Subject: Re: Hydrogen Energy
From: "Tim and Cheryl Day"
Date: 27 Sep 1996 13:39:20 GMT
Norman Yarvin wrote in article
<52fmokINN1c5@HOBBES.NA.CS.YALE.EDU>...
> Steinn Sigurdsson wrote:
>
> >> Drag force is proportional to the density of the air, times the square
> >> of the speed, times the frontal area. Thus, using the above numbers,
> >> airships would need about four times as much energy to overcome drag
as
> >> airplanes need, in order to transport the same cargo over the same
> >> distance. This is not the whole picture for energy use, since
> >
Well, three things. One, airships would be travelling a lot slower.
They'd be great for transporting freight that doesn't need to get to it's
destination as fast as stuff you'd normally transport by air, so they'd be
competing with surface freight rather than air freight. Obviously, this
would result in a lot less drag (the square of the velocity thing). Two,
heavier than air aircraft drag also results from the production of lift
(induced drag). Lighter than air aircraft induced drag would be minimal,
although I imagine some energy is needed to compress the gas (to let a gas
bag descend - unless you just release into the atmosphere) or heat air (to
let a hot air type airship climb). Three, there's another factor in the
drag equation: form factor. Some shapes effectively reduce drag compared
to some others. If I remember my aero correctly, a round object has about
nine times the effective surface area of a tear drop shaped object. Of
course, airships and aircraft are both designed with this in mind... The
real question is whether or not airships would be cheaper to operate per
unit weight per unit distance than surface freight. I'd guess yes, as long
as the destination was downwind! Does anyone feel like calculating how
much hydrogen you'd need to lift a freight container (100 tons or so?) to,
say, 5000 feet?
Tim Day
day@jax-inter.net
Subject: Re: Carbon in the Atmosphere
From: Steinn Sigurdsson
Date: 27 Sep 1996 14:44:40 +0100
rparson@spot.Colorado.EDU (Robert Parson) writes:
> In article ,
> Steinn Sigurdsson wrote:
> >
> >LeC's original (1888) formulation applied strictly to
> >isolated systems in chemical equilibrium.
>
> And that's the way the terminology is normally used today.
In whose field? ;-)
> >The general concept extends to systems in non-equilibrium
> >(or dynamic equilibrium with external forcing)
> >and analysis of global stability.
> >Prigogine, famously, has worked on formalising the generalised
> >principle, or rather a set of statements that reduce
> >to LeC's principle.
> Consulting De Groot and Mazur, _Thermodynamics of Irreversible
> Processes_, I see that they do discuss a theorem ("systems
> disturbed from a stationary state characterized by minimal
> entropy production return thence etc. etc.") which they characterize
> as an _extension_ of LeChatelier to nonequilibrium stationary states.
I'm quite willing to accept the argument I made characterised
as an extension of LeC's princip. Hell, I'll accept the
characterisation that it is a short hand description of
a heuristic statement.
> Not sure I like this nomenclature, though, since the original
> LeC. Principal compares two *different* equilibrium states (as
> it has to, since equilibrium thermodynamics never lets you do
> anything else.) Vary the state variables of an equilibrium system
> (add NaCl to a saturated solution of AgCl) and the system goes to
> a new equilibrium which is distinct from the original, but not as
> much so as the size of the "forcing" would suggest (Cl precipitates
> out, taking Ag with it, so as to keep the product of the Cl and Ag
> concentrations the same as decreed by St. Gibbs and St. Van't Hoff,
> so there is still more Cl in solution than there was before
> you added any, but there is less additional Cl than what you added).
> This seems to me to be rather different from the example of an
> asymptotically stable dynamical system, with some point or limit
> cycle or other attractor, that you seem to have in mind. There,
Well, I've been consciously trying not to use Chaos theory
language because I think it can be misleading.
> when you disturb the system a little, it goes back _to_ the stable state.
> (Or with no dissipation, does oscillations around the state as you
> discussed in another post.) In LeChatelier you go from one equilibrium
> to a *different* one, and you find that it's not as far away as you
> might have guessed. So I don't like the nomenclature. But I never did
> care for the Belgian School of nonequilibrium Thermo/Stat. Mech.
Well, one aspect of this I think people misperceptualise
is the concept of "artificial forcing". If we changed the
solar constant the climate would simply move in response
until radiation balance would be achieved, and it would
do whatever it takes. Anthropic CO2 forcing is somewhat different
in that it is a perturbation on a coupled system: neglecting
the high frequency modulations, the climate has some similarities
to a mixture being heated. It reaches chemical and thermal equilibrium
with some spatial gradient if heating is not homogenous, and that
there is a dynamic equilibrium does not mean LeC's principle
is inapplicable - mathematically it applies intensive variables
of closed systems, conceptually it is a refined instance of
the more general principle, natural systems don't tend to
hang around at the edge of unstable equilibria.
For another tack - anthropic emission is somewhat analogous
to enhanced volcanic activity. There is a net flux of CO2 from
a reservoir, combined with heterogenous aerosol and sulphate
emission. We expect moderate volcanic emission to be absorbed
by the climate system with small shifts in the mean
(and the analogy extends in that large volcanic emissions
do force large climate shifts). In both cases, for modest
amplitude perturbations we also expect the climate to seek
back to its original statistical equilibrium.
Subject: Re: Major problem with climate predictions
From: jgacker@news.gsfc.nasa.gov (James G. Acker)
Date: 27 Sep 1996 13:45:05 GMT
Eric Anderson (eric@as.arizona.edu) wrote:
: James R. Olson, jr. wrote:
: >
: > Eric Anderson wrote:
: >
: > ->Kirk Johnson wrote:
: > ->>
: > ->> Go ask someone at Allstate or any other large home-owners insurance
: > ->> company if they don't think the effects of global warming are real. I'm
: > ->> not joking.
: >
: > ->Yeah, they are an authority on the subject for sure.
: >
: > Their business depends on predicting the probabilities of disaster
: > accurately, so they have a strong non-politicized interest in accurate
: > models.
:
: Non-politicized, yes. But they have a large financial interest in
: models that predict disaster. This gives them justification for
: charging higher rates. Are you going to deny that? Or are you going to
: bring in lawyers as the next set of *credible* experts?
Insurance companies also have a large stake in not going
bankrupt. Take a look at the shudders Hurricane Andrew sent
through the industry.
: have risen *slightly* in the last century. But such a rise is
: completely within the realm of *natural* processes.
: Sure, it's fine to assume that increased CO2 levels have *something* to
: do with it. But we really don't know, do we?
It's really not an assumption that increased CO2 levels
have something to do with it. The uncertainties lie elsewhere,
primarily in climate feedback responses.
: > Are you saying that the sea level hasn't been rising?
:
: See above. Change out sea-level for temperature.
:
: > Are you saying that yearly temperature extremes haven't increased?
