Hi Mark,
Can you comment on the following? Just curious, TIA, Steven Bennett


"Volcanoes emit two sorts of ozone-depleting compounds. One is hydrochloric acid, but the amount of this chemical in the stratosphere, measured before and after Pinatubo's eruption in 1991, was found to be largely unchanged."

- Wallace, L. and W. Livingston. "The Effect of the Pinatubo
Cloud on Hydrogen Chloride and Hydrogen Fluoride."
Geophysical Research Letters, vol. 19, June 1992, p. 1209.

"The other ozone-depleting chemical emitted by Pinatubo, sulfur
dioxide, is converted in the stratosphere into tiny particles which,
acting in combination with man-made chlorofluorocarbons (CFC's),
temporarily increased the rate of ozone depletion by several
percentage points during 1992 and 1993. 6/ Nevertheless, nearly
all the particles resulting from the Mt. Pinatubo eruption have
already washed out of the atmosphere, unlike CFC's, which remain
in the stratosphere for as long as a century."

- Kerr, R.A. "Ozone Takes a Nose Dive After The Eruption of
Mt. Pinatubo." Science, vol. 260, April 1993, pp. 490-91;
Gleason, J.F., et al. "Record Low Global Ozone in 1992."
Science, vol 260, April 1993, pp. 523-26; and Hoffman, D.J.,
et al. "Ozone loss in the lower stratosphere over the United
States in 1992-93: Evidence for hetero- geneous chemistry
on the Pinatubo aerosol." Geophysical Research Letters, vol.
21, January 1994, pp. 65-68.

It is true that the greenhouse effect is, by and large, a natural phenomenon,
produced by gases in the atmosphere such as carbon dioxide and water vapor that have warmed the Earth for eons, making its climate moderate enough to support life as we know it. Without these gases, Earth would be forty to sixty degrees colder, essentially a frigid desert.

However, in nature these gases usually remain in balance, leading
to a stable climate, while the greenhouse gases added by humans
over the last two hundred years have accumulated to the point that
the amount of carbon dioxide in the atmosphere, for example, is
now more than 25 percent above what it had been for the previous
10,000 years. (Scientists have direct evidence of this data, from
measurements of air bubbles trapped in polar ice cores.) The
scientific consensus is that the accumulation of carbon dioxide and
other gases due to human activity will alter the climate substantially,
warming the globe by three to eight degrees Fahrenheit over the
next century.

- Intergovernmental Panel on Climate Change. Climate
Change: The IPCC Scientific Assessment. (New York, NY:
Cambridge University Press), 1990, p. xi.; Intergovernmental
Panel on Climate Change. Climate change 1992: The
Supplementary Report to The IPCC Scientific Assessment.
(New York, NY: Cammbridge University Press), 1992, p. 5.

It is worth reproducing the original IPCC statement on this
point from the 1990 report --

"We are certain of the following:

there is a natural greenhouse effect which already
keeps the Earth warmer than it would otherwise be.

emissions resulting from human activities are
substantially increasing the atmospheric concentrations
of the greenhouse gases: carbon dioxide, methane,
chlorofluorocarbons (CFCs) and nitrous oxide. These
increases will enhance the greenhouse effect, resulting
on average in an additional warming of the Earth's
surface. The main greenhouse gas, water vapor, will
increase in response to global warming and further
enhance it."

These conclusions were reaffirmed in the IPCC's 1992 report.




>If more people would do their own thinking instead of allowing the media or gov't do it for us, we would all be better off. One good volcanic eruption puts more "greenhouse" gases in the atmosphere than man has ever produced. I remember the environmentalists in the late 60s and early 70s predicting the doom of an impending ice age. Now its warming. Whatever floats your agenda rules the day.
>
>By nature, I am not an environmentalist. I believe in the rational and responsible use of all natural resources to their best benefits. Kind my definition of a conservationist.
>
>Environmentalist: someone who already has their house in the woods.
>
>Also, did you ever notice they all drive to wherever they are protesting? Not to mention they usually drive the worst polluting cars of anyone.
>
>>I guess we ought to consider that if man could truly control the weather, we'd all starve to death.
>>
>>Personally, I think global warming is a big sham, or perhaps more correctly, global warming caused by man. We might like to believe we control this planet, but we don't. We are actually at the mercy of something...
>>
>>Actually, if you want to control 'global warming' it would be better to control cloud formation. CO2 is such a miniscule proportion of the atmosphere. Of course, it is the only thing we CAN control, so it becomes the only thing that NEEDS controlling. How precious!
>>
>>The world would be a great place if it weren't for all the people trying to make it a great place.
>>
>>>Remember, we are the ones who insisted on putting MTBE in gasoline to improve air quality, perpetuate the myth that CFCs deplete ozone, and global warmingis a scientifically factual. Now our water supplies are being contaminated and air quality is worse because of MTBE. Pluse our Governor refused to pay the lawyers in Texas over $3 billion as their part of the tobacco settlement. He claimed it was too excessive. Way to go, GW! Too bad he has not yet forced MTBE out of our State as other States have wisely done, including California. I can't figure out whe Env Groups aren't sueing us over this. They do over every other EPA faux pas. Makes me wonder what their real agenda are.
>>>
>>>There I go blaspheming again!