----- Original Message -----
From: Steve <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, July 25, 2001 11:06 AM
Subject: Re: more on global warming models


> Ray,
> Further, from my
> readings on statistical models, the only real test of a model is how well
> its *predicitions* match up with the real data.
>
> Steve


Perhaps. The only way a model can be 'validated' is to run the model using
an 'independent' data set. This type of data set would have to be different
than the data set used to 'calibrate' the model. Time can only tell which
models are accurate and which ones are not.

For instance, the use of hydrological models to forecast water yields
arising from different scenarios of land use, et cetera, must have built
into them some extremely robust variables that can be measured accurately
and precisely. One variable is the 'infiltration' rate, another is
'evapotranspiration rates'. Even so if there are macro-climatic changes that
can be assumed regarding precipitation and temperature changes associated
with 'climate change' then the robustness of the data set may become valid
only in the case of the past. Changes in climate may greatly alter the
'constants' such as annual precipitation and evapotranspiration. Even such
changes as age class, canopy, species, et cetera, have a direct effect on
evapotranspiration.

In one model that was used to forecast or predict changes to the landscapes
of southern BC here, there was a statement made by the MOE (Min. of
Environ.) that some forested portions in the low elevations would change,
and the dominant biogeoclimatic zones would change with existing boundaries
shifting upward in elevation. This forecast implies that as the global mean
temperature rises that some formerly forested ecosystems would become
grasslands. This upward shifting in the phytogeography would also mean the
invasion of forest into the alpine areas. What the consequences are is
profound. One impact would be that many plantations which were established
with species that were preferred for that ecosystem would no longer be
suitable at the ecological level in the future (this is showing up in the
lodgepole pine and spruce plantations). Disease and insects would also
impact mature forests; and one early consequence that is mentioned as a
contributing factor causative of large scale outbreaks of the 'lodgepole
pine bark beetle' in central BC is warm winters. In fact since the 1980's
there has not been any extended periods of cold weather in the winter
(except for 1991) sufficient to kill large percentages of the brood that
occurs in the underbark of the pine. In the normal situation there are
sufficiently cold winters every few years that suppress the pine bark
beetle. It is recognized by forest entomologists that temperatures below -35
degrees for one to two weeks are required to kill the brood underbark. Cold
summers also delay the maturation of the brood.

So as a result of large scale forest fires that were started by Europeans to
remove forests for prospecting, for agriculture, to create fuel wood, and by
accident when the railroads burned coal, the existing forest in the central
interior of BC is largely composed of mid-seral forests ranging in age
between 60-120 years. These largely pine forests are not 'natural' (not a
condition that is expected based on pollen analysis) and therefore these
forests are subject to insect epidemics; however in the past when cold
winters were the rule rather than the exception, the bark beetles were kept
to endemic levels that were not a major threat.

As a consequence of climate change, biogeographers have determined that
ecosystems are not changed nor destroyed. The phenomenon that most often has
occurred is the 'shifting' in location of the major forest biomes. For
instance during the last glaciation, the boreal forest moved far south, as
far south as Kentucky. Here spruces were found to be common, as well as Lynx
and other boreal dependent species. Some parts of Kentucky still contain
'refugia' or patches of boreal forest (eg. Picea rubens).

The main problem with climate induced change is not so much the change per
se, but rather the rate of change. In the analysis taken from pollen and ice
cores it has been established that the rate of climate change occurring over
the last 100 years is unprecendented based on analysis of ice cores and
pollen over the last 100,000 years; there has been no other physical
phenomenon that has occurred over this time that comes close to being so
significant in magnitude. The main problem then for ecosystems is the 'rate
of change'; when the rate of change is accelerated, the possibility exists
for extinction of some species, and possible widespread 'maladaptation' and
further 'climatic induced change' (eg. Swiss needle cast in P. douglasii).
For some species the rate of change is not a problem, but for most species
it is a problem especially since much of the forest is 'fragmented' and it
is difficult for some (if not impossible) species to migrate. The ability of
coral reefs to 'migrate' or for 'mangroves' to migrate is limited.

There are many 'anthropogenic' stressors which include acid precipitation
and deposition, heavy metals, and persistent organic pesticides which also
negatively impact the ability of ecosystems to regenerate. The cumulative
effects of changes in predator-prey relations, the introduction of exotics,
and the further fragmentation of viable patches of forests and grasslands
also may have a further effect in exacerbating a 'primary source of stress'.
The forests in Europe have been said to be in a state of ecological
collapse; the cumulative effects of all the above factors and influences is
surely taking place in North America (though on a lessor scale dependent on
the region), but the trend is becoming extremely obvious to ecologists and
geographers. For instance the most significant impact to any class of
organisms in North America that has occurred due to industrialization is the
loss of many species of aquatic organisms; the highest percentage of species
extinction and local extirpation is in the fish and aquatic insect genera.
Very few 'crayfish' are now found in many streams when compared to the
earliest records. And is it any wonder? If you look at the state of Ohio for
instance, you will find that most of the original forest is gone. Perhaps
less than 5% of the original forests is left in any condition resembling
natural.

