Chuck

I can't help to recall a quotation from Robert Watson, Co-chair of the
Scientific Assessment Panel of the Protocol and former Chairman of the
Intergovernmental Panel on Climate Change, one of the world's most
renowned atmospheric scientists:
'Although scientific evidence that human activities were causing
stratospheric ozone depletion was quite robust in the late 1980s, there
were a number of sceptics who said, "wait for perfect knowledge; there
is uncertainty in the ozone models." Unfortunately, the sceptics were
absolutely right. The models were inaccurate. They underestimated the
impact of human activities on stratospheric ozone. This means that with
the Montreal Protocol and its adjustments and amendments, society will
have to live with stratospheric ozone depletion not only over
Antarctica, but over all of the globe, except for tropics and
subtropics, for at least another 50 years. Some of the same sceptics are
now saying that not enough is known about climate change.'

However, the populist article you cite is a classic example of the use
of half-truths to bolster a political cause. Yes, human activity has
altered climate. The island I live on was the main known world source of
copper from 3,000 BCE to 1,000 AD (the name in Greek of the island and
the word for copper in Greek are the same, but it is not known whether
copper was named from the island or vice versa). It has been possible to
estimate the quantity of copper ore mined and metal smelted. From 3,000
BCE to the birth of Jesus (remember that this period included the copper
and bronze ages), the quantity of charcoal required for smelting that
amount of ore has been estimated. To provide that charcoal would have
required the complete deforestation of the total surface area of the
island at least 12 times. Now, no one is going to tell me that this had
no effect on the microclimates: I'm sure it did. So, effectively, 12 x
9500 km2 of forest were burnt over 3,000 years to produce this copper or
  38 km2/year on an average (one wonders at the manpower required to cut
the trees, kiln and transport the charcoal at this almost industrial
scale). Yes, the carbon will be transformed into CO2, but this is
renewable energy, part of the natural carbon cycle. In the growth period
of the renewed forest, so an equivalent amount of carbon will be
absorbed to allow the new trees to grow to the same size as the old
ones. This is the basic error of "it is unlikely that the rather low
human populations of ancient times would have had the means to produce
such high CO2 levels" -- this statement presupposes they were using
fossil fuels and <emphasis> it is not the presence of CO2 in the natural
carbon cycle that is in cause, but the extra loading that is produced by
the combustion of fossil fuels, thereby changing the carbon
cycle</emphasis>. Furthermore, the theory that heat causes CO2, rather
than the reverse, does not hold water in this case, as there are cited
time lags of a few hundred years. A few hundred years ago, the
temperatures in the N Hemisphere were actually decreasing.

In addition, any web site, such as Tech Central Station, that promotes
the self-interest of large American Corporations with vested interests
in burning fossil fuels and which cites "European liberals" as being
responsible for all the fuss about Climate Change is hardly likely to be
considered as credible. I did not realise that over half the scientists,
universities and other organisations working for the scientific aspects
of the IPCC, all from America, including many in the South, and even the
worthy NASA, were all "European liberals". We live and learn! (You see,
you don't have the monopoly of sarcasm :-) )

Brian

Chuck Dolci wrote:

