Models and Science

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Bruce Skarin
Junior Member
Posts: 4
Joined: Fri Mar 29, 2002 3:39 am

Models and Science

Post by Bruce Skarin »

>From today's Washington Post:

""Myron Ebell, the Competitive Enterprise Institute's director of global
warming and international environmental policy, questioned the wisdom of
basing scientific conclusions on computer models.

""Modeling is not science,"" said Ebell,...

Humans May Double the Risk of Heat Waves:
Models Show That by 2040, Half of Europe's Summers Could Be as Hot as in
2003

http://www.washingtonpost.com/wp-dyn/ar ... 4Dec1.html

While all models have their limits, and many are fatally flawed, there is
actually a mental model in action to dismiss formal models. In Ebell's case
it is the inconsistency with his historical model (it was cool last summer).
If he had perhaps looked more closely he might have seen that the model may
allow for such yearly differences (I don't know the model, but if was any
good it would!).

It is one thing to disagree with a model's validity, but it is a whole other
thing to dismiss models all together. Poor Ebell might very well have been
quoted out of context, but the very reason a reporter might put it in such a
way is because the overall societal belief that models don't exist continues
unabated, when models are actually at the root of all our perceptual
existence.

Isn't nearly all our understanding of the world based on models that explain
the behavior of a system, but are not themselves the governing force for
such a system? My latest mantra said by a friend is ""feedback governs
dynamics.""

Our conceptual models do not govern any system other than our own thoughts
and the thoughts of others.

It is important to realize our complete dependency on models, because it is
our thoughts that lead to actions. And like I said, if our model is flawed
(i.e. models don't exist), then you are likely to draw 'very small-potatoes'
conclusions indeed!

I often wonder; when will the next time be when some of our most reputable
minds stick their necks out ounce again?

I'll certainly give it a shot, but then again, those that know me might not
call me respectable ;-)

-Bruce
From: ""Bruce Skarin"" <bruceskarin@hotmail.com>
Alan Graham
Member
Posts: 27
Joined: Fri Mar 29, 2002 3:39 am

Models and Science

Post by Alan Graham »

Re: ""Modeling is not science...""

Sir Isaac and his later colleague Albert would disagree.

cheers,

alan

Alan K. Graham, Ph.D.
Decision Science Practice
PA Consulting Group
Alan.Graham@PAConsulting.com
One Memorial Drive, Cambridge, Mass. 02142 USA
Direct phone (US) 617 - 252 - 0384
Main number (US) 617 - 225 - 2700
Mobile (US) 617 - 803 - 6757
Fax (US) 617 - 225 - 2631
Home office (US) 617 - 489 - 0842
Home fax (US) 617 - 489 - 0842 (by arr.)
Tom Fiddaman
Senior Member
Posts: 55
Joined: Fri Mar 29, 2002 3:39 am

Models and Science

Post by Tom Fiddaman »

Someone should take away Ebell's cell phone and any other modern
convenience created with the assistance of a model.

>While all models have their limits, and many are fatally flawed, there is
>actually a mental model in action to dismiss formal models. In Ebell's case
>it is the inconsistency with his historical model (it was cool last summer).
>If he had perhaps looked more closely he might have seen that the model may
>allow for such yearly differences (I don't know the model, but if was any
>good it would!).

Indeed, climate models do include variability (and getting the variability
right is one of the critical challenges). Reported results are almost
always the mean of an envelope of a number of simulations.

>It is one thing to disagree with a model's validity, but it is a whole other
>thing to dismiss models all together. Poor Ebell might very well have been
>quoted out of context, but the very reason a reporter might put it in such a
>way is because the overall societal belief that models don't exist continues
>unabated, when models are actually at the root of all our perceptual
>existence.

Regrettably he probably wasn't out of context.The CEI is one of a number of
organizations opposing emissions reductions and actively skeptical of
climate science findings, but with little if any scientific standing of its
own. (I checked their web site, http://www.cei.org/sections/section17.cfm ,
and found little of substance). Ebell appears to be more political
operative (see
http://observer.guardian.co.uk/internat ... 63,00.html )
than scientist (his CV includes nothing more scientific than appearing on TV).

