[Vision2020] CO2 & Global Warming: "Fixing" The Numbers

Tue Aug 29 12:04:15 PDT 2006

 Paul et. al.:

I sent this "Off List" to Paul, but I thought it might be of interest
generally, and of course we don't want any pseudo-science being swallowed
without question, now do we?  Besides, Paul asked on Vision2020 for comments
about the data on human CO2 contributions to global warming he gave from
clearlight.com...
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That web site you quoted claims that CO2's contribution to global warming is
only about 3.6 percent, with water vapor at 95%.  This web site presents
their arguments backed up by references to "experts," some of whom are PhDs.

They also claim that the human contribution to atmospheric CO2 levels is
3.225%.  This figure is very far off the generally accepted numbers, that
pre-industrial CO2 levels were around 270 parts per million and are now
around 370 parts per million (sources for these figures are given below),
mostly due to human contributions, an increase of around 30% due to
human impact, and at a level higher than at any other time in the
past 650,000 years, according to a study of antarctic ice core's trapped air
bubbles published in Science:

http://www.clearlight.com/~mhieb/WVFossils/greenhouse_data.html

   Based on concentrations (ppb) adjusted for heat retention
characteristics Percent
of Total  Percent of Total --adjusted for *water vapor*  *Water vapor*
 ----- * 95.000%*  Carbon Dioxide (CO2) 72.369%  * 3.618%*  Methane (CH4)
7.100%  * 0.360%* Nitrous oxide (N2O) 19.000%   *0.950%*  CFC's (and other
misc. gases) 1.432%  * 0.072%*  Total 100.000%   *100.000%*
 --------

The web site referenced above implies that the human sourced CO2 emissions
argument for global warming often ignores the huge contribution of water
vapor.  Really?  Read the data and arguments at these sites below:

http://www.eia.doe.gov/oiaf/1605/gg97rpt/chap1.html

http://www.enviroliteracy.org/article.php/428.html

---------

Here is another human sourced global warming skeptic site, and here is their
estimate of the impact of CO2 on global warming:

http://brneurosci.org/co2.html

Carbon dioxide, although present in much lower concentrations than water,
absorbs more infrared radiation than water on a per-molecule basis and
contributes about 84% of the total non-water greenhouse gas equivalents [3],
or about 4.2-8.4% of the total greenhouse gas effect.
---------
Note, though it is still much lower than the estimates of the scientists who
insist CO2 has much more of an impact on global warming, this figure is at
its high point estimates over twice the impact of the figure from
clearlight.com.
---------
Recall that CO2 atmospheric concentrations are estimated to have gone up due
to human contributions to the atmosphere, according to the Earth Sciences
Institute, and many other sources, by about 30-35 percent, maybe a bit less,
at this point in time.  But we are only starting to dump CO2 into the
atmosphere.  In the next 50-100 years, we could dump huge amounts of CO2
into the atmosphere, increasing the human contribution to 50% or more of the
total CO2 in the atmosphere.  But even at this point in time, if CO2 amounts
to at least 20% if the greenhouse effect, as many other experts estimate, as
you can read below, the human impact is at least 6-7% added to the total
greenhouse effect, if the percentage of CO2 impact on the greenhouse effect
is close to 20%.
--------
Consider these quotes on CO2 contributions to global warming, presenting
a variety of percentages for the impact of water vapor vs. CO2 contributions
to global warming:

http://www.pbs.org/wgbh/nova/ice/greenhouse.html

Each greenhouse gas has its own important role in trapping the sun's heat,
the most significant of which is water vapor. On a clear day, water vapor
can comprise 60 to 70 percent of the greenhouse effect. Next in line, carbon
dioxide contributes an additional 25 percent. Some gases trap solar
radiation from the sun better than others. For example, while man-made CFCs
are one of the least plentiful gases, they actually have a greater relative
impact than many others
----------------------

Here is another source claiming water vapor is a much lower percentage of
the greenhouse effect than clearlight.com:

http://encarta.msn.com/encyclopedia_761578504_3/Greenhouse_Effect.html

*Contributed By:*
Michael Mastrandrea, B.S.
Doctoral candidate, Department of Geological and Environmental Sciences,
Stanford University; Department of Energy Global Change and Environment
Program Fellow. Coauthor of *The Role of Tropical Forest Conservation in
Climate Change Mitigation.*
 Stephen H. Schneider, B.S., M.S., Ph.D.
Professor, Biological Sciences and Senior Fellow, Institute for
International Studies, Stanford University. Editor, *Climatic Change*;
author of *Global Warming: Are We Entering the Greenhouse Century?*

  A  Water Vapor

Water vapor is the most common greenhouse gas in the atmosphere, accounting
for about 60 to 70 percent of the natural greenhouse effect. Humans do not
have a significant direct impact on water vapor levels in the atmosphere.
However, as human activities increase the concentration of other greenhouse
gases in the atmosphere (producing warmer temperatures on Earth), the
evaporation of oceans, lakes, and rivers, as well as water evaporation from
plants, increase and raise the amount of water vapor in the atmosphere.

-----------------

And here is another site full of references to their sources that presents a
far more complex view of the influence of "water vapor" vs. CO2 in global
warming.  This analysis strikes me as without an axe to grind in the global
warming debate.  It attempts to explore how complex the issue of how to
measure the impact of water vapor and CO2 on global warming can be, and
gives numbers based on different ways of measuring this impact from 36% to
88% (look at the info from both pages of the website), for CO2 between
9-26%:

http://www.natexaminer.com/warming/gas.html

*Greenhouse gases* (GHG) are gaseous components of the atmosphere that
contribute to the greenhouse effect. The major natural greenhouse gases are
water vapor, which causes about 36-70% of the greenhouse effect on Earth
(not including clouds); carbon dioxide, which causes between 9-26%; and
ozone, which causes between 3-7% (note that it is not really possible to
assert that such-and-such a gas causes a certain percentage of the
greenhouse effect, because the influences of the various gases are not
additive. The higher ends of the ranges quoted are for the gas alone; the
lower end, for the gas counting overlaps). [1] [2].

