Reply #8: My analysis shows that CH3Br is not the albatross

[leebert]

... that the enviros want to hang around Bush's neck.

see:
http://www.epa.gov/Ozone/ods.html
and
http://www.igac.noaa.gov/newsletter/19/yvon-lewis.php

The science has shown that the natural reuptake mechanisms sequester CH3Br at a natural reuptake-to-source rate of 1.4-to-1. Moreover only 43 percent of CH3Br is anthropogenically sourced (agricultural fumigant, biomass burning, gasoline). And while the largest bulk of human-generated CH3Br is from agricultural use (25 percent) the fumigant is only 17% of total natural & man made sources. Moreover, although CH3Br's Ozone-Depleting Potential is amongst the top 50 worst chemicals with ozone-destroying potential, it is ranked 42nd from the top, and taken alone it represents less than 1 percent (1%) of the total ozone-depleting potentials of all man-made Class I ozone-destroying chemicals.

Unless an economically equivalent chemical alternative can be found, the economic costs of CH3Br curtailment will be significant to tomato and strawberry producers in the southern USA. As only more expensive or more dangerous alternatives exist, and with the research on CH3Br leaning towards CH3Br's risk being lowered by larger reuptake mechanisims in the biosphere, the American government is not pursuing as aggressive a phase-out of CH3Br as many environmental groups have publicly commented as being prudent.

Balancing the managed risk of ozone depletion against that the economic costs of ozone damage the Bush administration asked for a slower phase-out of CH3Br in light of these other mitigating factors. Even though CH3Br has the chemical potential to be very aggressive in ozone depletion, agricultural CH3Br constitutes a small piece in overall ozone-depleting chemical outgassing. The overall global reuptake balance (CH3Br sinks) suggests that the phase-out is a greater measure of precaution as than imperative remedy.

The conflicted science of methyl bromide:

http://www.igac.noaa.gov/newsletter/19/batchelor.php

"...Methyl bromide is a significant ozone depleter with a 0.4 Ozone Depletion Potential (ODP), according to the most recent Scientific Assessment on Ozone Depletion . This means that, on a per molecule basis, its effectiveness in depleting ozone is about four times that of methyl chloroform and 40% that of CFC-11, two chemicals banned in 1996. Thus, the bromine in CH3Br, known to deplete 40-50 times more ozone than chlorine (atom for atom), makes CH3Br one of the more hazardous substances for the ozone layer listed under the Protocol, despite its low atmospheric concentration.

"...As the upper atmosphere lags behind by about 6 years, it is predicted that a similar trend will be recorded there next year.

However, the stratosphere is most vulnerable to ozone depletion today and will remain so for the next couple of decades . There is no evidence of replenished levels of ozone and this is not expected for another 20-30 years. For these reasons, countries are constantly reminded not to be complacent and to make every endeavor to continue to phase out ozone-depleting chemicals."

http://www.igac.noaa.gov/newsletter/19/crill.php

Biomass burning is another important source of tropospheric methyl halides . Biomass burning may inject into the troposphere an amount of CH3Br that is similar in magnitude to oceanic and industrial sources. The uncertainty in the estimates is such that burning could contribute about 20% of the total source.

http://www.igac.noaa.gov/newsletter/19/yates.php

CH3Br has been an important component of agricultural systems in the U.S. and its phase-out is expected to cause financial hardship to agricultural producers. Recent economic assessments estimate that more than $1.5 billion in annual lost production would occur in the United States alone .

"...As the CH3Br phase-out date approaches, some questions remain whether restricting CH3Br use will have a significant effect on stratospheric ozone levels . Further, it appears that methodology exists that would enable CH3Br emissions from fumigated soils to be reduced by at least one order of magnitude. This would reduce the global CH3Br contribution from agricultural use to less than 1% of the worldwide sources."

http://www.igac.noaa.gov/newsletter/19/yvon-lewis.php

Source Type Emissions (Gg y-1)
Oceans 56 (5-130)i
Fumigation - soils 26.5 (16-48)
Fumigation - durables 6.6 (4.8-8.4)
Fumigation - perishables 5.7 (5.4-6.0)
Fumigation - structures 2 (2-2)
Gasoline 5 (0-10)
Biomass Burning 20 (10-40)
Wetlands 4.6b (?)
Salt marshes 14c (7-29)
Plants - rapeseed 6.6d (4.8-8.4))
Rice Fields 1.5e (0.5-2.5)
Fungus 1.7f (0.5-5.2)

Total = 151g (56-290)

Sink Type Uptake (Gg y-1)
Oceans -77 (37-133)i
OH and hn -86 (65-107)
Soils -46.8a (32-154)
Plants h

Total = -210g (134-394)

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The aforementioned press release (http://www.commondreams.org/archive/2007/09/21/4008) is naught more than anti-USA agitprop. What's shameful is how some environmental pundits manipulate their constituents with press releases designed to galvanize instead of inform.

The more some environmentalists game the dialectic the more they'll find it harder and harder to find industrialists and governments willing to negotiate in good faith with them, and the less benefit the public will derive from these organizations.

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From: http://www.epa.gov/Ozone/ods.html
(tab delimited... hopefully the tabs will persist for cut&paste...)