I find it a bit puzzling that the CEI apparently accepts the IPCC
assessment (see http://www.spusa.org/issue/gcc/gcc_interview2.html ) which
is founded completely on models, yet simultaneously maintains ""The computer
models have been used to produce wildly unrealistic predictions of future
warming... ."" In the same interview, I find it funny that Ebell asserts
that economic models are much more advanced than climate models, given
their gaping holes.

It's also worth noting that the Post's record on climate is less than
impressive. Last year they published a skeptical op-ed by James Schlesinger
(Climate Change: The Science Isn't Settled Monday, July 7, 2003; Page A17)
without bothering to mention that he's on the board of Peabody Energy,
self-proclaimed largest coal company in the world. Not that one's
employment should prevent one from having a voice, but axes to grind ought
to be acknowledged.

Tom


****************************************************
Tom Fiddaman
Ventana Systems, Inc. http://www.vensim.com
PO Box 153 Tel (406) 578 2168
Wilsall MT 59086 Fax (406) 578 2254
Tom@Vensim.com http://www.sd3.info
****************************************************
Tom Fiddaman
Senior Member
Posts: 55
Joined: Fri Mar 29, 2002 3:39 am

Models and Science

Post by Tom Fiddaman »

At 09:30 AM 12/9/2004, Mark Wallace wrote:

> > Re: ""Modeling is not science...""
> >
> > Sir Isaac and his later colleague Albert would disagree.
>I wouldn't be too sure about that. As the original poster pointed out,
>this quote was taken out of context (to say the least).
>My belief is that Mr. Ebell's point is along the lines of ""Don't confuse
>the map with the territory."" ...

Computer models are not the object of study, they are the means of study.
While there are meaningful insights about the basic physics and chemistry
of the atmosphere to be had with pencil and paper, I don't know of any
serious climate science that can be done without computers. Whichever you
use, it's hard to see how one could proceed without a model, as the essence
of science is formulating models and testing them against data to see which
work. You simply can't skip the first step (modeling), so it's hard to see
how the ""modeling is not science"" claim can be supported, except to the
extent that modeling is a necessary step in science, but not sufficient
without also doing the data work (verifying the map against the territory).

""Don't confuse the map with the territory"" is still an important
admonition, i.e. that one should be aware of the limitations of models.
However, it can be taken too far - to the point of ignoring the map, and
just doing whatever feels right given the local terrain. Ebell's assessment
of the territory appears to be at the level of ""it was cool last summer so
everything's OK."" This ignores at least two insights to be gained from
modeling (there's natural variability, and the climate system has many more
relevant state varaibles than just temperature), so it seems he would
benefit from a map.

I think it would be interesting to ask Mr. Ebell, ""If modeling is not
[climate] science, what is?"" Certainly there is an enormous amount of data
gathering and processing going on (the Earth Observing System is generating
terabytes), but none of it makes any sense until put into a model.

>For example, as far as I know, no existing GCM - Global Climate Model -
>can account for such sharp temperature rises as the recovery from the last
>Ice Age or such high temperatures as those prevailing in the Medieval Warm
>Period (around 1,000 years ago, when agriculture was common in areas of
>Greenland now covered in permafrost).

(A note to googlers: GCM more often refers to general circulation model
than to global climate model, though the two are used fairly interchangeably).

> > If he [Ebell] had perhaps looked more closely he might have seen that
> the model may
> > allow for such yearly differences (I don't know the model, but if was any
> > good it would!).
>Ebell has been looking a lot more closely than the poster might suspect,
>and that is precisely why he (and I) believe that there are no good GCM's
>yet. The modelers are trying to crawl (by concentrating on the last 20
>years) before they walk, and they are nowhere near to running. Their
>efforts are commendable, but what is completely irresponsible is to use
>their primitive results for purposes of public policy (e.g., the Kyoto
>Treaty).

It's unfair to suggest that modelers are just concentrating on the last 20
years. There are many paleoclimatic studies with models, both of the last
few interglacials and from millions of years ago when the earth's geography
was different. Just google ""GCM paleoclimate"" or visit
http://pgap.uchicago.edu/data-models.html for an example. Most GCM runs are
at least century scale. The real problem is that paleo data are so sparse
that it's harder to judge whether the model's right or not when simulating
ancient climates.

