scholarly journals A new formulation of equivalent effective stratospheric chlorine (EESC)

2007 ◽  
Vol 7 (2) ◽  
pp. 3963-4000 ◽  
Author(s):  
P. A. Newman ◽  
J. S. Daniel ◽  
D. W. Waugh ◽  
E. R. Nash
Keyword(s):  
Climate Change ◽  
Ozone Depletion ◽  
International Agreements ◽  
Quantitative Estimates ◽  
The Mean ◽  
Ozone Depleting Substances ◽  
New Formulation ◽  
Fractional Release

Abstract. Equivalent effective stratospheric chlorine (EESC) is a convenient parameter to quantify the effects of halogens (chlorine and bromine) on ozone depletion in the stratosphere. We show and discuss a new formulation of EESC that now includes the effects of age-of-air dependent fractional release values and an age-of-air spectrum. This new formulation provides quantitative estimates of EESC that can be directly related to inorganic chlorine and bromine throughout the stratosphere. Using this EESC formulation, we estimate that human-produced ozone depleting substances will recover to 1980 levels in 2041 in the midlatitudes, and 2067 over Antarctica. These recovery dates are based upon the assumption that the international agreements for regulating ozone-depleting substances are adhered to. In addition to recovery dates, we also estimate the uncertainties in the estimated time of recovery. The midlatitude recovery of 2041 has a 95% confidence uncertainty from 2028 to 2049, while the 2067 Antarctic recovery has a 95% confidence uncertainty from 2056 to 2078. The principal uncertainties are from the estimated mean age-of-air, and the assumption that the mean age-of-air and fractional release values are time independent. Using other model estimates of age decrease due to climate change, we estimate that midlatitude recovery may be accelerated from 2041 to 2031.

scholarly journals A new formulation of equivalent effective stratospheric chlorine (EESC)

2007 ◽  
Vol 7 (17) ◽  
pp. 4537-4552 ◽  
Author(s):  
P. A. Newman ◽  
J. S. Daniel ◽  
D. W. Waugh ◽  
E. R. Nash
Keyword(s):  
Climate Change ◽  
Ozone Depletion ◽  
International Agreements ◽  
Quantitative Estimates ◽  
Ozone Depleting Substances ◽  
New Formulation ◽  
Fractional Release

Abstract. Equivalent effective stratospheric chlorine (EESC) is a convenient parameter to quantify the effects of halogens (chlorine and bromine) on ozone depletion in the stratosphere. We show, discuss, and analyze a new formulation of EESC that now includes the effects of age-of-air dependent fractional release values and an age-of-air spectrum. This EESC can be more appropriately applied to various parts of the stratosphere because of this dependence on mean age-of-air. This new formulation provides quantitative estimates of EESC that can be directly related to inorganic chlorine and bromine throughout the stratosphere. In this paper, we first provide a detailed description of the EESC calculation. We then use this EESC formulation to estimate that human-produced ozone depleting substances will recover to 1980 levels in 2041 in the midlatitudes, and 2067 over Antarctica. These recovery dates are based upon the assumption that the international agreements for regulating ozone-depleting substances are adhered to. In addition to recovery dates, we also estimate the uncertainties and possible problems in the estimated times of recovery. The midlatitude recovery of 2041 has a 95% confidence uncertainty from 2028 to 2049, while the 2067 Antarctic recovery has a 95% confidence uncertainty from 2056 to 2078. The principal uncertainties are from the estimated mean age-of-air and fractional release values, and the assumption that these quantities are time independent. Using other model estimates of age decrease due to climate change, we estimate that midlatitude recovery may be significantly accelerated.

scholarly journals Separating the Dynamical Effects of Climate Change and Ozone Depletion. Part I: Southern Hemisphere Stratosphere