> Alright, I know I said I would only look to IPCC reports, but I just
> came across this piece of swiss cheese (is that like "Emmenthal
> cheese"?), that I thought might be tasty.
>
> Chuck Dolci
>
>  From http://www.techcentralstation.com/121903D.html
>
> Debate Over Temperatures Heats Up
> By George Taylor
> Published   12/19/2003
>
>
> A recent Associated Press article suggested that humans have been
> changing the global climate since thousands of years before the
> industrial revolution. 8,000 years ago atmospheric levels of carbon
> dioxide began to rise as humans began clearing forests, planting crops
> and raising livestock, according to the article. Methane levels started
> increasing 3,000 years later.
>
> The scientist quoted in the article was Bill Ruddiman, emeritus
> professor at the University of Virginia. Ruddiman suggested that the
> human-caused disruption would have been sufficient to create much warmer
> climate during ancient times than "natural" conditions would have
> suggested.
>
> Right now there is a raging debate occurring regarding the temperatures
> of the last several thousand years. The longstanding view, championed by
> H.H. Lamb and other climate historians, was that the Holocene (the
> pleasant interglacial period in which civilization has flourished since
> the last Ice Age 15,000 years ago) has been marked by several notable
> climate fluctuations:
>
>
> 1. a very warm period about 3,000 B.C., the warmest of the Holocene (the
> "Holocene Maximum";
>
> 2. a gradual cooling thereafter, reaching a low point around the time of
> Christ;
>
> 3. a warming for about 1,000 years, peaking in roughly 1,000 A.D.
> ("Medieval Warm Period")
>
> 4. a cooling for several hundred years, with the coldest period from
> about 1560-1830 ("Little Ice Age")
>
> 5. brief warm and cool periods from 1830-1870 and 1870-1910, respectively
>
> 6. a warmer 20th century, for the most part.
>
>
> On shorter scales (decades or less) there have been numerous rises and
> falls in temperatures, some of them quite significant, but the long-term
> changes are those listed above.
>
> Lamb and other historians using various recorded and anecdotal
> information concluded that the Medieval Warm Period temperatures were
> comparable to those of modern times, the Holocene Maximum was much
> warmer, and the little Ice Age was much cooler.
>
> Enter Michael Mann of the University of Virginia, lead author of a paper
> that presented a much different viewpoint. Using tree ring and other
> data for estimating temperature histories back to 1,000 AD, Mann created
> a new and very different history. The Medieval Warm Period no longer
> existed, scarcely distinguishable from the Little Ice Age. Suddenly our
> current temperatures had become "the highest in 1,000 years." This was
> proof, so it was claimed, that human-induced global warming was occurring!
>
> One of the most valuable and heavily-referenced "paleoclimate data sets"
> (data used to infer long-term climate change) is the Vostok ice core
> data. In January 1998, a collaborative ice-drilling project between
> Russia, the United States, and France at the Russian Vostok station in
> East Antarctica yielded the deepest ice core ever recovered, reaching a
> depth of 3,623 m (nearly 12,000 feet). The ice was deposited in layer
> upon layer, like dirt where the Grand Canyon intersects, each
> representing a year. The lowest layers were deposited about 400,000
> years ago.
>
> Ice cores are valuable because they contain tiny gas bubbles whose
> composition can be measured. CO2 is measured directly using a gas
> chromatograph, while temperature is estimated from concentrations of two
> gases, deuterium and Oxygen-18.
>
> Early Vostok data analysis looked at samples centuries apart, and
> concluded (correctly) that there is a very strong relationship between
> temperatures and CO2 concentrations. The conclusion for many was
> obvious: when CO2 goes up, temperatures go up, and vice-versa. This
> became the basis for a number of scary-looking graphs in books by the
> scientist Stephen Schneider, former Vice President Al Gore, and others,
> predicting a much warmer future (since most scientists agree that CO2
> will continue to go up for some time).
>
> Well, it's not as simple as that. When the Vostok data were analyzed for
> much shorter time periods (decades at a time rather than centuries),
> something different emerged. H. Fischer and coauthors reported in
> Science (283: 1712-1714, 1999) that "the time lag of the rise in CO2
> concentrations with respect to temperature change is on the order of 400
> to 1000 years." In other words, CO2 changes are caused by temperature
> changes! Many other recent studies have shown similar results. Studies
> by Indermuhle et al (2000), Monnin et al (2001), and Mudelsee et al
> (2001) indicated a lag of 800-1500 years between temperature and CO2.
> References are available on request.
>
> Ruddiman's study is interesting, and bears further analysis. But two
> counter-arguments stand out: it is unlikely that the rather low human
> populations of ancient times would have had the means to produce such
> high CO2 levels, aside from massive forest fires; and the high "spikes"
> in CO2 were more likely responses to the abrupt warm periods which are
> known to have existed. Warm periods would have triggered increases in
> plant life, which eventually would have died or been burned and released
> to the atmosphere -- as CO2. Warmer ocean temperatures would have
> released CO2 to the atmosphere (more CO2 is absorbed when water is cooler).
>
> And why would temperature have risen and fallen if CO2 were not to
> blame? It's anyone's guess -- but my guess is that changes in earth's
> orbit, solar activity and ocean circulation were chiefly responsible for
> the warm and cool periods.
>
>
> George H. Taylor, Oregon State Climatologist. Email him at
> [log in to unmask]
>
>