Also, there is evidence that models are improving. Short term weather
forecast skill has improved steadily in recent decades:
http://www.cpc.ncep.noaa.gov/products/p ... ll_ts.html
The time horizons of interest are obviously different, but the physics of
GCMs and short term weather simulations are much the same.

A corrolary to ""the map is not the territory"" might be ""you can't plan a
trip with the territory."" It's not irresponsible to use primitive results
for purposes of public policy; using nothing at all is worse. It's easy
enough to build policy models with an appreciation of the uncertainty. Even
if our subjective distribution of the climate sensitivity to 2x CO2 has
zero mean, it's likely to be optimal to take some action in order to
prevent scenarios in the tails. What is somewhat irresponsible in my view
is to construct an overly-complicated, non-inclusive set of capping and
trading mechanisms (Kyoto), simply because politicians can't bring
themselves to say the word ""tax."" A global, flat, adaptive carbon tax would
be much more efficient from a welfare standpoint.

>""Scientific American"" is among the most enthusiastic cheerleaders for the
>GWH - Global Warming Hypothesis (and ruthless censors of its
>skeptics). Please see the graph at the top of page 65 of last month's
>(November, 2004) issue. (The article is entitled ""Abrupt Climate
>Change."") Two facts are brutally obvious from this graph. One, the
>prevailing temperature was over 3 degrees C higher than it is now at
>around 3,500 years ago, and again around 7,000 years ago, and again around
>8,000 years ago. Two, around 11,500 years ago, and again around 14,500
>years ago, temperature increases of about 12 degrees C occurred in about a
>century. The article states that 11,500 years ago, the increase (of ""more
>than 10 degrees C"") occurred ""in a mere decade""! To put this in
>perspective, even the strongest claims regarding the temperature increase
>in the 20th Century are less than 1 degree C (i.e., contemporary dT/dt -
>which is touted as catastrophic - is two orders of magnitude less).
>No GCM, or cheerleader for the GWH, can explain why such high prevailing
>temperatures, or such sharp temperature increases, occurred in the past
>without any assistance from human burning of carbon-based energy sources.

The >10 degree jump at the end of the Younger Dryas and the <1 degree
increase in the 20th Century should not be compared because the first is
regional and the second is global. Regional shifts can be much more
dramatic; the 10 degree jump is evident elsewhere in the global record, but
not to such an extreme. Modeling abrupt changes is likely to remain
difficult, as they likely involve ocean circulation. Modeling the ocean
correctly is hard, at least in part due to sparse data and the fine spatial
scale needed to get turbulent flow right.

Also, climate models do replicate the Holocene warm period - for example,
simulated changes in climate (vs. present) qualitatively match changes in
the distribution of plants (from pollen records). Orbital forcing is a
strong candidate for the cause of the warmth without carbon emissions. In
fact, other greenhouse skeptics (
http://www.co2science.org/subject/h/sum ... esolar.htm ) claim
this as evidence against anthropogenic warming. Solar variation could also
be responsible for the Medieval Warm Period, but that event represents a
small enough excursion that it could easily be due to natural variation
(i.e. it is within the envelope of natural variability in GCM runs).

>In fact, when I look at that graph, one thought that occurs to me is that
>humankind has been the beneficiary of unusually warm temperatures for the
>last 10,000 years (maybe that's why we now have what we call
>civilization). The most likely future event is not a runaway increase,
>but a return to ""normal"" in the form of a runaway decrease of 10 degrees C
>or so.
>Mark Wallace

It's generally thought that the driver for ice age initiation is orbital
change, and nothing threatening is on the horizon for the next few thousand
years, so we can all breathe easier knowing a global runaway decrease is
unlikely. Inhabitants of the North Atlantic rim do have to contemplate the
possibility of a big decrease due to changes in ocean thermohaline
circulation, but that event ironically would be triggered by warming.