2010 ◽  
Vol 23 (18) ◽  
pp. 5002-5020 ◽  
Author(s):  
Charles McLandress ◽  
Andreas I. Jonsson ◽  
David A. Plummer ◽  
M. Catherine Reader ◽  
John F. Scinocca ◽  
...  
Keyword(s):  
Climate Change ◽  
Southern Hemisphere ◽  
Mass Flux ◽  
Ozone Depletion ◽  
Seasonal Changes ◽  
Middle Atmosphere ◽  
Wave Drag ◽  
Zonal Winds ◽  
Ozone Depleting Substances ◽  
Induced Changes

Abstract A version of the Canadian Middle Atmosphere Model that is coupled to an ocean is used to investigate the separate effects of climate change and ozone depletion on the dynamics of the Southern Hemisphere (SH) stratosphere. This is achieved by performing three sets of simulations extending from 1960 to 2099: 1) greenhouse gases (GHGs) fixed at 1960 levels and ozone depleting substances (ODSs) varying in time, 2) ODSs fixed at 1960 levels and GHGs varying in time, and 3) both GHGs and ODSs varying in time. The response of various dynamical quantities to the GHG and ODS forcings is shown to be additive; that is, trends computed from the sum of the first two simulations are equal to trends from the third. Additivity is shown to hold for the zonal mean zonal wind and temperature, the mass flux into and out of the stratosphere, and the latitudinally averaged wave drag in SH spring and summer, as well as for final warming dates. Ozone depletion and recovery causes seasonal changes in lower-stratosphere mass flux, with reduced polar downwelling in the past followed by increased downwelling in the future in SH spring, and the reverse in SH summer. These seasonal changes are attributed to changes in wave drag caused by ozone-induced changes in the zonal mean zonal winds. Climate change, on the other hand, causes a steady decrease in wave drag during SH spring, which delays the breakdown of the vortex, resulting in increased wave drag in summer.

scholarly journals Evaluation of stratospheric age of air from CF<sub>4</sub>, C<sub>2</sub>F<sub>6</sub>, C<sub>3</sub>F<sub>8</sub>, CHF<sub>3</sub>, HFC-125, HFC-227ea and SF<sub>6</sub>; implications for the calculations of halocarbon lifetimes, fractional release factors and ozone depletion potentials

2018 ◽  
Vol 18 (5) ◽  
pp. 3369-3385 ◽  
Author(s):  
Emma Leedham Elvidge ◽  
Harald Bönisch ◽  
Carl A. M. Brenninkmeijer ◽  
Andreas Engel ◽  
Paul J. Fraser ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
East Anglia ◽  
Release Factors ◽  
Independent Verification ◽  
The Mean ◽  
Stratospheric Circulation ◽  
Gas Measurements ◽  
The Impact ◽  
Fractional Release ◽  
Circulation Changes

Abstract. In a changing climate, potential stratospheric circulation changes require long-term monitoring. Stratospheric trace gas measurements are often used as a proxy for stratospheric circulation changes via the mean age of air values derived from them. In this study, we investigated five potential age of air tracers – the perfluorocarbons CF4, C2F6 and C3F8 and the hydrofluorocarbons CHF3 (HFC-23) and HFC-125 – and compare them to the traditional tracer SF6 and a (relatively) shorter-lived species, HFC-227ea. A detailed uncertainty analysis was performed on mean ages derived from these new tracers to allow us to confidently compare their efficacy as age tracers to the existing tracer, SF6. Our results showed that uncertainties associated with the mean age derived from these new age tracers are similar to those derived from SF6, suggesting that these alternative compounds are suitable in this respect for use as age tracers. Independent verification of the suitability of these age tracers is provided by a comparison between samples analysed at the University of East Anglia and the Scripps Institution of Oceanography. All five tracers give younger mean ages than SF6, a discrepancy that increases with increasing mean age. Our findings qualitatively support recent work that suggests that the stratospheric lifetime of SF6 is significantly less than the previous estimate of 3200 years. The impact of these younger mean ages on three policy-relevant parameters – stratospheric lifetimes, fractional release factors (FRFs) and ozone depletion potentials – is investigated in combination with a recently improved methodology to calculate FRFs. Updates to previous estimations for these parameters are provided.

