scholarly journals Integrating beef cattle on cropland affects net global warming potential

2021 ◽  
Author(s):  
M. A. Liebig ◽  
D. R. Faust ◽  
D. W. Archer ◽  
R. G. Christensen ◽  
S. L. Kronberg ◽  
...  
Keyword(s):  
Global Warming ◽  
Beef Cattle ◽  
Soil Carbon ◽  
Global Warming Potential ◽  
Ghg Emissions ◽  
Contributing Factors ◽  
Enteric Fermentation ◽  
Soil Carbon Stock ◽  
Soil Atmosphere ◽  
Net Global Warming Potential

AbstractRecent interest in integrated crop-livestock (ICL) systems has prompted numerous investigations to quantify ecosystem service tradeoffs associated with management. However, few investigations have quantified ICL management effects on net global warming potential (GWP), particularly in semiarid regions. Therefore, we determined net GWP for grazed and ungrazed cropland in a long-term ICL study near Mandan, ND USA. Factors evaluated for their contribution to net GWP included carbon dioxide (CO2) emissions associated with production inputs and field operations, methane (CH4) emissions from enteric fermentation by beef cattle, change in soil carbon stocks, and soil-atmosphere CH4 and nitrous oxide (N2O) fluxes. Net GWP was significantly greater for grazed cropland (946 kg CO2equiv. ha-1 yr-1) compared to ungrazed cropland (200 kg CO2equiv. ha-1 yr-1) (P=0.0331). The difference in net GWP between treatments was largely driven by emissions from enteric fermentation (602 kg CO2equiv. ha-1 yr-1). Among other contributing factors, CO2 emissions associated with seed production and field operations were lower under ungrazed cropland (P = 0.0015 and 0.0135, respectively), while soil CH4 uptake was greater under grazed cropland (P = 0.0102). Soil-atmosphere N2O flux from each system negated nearly all the CO2equiv. sink capacity accrued from soil carbon stock change. As both production systems resulted in net greenhouse gas (GHG) emissions to the atmosphere, novel practices that constrain GHG sources and boost GHG sinks under semiarid conditions are recommended.

scholarly journals Net global warming potential and greenhouse gas intensity in rice agriculture driven by high yields and nitrogen use efficiency: a 5 year field study

2015 ◽  
Vol 12 (22) ◽  
pp. 18883-18911 ◽  
Author(s):  
X. Zhang ◽  
Z. Zhou ◽  
Y. Liu ◽  
X. Xu ◽  
J. Wang ◽  
...  
Keyword(s):  
Global Warming ◽  
Food Security ◽  
Nitrogen Use Efficiency ◽  
Global Warming Potential ◽  
Rice Agriculture ◽  
Nitrogen Use ◽  
Use Efficiency ◽  
Greenhouse Gas Intensity ◽  
High Yields ◽  
Net Global Warming Potential

Abstract. Our understanding of how net global warming potential (NGWP) and greenhouse gas intensity (GHGI) is affected by management practices aimed at food security with respect to rice agriculture remains limited. In the present study, a 5 year field experiment was conducted in China to evaluate the effects of integrated soil-crop system management (ISSM) on NGWP and GHGI after accounting for carbon dioxide (CO2) emissions from all sources (methane, CH4, and nitrous oxide, N2O, emissions, agrochemical inputs, Ei, and farm operations, Eo) and sinks (i.e., soil organic carbon, SOC, sequestration). For the improvement of rice yield and agronomic nitrogen use efficiency (NUE), four ISSM scenarios consisting of different nitrogen (N) fertilization rates relative to the local farmers' practice (FP) rate were carried out, namely, N1 (25 % reduction), N2 (10 % reduction), N3 (FP rate) and N4 (25 % increase). The results showed that compared with the FP, the four ISSM scenarios, i.e., N1, N2, N3 and N4, significantly increased the rice yields by 10, 16, 28 and 41 % and the agronomic NUE by 75, 67, 86 and 82 %, respectively. In addition, compared with the FP, the N1 and N2 scenarios significantly reduced the GHGI by 14 and 18 %, respectively, despite similar NGWPs. The N3 and N4 scenarios remarkably increased the NGWP and GHGI by an average of 67 and 36 %, respectively. In conclusion, the ISSM strategies are promising for both food security and environmental protection, and the ISSM scenario of N2 is the optimal strategy to realize high yields and high NUE together with low environmental impacts for this agricultural rice field.