:
: Yes, that is exactly what I am saying. As I recall the global high
: temperature of 136 degrees in Death Valley has been standing for
: decades. Was matched once a few years ago. Now, where were those
: extremes you mentioned? Be sure to include in your data the
: mini-ice-age of the mid-19th century, oh and the one that occured some
: 300 years ago, lasting for decades. Gee, haven't seen anything like
: those *natural* occurances in this century, now have we?
This is the wrong way to define "extremes", which are
constrained by physics. By "extremes", what is normally meant
is a greater occurrence frequency of unusual conditions, i.e.
conditions at the outskirts of a normal distribution. For example,
say the mean # of 90+ degree days in Kansas in August is 12.
Increased yearly temperature extremes would be a trend toward
14 or 15 90+ degree days in Kansas in August. (Which could hurt
the corn crop, if it occurs. Likewise with colder-than-normal
conditions.)
: finally decided to move its weather station away from the *tarmack* at
: the airport. It's location was determined to be the reason for our
: string of record-breaking high temperatures over the last decade.
: Record-breaking temperatures that I am sure were added into the global
: average now used to predict the greenhouse effect. Guess what has
: happened now? Our temperatures have dropped by an average of 3
: degrees. I guess that means we have solved the problem of global
: warming. :)
The heat island effect was recognized almost 10 years
ago, and the record was corrected using comparisons of rural and
urban sites.
: > Strange coincidence. The ozone hole was predicted, and then when we
: > looked for it, there it was. What a strange coincidence, since you
: > claim that the models are invalid.
:
: And a couple of years ago I managed to get the writer of an "Ozone FAQ"
: (don't remember which one) to finally concede that human contributions
: to the ozone hole are on the order of 10%. I still think that's a high
Read the FAQ authored by Robert Parsons, which is probably
much better than whatever you read.
: number but I will concede to it. The moral is, there is obviously
: something much greater going on here that we have very little
: understanding of. 90% of ozone depletion is natural. I would assume
: then that there is a pretty big (natural) force working to restore it.
: Can this force handle our contributions? I don't know. Sure, the
: hole's been growing (usually) for 16 years now. But there have also
: been some big natural events that may be causing this. (It was proved
: that Pinatubo caused one increase.)
:
: BTW, the ozone hole was predicted as a natural phenomenon (which it
: is). I'm not sure if anyone predicted that it would be growing when we
No, that is totally incorrect. The hole first appeared in
the late 1970s, and is correlated with increasing concentrations of
chlorofluorocarbons in the upper atmosphere.
: found it. But that *is* the state it was in *when* we found it. How do
: we know that this growth isn't related to natural cycles or other
: natural phenomenon? I believe it was immediately assumed to be
: human-caused even before we studied it. Thus my belief that biased
: scientists have found exactly what they were looking for. (No, that
: *never* happens, does it?)
Not in this case.
: > First you claim we don't have the data to say whether our current
: > climate is aberrational, then you say we do. It's one way or the
: > other. Make up yyour mind.
:
: I'll try to clarify for you. What I'm saying is that we don't have the
: long-term data we need to *predict* future trends. And while we may
: have data on past climate, we still don't know the *causes* for past
: climate swings. Data is one thing. Predictions are another. For the
: past, we have some data with few explanations. Today we have
: inconsistant data used to support grand conclusions.
With regard to past climate changes (much larger time
scale than currently), geochemists and climatologists have a pretty
good understanding of the major forces driving the climate system.
There are plenty of causes, the largest one (and also the slowest-
moving one) being changes in the rate of plate tectonics. I
can give you some interesting references if you find this
intriguing.
===============================================
| James G. Acker |
| REPLY TO: jgacker@neptune.gsfc.nasa.gov |
===============================================
All comments are the personal opinion of the writer
and do not constitute policy and/or opinion of government
or corporate entities.
Subject: Re: Carbon in the Atmosphere
From: Steinn Sigurdsson
Date: 27 Sep 1996 14:57:41 +0100
pho@mserv1.dl.ac.uk (Pete Owens) writes:
> In article fsf@sandy.ast.cam.ac.uk, Steinn Sigurdsson () writes:
> >Brent Lofgren writes:
> >
> >> Brent Lofgren wrote:
> >
> >> > Bruce Scott TOK wrote:
> >> > > I'd really be surprised if the next century's worth of CO2 emissions
> >> > > could actually trigger a thermohaline disruption, but not actually
> >> > > shocked. But I had the impression that the strongest effect would be on
> >> > > greater instability in the mid-latitude eddy-transport mechanism (ie,
> >> > > more disruptive storms).
> >
> >> > I'm ashamed to say this, joining this thread late and trying to pass
> >> > myself off as at least somewhat of an expert on greenhouse warming, but
> >> > my brain is better at containing concepts themselves, rather than filing
> >> > them with their names. Could someone give a quick rundown on Le
> >> > Chatelier's principle? It sounds very familiar but I can't place it.
> >
> >> First to answer my own question, quoting from Reif, Fundamentals of
> >> Statistical and Thermal Physics, Le Chatelier's principle: "If a system
> >> is
> >> in a stable equilibrium, then any spontaneous change of its parameters
> >> must
> >> bring about processes which tend to restore the system to equilibrium."
> >
> >> Now some more comments on Bruce's statements, which also directly relate
> >> to some made by Steinn and others. It seems that the key qualifying
> >> words
> >> in the above quote are "stable" and "spontaneous." Greenhouse gases
> >
> >Hmm, this is not an exhaustive statement of LeC's principle.
> >
> >> would
> >> produce a forced perturbation, not a spontaneous one. The forcing
> >> itself
> >
> >Yes, _but_ we're not changing the solar constant, we're
> >shifting one source term in a large dynamic system.
> >Remember, there are significant natural processes for
> >CO2 emission and corresponding sinks. Anthropic emission
> >is a perturbation to that dynamic equlibrium, and the
> >carbon sinks can and have responded.
>
> Yes but an important consideration is that the anthropogenic
> forcing is sustained while any spontaineous pertubations
> tend to be transient. These pertubations may be large enough
This is an inaccurate generalisation.
For example, volcanic activity can and does lead
to a permanent release of immobilised carbon into
the atmosphere.
It is also partially the point of the thread,
the transient perturbations lead to climate
transients - if the climate were unstable the
transient perturbations would lead to climate shifts,
and the climate would not relax back to the original state.
> to cause a shift in climate regime if they occured at critical
> points in phase space. You also have to take account of the
Which begs the question.
I've been arguing that we can't be very close to a
critical point, because if we were we'd have crossed it.
> fact that the anthopogenic emmisions will occur *in addition*
> to natural pertubations not instead of them.
So?
> >If we were shifting the solar constant that would be
> >true external forcing as there is no feedback to the
> >suns centre from the Earth. But there is coupling back
> >to the other sink and source terms when anthropic perturbations
> >shift CO2 concentrations.
>
> Indeed, it is posible that eventually an equelibrium could
> be established where enhanced natural CO2 sinks absorb all
> anthropogenic emmisions. These sinks would require higher
> than current atmospheric CO2 concentrations in order to
> sustain them. It is not inevitable that any feedback will
> continue to be negative.
