Pub #brownchem: @alpha137
*** #brownchem :End of /NAMES list.
*** Mode is +
*** Craig_S (hummer@randolphmax2-2.megsinet.net) has joined channel #brownchem
Craig_S: hello professor
alpha137: hello
alpha137: Do any thinking?
Craig_S: I took a look at the past few conversations, their links, and Ab's chart. It's pretty good
Craig_S: and I've done some thinking, too
Craig_S: I'd like to ask you a question about the 750,000 year model
alpha137: OK, shoot.
Craig_S: are the amounts being measured read as "atmospheric CO_2" and "global ice volume?"
alpha137: Yes, I think so. There is a relationship between them.
Craig_S: Am I wrong in assuming that the graph shows that as global CO_2 rises, the amount of ice also rises?
alpha137: It is something like , as the ice melts it releases gas so there is a lag. Something like that.
alpha137: Yes, but there is a slight lag.
Craig_S: which one rises first?
alpha137: I am not on firm ground here, but as one moves from right to left as the ice melts (red curve) gas is released (blue curve). We are going from ice age to ice age. It is a bit confusing.
Craig_S: Is it established that ice traps more CO_2 than water?
alpha137: I found another interesting figure in the Wally book. It shows
calcium carbonate concentrations in sediments on the ocean floor (or below) as a
function of the same time span. Looks very similar to the 750,000 yr fig.
Needless to say, these cycles are all connected-and all
over the place.
alpha137: I would guess that ice traps more carbon dioxide than water. There is a temperature effect on solubility.
Craig_S: Could that mean that some other factors are responsible for both the temp and the CO_2 since they rise and fall at the same time?
Craig_S: I'm a little confused
alpha137: Well, they are going to be related if I understand your comment.
As the temp rises, ice melts releasing carbon dioxide.
As the temperature rises in the oceans CO_2 is also released.
Craig_S: ok. I think the idea of ice trapping more CO_2 than water is very important.
alpha137: The geologists say that the surface waters of the Antarctic sets the atmospheric carbon dioxide concentration.
alpha137: Know why they might say that?
Craig_S: Huh? No.
alpha137: Sure, because colder water can contain more CO_2.
Craig_S: But what about ice?
Craig_S: Doesn't ice have a different molecular arrangement?
alpha137: By extension it may contain the most.
alpha137: Yes, and that is why I hedged a bit.
Craig_S: Because I think we should be absolutely sure that ice traps more
CO_2 than water. Otherwise, we have to reinterpret the data.
But there is not as much ice available to yield CO_2 as
there is ocean. If polar caps melt they will release some CO_2. This will be a positive
feedback mechanism
alpha137: From a handbook, and without units, zero C water contains 179.7 "units" of CO_2 while 20 C water contains 90.1 "units"
alpha137: I see the units. For 100 parts of water it is 179.7 cubic cm of CO_2, etc.
Craig_S: is there any reason that ice, as opposed to water, would force CO_2 out?
alpha137: One big point of all this is that the oceans are very important.
Craig_S: Extremely important
alpha137: No, I do not see how ice would "force" CO_2 out. Just the opposite.
alpha137: I posted some stuff by " Wally " on the irc page. Something I scanned from his book. I will scan some more tomarrow.
alpha137: Have you read this?
Craig_S: no...probably should :)
Craig_S: can you give me the gist of it?
Craig_S: Or should we skip it for now?
alpha137: Well, it discusses the relationship between CO_2 in the atm with various processes in the ocean. There is also a relationship with plants as well.
Craig_S: That sounds important.
Craig_S: I don't really have much new to say right now.
alpha137: The carbon is stored in different forms depending on the temperature, etc.
alpha137: Perhaps an item not on Ab's chart is the ocean. Where would it go?
alpha137: Perhaps you could think about that?
alpha137: Also, if we are to make a model we need magnetudes for the different
components and rates as well.
Parts of Ab's diagram are for very slow processes-mountain
building times for example-and parts are very fast-the time scale of seasons. We
need to put these time constants into our model.
Craig_S: Would it amplify both positive and negative feedback, like vapor pressure?
Craig_S: Like vapor pressure does?
alpha137: The ocean is certainly going to be dynamic.
alpha137: If T goes up then plankton, algea, etc. increase. As these increase they "eat" CO_2 from the atm and atm CO_2 drops from this mechanism.
alpha137: CO_2 dissolves in the oceans and the amount that dissolves depends on simple chemistry.
alpha137: This CO_2 (aq) is in contact with CaCO_3 (limestone) on the ocean floor.
