Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEPWR/V1NO009.TXT

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Date: Fri,  4 Jun 93 04:04:45
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Space Power Digest          Fri,  4 Jun 93       Volume 1 : Issue 009

Today's Topics:
                            global warming

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Date: Thu,  3 Jun 1993 11:14 EDT
From: USRNAME <[e-mail]>
Subject: global warming

************ SOLAR POWER NEWS VIA INTERNET **************
June 3,1993
G.E. Canough
[e-mail]

GREENHOUSE EFFECT, GLOBAL WARMING AND CLIMATE CHANGE

The Earth is not just the right distance from the sun to
enable life. It also has an atmosphere with the correct
mixture of gases to maintain a certain temperature range. We
know from studies of Venus, that an atmosphere with lots of
CO2 retains more heat. In the case of Venus, temperatures
can reach upwards of 470 C, a hairy case of global
warming...

What we do not know in detail is the exact ratio of CO2 to
temperature. Because the atmosphere is a dynamic and large
system, it is very difficult to model it (although people do
try, especially for predicting the weather).

We are now in the midst of a global "experiment" in the
effects of increased levels of CO2. By burning fossil fuels,
we are putting CO2 into the air at a rapid pace (6 billion
tonnes per year). Other human activities generate other
types of "greenhouse gases" which are not CO2, but act
similarly in retaining heat. These include methane and
freon. For example, the increasing population of humans adds
to the methane production by natural bodily functions. The
question is, given that our models of what will happen to
the temperature of the planet and the climate are not very
good yet, is it wise to be doing this experiment?

THE AMOUNT OF CO2
There are many people still skeptical that addition of CO2
is much of a problem. In general, humans are still much less
effective at altering planet-wide parameters than natural
forces such as volcanic eruptions. In the last five years,
there has been growing evidence that we are effecting the
climate by the addition of CO2. To give you an idea of how
much CO2 we generate: Using data from Antarctic ice cores,
the CO2 content of the air can be traced back to 160000
years ago. 160000 years ago, the CO2 content was around 200
parts per million (ppm). Around 120000 years ago it jumped
up to 300 ppm. 40000 years ago, it dipped back down to 200
ppm. Today, we are up to 360 ppm and 410 ppm equivalent
(i.e. adding in other greenhouse gases).
***** In other words, there is now more CO2 in the
atmosphere than in the last 160 millennia!  ****

If we continue to burn fossil fuels at the current rate (and
the rate is actually increasing, not staying constant) the
CO2 concentration in the year 2050 will reach 600 ppm, fully
double any past concentration.

THE EFFECTS OF CO2
There is general agreement that more CO2 will cause the temp
to go up.

There is disagreement on
* how much the temp will rise as a function of concentration
* what will be the effect of increasing temperature
        * effect on climate
        * effect on oceans
* will there be positive of negative feedbacks

THE EFFECT OF TEMP INCREASE
Most of the media attention has been given to the
disagreement on the amount of temp rise. But any temp rise,
even a small one has its consequences. The fact is, we have
already experienced a small temp increase. The seas off
California have warmed by 0.8 C in the last 40 years. The
temps in Northern Canada have increased by 2 C. The average
snowfall over the Northern hemisphere has decreased by 8%
since 1973. The Arctic ice cap has declined by 2% between
1978 and 1987. Coral reefs are very sensitive to temp
increase and in fact reefs have been observed to be dying
off at an unprecedented rate. Corral reef experts have
recently been shocked at the level of this occurrence. They
were surprised that a temp increase of only 0.5 to 1 C could
have such a disastrous effect on the reefs. Southern Africa,
Oregon, California, and SE England are in the worst droughts
ever. These effects are all due to global warming. Some of
the warming may be natural variation in the climate, but do
we dare assume that none of it is caused by us?

INSURANCE COMPANIES GOING BROKE ON STORM DAMAGE CLAIMS
The climate change that has occurred in the last 5 years,
which has drawn the most attention and concern is the change
in the patterns of windstorms. The insurance industry has
been adversely affected by this to the tune of billions of
dollars. They have thus suddenly taken an intense interest
in climate change. Insurance companies decide whom to insure
and what premium to charge, based on past history. So, if
you want to buy hurricane insurance, the company goes to the
weather record to determine how often a hurricane is likely
to occur where you live. They calculate your premium based
on frequency of occurrence and intensity. To make money,
they have to make an educated bet that storms will not do
more damage than can be covered by a fraction of the
premiums. If you choose to live in a storm-ridden area, you
may not be able to obtain insurance at all. From 1966 to
1987, there were NO storms or other catastrophes which drew
claims of  more than $1 billion. Between 1987 and 1992,
there have been at least 15 such catastrophes. These
included mainly intense hurricane and typhoons, but also 1
bush fire (in drought-ridden California), 1 earthquake, and
3 oil accidents. Most of the disasters listed cost $2 to $5
billion, but hurricane Andrew cost a whopping $20 billion,
causing some insurance companies to go broke! Some of these
storms made historical records for their intensity. [This
list is from ref 1]