Tom



****************************************************
Tom Fiddaman
Ventana Systems, Inc. http://www.vensim.com
PO Box 153 Tel (406) 578 2168
Wilsall MT 59086 Fax (406) 578 2254
Tom@Vensim.com http://www.sd3.info
****************************************************
Mark B. Wallace
Newbie
Posts: 1
Joined: Fri Mar 29, 2002 3:39 am

Models and Science

Post by Mark B. Wallace »

On 15 Dec 2004 at 0:48, Tom Fiddaman wrote:
> ...
> Also, there is evidence that models are improving. Short term weather
> forecast skill has improved steadily in recent decades:
> http://www.cpc.ncep.noaa.gov/products/p ... ll_ts.html

They still can't tell me if it's going to rain tomorrow. The charts cited
above rely on something called a ""Heidke Skill Score,"" which is a
controversial verification technique, even within NOAA:

http://ams.confex.com/ams/84Annual/tech ... _68014.htm

Also, the ""Scientific American"" article expresses substantial concern over
the limitations of current climate models, especially at the extremes.

> ...
>
> A corrolary to ""the map is not the territory"" might be ""you can't plan a
> trip with the territory.""

If the map isn't that good, it might be optimal not to take the trip in the
first place.

> It's not irresponsible to use primitive results
> for purposes of public policy; using nothing at all is worse.

I respectfully disagree. While results are still primitive, the only
sensible public policy is ""hands- off."" The compulsion to DO SOMETHING
(i.e., act for the sake of acting, before carefully considering the
consequences) should be resisted. In particular, it is irresponsible to
propose (in effect) limits on energy consumption without making the
slightest attempt to evaluate the costs of imposing those limits. Doctors
understand that ""first of all, do no harm"" is an important principle when
dealing with the unknown. I see no such humility among Global Warmers.

> It's easy
> enough to build policy models with an appreciation of the uncertainty.
Even if
> our subjective distribution of the climate sensitivity to 2x CO2 has
zero mean,
> it's likely to be optimal to take some action in order to prevent
scenarios in
> the tails.

That depends on whether or not ""some action"" will keep billions of people
in a poverty they might otherwise have escaped had more energy been
available. And by the way, poverty, anywhere in the World, is a leading
cause of death.

I haven't seen any models of the effects on human well-being of reducing
energy consumption. This is an area where the SD community could make a
major contribution. SD is supposed to excel at pointing out unintended or
unobvious consequences. Here is an opportunity to do so. It is just
astonishing to me that SD has not been used to look at the cost of reducing
energy consumption. Or have I missed something?

>...
>
> The >10 degree jump at the end of the Younger Dryas and the <1 degree
> increase in the 20th Century should not be compared because the first is
> regional and the second is global.

I am curious if the poster knows this for a fact and, if so, how. The
article makes no mention of such a limitation (that the increase was
regional, only). Just because the data was collected at only one location
doesn't mean that the increase couldn't also have been occurring elsewhere.

>...

Mark
From: ""Mark B. Wallace"" <mbw2@cox.net>
Marcel Vallée
Junior Member
Posts: 2
Joined: Fri Mar 29, 2002 3:39 am

Models and Science

Post by Marcel Vallée »

Excerpt from comments by Mark B. Wallace

««I respectfully disagree. While results are still
primitive, the only sensible public policy is ""hands- off.""
The compulsion to DO SOMETHING (i.e., act for the sake of
acting, before carefully considering the consequences)
should be resisted. In particular, it is irresponsible to
propose (in effect) limits on energy consumption without
making the slightest attempt to evaluate the costs of
imposing those limits. Doctors understand that ""first of
all, do no harm"" is an important principle when dealing with
the unknown. I see no such humility among Global Warmers.»»


In a sustained development perspective, I definitely take
exception with the sentence «it is irresponsible to propose
(in effect) limits on energy consumption without taking the
costs of imposing these limits.»

Our current energy consumption levels are needlessly
wasteful and could be reduced. They could be called
irresponsible as they likely are not sustainable in the
longer term unless presently unknown technology and
resources become available on a wide scale. Let future
generations fend for themselves!

They also are a treat to the security level of countries in
northern climates like the USA and the European countries
that consume much more energy than what they could readily
obtain from easily accessible sources in a more volatile
political context. These considerations should also go into
responsible mid- to long- term models.