Strong mitigation of net global warming potential (GWP) via short-term aerobic pre-digestion of green manured soil in rice paddy

2020 ◽  
Author(s):  
Hyeonji Song ◽  
Jin Ho Lee ◽  
Songrae Cho ◽  
Hogyeong Chae ◽  
Pil Joo Kim
Keyword(s):  
Global Warming ◽  
Global Warming Potential ◽  
Cover Crop ◽  
Short Term ◽  
Input And Output ◽  
Cropping Season ◽  
Aerobic Decomposition ◽  
Soc Stock ◽  
Stock Change ◽  
Net Global Warming Potential

<p> Cover crop cultivation is strongly recommended during fallow season to increase soil organic carbon (SOC) stock. However, since its biomass recycling as green manure can dramatically increase greenhouse gas (GHG) emission, in particular, methane (CH<sub>4</sub>) during rice cropping season, smart cover crop management strategy should be developed. In our previous research, CH<sub>4</sub> emission during cropping season was dramatically reduced via short-term aerobic decomposition before irrigation (Lee et al.). However, due to a fast response rate of aerobic decomposition, the effect of mitigating CH<sub>4</sub> emission could be offset by SOC depletion which results in accelerating global warming. To evaluate the comprehensive impact of the short-term aerobic decomposition on global warming, net global warming potential (GWP), defined as the difference between GWP and SOC stock change was employed. SOC stock change was estimated using net ecosystem carbon budget (NECB), a balance between soil C input and output. The mixture of barley and hairy vetch cultivated during the dried fallow season, and then its whole biomass was incorporated 0-30 days before irrigation for rice transplanting. The aerobic decomposition of cover crop biomass significantly reduced CH<sub>4</sub> emission by 24-85% over control but negligibly influences N<sub>2</sub>O emission. Total C input and output were unaffected by the aerobic digestion. Although carbon emission before flooding dramatically increased after biomass application in aerobic decomposition treatments, the mineralized C losses exhibited no differences among treatments. Based on these results, NECB values were similar in all treatments. This implies the aerobic decomposition did not stimulate SOC depletion, compared to the control. Finally, the net GWP highly decreased by 30-86% by the aerobic digestion due to the significant reduction of CH<sub>4</sub> emission. In conclusion, earlier application of cover crops before irrigation is a smart strategy to decrease methane emission, maintaining soil carbon sequestration effect of cover crop biomasses application.</p>

Effect of cover cropping on the net global warming potential of rice paddy soil

Geoderma ◽  
2017 ◽  
Vol 292 ◽  
pp. 49-58 ◽  
Author(s):  
Hyun Young Hwang ◽  
Gil Won Kim ◽  
Sang Yoon Kim ◽  
Md. Mozammel Haque ◽  
Muhammad Israr Khan ◽  
...  
Keyword(s):  
Global Warming ◽  
Paddy Soil ◽  
Global Warming Potential ◽  
Rice Paddy ◽  
Rice Paddy Soil ◽  
Cover Cropping ◽  
Net Global Warming Potential

scholarly journals The impact on global warming potential of converting from disposable to reusable sharps containers in a large US hospital geographically distant from polymer and container manufacturer

2018 ◽  
Author(s):  
Brett McPherson ◽  
Mihray Sharip ◽  
Terry Grimmond
Keyword(s):  
Global Warming ◽  
Health System ◽  
Global Warming Potential ◽  
Ghg Emissions ◽  
Medical Waste ◽  
University Hospital ◽  
Waste Stream ◽  
Unit Process ◽  
Ghg Reduction ◽  
The Impact

