scholarly journals Technical note: On comparing greenhouse gas emission metrics

2021 ◽  
Vol 21 (6) ◽  
pp. 4699-4708
Author(s):  
Ian Enting ◽  
Nathan Clisby
Keyword(s):  
Global Warming ◽  
Greenhouse Gas ◽  
Global Warming Potential ◽  
Radiative Forcing ◽  
Greenhouse Gas Emission ◽  
Technical Note ◽  
Short Term ◽  
Rates Of Change

Abstract. Many metrics for comparing greenhouse gas emissions can be expressed as an instantaneous global warming potential multiplied by the ratio of airborne fractions calculated in various ways. The forcing equivalent index (FEI) provides a specification for equal radiative forcing at all times at the expense of generally precluding point-by-point equivalence over time. The FEI can be expressed in terms of asymptotic airborne fractions for exponentially growing emissions. This provides a reference against which other metrics can be compared. Four other equivalence metrics are evaluated in terms of how closely they match the timescale dependence of FEI, with methane referenced to carbon dioxide used as an example. The 100-year global warming potential overestimates the long-term role of methane, while metrics based on rates of change overestimate the short-term contribution. A recently proposed metric based on differences between methane emissions 20 years apart provides a good compromise. Analysis of the timescale dependence of metrics expressed as Laplace transforms leads to an alternative metric that gives closer agreement with FEI at the expense of considering methane over longer time periods. The short-term behaviour, which is important when metrics are used for emissions trading, is illustrated with simple examples for the four metrics.

scholarly journals Technical note: On comparing greenhouse gas emission metrics

2020 ◽  
Author(s):  
Ian Enting ◽  
Nathan Clisby
Keyword(s):  
Global Warming ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Global Warming Potential ◽  
Radiative Forcing ◽  
Greenhouse Gas Emission ◽  
Technical Note ◽  
Gas Emission ◽  
Gas Emissions ◽  
Over Time

Abstract. Many metrics for comparing greenhouse gas emissions can be expressed as an instantaneous Global Warming Potential multiplied by the ratio of airborne fractions calculated in various ways. The Forcing Equivalent Index (FEI) provides a specification for equal radiative forcing at all times at the expense of generally precluding point by point equivalence over time. The FEI can be expressed in terms of asymptotic airborne fractions for exponentially growing emissions. This provides a reference against which other metrics can be compared.

Modeling cell volume regulation in nonexcitable cells: the roles of the Na+ pump and of cotransport systems

1998 ◽  
Vol 275 (4) ◽  
pp. C1067-C1080 ◽  
Author(s):  
Julio A. Hernández ◽  
Ernesto Cristina
Keyword(s):  
Cell Volume ◽  
Volume Regulation ◽  
Present Model ◽  
Animal Cell ◽  
Cell Volume Regulation ◽  
Kinetic Scheme ◽  
Short Term ◽  
Rates Of Change

The purpose of this study is to contribute to understanding the role of Na+-K+-ATPase and of ionic cotransporters in the regulation of cell volume, by employing a model that describes the rates of change of the intracellular concentrations of Na+, K+, and Cl−, of the cell volume, and of the membrane potential. In most previous models of dynamic cellular phenomena, Na+-K+-ATPase is incorporated via phenomenological formulations; the enzyme is incorporated here via an explicit kinetic scheme. Another feature of the present model is the capability to perform short-term cell volume regulation mediated by cotransporters of KCl and NaCl. The model is employed to perform numerical simulations for a “typical” nonpolarized animal cell. Basically, the results are consistent with the view that the Na+ pump mainly plays a long-term role in the maintenance of the electrochemical gradients of Na+ and K+ and that short-term cell volume regulation is achieved via passive transport, exemplified in this case by the cotransport of KCl and NaCl.

scholarly journals Moving Beyond Global Warming Potentials to Quantify the Climatic Role of Ecosystems