Marcel Vallée, P. Eng., P.Geo.
Geoconsult M. Vallée Inc.
Email:
vallee.marcel@sympatico.ca
Tom Fiddaman
Senior Member
Posts: 55
Joined: Fri Mar 29, 2002 3:39 am

Models and Science

Post by Tom Fiddaman »

At 12:29 AM 12/17/2004, Mark Wallace wrote:

>They still can't tell me if it's going to rain tomorrow. The charts cited
>above rely on something called a ""Heidke Skill Score,"" which is a
>controversial verification technique, even within NOAA:
>http://ams.confex.com/ams/84Annual/tech ... _68014.htm

This is an interesting point, though I've seen it claimed elsewhere that
forecasters don't understand Heidke so it seems unlikely they'd
deliberately manipulate it. It would be interesting to know whether Garrity
scores are going up or not.

I think I dragged a red herring through the debate though. The improvement
in short term forecasts could be entirely due to improved data, for
example. However, this is the wrong question to ask of GCMs. Inability to
perform point predictions is not, by itself, a reason to reject a model.
There are lots of useful models of things like turbulent flow that
adequately reproduce the behavior of a phenomenon without actually
replicating any particular instance.

> > A corrolary to ""the map is not the territory"" might be ""you can't plan a
> > trip with the territory.""
>If the map isn't that good, it might be optimal not to take the trip in
>the first place.
> > It's not irresponsible to use primitive results
> > for purposes of public policy; using nothing at all is worse.
>I respectfully disagree. While results are still primitive, the only
>sensible public policy is ""hands- off."" The compulsion to DO SOMETHING
>(i.e., act for the sake of acting, before carefully considering the
>consequences) should be resisted. [...]

This is not an application for JWF's (possibly apocryphal) admonition to
""don't just do something, stand there."" We can't choose not to take the
trip (unless we all join the Voluntary Human Extinction movement) - we have
to choose which trip to take. Currently, we are taking a trip that
subsidizes resource extraction and consumption, taxes goods (wages) instead
of bads (emissions), ignores externalities associated with energy use
(especially in the transport sector), regulates the pollutants that are
controlled by inefficient means, prices electric power at average instead
of marginal cost, and values carbon emissions at 0 $/ton. That's hardly
""hands-off."" It's a ""hands-on"" policy based on assumptions that technical
progress will continue to outstrip declining resource quality, sensitivity
of climate to 2x CO2 is 0, etc.

>[...] In particular, it is irresponsible to propose (in effect) limits on
>energy consumption without making the slightest attempt to evaluate the
>costs of imposing those limits. Doctors understand that ""first of all, do
>no harm"" is an important principle when dealing with the unknown. I see
>no such humility among Global Warmers.

In fact there have been many attempts to evaluate the cost of limiting
emissions - there is an entire field of Integrated Assessment Modeling of
global change. There must be at least 20 significant IAMs out there, not
counting dozens of variants and small models. All of these explicitly trade
the benefits of avoided climate change against the economic costs of
current emissions reductions. Even the most conservative models - for
example, DICE (by economist William Nordhaus, one of the earliest and most
vehement critics of World Dynamics/Limits to Growth, hardly a ""Global
Warmer"") suggest an initial carbon tax in the ballpark of $10/ton, rising
over time. By ""conservative"" I mean that these models arrive at their
conclusions using assumptions that generally disfavor GHG emissions
reductions - infinite sinks for carbon, infinite technology, full
substitutability of environmental and market goods, discounting the welfare
of future generations for pure impatience, etc.

> > It's easy
> > enough to build policy models with an appreciation of the uncertainty.
> Even if
> > our subjective distribution of the climate sensitivity to 2x CO2 has
> zero mean,
> > it's likely to be optimal to take some action in order to prevent
> scenarios in
> > the tails.
>That depends on whether or not ""some action"" will keep billions of people
>in a poverty they might otherwise have escaped had more energy been
>available. And by the way, poverty, anywhere in the World, is a leading
>cause of death.

