Climate Change.

No evidence that earthworms increase soil greenhouse gas emissions (CO2 and N2O) in the presence of plants and soil-moisture fluctuations

2021 ◽  
Author(s):  
Pierre Ganault ◽  
Johanne Nahmani ◽  
Yvan Capowiez ◽  
Isabelle Bertrand ◽  
Bruno Buatois ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Greenhouse Gases ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Soil Water ◽  
Water Status ◽  
Soil Layer ◽  
Agricultural Practices ◽  
Biodiversity Loss ◽  
Gas Emissions

&lt;p&gt;Accelerating climate change and biodiversity loss calls for agricultural practices that can sustain productivity with lower greenhouse gas emissions while maintaining biodiversity. Biodiversity-friendly agricultural practices have been shown to increase earthworm populations, but according to a recent meta-analyses, earthworms could increase soil CO&lt;sub&gt;2&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O emissions by 33 and 42%, respectively. However, to date, many studies reported idiosyncratic and inconsistent effects of earthworms on greenhouse gases, indicating that the underlying mechanisms are not fully understood. Here we report the effects of earthworms (anecic, endogeic and their combination) with or without plants on CO&lt;sub&gt;2&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O emissions in the presence of soil-moisture fluctuations from a mesocosms experiment. The experimental set-up was explicitly designed to account for the engineering effect of earthworms (i.e. burrowing) and investigate the consequences on soil macroporosity, soil water dynamic, and microbial activity. We found that plants reduced N&lt;sub&gt;2&lt;/sub&gt;O emissions by 19.80% and that relative to the no earthworm control, the cumulative N&lt;sub&gt;2&lt;/sub&gt;O emissions were 17.04, 34.59 and 44.81% lower in the anecic, both species and endogeic species, respectively. CO&lt;sub&gt;2&lt;/sub&gt; emissions were not significantly affected by the plants or earthworms but depended on the interaction between earthworms and soil water content, an interaction that was also observed for the N&lt;sub&gt;2&lt;/sub&gt;O emissions. Soil porosity variables measured by X-ray tomography suggest that the earthworm effects on CO&lt;sub&gt;2&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O emissions were mediated by the burrowing patterns affecting the soil aeration and water status. N&lt;sub&gt;2&lt;/sub&gt;O emissions decreased with the volume occupied by macropores in the deeper soil layer, whereas CO&lt;sub&gt;2&lt;/sub&gt; emissions decreased with the macropore volume in the top soil layer. This study suggests that experimental setups without plants and in containers where the earthworm soil engineering effects via burrowing and casting on soil water status are minimized may be responsible, at least in part, for the reported positive earthworm effects on greenhouse gases.&lt;/p&gt;

Sugarcane fields: sources or sinks for greenhouse gas emissions?

1998 ◽  
Vol 49 (1) ◽  
pp. 1 ◽  
Author(s):  
K. L. Weier
Keyword(s):  
Greenhouse Gases ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Sugar Industry ◽  
N2o Emissions ◽  
Gas Emissions ◽  
Sugarcane Crop ◽  
Management Procedures ◽  
Degree Of Certainty ◽  
Carbon Dioxide Co2

The quantities of greenhouse gases emitted into the atmosphere from sugarcane fields, and their contribution to the total emissions from Australian agriculture, have never been estimated with any degree of certainty. This review was conducted to collate the available information on greenhouse gas emissions from the Australian sugarcane crop. Estimates were made for the emissions of the 3 major greenhouse gases―carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)―from known or suspected sources. Sinks for the sequestration of the gases also have been identified. CO2 was found to be emitted during burning of the crop and from trash-blanketed and bare sugarcane fields. Total emissions from these sources in the 1994 season were estimated at 7·6 Mt CO2-C/year. However, the sugarcane crop was identified as a major sink for C, with uptake by the crop in 1994 estimated at 13· 4 Mt CO2-C/year. N2O emanating from sugarcane soils via denitrification following application of fertiliser accounted for 45-78% of total gaseous N emissions. Estimates of N2O emissions from all land under sugarcane in 1994 totalled 4·4 kt N2O-N/year from denitrification with a further 6·3 kt N2O-N emitted from areas that are still burnt. This review suggests changes in management procedures that should limit the opportunities for denitrification in the soil and thus reduce N2O emissions. Methane evolution occurs during the smouldering phase, following burning of the crop, with production estimated at 6·7 kt CH4-C/year in 1994. CH4 oxidation in soil was identified as an important process for removal of atmospheric CH4, as were trash-blanketed soils. Although these figures are our best estimate of gaseous production from sugarcane fields, there still remains a degree of uncertainty due to sampling variability and because of the extrapolation to the entire sugarcane area. However, the coupling of new laser techniques with known micrometeorological methods will allow for a more precise sampling of greenhouse gas emissions over a larger area. Estimates would thus be more representative, resulting in a greater degree of confidence being placed in them by the sugar industry.

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