Ecosystems ◽  
2015 ◽  
Vol 18 (6) ◽  
pp. 1000-1013 ◽  
Author(s):  
Scott C. Neubauer ◽  
J. Patrick Megonigal
Keyword(s):  
Nitrous Oxide ◽  
Global Warming ◽  
Greenhouse Gas ◽  
Radiative Forcing ◽  
Global Climate ◽  
Nitrous Oxide Emissions ◽  
Implicit Assumption ◽  
Gas Emissions ◽  
Global Warming Potentials

Abstract For decades, ecosystem scientists have used global warming potentials (GWPs) to compare the radiative forcing of various greenhouse gases to determine if ecosystems have a net warming or cooling effect on climate. On a conceptual basis, the continued use of GWPs by the ecological community may be untenable because the use of GWPs requires the implicit assumption that greenhouse gas emissions occur as a single pulse; this assumption is rarely justified in ecosystem studies. We present two alternate metrics—the sustained-flux global warming potential (SGWP, for gas emissions) and the sustained-flux global cooling potential (SGCP, for gas uptake)—for use when gas fluxes persist over time. The SGWP is generally larger than the GWP (by up to ~40%) for both methane and nitrous oxide emissions, creating situations where the GWP and SGWP metrics could provide opposing interpretations about the climatic role of an ecosystem. Further, there is an asymmetry in methane and nitrous oxide dynamics between persistent emission and uptake situations, producing very different values for the SGWP vs. SGCP and leading to the conclusion that ecosystems that take up these gases are very effective at reducing radiative forcing. Although the new metrics are more realistic than the GWP for ecosystem fluxes, we further argue that even these metrics may be insufficient in the context of trying to understand the lifetime climatic role of an ecosystem. A dynamic modeling approach that has the flexibility to account for temporally variable rates of greenhouse gas exchange, and is not limited by a fixed time frame, may be more informative than the SGWP, SGCP, or GWP. Ultimately, we hope this article will stimulate discussion within the ecosystem science community about the most appropriate way(s) of assessing the role of ecosystems as regulators of global climate.

Biochar production under low pyrolysis temperature leads to lesser overall global warming potential and greenhouse gas intensity under lowland and upland short-term condition

2020 ◽  
Author(s):  
Ronley Canatoy ◽  
Seung Tak Jeong ◽  
Pil Joo Kim
Keyword(s):  
Global Warming ◽  
Greenhouse Gas ◽  
Global Warming Potential ◽  
Soil Amendment ◽  
Pyrolysis Temperature ◽  
Ghg Emissions ◽  
Ghg Emission ◽  
Short Term ◽  
Greenhouse Gas Intensity ◽  
Upland Condition

<p>Biochar is a carbon-rich black stable solid substance that when utilized as soil amendment can effectively mitigate greenhouse gas (GHG) emission. However, during the pyrolysis process of organic feedstock (i.e. manure) greenhouse gases are released as the feedstock undergo thermochemical degradation. Many studies were reported with regards to the effectiveness of biochar to mitigate greenhouse gas emission and to maintain soil quality via carbon sequestration. However, no clear investigation was done regarding biochar utilization on reducing GHG emission in an integrated perspective that starts from pyrolysis (production) to field application (utilization). To evaluate the integrated influence of biochar utilization on the overall Global Warming Potential (GWP) and (Greenhouse Gas Intensity) GHGI at different temperature, the fluxes of GHGs during feedstock pyrolysis to soil application were calculated. The key components include GHGs released during production processes and biogenic GHG emissions taking place in the soil via short-term incubation experiment in lowland and upland condition treated with biochar pyrolyzed at different temperature. Highest pyrolysis temperature of 700<sup>o</sup>C emitted 6.92 Mg CO<sub>2</sub>-eq ton<sup>-1</sup> biochar, wherein 8.7% and 91.2% was contributed by Carbon dioxide (CO<sub>2</sub>) and Methane (CH<sub>4</sub>) effluxes, respectively, during pyrolysis. This GHG emission during pyrolysis at 700<sup>o</sup>C was 5.6, 2.2, and 1.5 times higher than at 400<sup>o</sup>C, 500<sup>o</sup>C and 600<sup>o</sup>C, respectively. Meanwhile, biochar produced at lowest temperature (Biochar400) when utilized as soil amendment emitted 43.4 and 38.2 Mg CO<sub>2</sub>-eq ha<sup>-1</sup> in lowland and upland condition, respectively. In addition, this emission value under lowland (and upland) condition was 1.38 (1.36), 1.51 (1.56) and 1.86 (1.91) times higher than Biochar500, Biochar600 and Biochar700, respectively. Combining the GWP during the production and the utilization processes in lowland and upland condition reveal that at 400<sup>o</sup>C emanates the lowest overall GWP of 93.3 and 88.1 Mg CO<sub>2</sub>-eq ha<sup>-1</sup>, respectively.  Moreover, under lowland (and upland) condition, overall GWP at 400<sup>o</sup>C was noted to be 65.7% (71.7%), 131.6% (140.4%) and 221.9% (237.1%), lower than at 500<sup>o</sup>C, 600<sup>o</sup>C and 700<sup>o</sup>C, respectively. In conclusion, the use of lower temperature during biomass pyrolysis and utilization of its derived biochar could be a practical approach to mitigate GHG emissions.</p><p> </p><p>Keywords: Biochar, Pyrolysis, Greenhouse gas, Methane, Global warming potential, Greenhouse gas intensity</p>