It's a gross overstatement to claim that GHG emissions reductions will keep
billions of people in poverty. The energy sector is not that big in the
economy - even a ""ruinous"" total elimination of emissions in the DICE model
doesn't cause a decline in global GDP/capita; it just requires foregoing a
couple of years of growth.

The absolute global growth impacts of climate damage and emissions
reductions are insignificant compared to distributional issues. From a
welfare standpoint, the victims of climate change will be
disproportionately in places like Bangladesh, and disproportionately unable
to use the products of growth to invest in things like irrigation and
coastal defence. Again, some existing IAMs make this tradeoff explicitly.
To continue with the same example, there is a regional version of DICE,
called RICE, that includes seven regions at varying levels of development.
It still concludes that modest carbon taxes are beneficial. It does this
using an optimization framework that assigns greater weight to the welfare
of individuals in wealthier regions (in order to prevent large capital
flows to the developing world). If you relax that morally bankrupt
assumption, and set climate policy with fair welfare weights, I expect that
the outcome would show that emissions reductions in the developed world are
the ultimate form of development aid, because unlike monetary payments they
can't be squandered by institutions.

In order to favor doing absolutely nothing, you have to believe that
climate change won't happen, or won't be damaging, and that there's zero
chance of being wrong. For the rich to be cheerleaders for growth in the
name of the poor, while subjecting the poor to greater risks than the rich,
seems at best self-serving.

>I haven't seen any models of the effects on human well-being of reducing
>energy consumption. This is an area where the SD community could make a
>major contribution. SD is supposed to excel at pointing out unintended or
>unobvious consequences. Here is an opportunity to do so. It is just
>astonishing to me that SD has not been used to look at the cost of
>reducing energy consumption. Or have I missed something?

You have definitely missed something. There has been a great deal of energy
work in SD. Check the SD bibliography for Andy Ford's papers or MIT
Archives online for dissertations (John Sterman's and mine), to name just a
few. The energy-economy models in SD, like climate IAMs, frequently include
an explicit utility function or other output metrics representing the
benefits of goods and services consumption. Energy is seldom a direct
component of utility because it's not energy per se that is in demand.
People want warmth, light and mobility, not gigajoules. The real question
is how to deliver energy services efficiently. In SD and other models, the
direct cost of reducing energy consumption is generally the substitution of
capital for energy through installation of more efficient, but more
expensive, devices.

To the extent that there are costs associated with energy use that are not
internalized in current markets there can be negative net costs for many
energy/emissions reducing policies. Obvious examples include surface air
pollutants, which go nearly untaxed in the transport market. Not-so-obvious
examples include things like insurance externalities (i.e. making some of
the fixed cost of vehicle insurance into a variable cost through a gas tax
would have net benefits).

In addition, bottom-up engineering-economic studies generally indicate
potential for negative costs of energy conservation, even when
externalities are neglected. This might be due, for example, to biases in
perception of costs and benefits. Economists have more or less unilaterally
declared that this ain't so, e.g. due to hidden costs of implementation,
but on the basis of fairly flimsy evidence and circular logic in my opinion.

> > The >10 degree jump at the end of the Younger Dryas and the <1 degree
> > increase in the 20th Century should not be compared because the first is
> > regional and the second is global.
>I am curious if the poster knows this for a fact and, if so, how. The
>article makes no mention of such a limitation (that the increase was
>regional, only). Just because the data was collected at only one location
>doesn't mean that the increase couldn't also have been occurring elsewhere.

There are several reasons one should use caution when comparing regional
and global temperatures. First, changes at high latitudes tend to be bigger
than changes in the tropics. Second, if local climates were just random one
would expect regional variations to exceed global variation because the
mean of a bunch of measurements is more stable than the individuals.
Third, climate isn't random, but one would still expect the same kind of
behavior for physical reasons: for example, a warm current could shift from
the east of Greenland to the west, dramatically changing local climate
without having much effect on the global energy balance.

The increase at the end of the Younger Dryas is visible elsewhere in the
global record, though not all abrupt changes are. (""This abrupt event can
be found in paleo records from many parts of the world, although not
necessarily to such an extreme degree.""
http://www.ngdc.noaa.gov/paleo/ctl/abrupt.html ; See also
http://www.ncdc.noaa.gov/paleo/abrupt/data_glacial.html .) However, the >10
and <1 degrees are not on the same yardstick.