What with that kind of ecosystem change occurring over a few hudred years,
then, it would be no suprize that forest dependent species like fish and
forest stream dependent insects would vanish rapidly.

chao

john foster




>
>
>
> --- Ray Lanier <[log in to unmask]> wrote:
> > Hello Steven,
> >
> > It seems to me that your comments are not well-grounded, perhaps I am
> > wrong.
> > Let me offer my experience in an effort to clarify for us both.  I'm
> > obviously biased! :-)
> >
> > All  models that I have been involved with - on agriculture water & land
> > use
> > issues - have begun with many trial runs to test validity of the data
> > and
> > assumptions used in model construction.  These analyses were then
> > analyzed
> > by professionals in the several fields involved:  agr production and
> > yield
> > assumptions, current and over time, technology, water available, costs &
> > prices, land available and productivity, environmental factors,  etc.
> > For
> > example, I remember particularly one model 35 years ago.  When I
> > presented
> > it for review by the several specialists one old agricultural specialist
> > sorta drawled: "Well, I see you have projected a move of the dairy
> > industry
> > from Wisconsin to Iowa!"  For various institutional reasons that was not
> > a
> > valid outcome in the time-frame involved.  So go back to the drawing
> > board
> > to see where the data and/or assumptions were not acceptable.
> >
> > Once the model was judged "reasonable" in data and basic assumptions the
> > analysis could begin.  First we would evaluate the situation based on
> > the
> > assumption that there would be no change in poliicy/program.  This is
> > extremely important because it establishes a baseline that suggests the
> > magnitude of, for example, the potential water supply problems, if any.
> > Then it offers a baseline against which the several proposals to
> > alleviate
> > any water supply problems that might be proposed.  These programs offer
> > us
> > an opportunity to evaluate, relatively easily, many policy/program
> > options
> > to enable us to better select those that are most helpful and least
> > damaging.
> >
> > None of these analyses were "predictions" - implying factual accuracy.
> > They
> > were *projections*, implying best estimates of the relative consequences
> > that could be expected under the assumptions and the data available at
> > the
> > time of study.
> >
> > Those models were extremely important because they enabled us to
> > incorporate
> > interrelationships among many activities in a way that the old hand
> > calculators could not provide.  And, in today's modelling world, they
> > were
> > very primitive.  The model outlined above was a matrix of about 200+/-
> > columns and about 100+/- rows with a large percentage of empty cells.
> > Yet
> > it still took over 12 hours to run on an IBM computer complex taking up
> > most
> > of a building at U. Illinois Champaign-Urbana - and that was just to see
> > if
> > we had a potential feasible solution.  And we ran the problem on the
> > weekends to save money - it would take a weekend to get to a feasible
> > solution.  Today, I could run that problem on my little old desktop in
> > minutes.
> >
> > Now the analytical capabilities are far in advance of the little work we
> > did.  But for me, the significance of the great expansion in computer
> > power
> > is, first, the savings in time & money; second, the opportunity to
> > incorporate more of the complexity of the environmental problems in the
> > analysis.
> >
> > The important ethical issues for me are whether the data and assumptions
> > are
> > valid in the eyes of the professionals reviewing the work and whether
> > the
> > problem is appropriate to the particular computer complex used.  In
> > today's
> > world, I think that the organization and review of data and assumptions
> > in
> > such large problems must be horrendous.  We should expect errors; the
> > test -
> > whether there is adequate review by competent professionals of the base
> > program and the analyses.
> >
> > And these are only projections to help society visualize the potential
> > problems and to get some understanding of the *relative* worthwhileness
> > of
> > proposed policies/programs.
> >
> > I think it would be unethical not to use the newest computer technology
> > as
> > it becomes tested and available.
> >
> > Steven, and all, I would appreciate any comments.
> >
> > Ray
> > -------------
> >
> > ----- Original Message -----
> > From: "Steven Bissell" <[log in to unmask]>
> > To: <[log in to unmask]>
> > Sent: Wednesday, July 25, 2001 10:16 AM
> > Subject: more on global warming models
> >
> >
> > > Here is another article (I haven't seen the cited article in
> > _Science_)
> > that
> > > seems to me to be based on the use of models. This is not new
> > evidence, it
> > > is just more modeling of old data and, worse, it is based on
> > assumption
> > > about policy. I'm not sure this serves anyone very well.
> > >
> > > Steven
> > >
> >
>
http://www.enn.com/news/enn-stories/2001/07/07242001/warming_44399.asp?site=
> > > email
>
>
> =====
> "In a nutshell, he [Steve] is 100% unadulterated evil. I do not believe in
a 'Satan', but this man is as close to 'the real McCoy' as they come."
> --Jamey Lee West
>
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