scholarly journals Fractional release factors of long-lived halogenated organic compounds in the tropical stratosphere

2010 ◽  
Vol 10 (3) ◽  
pp. 1093-1103 ◽  
Author(s):  
J. C. Laube ◽  
A. Engel ◽  
H. Bönisch ◽  
T. Möbius ◽  
W. T. Sturges ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Climate Projections ◽  
Ozone Level ◽  
Data Set ◽  
Release Factors ◽  
Transit Times ◽  
The Mean ◽  
Global Warming Potentials ◽  
Organic Trace ◽  
Fractional Release

Abstract. Fractional release factors (FRFs) of organic trace gases are time-independent quantities that influence the calculation of Global Warming Potentials and Ozone Depletion Potentials. We present the first set of vertically resolved FRFs for 15 long-lived halocarbons in the tropical stratosphere up to 34 km altitude. They were calculated from measurements on air samples collected on board balloons and a high altitude aircraft. We compare the derived dependencies of FRFs on the mean stratospheric transit times (the so-called mean ages of air) with similarly derived FRFs originating from measurements at higher latitudes and find significant differences. Moreover a comparison with averaged FRFs currently used by the World Meteorological Organisation revealed the limitations of these measures due to their observed vertical and latitudinal variability. The presented data set could be used to improve future ozone level and climate projections.

scholarly journals Evaluation of stratospheric age-of-air from CF<sub>4</sub>, C<sub>2</sub>F<sub>6</sub>, C<sub>3</sub>F<sub>8</sub>, CHF<sub>3</sub>, HFC-125, HFC-227ea and SF<sub>6</sub>; implications for the calculations of halocarbon lifetimes, fractional release factors and ozone depletion potentials

2017 ◽  
Author(s):  
Emma Leedham Elvidge ◽  
Harald Bönisch ◽  
Carl A. M. Brenninkmeijer ◽  
Andreas Engel ◽  
Paul J. Fraser ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
East Anglia ◽  
Release Factors ◽  
Independent Verification ◽  
The Mean ◽  
Stratospheric Circulation ◽  
Gas Measurements ◽  
The Impact ◽  
Fractional Release ◽  
Circulation Changes

Abstract. In a changing climate, potential stratospheric circulation changes require long-term monitoring. Stratospheric trace gas measurements are often used as a proxy for stratospheric circulation changes via the mean age of air values derived from them. In this study, we investigated five potential age of air tracers – the perfluorocarbons CF4, C2F6 and C3F8 and the hydrofluorocarbons CHF3 (HFC-23) and HFC-125 – and compare them to the traditional tracer SF6 and a (relatively) shorter-lived species, HFC-227ea. A detailed uncertainty analysis was performed on mean ages derived from these new tracers to allow us to confidently compare their efficacy as age tracers to the existing tracer, SF6. Our results showed that uncertainties associated with the mean age derived from these new age tracers are similar to those derived from SF6, suggesting these alternative compounds are suitable, in this respect, for use as age tracers. Independent verification of the suitability of these age tracers is provided by a comparison between samples analysed at the University of East Anglia and the Scripps Institution of Oceanography. All five tracers give younger mean ages than SF6, a discrepancy that increases with increasing mean age. Our findings qualitatively support recent work that suggests the stratospheric lifetime of SF6 is significantly less than the previous estimate of 3200 years. The impact of these younger mean ages on three policy-relevant parameters – stratospheric lifetimes, Fractional Release Factors (FRFs), and Ozone Depletion Potentials – is investigated in combination with a recently improved methodology to calculate FRFs. Updates to previous estimations for these parameters are provided.

scholarly journals Fractional release factors of long-lived halogenated organic compounds in the tropical stratosphere

