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Re: 'Global warming is great,'



I've been following the global warming/climate change research published in
Science for several years now. A few years ago, the editors of Science
published a statement from the AAAS that summarized some of the evidence and
conclusions based on a mountain of papers published over the past 20 years,
to wit:

1. Global warming is real.
2. The current spate of global warming is at least partially caused by human
activity.

While no single research paper proves these conclusions by itself, the sum
of many lines of evidence from many scientific fields is now impossible to
ignore. Some of the lines that I've seen include:

-analysis of ice cores from Greenland and Antarctica, in which isotope
ratios and dust/pollen inclusions provide climate data
-analysis of ocean sediment cores, ditto
-analysis of carbon-14 ratios in tree rings which shed light on solar
activity (and incidentally calibrates the C-14 "clock")
-analysis of changes in the observed population ranges of many species of
animals and plants
-analysis of the sizes and movements of glaciers, polar ice caps, and annual
sea ice, all of which are decreasing in volume
-observations of increases of the length of the growing season in North
America (up to two weeks longer than 50 years ago)
-observations of annual migrations of birds, mammals, and insects
-observations of global ocean temperatures
-isotopic, structural, and ecological analysis of coral reefs
-studies of the El Nino and La Nina events, which are increasing in both
severity and frequency
-correlations of observed weather patterns with climate models incorporating
global warming
-increases in sea level (an interesting line of evidence comes from
analyzing one artist's paintings of 18th(?) century Venice)
-analysis of global meteorlogical data
-observed changes in the oblateness of the Earth due to the redistribution
of water (a new one)
-studies of atmospheric chemistry, and atmospheric particulates
-data on high-level clouds due to aircraft traffic (especially one study
done in the 3 days after 9-11)
-satellite measurements of Earth's albedo, land and water surface
temperatures, annual snow pack, solar activity, etc.

It is difficult to separate the effects of global warming from normal
short-term fluctuations. However, the observational database has been
increasing. The literature clearly shows that global warming is a small but
measurable and growing effect. The question of whether global warming is
human-caused has also been addressed, with an answer that is less certain
but definitely leaning toward the affirmative.

Climate modelers are actively trying to tie vast amounts of data together in
order to predict the effects and the ultimate extent of global warming. This
is a very difficult undertaking, and most climate models are acknowledged to
have limited reliability. Possible scenarios do include the re-routing or
destruction of the Gulf Stream, the collapse (or at least great reduction)
of the polar ice caps, the reduction of glaciers, changes to Pacific Ocean
temperature cycles, and changes to rainfall patterns that could be
devastating to the parts of the world that currently grow the most food.
Compared to this, the flooding of coastal cities is a trivial annoyance.
Paradoxically, global warming may also result in unusually severe and cold
winters in some places, as increased temperature differentials contribute to
stronger global air circulations. Climate modeling is inexact, however, with
results that frequently (and predictably) lead to too much wild speculation
on the part of the popular press and an increase in skepticism among the
general public.

If we can put the speculations aside, we can note that some consequences of
global warming are happening. Some kinds of animals and plants do live
farther north than they used to. The growing season is longer, and ocean
water temperatures are affecting coral reefs. Glaciers have retreated in the
past decade, sometimes for miles, uncovering archaeological artifacts that
are thousands of years old. At least one Antarctic ice shelf has been
reduced to a fleet of icebergs, and researchers in Greenland are losing data
because the top thousand years or so of ice is melting.

How far will global warming go? That's more speculation. Global warming is
tied to the world's energy concerns, and there are no easy solutions or
substitutes for oil. It's clear that no major oil fields have been
discovered in a long time, and not for lack of looking. Statistical analysis
of oil finds indicates that there aren't many more oil fields to be found.
Global warming may not go too much farther, because we've burned
approximately half of the global reserves of petroleum already. Most of what
remains is in the Middle East, and we're already starting to see the
political and socioeconomic consequences of that little fact. Oil companies
know the oil's not going to last forever...hence British Petroleum's
emphasis on alternative energy. They're looking at what they have to do to
stay in business 30 years from now. Once the oil's gone, there's coal.
However, most of the coal is the low quality, high-sulfur variety that leads
to additional problems. Biomass is no solution to our energy needs (there's
not enough land to do it sustainably), nor is solar. (It's not clear to me
that a photovoltaic cell will, over its lifetime, output more energy than it
took to manufacture it.) Hydroelectric power generation will dry up in a few
hundred years due to silting of reservoirs in all of the geologically
friendly locations. Nuclear has its own problems, and it's not clear that
there's enough uranium in the world to provide the current global population
with the current level of energy use for more than a few hundred years.

I just got Herb's post. Yes, Herb, this kind of thing is cyclic.
Civilizations have risen and fallen many times before due to the
availability/depletion of resources. The archaeological evidence is abundant
on every continent except Antarctica. An example in my home state is Cahokia
Mounds, a city of 20,000 lasting 600 years that probably was abandoned due
to deforestation, judging from the decline in the quality of wood used in
its construction. The big difference is that in our civilization, the
depletion of resources is *global* and, in the case of key resources,
*permanent*.

Civilization is 10,000 years old. We can't keep the current level of
civilization going, for this many people, for another 10,000. In other
words, enjoy the peak of civilization while you've got it. Have a nice
day...

Vickie Frohne

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