It is not inevitable, of course, in fact I repeatedly point
out instance where the feedback does become positive and
the climate runs away to a new equilibrium.
Question is, is the current state anywhere near doing so.
> >> may alter the terrain of attraction (have I coined a term?). It may
> >
> >nah, sorry. In more prosaic language you're suggesting the
> >potential minima can shift and there might be shift to a
> >new accessible minumum (chaos theory is cute, but its language
> >can be misleading as well as instructive),
> Only if you don't understand it.
Well, if you come across people who don't understand it,
do be careful.
> Using the language of stable equelibrium is misleading when discussing
> a dynamic non-linear system such as the atmosphere.
No, not necessarily. Consider water - forms strongly non-linear
dynamic systems, yet many of the key aspects of behaviour
of water are well characterised by considering stable equilibrium
conditions for the system.
> >> also
> >> force the system into another basin of attraction. LC's principle does
> >> not say that THE SAME equilibrium will be restored. In the example of
> >What it says is that for small perturbations the final equilibrium
> >will be near the original equilibrium (or at it if the dynamics damp).
> This is not the case for dynamic non-linear systems. These can
> by very sensitive to minute changes in conditions. Note that
> this is true even for simple unforced closed systems where
> all the forces acting are completely understood.
And this is why I feel the language of chaos theory is often
misleading. The fact that dynamic non-linear systems
_can_be_ very sensitive to small changes in conditions
does not justify people claiming _all_ of the are very
sensitive to _any_ chance in conditions.
Nor is it necessary to have chaotic systems to get
runaway behaviour, very nicely behaved analytic systems
can diverge exponentially, while strongly chaotic systems
can be statistically stable to strong perturbations.
> >> the Manabe and Stouffer paper, the 2X case had the thermohaline
> >> circulation perturbed but then restored to near the original
> >> equilibrium.
> >> The 4X case had it pushed to a different equilibrium. At some point
> >> between the two, the system would have balanced on a knife edge between
> >> two attractors. So, at least in their model, the potential decidedly
> >> exists.
> >
> >Sure it exists. In the other direction lowering of CO2 would
> >eventually lead to an ice age and then permanent ice age as
> >albedo and opacity started to couple strongly.
> Quite, now you asre starting to get the picture that a small
> change in forcing can alter the climate catastrophically.
"now"? [sic]
If we're unstable to forcing in either direction then
we're screwed anyway, mate. Given that the climate has
been unusually stable for the best part of this interglacial
there has to be some basin of stability in currently accessible
phase space - and its not in the direction of lower CO2.
Subject: Re: What Chemical Is Used To "Mask" Aviation Smoke
From: Sam McClintock
Date: Fri, 27 Sep 1996 10:28:54 -0400
First, a few odds and ends regarding this thread:
1. Grade 54 kerosene contains sulfur levels of <0.3%; Grade 55
contains sulfur levels of <0.04%. Both can be used for
aviation fuel (JPA). I believe the only difference between
aviation grade kerosene and K1 (road quality) is that aviation
fuel is additional filtering for water.
2. De-icing additives can be added to JPA; this is usually a
customer request and is added at the terminal. Obviously,
locale and time of year has a great deal of influence on
whether this is added.
3. I did not want to give the impression that anti-smoke
additive use was wide-spread - it was not. Their use was
fairly limited.
charliew wrote:
>> If these stupid environmentalists keep trying, they may be
>> able to collapse the world economy. I wonder how important
>> clean air is going to be to nations whose people are largely
>> unemployed? Oh, I forgot. The liberal agenda of the
>> environmentalists will ensure that big government takes care
>> of the unemployed.
Then later wrote:
> Incidentally, I am not anti-environment.
I don't mean to flame here, but a reality check is due.
I think it is fairly safe to say that you are against all
environmentalists, with such descriptive comments as: stupid,
collapsing the world economy, liberal agenda, and other heaps
of generous innuendo that lacks any real detail or references
and comes straight from land of talk-show radio.
By inference, we should probably assume you are anti-environment.
With such bitter and basically false characterization of all
environmentalists, you are detracting from and denigrating any
good and meaningful work done in this field.
If on the other hand if you do not mean to infer that environmental
rules and regulations are bad, just the few that go overboard and
do not allow a company any latitude for compliance or remediation
with the same impact, then say so. Point to the issue, statement,
or specific part of a rule you don't like and address the ISSUE. And
if you have a problem with specific environmental groups (which I
certainly do), then say which ones and why SPECIFICALLY they are
a problem.
But continued broad-based attacks on all environmental issues and
their advocates can only boil down to - if the shoe fits . . .
Sam McClintock
sammcc@nando.net
Subject: Re: Hydrogen Energy
From: snark@swcp.com (snark@swcp.com)
Date: 27 Sep 1996 14:23:16 GMT
In article <52fmokINN1c5@HOBBES.NA.CS.YALE.EDU>,
Norman Yarvin wrote:
>Steinn Sigurdsson wrote:
>>> Drag force is proportional to the density of the air, times the square
>>> of the speed, times the frontal area. Thus, using the above numbers,
>>> airships would need about four times as much energy to overcome drag as
>>> airplanes need, in order to transport the same cargo over the same
>>> distance. This is not the whole picture for energy use, since
>>Propulsion power is F.v, so power requirement scales as v^3.
>Power is energy used per unit time. The relevant quantity here is
>energy used per distance traveled. This is equal to the drag force.
The F*v power requirement is important, too, as you must expend the
energy at a much faster rate if you are moving faster, in order to
compensate for the drag. For a "medium" range of speeds, the drag
force scales as approximately v^2, so the power requirement is
proportional to v^3, as Steinn notes.
The F*v "effect" was not always obvious. I recall reading about some
of the early two-stage rocket experiments. It used to be that, after
the separation of the first stage, they would let the second stage
coast until the altitude peaked, then fire the 2nd stage (note: when v
was zero). One time, accidently, the 2nd stage fired shortly after
separation (when v was high), and the rocket reached a *much* higher
altitude (I.e., the effective power, F*v, was much higher). I think
this may also be the reason that "slingshot" trajectories for space travel
are effective--one builds up speed by falling towards a body, then
fires ones rockets at high speed. (I'm out on a limb here; I haven't
really checked this).
>Norman Yarvin yarvin@cs.yale.edu
snark
Subject: Re: Freon R12 is Safe
From: Dodge Boy
Date: Fri, 27 Sep 1996 11:25:46 -0400
R. Tang wrote:
>
> In article <324A8317.30F4@howellautomotive.com>,
> Dodge Boy wrote:
> >Lloyd R. Parker wrote:
> >> Dodge Boy (DodgeBoy@howellautomotive.com) wrote:
> >> : There is no confirmed evidence that R12 has damaging effect on the ozone layer.