2009 ◽  
Vol 9 (5) ◽  
pp. 20283-20307 ◽  
Author(s):  
J. C. Laube ◽  
A. Engel ◽  
H. Bönisch ◽  
T. Möbius ◽  
W. T. Sturges ◽  
...  
Keyword(s):  
Ozone Depletion ◽  
Climate Projections ◽  
Ozone Level ◽  
Data Set ◽  
Release Factors ◽  
Transit Times ◽  
The Mean ◽  
Global Warming Potentials ◽  
Organic Trace ◽  
Fractional Release

Abstract. Fractional release factors (FRFs) of organic trace gases are time-independent quantities that influence the calculation of Global Warming Potentials and Ozone Depletion Potentials. We present the first set of vertically resolved FRFs for 15 long-lived halocarbons in the tropical stratosphere up to 34 km altitude. They were calculated from measurements on air samples collected on board balloons and a high altitude aircraft. We compare the derived dependencies of FRFs on the mean stratospheric transit times (the so-called mean ages of air) with similarly derived FRFs originating from measurements at higher latitudes and find significant differences. Moreover a comparison with averaged FRFs currently used by the World Meteorological Organisation revealed the latter to be imprecise measures due to their observed vertical and latitudinal variability. The presented data set could thus be used to improve future ozone level and climate projections.

scholarly journals Consumer willingness-to-pay for restaurant surcharges to reduce carbon emissions: default and information effects

2021 ◽  
pp. 1-29
Author(s):  
Dede Long ◽  
Grant H. West ◽  
Rodolfo M. Nayga
Keyword(s):  
Climate Change ◽  
Willingness To Pay ◽  
Contingent Valuation ◽  
Carbon Emissions ◽  
Emission Reduction ◽  
Carbon Emission ◽  
Dichotomous Choice ◽  
Carbon Reduction ◽  
The Mean ◽  
Agriculture And Food

Abstract The agriculture and food sectors contribute significantly to greenhouse gas emissions. About 15 percent of food-related carbon emissions are channeled through restaurants. Using a contingent valuation (CV) method with double-bounded dichotomous choice (DBDC) questions, this article investigates U.S. consumers’ willingness to pay (WTP) for an optional restaurant surcharge in support of carbon emission reduction programs. The mean estimated WTP for a surcharge is 6.05 percent of an average restaurant check, while the median WTP is 3.64 percent. Our results show that individuals have a higher WTP when the surcharge is automatically added to restaurant checks. We also find that an information nudge—a short climate change script—significantly increases WTP. Additionally, our results demonstrate that there is heterogeneity in treatment effects across consumers’ age, environmental awareness, and economic views. Our findings suggest that a surcharge program could transfer a meaningful amount of the agricultural carbon reduction burden to consumers that farmers currently shoulder.

scholarly journals Drivers of changes in stratospheric and tropospheric ozone between year 2000 and 2100

2016 ◽  
Vol 16 (5) ◽  
pp. 2727-2746 ◽  
Author(s):  
Antara Banerjee ◽  
Amanda C. Maycock ◽  
Alexander T. Archibald ◽  
N. Luke Abraham ◽  
Paul Telford ◽  
...  
Keyword(s):  
Climate Change ◽  
Greenhouse Gases ◽  
Tropospheric Ozone ◽  
Climate Forcing ◽  
Atmospheric Response ◽  
Chemical Production ◽  
The United Kingdom ◽  
Ozone Precursor ◽  
Ozone Depleting Substances ◽  
Year 2000

