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Re: Human vs. natural influences on the environment
In article <4vn2e4$9h3@igc.apc.org>, tomgray
<tomgray@igc.apc.org> wrote:
>brshears@whale.st.usm.edu (Harold Brashears) wrote:
>>kowens@teleport.com (Jeff Owens) wrote for all to see:
>>
>>[edited]
>>
>>>There are thousands of subjects we do not have full
understanding
>>>of, but that should not stop people from trying.
Knowledge is
>>>gained by suggesting a model and then trying to disprove
it.
>>>The real issue here is: do we have enough information to
suggest
>>>models. The answer from the scientific community is a
clear YES.
>>
>>While I think it is always worth it to build models and to
test them
>>(otherwise, I would have been in some other business), I do
not
>>believe that means we must act on the output of these
models at this
>>time. If you have some reason to believe that the models
under
>>discussion are accurate, tell everyone about those reasons.
>
>Well, far be it from me to quarrel with anyone's religious
beliefs.
>
>I don't know that a strong belief in models is required,
though, to
>simply note that we are clearly changing atmospheric CO2
concentrations
>and therefore the earth's energy balance.
Tom,
This is where I continue to disagree with you. We know that
we are changing the amount of CO2 in the atmosphere.
However, we don't know if it will keep increasing in
concentration, and we don't know if there is a threshold
concentration above which "it is bad". You are making a BIG
assumption that we are changing the energy balance of the
earth at this point, because there is no clear documented set
of measurements that indicate that this is so.
Why am I worried about making the measurement of increases in
global temperature? Because anyone can formulate a
mathematical or computer model. Often, these models are very
large and complex. And ALWAYS, the computer code that makes
up these models has errors in it. I have been programming
computers for many years now, and I can guarantee that any
code with more than a very few hundred lines in it cannot be
absolutely debugged and verified. Thus, without making
physical measurements to validate the model, you are on very
shaky ground. This necessarily means that we must be able to
measure a definite change in global temperatures before we
can select the most appropriate (or least error free) model
upon which we can base future work. Since the changes we are
trying to make take decades to happen, I suggest that we use
a good model when we get to the point of trying to move
atmospheric temperatures in a given direction. This would
give us the advantage of choosing the most effective method,
being able to measure our progress, and having confidence
that we are on the chosen path long before we can see the
results.
By the way, if you are thinking about using the argument that
we know CO2 is bad, so we should reduce it to reduce its
impact on global temperatures, let's go into this a bit. If
the atmosphere is that simple to change, why are we working
on all of these models? One possible reason occurs in the
world of process control (I have experience in this area).
There are some process variables in refineries that move in a
direction opposite to what is intended, but only for a short
amount of time. These variables then move as expected. This
effect is termed "inverse response". We don't know enough
about the atmosphere yet to know if there are any variables
of this type, but if there are, it would be very good to know
about it before we try to change them. Obviously, if you are
trying to move a variable that has inverse response, and it
takes decades to see the effect, you can't get the desired
effect without a good model, because the short term inverse
response will cause people to invariably move in the wrong
direction. Think about it.
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