On Sun, 25 Jul 2010 22:59:02 -0400, "Ed Huntress"
wrote:



Don, that wasn't the question I addressed. Once again, there are two
questions: whether human respiration adds CO2 to the atmosphere (no), and
whether burning fossil fuels adds CO2 to the atmosphere (yes).

Are we agreed on this?

No. Both processes immediately add CO2 to the atmosphere. Meanwhile,
photosynthesis consumes CO2 from the atmosphere. If the rate of
photosynthesis consumption matches the rate of natural production,
then there is no net change in atmospheric concentration. There may
be seasonal variance, but the volume of the atmosphere would make that
unmeasurable.

The only time constant here is the rate of concentration
change, which is proportional to the net increase of atmospheric CO2
per unit time divided by the total atmospheric volume.

No, that wasn't the question. That's a larger question, but my responses are
true, regardless of what you may want to speculate about what happens to
that CO2 after it's in the atmosphere.

I didn't speculate about that at all. To which CO2 do you refer: that
which was added by burning fossil fuel, or that which you insist
wasn't added because it came from respiration? I didn't and don't
differentiate.



CO2 from animal respiration doesn't magically migrate to trees while
CO2 from fossil fuel combustion goes directly to greenhouse. It may
be politically expedient to represent things that way, but that isn't
what happens.

It doesn't matter which CO2 goes where.

My point. Thank you.

The question is whether the CO2
emitted by humans comes from a short-term sequestration -- whether that CO2
we exhale was in the atmosphere a few minutes, months, or possibly a few
years ago, and we've just put it back where it was -- and whether the CO2
emitted by burning fossil fuels comes from sequestration effected millions
of years ago. The answer to both is yes.

No, it isn't. The term of sequestration is irrelevant. What matters
is if the rate of addition exceeds the rate of consumption. When we
burn fossil fuel we increase the rate of production with no
corresponding increase in consumption.

No matter how much you complicate it, those two things are facts. And that
was the issue. The net effect of one is to neither add nor subtract from
atmospheric CO2. The net effect of the other is to add to atmospheric CO2.

I didn't complicate it, I showed how simple it is. There's no magic
process wherein expirated CO2 magically goes to green vegetation while
CO2 from burning coal or oil doesn't. An individual carbon molecule
may experience the cycle you describe, but the concentration of CO2 in
the atmosphere is the result of continuous processes. Over any period
whether millisecond or millenium, the net change in atmospheric carbon
will be the difference between what was added and what was subtracted
during that period.

I don't dispute that increasing the output by burning fossil fuels has
increased the load, but it's also true that reducing the amount
being removed by replacing vegetation with concrete decreases the rate
of removal -- again raising concentration.

That's another issue. Neither you nor I can put numbers on it, so all we can
do is name some effects, without qualifying whether they're significant or
just distractions. You CAN put some reasonable numbers on the amount of
fossil fuel we burn, and thus on the amount of CO2 that's added to the
current atmospheric volume of CO2.

I can't put numbers on any of it. It may be easier to put numbers on
the amount of fossil fuel we burn, and that may be the sticking point
here. It's easier to sell simple to politicians and zealots than it
is to bother with understanding the processes.

You seem to assume that if we can't put numbers on rate of removal, we
can ignore it. Just quit burning fossil fuel and all will be OK.
That's exactly why I keep arguing here. It IS important. Your model
where expirated CO2 doesn't count because it get sequestered for just
a short time in organic matter by photosynthesis is specious because
it assumes that these two processes are and will always be in perfect
balance. That is clearly false if the number of breathers increases
while the amount of vegetation decreases, as has happened in the past
200 years. We need to look at the whole CO2 budget, both production
and consumption.

I agree that we must reduce and eventually eliminate use of fossil
fuels.


It's more sensible to think of this as an accounting problem, and in
fact responsible scientists do look at it in that way by defining
carbon sources and carbon sinks.

Carbon sources emit carbon into the atmosphere. Those include animal
respiration, combustion, and various other sources.

Animal respiration does not ADD to the carbon in the atmosphere, in any
meaningful time frame.

Of course it does.

Nonsense. That carbon was trapped for a short time, in a closed loop that
starts with photosynthesis. Do you deny this?