Chemical Name Lifetime, in years ODP1 (WMO 20021) ODP2 (Montreal Protocol) ODP3 (40 CFR)
Group I (from section 602 of the CAA)
CFC-11 (CCl3F) Trichlorofluoromethane 45 1 1 1
CFC-12 (CCl2F2) Dichlorodifluoromethane 100 1 1 1
CFC-113 (C2F3Cl3) 1,1,2-Trichlorotrifluoroethane 85 1 0.8 1
CFC-114 (C2F4Cl2) Dichlorotetrafluoroethane 300 0.94 1 1
CFC-115 (C2F5Cl) Monochloropentafluoroethane 1700 0.44 0.6 0.6
Group II (from section 602 of the CAA)
Halon 1211 (CF2ClBr) Bromochlorodifluoromethane 16 6 3 3
Halon 1301 (CF3Br) Bromotrifluoromethane 65 12 10 10
Halon 2402 (C2F4Br2) Dibromotetrafluoroethane 20 8.5 6 6
Group III (from section 602 of the CAA)
CFC-13 (CF3Cl) Chlorotrifluoromethane 640 1 1 1
CFC-111 (C2FCl5) Pentachlorofluoroethane 1 1 1
CFC-112 (C2F2Cl4) Tetrachlorodifluoroethane 1 1 1
CFC-211 (C3FCl7) Heptachlorofluoropropane 1 1 1
CFC-212 (C3F2Cl6) Hexachlorodifluoropropane 1 1 1
CFC-213 (C3F3Cl5) Pentachlorotrifluoropropane 1 1 1
CFC-214 (C3F4Cl4) Tetrachlorotetrafluoropropane 1 1 1
CFC-215 (C3F5Cl3) Trichloropentafluoropropane 1 1 1
CFC-216 (C3F6Cl2) Dichlorohexafluoropropane 1 1 1
CFC-217 (C3F7Cl) Chloroheptafluoropropane 1 1 1
Group IV (from section 602 of the CAA)
CCI4 Carbon tetrachloride 26 0.73 1.1 1.1
Group V (from section 602 of the CAA)
Methyl Chloroform (C2H3Cl3) 1,1,1-trichloroethane 5 0.12 0.1 0.1
Group VII (listed in the Accelerated Phaseout Final Rule)
CHFBr2 1 1
HBFC-12B1 (CHF2Br) 0.74 0.74
CH2FBr 0.73 0.73
C2HFBr4 0.55 0.55 0.55
C2HF2Br3 1.15 1.15 1.15
C2HF3Br2 1 1 1
C2HF4Br 0.95 0.95 0.95
C2H2FBr3 0.6 0.6 0.6
C2H2F2Br2 0.85 0.85 0.85
C2H2F3Br 1.15 1.15 1.15
C2H3FBr2 0.9 0.9 0.9
C2H3F2Br 0.65 0.65 0.65
C2H4FBr 0.09 0.09 0.09
C3HFBr6 0.9 0.9 0.9
C3HF2Br5 1.05 1.05 1.05
C3HF3Br4 1.05 1.05 1.05
C3HF4Br3 1.35 1.35 1.35
C3HF5Br2 1.45 1.45 1.45
C3HF6Br 2 2 2
C3H2FBr5 1 1 1
C3H2F2Br4 1.15 1.15 1.15
C3H2F3Br3 2.9 2.9 2.9
C3H2F4Br2 3.9 3.9 3.9
C3H2F5Br 1.15 1.15 1.15
C3H3FBr4 0.99 0.99 0.99
C3H3F2Br3 1.6 1.6 1.6
C3H3F3Br2 1.3 1.3 1.3
C3H3F4Br 2.35 2.35 2.35
C3H4FBr3 0.17 0.17 0.17
C3H4F2Br2 0.55 0.55 0.55
C3H4F3Br 0.44 0.44 0.44
C3H5FBr2 0.22 0.22 0.22
C3H5F2Br 0.44 0.44 0.44
C3H6FBr 0.36 0.36 0.36
Group VIII (from the Chlorobromomethane Phaseout Final Rule)
CH2BrCl Chlorobromomethane 0.37 0.12 0.12
--
Total ODP, non-CH3Br Class I compounds 78.39 71.38 69.11
--
Group VI (listed in the Accelerated Phaseout Final Rule)
Methyl Bromide (CH3Br) 0.7 0.38 0.6 0.6
--
All ODP totaled 78.77 71.98 69.71
--
CH3Br, percent, all ODP total 0.0048 0.0083 0.0086

From: http://www.igac.noaa.gov/newsletter/19/yvon-lewis.php

Source Type Emissions (Gg y-1) Gg y-1 Balance Gg y-1
Oceans 56 (5-130) 56.00
Fumigation - soils 26.5 (16-48) 26.50
Fumigation - durables 6.6 (4.8-8.4) 6.60
Fumigation - perishables 5.7 (5.4-6.0) 5.70
Fumigation - structures 2 (2-2) 2.00
Gasoline 5 (0-10) 5.00
Biomass Burning 20 (10-40) 20.00
Wetlands 4.6 (?) 4.60
Salt marshes 14 (7-29) 14.00
Plants - rapeseed 6.6 (4.8-8.4)) 6.60
Rice Fields 1.5 (0.5-2.5) 1.50
Fungus 1.7 (0.5-5.2) 1.70

Total = 151g (56-290) 151.00 151.00

Sink Type Uptake (Gg y-1)
Oceans 77 (37-133) -77.00
OH and hn 86 (65-107) -86.00
Soils 46.8 (32-154) -47.00
Plants h ?

Total = 210g (134-394) -210.00 -210.00

Total Global CH3Br Budget -59.00

(a negative number indicates a CH3Br "sink" reuptake function)

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see also ... how partisan enviros helped to torpedo a clean air bill:
http://findarticles.com/p/articles/mi_m1316/is_12_36/ai_n8643128/pg_1