Tom



****************************************************
Tom Fiddaman
Ventana Systems, Inc. http://www.vensim.com
PO Box 153 Tel (406) 578 2168
Wilsall MT 59086 Fax (406) 578 2254
Tom@Vensim.com http://www.sd3.info
****************************************************
John Sterman
Senior Member
Posts: 117
Joined: Fri Mar 29, 2002 3:39 am

Models and Science

Post by John Sterman »

In his response to Tom Fiddaman about policy to
address the risks of climate change, Mark Wallace
argues that ""the only sensible public policy""
response to the threat of global warming is
""hands-off"" until science can supply definitive
answers through improved models and empirical
study. He further accuses climate modelers of
lacking humility. On the contrary, those who
advocate ""wait and see"" policies seek to pursue
an active policy of human intervention in earth's
ecosystems and biogeophysical processes.
Allowing business as usual to proceed means
continuing the growth of fossil fuel consumption
and GHG production. The continued growth of GHG
emissions constitutes an unprecedented human
intervention in the climate that has already
raised the atmospheric concentration of CO2 from
preindustrial levels of about 280 ppm to 375 ppm
today, and is projected, under the business as
usual scenario Mark Wallace apparently
recommends, to raise it to somewhere in the
neighborhood of 700-1000ppm (per IPCC and many
other analyses). Contrary to Wallace's
assertion, those who advocate mitigation policies
today are the ones who seek to ""do no harm.""
Continued growth in GHG emissions recklessly
subjects all of us, all our children, and all our
grandchildren, to the risks of harmful climate
change.

The fact that there remains uncertainty about the
ways in which climate might respond to
anthropogenic GHG forcing, and how much damage
that may cause to humanity (and other species) is
no argument for delay. Despite well publicized
(and primarily industry funded) attempts to
suggest otherwise, there is strong scientific
consensus that anthropogenic GHG emissions are
already having a measurable impact on global
climate, and that risks of greater change
increase with the GHG concentration. Naomi
Oreskes (The Scientific Consensus on Climate
Change 3 DECEMBER 2004 VOL 306 SCIENCE, p. 1686)
analyzed nearly 1000 papers on climate change in
the top peer reviewed journals. None disagreed
with the consensus position, expressed in the
IPCC Third Assessment Report, that """"Human
activities S are modifying the concentration of
atmospheric constituents S that absorb or scatter
radiant energy. S [M]ost of the observed warming
over the last 50 years is likely to have been due
to the increase in greenhouse gas
concentrations..."".

Yet there are genuine uncertainties about how
much and in what ways climate would change if the
active intervention of humans accelerates, as
Mark Wallace would have it. Research should of
course continue to reduce these uncertainties.
But the uncertainty in no way justifies delay.
You don't know if a fire may break out in your
house this coming year, or whether you will get
in a car accident. That uncertainty is, of
course, no excuse for removing the smoke
detectors from your home or canceling your
insurance. If it turns out that you do have a
fire or accident, it will be too late to protect
yourself and your family. You carry insurance
precisely because there is uncertainty, not
despite it. The delays in the response of the
climate to anthropogenic forcing are extremely
long. If we pursue the risky experiment of
continued GHG emissions growth and it turns out
that the resulting climate changes are harmful it
will be too late.

Doctors are enjoined, as Wallace says, to do no
harm. That principle applies with even more
force to climate change, where the risks we
create will be imposed on future generations
without their knowledge or consent. Contrary to
the Hippocratic precept, those who advocate
continued emissions growth and oppose policies to
reduce GHG emissions not only put themselves at
risk but impose those risks on everyone,
including all our children and their children.
The only way continued GHG emissions growth can
be construed as a prudent course is to argue that
the risks of harmful climate change are so low,
and the costs of mitigating them so high, that it
can never make sense to reduce emissions, and to
believe further that there is no possibility of
being wrong in that judgment. That strikes me as
a remarkable lack of humility. One can't have it
both ways: if there is a lot of uncertainty
about the impact of human activity on the
climate, you can't simultaneously argue that
there is no uncertainty about the policy
conclusion that insurance against those risks
isn't needed.