The carbon's history is immaterial, and there is no closed loop though
it may be so depicted for illustration in some elementary school
science books. Release and sequestration of carbon are both
continuous processes.

Then other processes subract.

You have it backwards. First, there is short-term sequestration by
photosynthesis. Then we eat food thus produced, and re-release the carbon.

There's no such order. Both processes are continous.

If it was as you describe, what would we be eating in the first place? Air?

Chicken and egg polemic. Shame on you.

Don, trying to equate the trapping and releasing of CO2 in the production of
food, and then eating it and exhaling CO2, with burning fossil fuels is
profoundly misleading about the net effects.

I didn't equate anything with anything else. I merely describe the
processes without regard to spin value. Exhaling CO2 and burning
fossil fuels both produce CO2. Photosynthesis consumes CO2. If rate
of production exceeds rate of consumption, then atmospheric CO2 must
increase over time.

It should not be misleading at all to anyone who can understand a
budget, and it is considerably more accurate than the spin mythology
about short cycles and sequestration time.

Larry sounded like he was
equating the two. That's why I commented. I've pointedly avoided discussing
the system-wide effects of CO2 sequestration and release, and of its effects
on global warming, because they have nothing to do with the original point.

Let me reiterate that point so there is no confusion.

Again?

Burning fossil fuel
releases carbon into the atmosphere that was sequestered for millions of
years.

It does release carbon into the atmosphere, regardless of how long
sequestered.

We do it relatively quickly, so the net effect is to increase the
levels of atmospheric CO2 to something higher, in the direction of the
levels that existed millions of years ago.

That's true, though a bit loaded by the reference to millions of years
ago. The effect is to increase atmospheric CO2 because the rate of
subtraction by photosynthesis didn't increase correspondingly. If
anything, it decreased.

Eating and exhaling does not.

False. Exhaling won't only if the rate of consumption by
photosynthesis balances the rate of production by expiration.

Before you have something to eat, CO2 must be
sequestered from the atmosphere into plant life, at some recent time. And
it's a continuous process. There is some mean time of CO2 sequestration for
that plant life, and it's on the order of a few years.

True, but irrelevant. That CO2 becomes relevant at the time it is
released, regardless of where and how long it was sequestered.

The CO2 that we
release from burning fossil fuels was sequestered for MILLIONS of years.

True but irrelevant.

The net effect in each case is vastly different.

The net effect in each case is exactly the same. CO2 is CO2.

In the case of eating plants or
animals that eat plants, we're participating in a cycle that requires,
first, that CO2 must be sequestered from the atmosphere within recent years.
Then we release it, and the cycle, measured in a few years, repeats. There
is no net increase in atmospheric CO2.

Fallacious conclusion. See above.

If the subtractive
processes can't keep up with the additive processes, then atmospheric
concentration increases.

Something else, much more consequential, happens first: We starve. g

Geez, Ed! We starve before atmospheric concentration changes? How
might that be? For that matter, how does increase in atmospheric CO2,
which may facilitate photosynthesis, portend starvation?

Again, you have the process backwards. First, short-term sequestration. Then
we eat. Then there is more short-term sequestration -- or we don't eat
again.

Chicken and egg. Which happened first in the primordial ooze? Doesn't
matter. They are both now continuous processes. There are always
critters eating, breathing, reproducing and dying, and there are
always plants consuming CO2 as they do photosynthesis.

But we do. And ALL of the carbon we emit comes from that short-term
sequestration, and that particular cycle keeps repeating. Even if we had no
relationship to other trapping and emitting of CO2, that closed cycle, which
is quantifiable to a reasonable degree, would continue.

It isn't a closed cycle, Ed. It's a set of continuous processes. Your
assertion could only be true if increased CO2 level caused by
increased number of breathers and decreased vegetation would result in
more prolific growth and photosynthesis of remaining vegetation, thus
establishing a new equilibrium -- and even that doesn't take into
account the additional CO2 influx from combustion of fossil fuels.

You can treat it in
isolation of other effects because you know quite accurately how much carbon
is involved, how it's trapped, and how it's emitted -- and trapped again,
and re-emitted, etc.