Background. Sustainable purchasing can reduce greenhouse gas (GHG) emissions at healthcare facilities (HCF). A previous study found that converting from disposable to reusable sharps containers (DSC, RSC) reduced sharps waste stream GHG by 84% but, in finding transport distances impacted significantly on GHG outcomes, recommended further studies where transport distances are large. This case-study examines the impact on GHG of nation-wide transport distances when a large US health system converted from DSC to RSC. Methods. The study examined the alternate use of DSC and RSC at a large US university hospital where: the source of polymer was distant from the RSC manufacturing plant; both manufacturing plants were over 3,000 km from the HCF; and the RSC disposal plant was considerably further from the HCF than was the DSC disposal plant. Using a “cradle to grave” life cycle assessment (LCA) tool we calculated annual GHG emissions (CO2, CH4, N2O) in metric tonnes of carbon dioxide equivalents (MTCO2eq) to assess the impact on global warming potential (GWP) of each container system. Primary energy input data was used wherever possible and region-specific impact conversions used to calculate GWP of each activity over a 12-month period. Unit process GHG were collated into Manufacture, Transport, Washing, and Treatment & disposal. Emission totals were workload-normalized and analysed using CHI2 test with P ≤0.05 and rate ratios at 95% CL. Results. The hospital reduced its annual GWP by 168 MTCO2eq (-64.5%; p < 0.001), and annually eliminated 50.2 tonnes of plastic DSC and 8.1 tonnes of cardboard from the sharps waste stream. Of the plastic eliminated, 31.8 tonnes were diverted from landfill and 18.4 from incineration. Discussion. Unlike GHG reduction strategies dependent on changes in staff behaviour (waste segregation, recycling, turning off lights, car-pooling, etc), purchasing strategies can enable immediate, sustainable and institution-wide GHG reductions to be achieved. Medical waste containers contribute significantly to the supply chain carbon footprint and, although non-sharp medical waste volumes have decreased significantly with avid segregation, sharps wastes have increased, and can account for 50% of total medical waste volume. Thus converting from DSC to RSC can assist reduce the GWP footprint of the medical waste stream. This study confirmed that large transport distances between polymer manufacturer and container manufacturer; container manufacturer and user; and/or between user and processing facilities, can significantly impact the GWP of sharps containment systems. However, even with large transport distances, we found that a large university health system significantly reduced the GWP of their sharps waste stream by converting from DSC to RSC.

scholarly journals The impact on global warming potential of converting from disposable to reusable sharps containers in a large US hospital geographically distant from polymer and container manufacturer

2018 ◽  
Author(s):  
Brett McPherson ◽  
Mihray Sharip ◽  
Terry Grimmond
Keyword(s):  
Global Warming ◽  
Health System ◽  
Global Warming Potential ◽  
Ghg Emissions ◽  
Medical Waste ◽  
University Hospital ◽  
Waste Stream ◽  
Unit Process ◽  
Ghg Reduction ◽  
The Impact

