Re: AAPG on Global Climate Change

On Mon, 19 Feb 2007 12:54:43 -0600, Jo Schaper
<jospamnotschaper34@5socket78dot9net> wrote:

J. Taylor wrote:
On 18 Feb 2007 19:56:47 -0800, "Daryl Krupa" <icycalmca@xxxxxxxxx>
wrote:

Very good Daryl, it is so hard to detect those subtle ad hominem.

It is completely irrelevant it was a personal website or the
occupation of owner of it.

What do you have to say about the pie?

JT

I would say it makes a very nice Pacman graphic, though it is the wrong
color. *|:-)

If folks are looking for a well-researched overview of the subject of
atmospheric composition/change etc.,with lots of data in a readable
format, but without only a tiny ax to grind, (what if scenarios
presented as predictions, not as inevitabilities) I recommend Global
Environment: Water, Air and Geochemical Cycles, By Elizabeth and Robert
Berner.

They quite ably explain, using hard numbers from journal and academic
sources, how the atmosphere works and what threatens it in a text which
is quite readable to college freshmen or reasonably well-educated high
schoolers. I refer people to it all the time--you can't explain change
without knowing from what it is changing.

No one disputes water vapor is a very effective or influential
greenhouse gas. The graphic on the final page showing water vapor as the
overwhelming contributor to the greenhouse effect is likely correct when
looking at the big picture (greenhouse effect as moderating
temperatures, acting as an insulator, redistributing humidity, etc.) It
is misleadingly used on the card, because it implies that because water
vapor is quite important in the greenhouse effect,(true) it is also a
large source of correlated directional temperature change (false).

The difficulty with quantifying water vapor as greenhouse gas with a
changing and humanly negative impact is because
a) water vapor acts differently depending upon residence in which
atmospheric layer;
b) it has an average residence time in the atmosphere of 11 days;
c) while there are decent weather records of daily relative humidity
(dependent on dew point), there are very scarce long-term records of
absolute humidity, since it is quite variable even over a 24 hr
period(from less than 0.01% to 3% of the atmosphere,depending on
latitude, altitude and weather conditions;
d) water vapor is comes from a wide variety of sources, and picking
apart anthropogenic water vapor (additions from irrigation, industrial
processes and increase due to breakdown of more complex human produced
gases) is extremely difficult;
e) the water vapor feedback mechanism, while understood qualitatively is
poorly understood quantitatively;
f)clouds are water vapor, but water vapor as clouds,or as ice has a
different effects on heat transfer than diffused aerosol water vapor,
including dissipation;
g) even people who claim atmospheric water vapor is rising have few
mechanisms to correlate a specific human activity to a quantifiable
specific increase (possibly stratospheric disturbance due to air flight,
but that's the only being proposed)(anyone seen any studies on change in
atmospheric water vapor due to irrigation?);
h) in short, the effects of human perturbation of the hydrologic cycle
and on the amount of atmospheric water vapor seem a reasonable
assumption, but this perturbation is very small (the butterfly in the
tornado) compared to the movement of water vapor by solar energy and wind.

See below:

http://lwf.ncdc.noaa.gov/oa/climate/gases.html#wv

Water Vapor

"Water Vapor is the most abundant greenhouse gas in the atmosphere,
which is why it is addressed here first. However, changes in its
concentration is also considered to be a result of climate feedbacks
related to the warming of the atmosphere rather than a direct result of
industrialization. The feedback loop in which water is involved is
critically important to projecting future climate change, but as yet is
still fairly poorly measured and understood.

As the temperature of the atmosphere rises, more water is evaporated
from ground storage (rivers, oceans, reservoirs, soil). Because the air
is warmer, the relative humidity can be higher (in essence, the air is
able to 'hold' more water when its warmer), leading to more water vapor
in the atmosphere. As a greenhouse gas, the higher concentration of
water vapor is then able to absorb more thermal IR energy radiated from
the Earth, thus further warming the atmosphere. The warmer atmosphere
can then hold more water vapor and so on and so on. This is referred to
as a 'positive feedback loop'. However, huge scientific uncertainty
exists in defining the extent and importance of this feedback loop. As
water vapor increases in the atmosphere, more of it will eventually also
condense into clouds, which are more able to reflect incoming solar
radiation (thus allowing less energy to reach the Earth's surface and
heat it up). The future monitoring of atmospheric processes involving
water vapor will be critical to fully understand the feedbacks in the
climate system leading to global climate change. As yet, though the
basics of the hydrological cycle are fairly well understood, we have
very little comprehension of the complexity of the feedback loops. Also,
while we have good atmospheric measurements of other key greenhouse
gases such as carbon dioxide and methane, we have poor measurements of
global water vapor, so it is not certain by how much atmospheric
concentrations have risen in recent decades or centuries, though
satellite measurements, combined with balloon data and some in-situ
ground measurements indicate generally positive trends in global water
vapor."

See also:
http://www.nsc.org/EHC/climate/ccucla6.htm

Thanks, here is something else from one of the authors of the card

Dr. Lee C. Gerhard, senior scientist emeritus at the Kansas Geological
Survey
http://www.kansasenergy.org/documents/Gerhard_Climate_Change.pdf

One of the things in the PDF is a graph showing carbon increase
follows temperature

What is going on there?

JT


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