> >> Sorry, there is overwhelming evidence that R12 has damaged the ozone
> >> layer. A simple glance in any SCIENTIFIC journal would show you that.
> >> I've been through this every week with another neophyte it seems, so I'll
> >> just say the evidence is there, the proponents won the Nobel Prize, and
> >> it is accepted by science and the world's leaders. To deny it is sophistry.
> >Sorry, maybe I should rephrase what I meant.
>
> Perhaps you ought to do some research. Period.
I did some research and I came up with a different conclusion than you. That
doesn't make my conclusion wrong, and it doesn't make it right, just different.
Now I'm willing to change my opinion if presented with a good argument, and not
people saying your wrong with no explination. And I have some questions that I
want answered.
>
> > Yes you are right that R12 damages
> >the ozone, but there is no evidence that the effect makes any difference. It is a
> >drop in the bucket, compared to the ozone damaging Chlorine radicals released by
> >natural volcanic eruptions.
>
> This is quite incorrect. Volcanic eruptions release HCl, which is
> soluble and thus does not reach the stratosphere.
If it gets blasted higher than the rain clouds it will not get washed out.
Several planes have had air intakes clogged with volcanic dust, while flying
above the level of rain. That is hard evidence that some of the volcanic
eruptions go above the level of rain clouds. This would tend to put some of
the particles into the stratosphere, they may not cause a problem with the
ozone, but this would tend make your above statment false, and if it is not
accurate are there other mistakes in the information that you have been
presented with?
> Scientists making direct
> stratospheric measurements of volcanic chlorine found very little chlorine
> in the stratosphere.
> Who's scientist. EPA, Greenpeace, MIT, NOAA, who? If they found little
chlorine in the stratosphere, then where is all the chlorine that is damaging
the ozone. If the chlorine from CFC's is damaging the ozone, then it has to be
in the stratosphere, but your research information says that there is very
little. So is the chlorine there or not. If not then is something else
damaging the ozone, that has yet to be discovered, or is the hole just there
naturaly and always has been? That is part of the problem, both side of the
argument have contradictions.
> --
> Roger Tang, gwangung@u.washington.edu, Artistic Director PC Theatre
> Editor, Asian American Theatre Revue:
> http://weber.u.washington.edu/~gwangung/TC.html
> Declared 4-F in the War Between the Sexes
Subject: Re: electric vehicles
From: johnth39@mail.idt.net (John Theofanopoulos)
Date: Fri, 27 Sep 1996 19:20:43 GMT
On Fri, 27 Sep 1996 05:04:24 GMT, hatunen@netcom.com (DaveHatunen)
wrote:
>One of the problems with the discussions about EVs in these venues is
>that everybody is talking about different things. Some people think EVs
Actually, the biggest problem with our discussion is you went from
telling me that the fast charger I use almost daily doesn't exist, to
talking about what EV's are going to be used for. You seem to be
grasping at straws as far as making your point goes. Let's see what
else you have to say.
>will only be used for short trips, and an ICV will be retained for
>everything else (of course, for many people the day consists of a quick
>series of short trips: for isntance, my wife can easily put 100 miles
>or more on her car running short trip errands). Others think problems
Sounds like me. I used to make a heck of a lot of miles on my car
going in circles. Now I take the EV home and somehow I still manage
to get all my errands done. Hmm.. Could it be that since I know I
have a certain range I plan my day out better? Nah, that couldn't
possibly be it.
>will only be solved if ICVs disappear. So we really need to talk about
>how high a penetration into the number of vehicles is to be made by EVs
>before some questions can be properly addressed.
Not really. You buy an EV if you think it's practical. Would you buy
a 10 wheeler to commute to work? No. Same applies here. The
consumer in the end will decide if the EV with all its limitations is
practical for their application. Argueing the point solves nothing as
we cannot force them to buy either and EV or and ICV.
>
>That being said, the cars must be charged, whether at home, at work, or
>at some sort of special charging station, and the problem should be
>addressed on a day-round basis. The total daily energy requirement of
>the entire fleet of EVs in a given region must be considered.
I'll bite. You go to work and you put your car on the slow charge (if
need be). End of the 8 hour day, it's fully charged (hence the EV
America requirement that the vehicle fully charge in under 8 hours).
If you drive all day (such as the UPS vehicles or other utility
vehicles) then you will use the Fast Chargers located at your home
base (or whatever you want to call it). 20-25 minutes will give you
90% of your full SOC back. If as a consumer you feel the need to
drive around all day, then you can use the public fast chargers
located wherever they may be. Of course as a consumer, you can opt to
stay with your current IC vehicle, which of course means you can drive
around all day and not care about recharging.
>
>So, how about some numbers to discuss? Assume an area like Sothern
>California, which probably has probably has some 20,000,000 ICVs. What
There are no assumptions to be made here. The amount of EV's out
there will depend on what consumers (private and public) need and
want. This however is irrelevant to the discussion. To make this
relevant, you need to get the numbers of how a Nuclear Generator
affects the ecosystem for every MW it puts out. Once you get those
numbers get back to me.
>can make some educated estimates of the actual power requirements for
>recharging.
Not really. You can't guarantee where each of these EV's will be at
any given time, never mind guaranteeing that even 50% of them will be
at the fast charge stations at a given time. Therefore, unless you
start tracking vehicles and compiling data, you are just talking
nonsense. This thread is at this point exhausted as you have
absolutely no (O) facts to back up any of your claims with.
>>I don't even want to get into something I know very little about
>>(efficiency and safety of nuclear plants),
>
>That didn't stop you above.
This coming from a guy who told the engineer who's been fast charging
his EV or a regular basis that a fast charger does not exist and is in
fact not feasible because of wire gauging. Hmm. Maybe I should call
the Ford guy back and tell him that I can't give him the info he
requested on the fast charger because Dave on the Interner says it
doesn't exist. I'm sure he'll like that response (considering he's
seen our portable trailer).
John Theofanopoulos |The views expressed above are mine and
jt45@chrysler.com |mine alone, and do not reflect the views
johnth39@mail.idt.net |of my employer nor are they endorsed in
NS-EV E/E Systems |any way by said employer
Subject: Re: What Chemical Is Used To "Mask" Aviation Smoke
From: charliew@hal-pc.org (charliew)
Date: Fri, 27 Sep 96 15:30:14 GMT
In article <324BE4A6.5848@nando.net>, Sam McClintock
wrote:
>First, a few odds and ends regarding this thread:
>
>1. Grade 54 kerosene contains sulfur levels of <0.3%; Grade
55
>contains sulfur levels of <0.04%. Both can be used for
>aviation fuel (JPA). I believe the only difference between
>aviation grade kerosene and K1 (road quality) is that
aviation
>fuel is additional filtering for water.
>
>2. De-icing additives can be added to JPA; this is usually a
>customer request and is added at the terminal. Obviously,
>locale and time of year has a great deal of influence on
>whether this is added.