------

And from the same web site at a different page:

http://www.natexaminer.com/warming/greenhouse.html
Effects of various gases

It is hard to disentangle the percentage contributions to the greenhouse
effect by different gases, because their respective infrared spectrums
overlap. However, one can calculate the percentage of trapped radiation
remaining, and discover:
  Species
removed % trapped radiation
remaining All 0 H2O, CO2, O3 50 H2O 64 Clouds 86 CO2 88 O3 97 None 100

(Source: Ramanathan and Coakley, Rev. Geophys and Space Phys., 16 465
(1978)); see also [3].
Water vapor effects

Water vapor is the major contributor to Earth's greenhouse effect. Its
effects vary due to localized concentrations, mixture with other gases,
frequencies of light, different behavior in different levels of the
atmosphere, and whether positive or negative feedback takes place. High
humidity also affects cloud formation, which has major effects upon
temperature but is distinct from water vapor gas.

The IPCC TAR (2001; section 2.5.3) reports that, despite non-uniform effects
and difficulties in assessing the quality of the data, water vapor has
generally increased over the 20th Century.

Estimates of the percentage of Earth's greenhouse effect due to water vapor:

   - 36% (table above)
   - 60–70% Nova. *Greenhouse—Green Planet* [4]

Including clouds, the table above would suggest 50%. For the cloudless case,
IPCC 1990, p 47–48 estimate water vapor at 60–70% whereas Baliunas & Soon
estimate 88% [5] considering only H2O and CO2. Water vapor in the
troposphere, unlike the better-known greenhouse gases such as CO2, is
essentially passive in terms of climate: the residence time for water vapor
in the atmosphere is short (about a week) so perturbations to water vapor
rapidly re-equilibriate. In contrast, the lifetimes of CO2, methane, etc,
are long (hundreds of years) and hence perturbations remain. Thus, in
response to a temperature perturbation caused by enhanced CO2, water vapor
would increase, resulting in a (limited) positive feedback and higher
temperatures. In response to a perturbation from enhanced water vapor, the
atmosphere would re-equilibriate due to clouds causing reflective cooling
and water-removing rain. The contrails of high-flying aircraft sometimes
form high clouds which seem to slightly alter the local weather.

-----------------------------------

Now we have radically different numbers given for a fundamental issue in the
whole global warming debate, water vapor contributions vs. CO2, numbers
backed up by credentialed sources.  Who is right?

Consider one factor mentioned several times in the discussions and arguments
and "data" presented above:  human sourced CO2 can warm the atmosphere,
causing a feedback loop to increase water vapor.  Thus the effects of water
vapor can become part of the human caused global warming problem.

I think the answer to the question lies in part in the well documented
empirical data about the melting of ice packs (the Arctic is undergoing
dramatic melting as is Greenland) and glaciers around the world, the changes
in the migration and maturation patterns of life forms, many of which are
responding to warmer and earlier Springs by altering their behavior in very
profound ways, and the clustering of warm years in recent times, with 5 of
the warmest years on record since 1890 all from 1998-2005, which I know by
itself could just be a random "clustering:"

Info on warmest years since 1890:

http://www.nasa.gov/vision/earth/environment/2005_warmest.html

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A published peer reviewed study, results of which I posted to
Vision2020, was done recently showing that earlier Springs at high
elevations in the forests of the Western US are the primary cause of
increased forest fire intensity and duration due to increased and earlier
drying of tinder due to global warming melting winter snow packs earlier in
the season.  The authors of the study said they were not even looking at
global warming, but the data led them to this variable.

Of course it can be argued that these significant changes are just a natural
cycle of some sort.  But these changes are sudden (in the grand time scale
of the planet) and dramatic, and must be caused by some variable or
variables.  We can examine the dominate climate change variables.  We can
measure output from the sun, the content of water vapor in the atmosphere,
the greenhouse gases, the contribution of albedo, the effects of cloud
cover.   We know of the variations in the Earth's orbit, precession of the
equinoxes, and of the influence of volcanoes and aerosols.  We can estimate
influences of farming and animal food impacts, along with deforestation.  We
understand how plants and the ocean absorb CO2, how natural methane releases
occur, and the potential impacts of methane hydrates, etc. etc.

While climate change is far from a perfect science, the evidence points
quite clearly that the main variable that is causing these sudden and very
significant changes to the Earth's climate is mostly human contributions of
CO2 to the atmosphere, though some argue farming and deforestation should be
considered more in the human impact on climate change.

If we continue this pattern, increasing atmospheric CO2 by hundreds of parts
per million, to levels 100% or more above pre-industrial levels, we may
induce severe climate change.  This is not worth the risk to experiment
with, in my opinion.

Of course there are numerous other reasons to conserve fossil fuels, the
most important being, they are finite, besides being controlled by "enemy"
states, and economic and other disruptions of great magnitude are possible
if we do not conserve and prepare for the end of the age of fossil fuels,
coming in just a couple of hundred years, given an optimistic outlook on
accessible resources.  The later reason alone is sufficient reason to enact
radical conversation of fossil fuels, forgetting global warming.

Ted Moffett
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