Re: What caused the other Ice Ages before man?

Bob Brown <.> writes:

On 28 Jan 2007 18:15:50 -0600, D Smith <maji1234@xxxxxxxxxxxxx> wrote:

So, are you convinced that the current increase in CO2 is from fossil
fuels, as Bob Grumbine has explained? This question is largely independent
of what has happened eons ago, as the methods Bob Grumbine described do
NOT require looking at CO2 levels prior to the current (say, past 50
years) time. Your other post, in reply to Grumbine, makes it look like you
still don't accept his argument, even though you don't point out anything
specifically wrong with it. Instead, you started to talk about periods
well into the past, which are irrelevant to the point Grumbine was making.

After all, if you catch me taking money out of your wallet, the judge
isn't going to ask you to demonstrate an entire history of previous
additions and removals of money from your wallet, for the entire time you
owned it, before I'll be convicted. All you'll need is a reliable witness
to the event of me taking the money out.

Now, to be specific: what is wrong with Grumbine's explanation, which
tells us how we can determine where the RECENT CO2 increase has come from,
regardless of what has caused CO2 changes in the distant past? If you
think his explanation has hidden assumptions about CO2 levels or fluxes
from the past, then what are they?

I may being doing a poor job of asking this but here goes. My problem
is I will assume CO2 levels in the recent past have increased at
alarming rates. My problem with this is it seems to ignore the levels
of CO2 that existed before the CO2 levels he, or anyone, mentions.


I need a clearer explanation of what makes you wonder about past CO2
levels/changes in relation to the current changes (by current, meaning
past 50 years or so - the time period we do have good measurements and
isotope information).

Go back to Bob Grumbine's explanation, go to his web site
(http://www.radix.net/~bobg, IIRC) and read the FAQ written by Jan
Schloerer, and then do a detailed critique of Bob's explanation with the
following in mind:

- examine each point Grumbine has made, and try to figure out the
underlying reasoning for Bob saying that point
- ask yourself whether or not changes in CO2 in the distant past (from
whatever source you choose to imagine) strengthen, weaken, or are
irrelevant to Grumbine's evidence. Do this point by point.

Then, once you have come up with a reason why some change in the past
make's Grumbine's (or Schloerer's) analysis weaker, come back and point
that out to us.


If I can explain it this way: Go back 50K years and see what the
increases and decreases were in CO2. Do those variations mimic the
increases and decreases of CO2 in the recent past?

But why is this relevant? The answer must lie in exactly what you mean
by "mimic", which I can only speculate on. Do you just simply mean "goes
up and down with similar rates of change and similar total levels"?
Grumbine's post discusses a level of analysis that is far more detailed
than just looking at totals and rates of change - it discusses methods of
identifying where carbon comes from based on its isotopic composition. Is
this not independent of whatever (perhaps different) source that may or
may not have been active in the past?

I will go back to the analogy of me stealing money from your wallet.
(This may not help, but what the heck - it's my free time).

Let's imagine two scenarios. In both scenarios, I really am the one
that took the money. In both scenarios, you saw me pick up your jacket
earlier in the evening (where your wallet was), but you didn't actually
see me handle your wallet or take the money. The difference between the
two scenarios is the type of evidence available.

In scenario 1, you had $500 in mixed bills, accumulated from several
sources, in denominations you can't remember. It's now gone. You know you
had it yesterday, but haven't looked in your wallet since. The cops come
in, and everyone has to show what they have in their pockets. Three of us,
including me, have over $500 in cash, in denominations similar to what you
remember having (but you don't remember what you had EXACTLY, so you can't
say "that's mine"). You accuse me, I'm arrested and sent to trial. At
trial:

- there is no evidence that clearly shows the money in my pocket
matched the money in your pocket. All that is known is that $500
disappeared from your wallet, and three of us have >$500 in ours.
- I provide evidence that you have been known in the past to lose
money, by having it fall out of an unsecured wallet lying around the
house.
- I provide evidence that the other two individuals who had >$500 also
have criminal records for petty theft.
- none of the three of us have a good explanation of where we got the
money we have.

So, even though you saw me handle your jacket, is there reasonable
doubt that I took the money? Is the evidence I supply about your tendency
to lose money and the criminal records of other guests even relevant? Will
I be convicted?


Scenario 2: same amount of money, same observation that I handled your
jacket, except this time:

- you picked up the money from the bank machine just before the
get-together, and the bank has a record of the serial numbers of the cash
they put in the machine and an electronic record of the denominations that
you withdrew.
- the money in my pocket falls in the range of serial numbers the bank
put in that machine, and matches the denominations that you withdrew.
- the money in the other people's pockets does NOT fall in the range of
serial numbers from that bank, and does NOT match the denominations that
you withdrew.
- I have no evidence as to where I got my $500, but the other two have
ATM receipts that they made withdrawals in the past 24 hours, and the $500
that they each have matches the serial numbers and denominations that
their banks said were taken.
- your wallet has my fingerprints on it, and "my" money has your
fingerprints on it, even though we just met for the first time.
- I supply the same evidence of your tendency to lose money and the
criminal records of the other people in the room.

So, we ask the same questions. Is there reasonable doubt that I took
the money? Is the evidence I supply about your tendency to lose money and
the criminal records of other guests even relevant? Will I be convicted? I
think the answer in the second scenario is quite different from the first.
The fingerprint and serial number evidence is strong enough that it
shouldn't matter about you tending to lose things or other people being
thieves, in the past. Or should it? Is that ancient history important?

Getting back to the CO2 question, Grumbine' discussion is about
fingerprinting and identifying the source of the carbon. Is it strong
evidence? If so, and the source of carbon can be identified,is it relevant
that at some point in the past carbon came from different sources, even
if the CO2 levels and rates of change are similar??

It just seems that everyone is focused on the "fossil fuel burning
era" of mankind and not looking at any measurements in the past to
compare with current increases.

a) beyond a reasonable doubt, the current rise in atmospheric CO2 is
from burning fossil fuels (at least, a very high proportion). Unless
significant new evidence is found of a previously-undetected source of CO2
with the same finerprints as fossil fuels, there is little point in
re-opening the case.

b) in spite of a), there are lots of people that spend lots of time and
money trying to collect whatever information they can on past climates and
past CO2 levels. One reason they do this is to help understand the global
carbon cycle. For example, currently, natural systems remove about half of
the CO2 added to the atmosphere from fossil fuels. Will this remain
constant, or will the ratio rise or fall? This is important in being able
to predict atmospheric CO2 in the future, based on the amount of fossil
fuels that are consumed. Understanding past CO2 levels and how they change
will help.

Just because it isn't discussed in the places you have read (or
listened) doesn't mean it isn't being done.


I try to imagine a human making assumptions based on their first 10
years of life. They would assume that they would one day grow to be 50
feet tall and weigh several thousand pounds. We know, from experience,
that this is not the outcome. But, if all we did was look at brief
samples of history we would make the same mistakes as the 10 year old
child.

If the prediction is made on the basis of a simple extrapolation of
total weight and height, then yes. If you have an understanding of human
physiology and appply that knowledge, then you likely wouldn't make that
mistake.

Am I explaining this well enough so that I could get a debate going?

Yes, much better. But again, Grumbine's argument (well, his post - it
isn't his argument, he's just the messenger) is NOT based on looking
exclusively at the rates of change of atmospheric CO2, so past histories
do not count.

Another suggestion: go back and read Grumbine's post, and ask youself
"Is this method capable of determining the source of current atmospheric
CO2, even if the total amount of CO2 was not changing?" Does that help
illustrate the importance (or lack thereof) of pre-inductrial changes?

.

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