There are other ways to "get there". My employer has a
maximum freeze point specification on kerosene. A freeze
point analyzer ensures that we stay below this number during
manufacture. Thus, kerosene composition by itself can keep
jet fuel from freezing at too high of a temperature.
>
>3. I did not want to give the impression that anti-smoke
>additive use was wide-spread - it was not. Their use was
>fairly limited.
>
>charliew wrote:
>>> If these stupid environmentalists keep trying, they may
be
>>> able to collapse the world economy. I wonder how
important
>>> clean air is going to be to nations whose people are
largely
>>> unemployed? Oh, I forgot. The liberal agenda of the
>>> environmentalists will ensure that big government takes
care
>>> of the unemployed.
>
>Then later wrote:
>> Incidentally, I am not anti-environment.
>
>I don't mean to flame here, but a reality check is due.
I agree. A reality check is *over-due*. If any
environmentalists out there think for a moment that industry
can be coerced into operating with zero emissions, they are
sadly deluded. This is an *impossible* requirement. The
only way to comply is to shut down. It's time to set some
low and achievable level of emissions, and live with it,
without constant demands for ever decreasing emissions.
>
>I think it is fairly safe to say that you are against all
>environmentalists, with such descriptive comments as:
stupid,
>collapsing the world economy, liberal agenda, and other
heaps
>of generous innuendo that lacks any real detail or
references
>and comes straight from land of talk-show radio.
>
>By inference, we should probably assume you are
anti-environment.
>With such bitter and basically false characterization of all
>environmentalists, you are detracting from and denigrating
any
>good and meaningful work done in this field.
>
>If on the other hand if you do not mean to infer that
environmental
>rules and regulations are bad, just the few that go
overboard and
>do not allow a company any latitude for compliance or
remediation
>with the same impact, then say so. Point to the issue,
statement,
>or specific part of a rule you don't like and address the
ISSUE. And
>if you have a problem with specific environmental groups
(which I
>certainly do), then say which ones and why SPECIFICALLY they
are
>a problem.
I addressed the issue above. Although my statement is broad
in that it doesn't mention a particular pollutant, I am
hoping you get the idea.
============================================================================
For some *very* interesting alternate viewpoints, look at
http://www.hamblin.com/mf.main/articles.html
Subject: Re: Carbon in the Atmosphere
From: rparson@spot.Colorado.EDU (Robert Parson)
Date: 27 Sep 1996 16:42:22 GMT
In article ,
Steinn Sigurdsson wrote:
>rparson@spot.Colorado.EDU (Robert Parson) writes:
>
>> And that's the way the terminology is normally used today.
>
>In whose field? ;-)
All of Chemistry, and Physics at the undergrad/ first year grad
level. (Consulted a few Thermo/Stat Mech texts - e.g. Lifshitz
and Pitaevski p. 22). L.E. Reichl, _Statistical Physics_, does give
a definition which seems formulated so to make your extension natural,
but Reichl's book suffers, in my not at all humble opinion, from
the Malign Influence of the Belgian School ;-) (She wrote the book
on sabbatical in Brussels, and Prigogine wrote a forward for it.)
>> This seems to me to be rather different from the example of an
>> asymptotically stable dynamical system, with some point or limit
>> cycle or other attractor, that you seem to have in mind. There,
>
>Well, I've been consciously trying not to use Chaos theory
>language because I think it can be misleading.
Agree, but you don't need to bring "chaos" into it, just damped
oscillators and limit cycles. OK I see the problem - ever since
chaos became trendy, it's sort of subsumed the whole field of
dynamical systems so that when you say "attractor" or something
people automatically think you're bringing in chaos theory.
>Well, one aspect of this I think people misperceptualise
>is the concept of "artificial forcing". If we changed the
>solar constant the climate would simply move in response
>until radiation balance would be achieved, and it would
>do whatever it takes. Anthropic CO2 forcing is somewhat different
>in that it is a perturbation on a coupled system: neglecting
>the high frequency modulations, the climate has some similarities
>to a mixture being heated. It reaches chemical and thermal equilibrium
>with some spatial gradient if heating is not homogenous, and that
>there is a dynamic equilibrium does not mean LeC's principle
>is inapplicable - mathematically it applies intensive variables
>of closed systems, conceptually it is a refined instance of
>the more general principle, natural systems don't tend to
>hang around at the edge of unstable equilibria.
I follow you now. But I think that unless you're talking to an
audience of aficionadoes of the Thermodynamics of Nonequilibrium
Stationary States, using "LeChatelier" in your heuristic is going
to cause some confusion.
Subject: Re: Freon R12 is Safe
From: brshears@whale.st.usm.edu (Harold Brashears)
Date: Fri, 27 Sep 1996 17:03:01 GMT
Dodge Boy wrote for all to see:
Saoory to query thruogh Dodge Boy, but Parker's post did not hit my
server.
>First off presented with evidence, I am willing to change my views, but you are going
>to have to answer some questions to my satisfaction.
>
>Lloyd R. Parker wrote:
>>
>> Dodge Boy (DodgeBoy@howellautomotive.com) wrote:
>> :
>> : Sorry, maybe I should rephrase what I meant. Yes you are right that R12 damages
>> : the ozone, but there is no evidence that the effect makes any difference. It is a
>> : drop in the bucket, compared to the ozone damaging Chlorine radicals released by
>> : natural volcanic eruptions. You cut down one tree in a forest of thousands it
>> : doesn't harm the forest, but if you cut them all down it becomes a desert. R12
>> : is one tree in a forest of millions.
>> :
>> : Dodge Boy
>>
>> Sorry, what you meant was quite clear, and quite wrong. We know
>> volcanoes do not put Cl into the stratosphere -- we measured no Cl
>> increase there after Pinatubo.
I read in Science, vol 226 (1984) the article "Increased Stratospheric
Hydrogen Chloride in the El Chichon Cloud", by Coffey and Mankin. Are
you telling me that this data is wrong? I would like to see where
their conclusions were refuted. Thanks.
[deleted]
Regards, Harold
----
"In 1992 the Democrats finally got -- well, you might say cynical or
you might say serious. ...So they nominated a man who is no one's
idea of a goody-goody. They nominated a slippery politician. Not
coincidentally, he is also a morally flawed character with personal
and (perhaps) financial peccadilloes."
--Essayist Michael Kinsley (Time, 4/29/96)
Subject: Re: Freon R12 is Safe
From: gwangung@u.washington.edu (R. Tang)
Date: 27 Sep 1996 17:11:32 GMT
In article <324BF1FA.1199@howellautomotive.com>,
Dodge Boy wrote:
>R. Tang wrote:
>> >Sorry, maybe I should rephrase what I meant.
>>
>> Perhaps you ought to do some research. Period.
>
>I did some research and I came up with a different conclusion than you.
Not from the literature, I'm afraid.
>> > Yes you are right that R12 damages
>> >the ozone, but there is no evidence that the effect makes any difference. It is a
>> >drop in the bucket, compared to the ozone damaging Chlorine radicals released by
>> >natural volcanic eruptions.