Other storms of note: During the 1992 ISU summer session in
Kitakyushu Japan, we had 3 typhoons in the space of 1 month.
This was said to be quite unusual, although only one of them
was intense and did damage. In early 1993, the worst snow
storm in at least a century (essentially a "winter
hurricane") hit the eastern US. As we sat around shivering
here in Endicott, during the blizzard of '93, people would
laugh at the idea that maybe global warming has arrived.

ERRATIC WEATHER HARBINGER OF GLOBAL WARMING
However, the weather we have had in the last 5 years may be
an ugly harbinger of global warming. Realize that global
warming's first effect may not be continuously warmer days
(although the last 5 years are the warmest on record).
*** It is most likely to be manifest in erratic weather. ***
Why? Because the atmosphere is a giant convection engine.
The temp of the air masses has everything to do with how
weather develops. Raise the temp and the engine runs faster
and more intensely. This means more storms and/or more
intense storms. So you can see why insurance companies are
worried. In the short term they can raise their rates or
refuse to insure FLoridians, but if there continue to be
more and more storms, some of them in unlikely places (such
as Endicott) something more will have to be done.

FEEDBACK
There has been discussion as to the possibility of feedback
that could either lessen (negative) global warming or
increase (positive) it. For example, more CO2 helps some
types of plants grow more. I discussed this briefly with
Mark Nelson in Biosphere 2 and he explained that some types
of plants do better and over-run other types. Many of the
hardy types are what we would consider to be weeds. So maybe
the weeds would over-take the crops? Trees do better and
could take over grass lands (who knows if this would be good
or bad?) Although the Biosphere-2 has a controlled climate,
they have been able to gather data on the effects of CO2
concentration on plants and the results of this will be
important to our understanding of the "plant feedback"
mechanism, and whether it is positive or negative. I'll
leave it Mark to expound on this...

Of course, more CO2 might also lead to fewer plants (due to
higher temps, flooded lands, etc.) which would be positive
feedback causing still more CO2 build up. There might be
other positive feedback we don't know about yet. And what's
worse, we don't really know what the threshold might be. We
could stumble on to it any time now and be in deep trouble
fast. This is the root of the idea that we might run into a
"run-away greenhouse". We have been in the habit of thinking
that climate change onsets very slowly, over centuries. But
recent evidence (ice cores from Greenland) shows that
dramatic climate change can happen very suddenly, in just a
year or two[see ref 2]. Do we bet the planet that maybe this
won't happen? If the climate does change drastically, humans
are likely to end up on the endangered species list, where-
as the Earth itself will continue on its way. (So we are
really betting human life...)

There is some interesting literature available on all of
this. Read some of it, and you will be up nights wondering.
You will ride your bike more and turn down the thermostat.
Peter Glaser quantified our excesses neatly when he said
that each kW-hr of electricity made puts another kilogram of
CO2 into the air. So if you use your air conditioner or
clothes dryer for an hour, there goes another kilogram of
CO2.

REFERENCES

1) Climate Change and the Insurance Industry
by Jeremy Leggett, Greenpeace International [Copies
available from The SUNSAT Energy Council Newsletter, c/o
ETM, PO Box 67, Endicott, NY 13760 ($5 for copying and
postage) Or contact Jeremy Leggett, Greenpeace
International, Canonbury Villas, London, N1 2PN fax = 71 696
0012] This article is very well written and describes
discussions going on in the insurance industry. As you might
expect, any article on global warming will have its biases,
but in this case, the biases were not outrageous or hidden.
The article is well referenced to various studies of global
warming. There has been a conference of insurance people and
global warming experts just last week in London. A second
one is scheduled for September 28 in New York City.

2) Ice core shows speedy climate change, R. Monastersky
Science News v 142, Dec 12,1992, p 404.



Dr. Gay E. Canough ETM,Inc. and BU-SUNY, dept.of physics
e-mail(Internet):  [e-mail]
         (GEnie)   :  G.CANOUGH
phone/fax= 607 785 6499    voice mail = 800 673 8265
radio call sign:   KB2OXA

'Snail Mail:
ETM, Inc.
PO Box 67
Endicott, NY 13761

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End of Space Power Digest Volume 1 : Issue 009
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