No, I don't know, and neither do you. You will never know if you are
unable to comprehend the nature of interacting continuous processes.

Burning fossil fuels releases CO2. So does animal respiration, forest
fires, and warming oceans.

Burning wood does not,
as long as you replace those trees.

Of course it does. If trees are replaced, then they will serve as a
CO2 sink but not until they are replaced and grow to size.

And how many millions of years does that take?

As long as it takes a tree to grow.

Do you recognize the
qualitative difference that results from the different time scales?

No. The only time scale that matters is from this point forward. What
happens to the atmosphere from this point forward depends entirely on
our finding a way to balance release of CO2 with consumption of same
by photosynthesis and other mechanisms. Or not.


If production equals consumption, there is no cycle length at all.
Whenever production exceeds consumption, concentration will steadily
increase.

No, the cycles still exist. Mixing the CO2 together doesn't change that. All
it does is obscure the cycles that are at work.

These mythical cycles do seem to have some mystical fascination for
you. Individual carbon atoms may experience various cycles but release
and consumption of CO2 are both continuous processes. Burning fossil
fuel certainly increases the rate of release.



The fact that fossil fuel is millions of years old is immaterial.

That's a foolish thing to say, Don. You're ignoring the relative time to
sequester a fossil fuel, versus a plant that's used for food.

Yes, I am ignoring that history as irrelevant. Change in CO2
concentration from this point forward is not a matter of history, only
of what we're doing now and the course we choose henceforth.

The carbon
cycle for food is 100% (or nearly so) contained within a matter of years.
The cycle for fossil fuel is millions of years in, and now hundreds of years
out. We're dumping large amounts of CO2 into the atmosphere that required
millions of years to sequester.

That's true, but the problem has nothing to do with how long it was
sequestered and everything to do with the increased rate of release --
which you describe as dumping, perhaps a bit of spin there?

When we eat, we're emitting at about the
same rate as the sequestration of CO2 in food.

You keep reciting that almost as an article of faith. If that were
true 200 years ago, then how can it possibly be true today with more
breathers and less vegetation?

Only way to deal with that question is by examining rates of
production and consumption in the continuous processes, not blind
faith in mythical cycles.


The amount of CO2 in the atmosphere increases if the amount being
released exceeds the amount being removed. Even if we eliminated all
fossil fuel combustion, if we reduce the planet's ability to remove
CO2, as by replacing vegetation with concrete, then the CO2 emitted
from people would increase the amount in the atmosphere.

No, it wouldn't. It CAN'T. All of the CO2 emitted by people HAS TO be
sequestered first in plants, through photosynthesis, over the short term.

At risk of challenging a fervent belief and article of faith, it ain't
necessarily so. CO2 emitted by people goes into the atmosphere,
plants remove CO2 from the atmosphere for photosynthesis, both
processes are continuous. There is no cosmic guarantee of equity or
balance.


We need to look at the whole issue, not just one aspect of it.

Not if the question is about the emission of CO2 by people, versus engines
burning fossil fuels. That's ALL I've commented upon. And your statement
above, about increased CO2 emitted by people if we pave over the land with
concrete, is the fundamental flaw in your logic. It is impossible -- at
least, until we're able to synthesize food from something other than plant
sources. Maybe we can eat carbonate rocks. g

Detail nit, paving the land doesn't increase emission by people; it
reduces consumption by vegetation. It's that pesky gozinto vs gozoutta
budget concept again.

It isn't impossible at all, though definitely short-sighted and
foolish. There's a lot less green forest on the planet than there was
200 years ago.

ALL of the CO2 we emit must first be sequestered in plants, via
photosynthesis. It's a short, closed cycle. If we pave over the land, we
have nothing to eat.

Some of the deforestation was conversion to land more suitable for
raising livestock. The livestock becomes food eventually, but the
photosynthetic contribution from that land is greatly diminished.

The only "emitting" we'll do then will occur as our
bodies decompose. But even that CO2 "emission" is the result of plant life
stored in our bodies over a matter of decades. It has no net effect on
atmospheric CO2.

No long term effect anyway. We'll spoil quickly, combustion of fossil
fuels will cease and the processes will continue as they have for
eons.