Abstract. A stratosphere-resolving configuration of the Met Office's Unified Model (UM) with the United Kingdom Chemistry and Aerosols (UKCA) scheme is used to investigate the atmospheric response to changes in (a) greenhouse gases and climate, (b) ozone-depleting substances (ODSs) and (c) non-methane ozone precursor emissions. A suite of time-slice experiments show the separate, as well as pairwise, impacts of these perturbations between the years 2000 and 2100. Sensitivity to uncertainties in future greenhouse gases and aerosols is explored through the use of the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. The results highlight an important role for the stratosphere in determining the annual mean tropospheric ozone response, primarily through stratosphere–troposphere exchange (STE) of ozone. Under both climate change and reductions in ODSs, increases in STE offset decreases in net chemical production and act to increase the tropospheric ozone burden. This opposes the effects of projected decreases in ozone precursors through measures to improve air quality, which act to reduce the ozone burden. The global tropospheric lifetime of ozone (τO3) does not change significantly under climate change at RCP4.5, but it decreases at RCP8.5. This opposes the increases in τO3 simulated under reductions in ODSs and ozone precursor emissions. The additivity of the changes in ozone is examined by comparing the sum of the responses in the single-forcing experiments to those from equivalent combined-forcing experiments. Whilst the ozone responses to most forcing combinations are found to be approximately additive, non-additive changes are found in both the stratosphere and troposphere when a large climate forcing (RCP8.5) is combined with the effects of ODSs.

Evaluation of the daily cycle in the simulation of the ClimEx large-ensemble

2021 ◽  
Author(s):  
Anne-Marie Begin
Keyword(s):  
Climate Change ◽  
Estimation Error ◽  
Natural Variability ◽  
Extreme Weather Events ◽  
Large Ensemble ◽  
Daily Cycle ◽  
Minimum Number ◽  
The Mean ◽  
Mean Cycle ◽  
The Impact

&lt;p&gt;To estimate the impact of climate change on our society we need to use climate projections based on numerical models. These models make it possible to assess the effects on climate of the increase in greenhouse gases (GHG) as well as natural variability. We know that the global average temperature will increase and that the occurrence, intensity and spatio-temporal distribution of extreme precipitations will change. These extreme weather events cause droughts, floods and other natural disasters that have significant consequences on our life and environment. Precipitation is a key variable in adapting to climate change.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;This study focuses on the ClimEx large ensemble, a set of 50 independent simulations created to study the effect of climate change and natural variability on the water network in Quebec. This dataset consists of simulations produced using the Canadian Regional Climate Model version 5 (CRCM5) at 12 km of resolution driven by simulations from the second generation Canadian Earth System Model (CanESM2) global model at 310 km of resolution.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;The aim of the project is to evaluate the performance of the ClimEx ensemble in simulating the daily cycle and representing extreme values.&amp;#160; To get there, 30 years of hourly time series for precipitation and 3 hourly for temperature are analyzed. The simulations are compared with the values from the simulation of CRCM5 driven by ERA-Interim reanalysis, the ERA5 reanalysis and Environment and Climate Change Canada (ECCC) stations. An evaluation of the sensitivity of different statistics to the number of members is also performed.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;The daily cycle of precipitation from ClimEx shows mainly non-significant correlations with the other datasets and its amplitude is less than the observation datas from ECCC stations. For temperature, the correlation is strong and the amplitude of the cycle is similar to observations. ClimEx provides a fairly good representation of the 95, 97, 99&lt;sup&gt;th&lt;/sup&gt; quantiles for precipitation. For temperature it represents a good distribution of quantiles but with a warm bias in southern Quebec. For precipitation hourly maximum, ClimEx shows values 10 times higher than ERA5.&amp;#160; For temperature, minimum and maximum values may exceed the ERA5 limit by up to 20&amp;#176;C. For precipitation, the minimum number of members for the estimation of the 95 and 99&lt;sup&gt;th&lt;/sup&gt;&lt;sup&gt;&lt;/sup&gt;quantiles and the mean cycle is between 15 and 50 for an estimation error of less than 5%. For the 95, 99&lt;sup&gt;th&lt;/sup&gt; quantiles of temperature, the minimum number of members is between 1 and 17 and for the mean cycle 1 to 2 members are necessary to obtain an estimation error of less than 0.5&amp;#176;C.&lt;/p&gt;

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