>> This is quite incorrect. Volcanic eruptions release HCl, which is
>> soluble and thus does not reach the stratosphere.
>
>If it gets blasted higher than the rain clouds it will not get washed out.
Yes, it will.
>> stratospheric measurements of volcanic chlorine found very little chlorine
>> in the stratosphere.
>> Who's scientist. EPA, Greenpeace, MIT, NOAA, who?
Peer-reviewed.
> If they found little
>chlorine in the stratosphere, then where is all the chlorine that is damaging
>the ozone.
Read carefully. I said very little volcanic chlorine.
--
Roger Tang, gwangung@u.washington.edu, Artistic Director PC Theatre
Editor, Asian American Theatre Revue:
http://weber.u.washington.edu/~gwangung/TC.html
Declared 4-F in the War Between the Sexes
Subject: Guide to Enviro Computing v1.2
From: greendisk@igc.org
Date: 27 Sep 1996 10:00:10
From: The GreenDisk Journal
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
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Subject: Re: electric vehicles
From: hatunen@netcom.com (DaveHatunen)
Date: Fri, 27 Sep 1996 17:48:11 GMT
In article <324c0ac3.263888@news.idt.net>,
John Theofanopoulos wrote:
>On Fri, 27 Sep 1996 05:04:24 GMT, hatunen@netcom.com (DaveHatunen)
>wrote:
>
>>One of the problems with the discussions about EVs in these venues is
>>that everybody is talking about different things. Some people think EVs
>
>Actually, the biggest problem with our discussion is you went from
>telling me that the fast charger I use almost daily doesn't exist, to
>talking about what EV's are going to be used for. You seem to be
>grasping at straws as far as making your point goes. Let's see what
>else you have to say.
It would be helpful if you were to supply some information instead of
just griping. Please describe this fast charger for your car: total
charge in kwh or some other suitable energy unit, and input voltage and
current or kwh. So far you've only talked about your welder in any
detail.
>
>>will only be used for short trips, and an ICV will be retained for
>>everything else (of course, for many people the day consists of a quick
>>series of short trips: for isntance, my wife can easily put 100 miles
>>or more on her car running short trip errands). Others think problems
>
>Sounds like me. I used to make a heck of a lot of miles on my car
>going in circles. Now I take the EV home and somehow I still manage
>to get all my errands done. Hmm.. Could it be that since I know I
>have a certain range I plan my day out better? Nah, that couldn't
>possibly be it.
For all I know your errands consist of two block runs from the house.
How about some details?
>>will only be solved if ICVs disappear. So we really need to talk about
>>how high a penetration into the number of vehicles is to be made by EVs
>>before some questions can be properly addressed.
>
>Not really. You buy an EV if you think it's practical. Would you buy
>a 10 wheeler to commute to work? No. Same applies here. The
>consumer in the end will decide if the EV with all its limitations is
>practical for their application. Argueing the point solves nothing as
>we cannot force them to buy either and EV or and ICV.
I can't argue with that, and won't. In fact, that's always been my
point: the consumer in the end will decide. Some of us feel that the
consumer will not decide for EVs in significant numbers, some think
they will jump on them.
That is, of course, a bit different from my other contention: that
should some very significant number of consumers decide over a period of
time to convert to EVs, say one-third to one-half, there will be major
impacts on the infrastructure, including the need for more generating
capacity at the utilites.
>>That being said, the cars must be charged, whether at home, at work, or
>>at some sort of special charging station, and the problem should be
>>addressed on a day-round basis. The total daily energy requirement of
>>the entire fleet of EVs in a given region must be considered.
>
>I'll bite. You go to work and you put your car on the slow charge (if
>need be).
There's a world of presumption in that statement. One cannot just go to
a parking lot and find an outlet there usable for a free slow charge.
Not even in the parking garage at work.
[...]
>There are no assumptions to be made here. The amount of EV's out
>there will depend on what consumers (private and public) need and
>want. This however is irrelevant to the discussion. To make this
>relevant, you need to get the numbers of how a Nuclear Generator
>affects the ecosystem for every MW it puts out. Once you get those
>numbers get back to me.
Actually, a nuclear power plant has virtually no effect on the
ecosystem. Some waste heat (typical of any power plant) but that's
about all.
>>can make some educated estimates of the actual power requirements for
>>recharging.
>
>Not really. You can't guarantee where each of these EV's will be at
>any given time, never mind guaranteeing that even 50% of them will be
>at the fast charge stations at a given time. Therefore, unless you
>start tracking vehicles and compiling data, you are just talking
>nonsense. This thread is at this point exhausted as you have
>absolutely no (O) facts to back up any of your claims with.
>
>>>I don't even want to get into something I know very little about
>>>(efficiency and safety of nuclear plants),
>>
>>That didn't stop you above.
>
>This coming from a guy who told the engineer who's been fast charging
>his EV or a regular basis that a fast charger does not exist and is in
>fact not feasible because of wire gauging. Hmm. Maybe I should call
>the Ford guy back and tell him that I can't give him the info he
>requested on the fast charger because Dave on the Interner says it
>doesn't exist. I'm sure he'll like that response (considering he's
>seen our portable trailer).
I NEVER said fast charges didn't exist, nor did I say they couldn't
exist.
--
********** DAVE HATUNEN (hatunen@netcom.com) **********
* Daly City California *
* Between San Francisco and South San Francisco *
*******************************************************
Subject: Re: Carbon in the Atmosphere
From: pho@mserv1.dl.ac.uk (Pete Owens)
Date: 27 Sep 1996 09:26:20 GMT
In article fsf@sandy.ast.cam.ac.uk, Steinn Sigurdsson () writes:
>Brent Lofgren writes:
>
>> Brent Lofgren wrote:
>
>> > Bruce Scott TOK wrote:
>
>
>> > > I'd really be surprised if the next century's worth of CO2 emissions
>> > > could actually trigger a thermohaline disruption, but not actually
>> > > shocked. But I had the impression that the strongest effect would be on
>> > > greater instability in the mid-latitude eddy-transport mechanism (ie,
>> > > more disruptive storms).
>
>> > I'm ashamed to say this, joining this thread late and trying to pass
>> > myself off as at least somewhat of an expert on greenhouse warming, but
>> > my brain is better at containing concepts themselves, rather than filing
>> > them with their names. Could someone give a quick rundown on Le
>> > Chatelier's principle? It sounds very familiar but I can't place it.
>
>> First to answer my own question, quoting from Reif, Fundamentals of
>> Statistical and Thermal Physics, Le Chatelier's principle: "If a system
>> is
>> in a stable equilibrium, then any spontaneous change of its parameters
>> must
>> bring about processes which tend to restore the system to equilibrium."
>
>> Now some more comments on Bruce's statements, which also directly relate
>> to some made by Steinn and others. It seems that the key qualifying
>> words
>> in the above quote are "stable" and "spontaneous." Greenhouse gases
>
>Hmm, this is not an exhaustive statement of LeC's principle.