Craig_S: Yes...we would need to know numbers of how algea affects the CO_2 amounts, but wouldn't the algea be only a partial inhibitor of CO_2 ?
alpha137: This limestone dissolves to some extent producting Ca^++ and CO_3^--
alpha137: And therefore the amount of dissolved CO_2 will depend on these ions!
Craig_S: What affects the amount of limestone?
alpha137: Certainly, the algea are only part of the question.
Craig_S: You said there was a chart for it?
alpha137: But I am told that the algea act fast (from a geologists perspective) during the time of the seasons.
alpha137: Well, the amount of limestone is affected by the carbon dioxide concentration in the atmosphere!
Craig_S: So does CO_2 affect limestone, or does limestone affect CO_2 ?
alpha137: For starters, the CO_2 is consumed by little shell creatures (their shells are basically limestone) and these sink to the bottom when they die.
alpha137: That connects atm CO_2, the biota, and the limestone and it goes both ways depending.
alpha137: Depending, that is the question.
Craig_S: There must be hundreds of individual relationships like that.
alpha137: Right.
alpha137: We are learning that the details of this global CO_2 problem are very complex and interdependent.
Craig_S: Shouldn't we get the big picture in focus first, or does Abhas's diagram do most of that? Can we sum up the overall effect the ocean has on global warming?
alpha137: I think we need a big picture. We make a model that averages over these details.
alpha137: Perhaps the ocean is in Ab's diagram where it says "Increasing Green Algae"
Craig_S: Yes, but maybe as the temperature rises, these green algae only take in a fraction of the amount of CO_2 that the ocean releases with the increase in temperature.
alpha137: Notice that this diagram consists of two parts. The upper part is the pos feedback part and the lower the neg feedback part. These are connected in only two places!
Craig_S: Maybe his chart should have arrows that connect "increase in temperature" and "decrease in temperature" to more of the factors.
alpha137: I am not so sure. It basically looks OK as one travels up in the + feedback region and down in the - one.
alpha137: Also, in answer to your comment about temperature and the competing processes of algea, etc. consuming carbon and the ocean releasing it. This must be known.
alpha137: The relative magnetudes and rates of these factors has to be known for us to make a model.
alpha137: Of course, complicated models do exist and they run on supercomputers.
Craig_S: have you ever seen these models?
alpha137: They must be large programs and have many details for the various parts of Ab's chart. No, I have not seen these models, but I will ask my geo collegues where there might be a description.
Craig_S: My thought's aren't connecting right now. Can we stop for today?
alpha137: A major question for us is "does a human component to the greenhouse effect exist?"
Craig_S: Is that even a question?
Craig_S: The CO_2 levels have risen much more quickly.
alpha137: Yes, I think it is. That is since the industrial revolution man has added to the atmosphere around 80 ppm of carbon dioxide.
alpha137: The graphs show this is greater than anything on the 750,000 year graph.
alpha137: So we must have done it.
Craig_S: But how much has the vapor pressure increased?
alpha137: We can only guess.
alpha137: We have to make some kind of a prediction about the temperature rise due to this 80 ppm CO_2 and then we can know the increase in the water vapor.
alpha137: It is, perhaps from the geological record that we can make this guess, or prediction.
Craig_S: Yes. Do we the average earth temperature fluctuations for any amount of time?
Craig_S: Do we = do we know
Yes, I think geologists have a handle on this. See this article by W. Boecker. Especially
the abstract and the first paragraph for an overview.
alpha137: I guess so. This is the reason one has to use computer models.
alpha137: The computer models have to be tested and the only way to test them is to have them predict the past.
alpha137: I am told that they are now good at this.
alpha137: Most people in this field now believe in the computer models and of course the geological evidence is just that.
Craig_S: So they have numbers for the average temperature of the earth for some years?
alpha137: Yes.
Craig_S: Actually, we could just see the changes in many places around the world. That could be a good indicator.
alpha137: You wanted to stop and so do I. Let us ponder this stuff and
maybe try and simplify Ab's graph, or perhaps think how it works to make an oscillat
ing global temperature. OK?
The electronic analogy with a multivibrator is pretty good.
There are a couple of amplifiers (for temperature) and a couple of feedback loops
coupling them. This leads to a two state, oscillating system. Changing the feedback
paramters affects the period of the oscillations and even their regularity. Looking
at the 750,000 year diagram this model fits.
That is, the earth has these two states that it seems to oscillate between. The idea
is that excess carbon dioxide could trigger the warm state by changing part of the
feedback even though this CO_2 may be ten times less in concentration than is water
vapor.
Craig_S: sounds good
alpha137: bye
Craig_S: bye
*** Craig_ has left channel #brownchem