Background. Sustainable purchasing can reduce greenhouse gas (GHG) emissions at healthcare facilities (HCF). A previous study found that converting from disposable to reusable sharps containers (DSC, RSC) reduced sharps waste stream GHG by 84% but, in finding transport distances impacted significantly on GHG outcomes, recommended further studies where transport distances are large. This case-study examines the impact on GHG of nation-wide transport distances when a large US health system converted from DSC to RSC. Methods. The study examined the alternate use of DSC and RSC at a large US university hospital where: the source of polymer was distant from the RSC manufacturing plant; both manufacturing plants were over 3,000 km from the HCF; and the RSC disposal plant was considerably further from the HCF than was the DSC disposal plant. Using a “cradle to grave” life cycle assessment (LCA) tool we calculated annual GHG emissions (CO2, CH4, N2O) in metric tonnes of carbon dioxide equivalents (MTCO2eq) to assess the impact on global warming potential (GWP) of each container system. Primary energy input data was used wherever possible and region-specific impact conversions used to calculate GWP of each activity over a 12-month period. Unit process GHG were collated into Manufacture, Transport, Washing, and Treatment & disposal. Emission totals were workload-normalized and analysed using CHI2 test with P ≤0.05 and rate ratios at 95% CL. Results. The hospital reduced its annual GWP by 168 MTCO2eq (-64.5%; p < 0.001), and annually eliminated 50.2 tonnes of plastic DSC and 8.1 tonnes of cardboard from the sharps waste stream. Of the plastic eliminated, 31.8 tonnes were diverted from landfill and 18.4 from incineration. Discussion. Unlike GHG reduction strategies dependent on changes in staff behaviour (waste segregation, recycling, turning off lights, car-pooling, etc), purchasing strategies can enable immediate, sustainable and institution-wide GHG reductions to be achieved. Medical waste containers contribute significantly to the supply chain carbon footprint and, although non-sharp medical waste volumes have decreased significantly with avid segregation, sharps wastes have increased, and can account for 50% of total medical waste volume. Thus converting from DSC to RSC can assist reduce the GWP footprint of the medical waste stream. This study confirmed that large transport distances between polymer manufacturer and container manufacturer; container manufacturer and user; and/or between user and processing facilities, can significantly impact the GWP of sharps containment systems. However, even with large transport distances, we found that a large university health system significantly reduced the GWP of their sharps waste stream by converting from DSC to RSC.

scholarly journals Estimating the permafrost-carbon feedback on global warming

2011 ◽  
Vol 8 (3) ◽  
pp. 4727-4761 ◽  
Author(s):  
T. Schneider von Deimling ◽  
M. Meinshausen ◽  
A. Levermann ◽  
V. Huber ◽  
K. Frieler ◽  
...  
Keyword(s):  
Global Warming ◽  
Carbon Cycle ◽  
Soil Carbon ◽  
Temperature Increase ◽  
Climate Model ◽  
Soil Layer ◽  
Ghg Emissions ◽  
Permafrost Degradation ◽  
Uncertainty Range ◽  
Permafrost Thaw

Abstract. Thawing of permafrost and the associated release of carbon constitutes a positive feedback in the climate system, elevating the effect of anthropogenic GHG emissions on global-mean temperatures. Multiple factors have hindered the quantification of this feedback, which was not included in the CMIP3 and C4MIP generation of AOGCMs and carbon cycle models. There are considerable uncertainties in the rate and extent of permafrost thaw, the hydrological and vegetation response to permafrost thaw, the decomposition timescales of freshly thawed organic material, the proportion of soil carbon that might be emitted as carbon dioxide via aerobic decomposition or as methane via anaerobic decomposition, and in the magnitude of the high latitude amplification of global warming that will drive permafrost degradation. Additionally, there are extensive and poorly characterized regional heterogeneities in soil properties, carbon content, and hydrology. Here, we couple a new permafrost module to a reduced complexity carbon-cycle climate model, which allows us to perform a large ensemble of simulations. The ensemble is designed to span the uncertainties listed above and thereby the results provide an estimate of the potential strength of the permafrost-carbon feedback. For the high CO2 concentration scenario (RCP8.5), 12–52 PgC, or an extra 3–11 % above projected net CO2 emissions from land carbon cycle feedbacks, are released by 2100 (68 % uncertainty range). This leads to an additional warming of 0.02–0.11 °C. Though projected 21st century emissions are relatively modest, ongoing permafrost thaw and slow but steady soil carbon decomposition means that, by 2300, more than half of the potentially vulnerable permafrost carbon stock in the upper 3m of soil layer (600–1000 PgC) could be released as CO2, with an extra 1–3 % being released as methane. Our results also suggest that mitigation action in line with the lower scenario RCP3-PD could contain Arctic temperature increase sufficiently that thawing of the permafrost area is limited to 15–30 % and the permafrost-carbon induced temperature increase does not exceed 0.01–0.07 °C by 2300.

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