>
>> would
>> produce a forced perturbation, not a spontaneous one. The forcing
>> itself
>
>Yes, _but_ we're not changing the solar constant, we're
>shifting one source term in a large dynamic system.
>Remember, there are significant natural processes for
>CO2 emission and corresponding sinks. Anthropic emission
>is a perturbation to that dynamic equlibrium, and the
>carbon sinks can and have responded.
Yes but an important consideration is that the anthropogenic
forcing is sustained while any spontaineous pertubations
tend to be transient. These pertubations may be large enough
to cause a shift in climate regime if they occured at critical
points in phase space. You also have to take account of the
fact that the anthopogenic emmisions will occur *in addition*
to natural pertubations not instead of them.
>If we were shifting the solar constant that would be
>true external forcing as there is no feedback to the
>suns centre from the Earth. But there is coupling back
>to the other sink and source terms when anthropic perturbations
>shift CO2 concentrations.
Indeed, it is posible that eventually an equelibrium could
be established where enhanced natural CO2 sinks absorb all
anthropogenic emmisions. These sinks would require higher
than current atmospheric CO2 concentrations in order to
sustain them. It is not inevitable that any feedback will
continue to be negative.
>> may alter the terrain of attraction (have I coined a term?). It may
>
>nah, sorry. In more prosaic language you're suggesting the
>potential minima can shift and there might be shift to a
>new accessible minumum (chaos theory is cute, but its language
>can be misleading as well as instructive),
Only if you don't understand it.
Using the language of stable equelibrium is misleading when discussing
a dynamic non-linear system such as the atmosphere.
>> also
>> force the system into another basin of attraction. LC's principle does
>> not say that THE SAME equilibrium will be restored. In the example of
>
>What it says is that for small perturbations the final equilibrium
>will be near the original equilibrium (or at it if the dynamics damp).
This is not the case for dynamic non-linear systems. These can
by very sensitive to minute changes in conditions. Note that
this is true even for simple unforced closed systems where
all the forces acting are completely understood.
>> the Manabe and Stouffer paper, the 2X case had the thermohaline
>> circulation perturbed but then restored to near the original
>> equilibrium.
>> The 4X case had it pushed to a different equilibrium. At some point
>> between the two, the system would have balanced on a knife edge between
>> two attractors. So, at least in their model, the potential decidedly
>> exists.
>
>Sure it exists. In the other direction lowering of CO2 would
>eventually lead to an ice age and then permanent ice age as
>albedo and opacity started to couple strongly.
Quite, now you asre starting to get the picture that a small
change in forcing can alter the climate catastrophically.
---
Pete Owens
P.Owens@dl.ac.uk
Subject: Re: Freon R12 is Safe
From: B.Hamilton@irl.cri.nz (Bruce Hamilton)
Date: Fri, 27 Sep 1996 17:43:35 GMT
Dodge Boy wrote:
>R. Tang wrote:
>> In article <...> Dodge Boy wrote:
>> >Lloyd R. Parker wrote:
>> >> Dodge Boy (DodgeBoy@howellautomotive.com) wrote:
>> >> : There is no confirmed evidence that R12 has damaging effect on the ozone layer.
>> >> Sorry, there is overwhelming evidence that R12 has damaged the ozone
>> >> layer. ....
>> >Sorry, maybe I should rephrase what I meant.
>> Perhaps you ought to do some research. Period.
>I did some research and I came up with a different conclusion than you. That
>doesn't make my conclusion wrong, and it doesn't make it right, just different.
No. It indicates that your "research" is incomplete. Have you read the
Ozone Depletion FAQ yet, you have been referred to it. If so, what aspects
of the information presented are you disputing?.
>Now I'm willing to change my opinion if presented with a good argument, and not
>people saying your wrong with no explination. And I have some questions that I
>want answered.
Several people have pointed you to specific research articles, and
general, easily accessible references such as the FAQ. Either read
them and come back to sci.environment with sensible comments or
questions, or stop splattering your assertions across Usenet.
>If it gets blasted higher than the rain clouds it will not get washed out.
>Several planes have had air intakes clogged with volcanic dust, while flying
>above the level of rain. That is hard evidence that some of the volcanic
>eruptions go above the level of rain clouds. This would tend to put some of
>the particles into the stratosphere, they may not cause a problem with the
>ozone, but this would tend make your above statment false, and if it is not
>accurate are there other mistakes in the information that you have been
>presented with?
You continued wilful failure to read the FAQ is disappointing. Let me
provide an example of the quality *referenced* information available to
people who want to just perform the simplest research ( FTP the FAQ
from rtfm.mit.edu in the pub/usenet-by-hierarchy/sci/environment ) by
adding the relevent section from the FAQ to the bottom of this post.
This clearly demonstrates the trivial nature of the volcanic contribution.
>> Scientists making direct
>> stratospheric measurements of volcanic chlorine found very little chlorine
>> in the stratosphere.
> Who's scientist. EPA, Greenpeace, MIT, NOAA, who? If they found little
>chlorine in the stratosphere, then where is all the chlorine that is damaging
>the ozone. If the chlorine from CFC's is damaging the ozone, then it has to be
>in the stratosphere, but your research information says that there is very
>little. So is the chlorine there or not. If not then is something else
>damaging the ozone, that has yet to be discovered, or is the hole just there
>naturaly and always has been? That is part of the problem, both side of the
>argument have contradictions.
The poster was clearly talking about chlorine from volcanoes.
Read the FAQ and the specific articles others have pointed
you towards, including "Satellite confirmation of the dominance
of chlorofluorocarbons in the global stratospheric chlorine budget"
J.M.Russell III, M.Luo, R.J.Cicerone, L.E.Deaver
Nature v.379 p.526-529 ( 8 February 1996 ); along with the
commentary article describing the significance of that research
in the same issue " There's safety in numbers" W.Brune p.486-487.
Please, if your really do want to be informed, get the FAQ and some
of the references therein, and *read* them!. If you then have any
questions, post them to sci.environment where people will try to
help. The science is robust.
Bruce Hamilton
[ Begin extract from the Ozone Depletion FAQ ]
Subject: 4.4) Volcanoes put more chlorine into the stratosphere than CFC's.
Short Reply: False. Volcanoes account for at most a few percent
of the chlorine in the stratosphere.
Long reply: This is one of the most persistent myths in this
area. As is so often the case, there is a seed of truth at the
root of the myth. Volcanic gases are rich in Hydrogen Chloride, HCl.
As we have discussed, this gas is very soluble in water and is
removed from the troposphere on a time scale of 1-7 days, so we can
dismiss quietly simmering volcanoes as a stratospheric source, just
as we can neglect sea salt and other natural sources of HCl. (In fact
tropospheric HCl from volcanoes is neglible compared to HCl from
sea salt.) However, we cannot use this argument to dismiss MAJOR
volcanic eruptions, which can in principle inject HCl directly into
the middle stratosphere.