scholarly journals Do greenhouse gas mitigation cost-effectiveness rankings based on the global warming potential favor sub-optimal allocation of resources?

2021 ◽  
Author(s):  
Franz Weiss ◽  
Adrian Leip ◽  
Vera Eory
Keyword(s):  
Carbon Dioxide ◽  
Nitrous Oxide ◽  
Global Warming ◽  
Cost Effectiveness ◽  
Soil Carbon ◽  
Greenhouse Gas ◽  
Global Warming Potential ◽  
Radiative Forcing ◽  
Greenhouse Gas Mitigation ◽  
Mitigation Measures

Abstract The global warming potential GWPgas(H) relates radiative forcing of a single pulse emission of a greenhouse gas, the absolute global warming potential AGWPgas(H), to the respective radiative forcing of carbon dioxide over a defined time horizon H. Mitigation measures targeting short-lived climate forcers (SLCFs) or reversible measures need to be applied permanently to be effective in the long run, but cost effectiveness for a permanent application of a measure differs from a single application. We propose a concept for an absolute global warming potential of permanent yearly pulses AGWP’gas(H), and several options for alternative indices to replace or complement the GWP: For the GWPgas(H/H) and the GWPcgas(H/H) we keep the AGWPCO2(H) in the denominator, which allows the direct comparison with conventional estimates, while for the GWP’gas(H) we define a new metric replacing the denominator by the AGWP’CO2(H). Different cost-effectiveness indicators can be defined respectively. We demonstrate the concept on the example of typical greenhouse gases emitted or removed by the agricultural sector: methane, nitrous oxide and carbon dioxide, fossil and stored as soil carbon. We show that, compared to GWP-based cost-effectiveness analysis, measures targeting soil carbon are discouraged relative to measures targeting methane, nitrous oxide and fossil carbon dioxide.

Impact of FII’s and FDI’s on Indian Stock Market

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Dr. Kamlesh Kumar Shukla
Keyword(s):  
Stock Market ◽  
Financial Markets ◽  
Global Economy ◽  
Short Term ◽  
Earnings Growth ◽  
The Past ◽  
Bull Market ◽  
Indian Stock Market

FIIs are companies registered outside India. In the past four years there has been more than $41 trillion worth of FII funds invested in India. This has been one of the major reasons on the bull market witnessing unprecedented growth with the BSE Sensex rising 221% in absolute terms in this span. The present downfall of the market too is influenced as these FIIs are taking out some of their invested money. Though there is a lot of value in this market and fundamentally there is a lot of upside in it. For long-term value investors, there’s little because for worry but short term traders are adversely getting affected by the role of FIIs are playing at the present. Investors should not panic and should remain invested in sectors where underlying earnings growth has little to do with financial markets or global economy.

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