What is a "major" eruption? There is a sort of "Richter scale" for
volcanic eruptions, the so-called "Volcanic explosivity index" or
VEI. Like the Richter scale it is logarithmic; an eruption with a
VEI of 5 is ten times "bigger" than one with a VEI of 4. To give a
sense of magnitude, I list below the VEI for some familiar recent
and historic eruptions:
Eruption VEI Stratospheric Aerosol,
Megatons (Mt)
Kilauea 0-1 -
Erebus, 1976-84 1-2 -
Augustine, 1976 4 0.6
St Helen's, 1980 5 (barely) 0.55
El Chichon, 1982 5 12
Pinatubo, 1991 5-6 30
Krakatau, 1883 6 50 (estimated)
Tambora, 1815 7 80-200 (estimated)
[Smithsonian] [Symonds et al.] [Sigurdsson] [Pinatubo] [WMO 1988]
[Bluth et al.] [McCormick et al. 1995]
Roughly speaking, an eruption with VEI>3 can penetrate the
stratosphere. An eruption with VEI>5 can send a plume up to 25km, in the
middle of the ozone layer. Such eruptions occur about once a decade.
Since the VEI is not designed specifically to measure a volcano's impact
on the stratosphere, I have also listed the total mass of stratospheric
aerosols (mostly sulfates) produced by the eruption. (Note that St.
Helens produced much less aerosol than El Chichon - St. Helens blew out
sideways, dumping a large ash cloud over eastern Washington, rather than
ejecting its gases into the stratosphere.) Passively degassing volcanoes
such as Kilauea and Erebus are far too weak to penetrate the
stratosphere, but explosive eruptions like El Chichon and Pinatubo need
to be considered in detail.
Before 1982, there were no direct measurements of the amount of HCl
that an explosive eruption put into the stratosphere. There were,
however, estimates of the _total_ chlorine production from an
eruption, based upon such geophysical techniques as analysis of
glass inclusions trapped in volcanic rocks. [Cadle] [Johnston]
[Sigurdsson] [Symonds et al.] There was much debate
about how much of the emitted chlorine reached the stratosphere;
estimates ranged from < 0.03 Mt/year [Cadle] to 0.1-1.0 Mt/year
[Symonds et al.]. During the 1980's emissions of CFC's and related
compounds contributed ~1 Mt of chlorine per year to the
atmosphere. [Prather et al.] This results in an annual flux of >0.3
Mt/yr of chlorine into the stratosphere. The _highest_ estimates
of volcanic emissions - upper limits calculated by assuming that
_all_ of the HCl from a major eruption reached and stayed in the
stratosphere - were thus of the same order of magnitude as human
sources. (There is no support whatsoever for the claim that a
_single_ recent eruption produced ~500 times as much chlorine as a
year's worth of CFC production. This wildly inaccurate number appears
to have originated as an editorial mistake in a scientific encyclopedia.)
It is very difficult to reconcile the higher estimates with the
altitude and time-dependence of stratospheric HCl. The volcanic
contribution to the upper stratosphere should come in sudden bursts
following major eruptions, and it should initially be largest in
the vicinity of the volcanic plume. Since vertical transport in the
stratosphere is slow, one would expect to see the altitude profile
change abruptly after a major eruption, whereas it has maintained
more-or-less the same shape since it was first measured in 1975.
One would also not expect a strong correlation between HCl and
organochlorine compounds if volcanic injection were contributing
~50% of the total HCl. If half of the HCl has an inorganic origin,
where is all that _organic_ stratospheric chlorine going?
The issue has now been largely resolved by _direct_ measurements of the
stratospheric HCl produced by El Chichon, the most important eruption of
the 1980's, and Pinatubo, the largest since 1912. It was found that El
Chichon injected *0.04* Mt of HCl [Mankin and Coffey]. The much bigger
eruption of Pinatubo produced less [Mankin, Coffey and Goldman] [Wallace
and Livingston 1992], - in fact the authors were not sure that they had
measured _any_ significant increase. Analysis of ice cores leads to
similar conclusions for historic eruptions [Delmas]. The ice cores show
significantly enhanced levels of sulfur following major historic
eruptions, but no enhancement in chlorine, showing that the chlorine
produced in the eruption did not survive long enough to be transported
to polar regions. It is clear, then, that even though major eruptions
produce large amounts of chlorine in the form of HCl, most of that HCl
either never enters the stratosphere, or is very rapidly removed from it.
Recent model calculations [Pinto et al.] [Tabazadeh and Turco]
have clarified the physics involved. A volcanic plume contains
approximately 1000 times as much water vapor as HCl. As the plume
rises and cools the water condenses, capturing the HCl as it does
so and returning it to the earth in the extensive rain showers that
typically follow major eruptions. HCl can also be removed if it
is adsorbed on ice or ash particles. Model calculations show that
more than 99% of the HCl is removed by these processes, in good
agreement with observations.
.............................
In summary:
* Older indirect _estimates_ of the contribution of volcanic
eruptions to stratospheric chlorine gave results that ranged
from much less than anthropogenic to somewhat larger than
anthropogenic. It is difficult to reconcile the larger estimates
with the altitude distribution of inorganic chlorine in the
stratosphere, or its steady increase over the past 20 years.
Nevertheless, these estimates raised an important scientific
question that needed to be resolved by _direct_ measurements
in the stratosphere.
* Direct measurements on El Chichon, the largest eruption of
the 1980's, and on Pinatubo, the largest since 1912, show
that the volcanic contribution is small.
* Claims that volcanoes produce more stratospheric chlorine than
human activity arise from the careless use of old scientific
estimates that have since been refuted by observation.
* Claims that a single recent eruption injected ~500 times a year's
CFC production into the stratosphere have no scientific basis
whatsoever.
.................................................................
To conclude, we need to say something about Mt. Erebus. In an
article in _21st Century_ (July/August 1989), Rogelio Maduro
claimed that this Antarctic volcano has been erupting constantly
for the last 100 years, emitting more than 1000 tons of chlorine
per day. Mt. Erebus has in fact been simmering quietly for over a
century [ARS] but the estimate of 1000 tons/day of HCl only applied
to an especially active period between 1976 and 1983 [Kyle et al. 1990].
Moreover, that estimate has been since been reduced to 167 tons/day
(0.0609 Mt/year). By late 1984 emissions had dropped by an order of
magnitude, and have remained at low levels since; HCl emissions
_at the crater rim_ were 19 tons/day (0.007 Mt/year) in 1986,
and 36 tons/day (0.013 Mt/year) in 1991. [Zreda-Gostynska et al.]
Since this is a passively degassing volcano (VEI=1-2 in the active
period), very little of this HCl reaches the stratosphere. The
Erebus plume never rises more than 0.5 km above the volcano,
and in fact the gas usually just oozes over the crater rim. Indeed,
one purpose of the measurements of Kyle et al. was to explain high
Cl concentrations in Antarctic snow.