There are other errors and misconceptions in
Wallace's argument. Most notably, reducing GHG
emissions is not the same as reducing energy
consumption. Further, it is simply not true, as
Wallace alleges, that climate modelers propose
""limits on energy consumption without making the
slightest attempt to evaluate the costs of
imposing those limits."" A wide range of
scientists, economists, and others are actively
studying the economic, social, political,
military, and other costs of climate change to
humanity and other species. Wallace correctly
notes that the prudent degree of mitigation
depends not only on the risks of harmful climate
change but on the costs of mitigation, but then
suggests that mitigating GHG emissions might
""keep billions of people in a poverty they might
otherwise have escaped had more energy been
available."" The vast majority of GHG emissions
today arise from the developed economies, not
from those living in poverty. The strongest
opposition to GHG emissions reductions comes from
people who, by global standards, are rich beyond
measure, not from Bangladeshis living in poverty.
The suggestion that GHG emissions reductions
would entail huge costs is not supported by the
data; rather, it reflects a deep pessimism about
our ability to innovate, to develop new
technologies -- to rise to the challenge of
creating a sustainable society with the same
creativity and entrepreneurial energy that
generated the automobile, the microchip, and
polio vaccine.

John Sterman
From: John Sterman <jsterman@MIT.EDU>
Khalid Saeed
Senior Member
Posts: 79
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Post by Khalid Saeed »

Tom Fiddaman, Mark Wallace and John Sterman have all touched on important
aspects of intervention into environment. In my observation, the real
problems is the misconception that environment is a weak and precariously
balanced system that needs to be protected by man. It is often too late for
us to recognize the fact is that the environment we live in is a robust
system that is capable of correcting any discrepancies that we introduce in
its functions since the time constants of this system are much longer than
our own life times. Hence, current generations feel safe about discounting
the future and externalizing the costs their over-consumption on the future
generations. Unfortunately, when the environmental system unleashes its
forces to overcome the dysfunctions that have accumulated over time, the
repercussions of these forces might be experienced by the generation that
might have contributed very little to the creation of the dysfunction being
corrected. In the end, the environment would survive the transition, the
human society may not.

While we may never know enough about the environment, we know a lot about
our own behavior. Hence, hands-off the environment makes sense, but
intervention into our economic and societal functions makes a lot of sense.
Our commitment to support societal welfare rather than the environment per
se makes sense, but the concept of anthropocentricity in mainstream
economics is limited mostly to here and now. Value added to the economy is
often the value taken away from the environment and growth attributed to
technological progress is often achieved at the cost of depletion of
material and environmental resources. There is a need to internalize
restoration of what has been depleted by production and consumption into
the economy so we are able to live in perpetuity within the environmental
capacity that we can fathom at any point in time, not beyond it. Only moral
and ethical appeals would not achieve this end, but new environmental
responsibility institutions need to be explored and formed to complement
current economic and societal institutions - to create internal checks and
balances in the human system that apply the doctrine of anthropocentricity
to perpetuity not only to here and now. I have explored such a concept in:

Saeed, K. (2004). Designing an Environmental Mitigation Banking Institution
for Linking the Size of Economic Activity to Environmental Capacity.
Journal of Economic Issues. 38(4):909-937

but, to be honest, I remain pessimistic about our will to accept our
subservience to the power of the environment we live in and proceed to
develop such institutions at a needed scale.

Khalid Saeed
From: SD List Moderator <system-dynamics@vensim.com
Cc: Khalid Saeed <saeed@WPI.EDU>
Dr David Corben
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Post by Dr David Corben »

If you want people to adopt a precautionary principle then you need to
have some degree of credibility based upon a track record of getting it
right. I am afraid that the environmentalists have cried wolf so many
times that most people just switch off.

Does any one remember the hole in the ozone layer and all the
apocalyptic predictions the environmentalist were making 15 years ago?
It's still there by the way, but nobody seems that worried about it
anymore.

What about the one where all the resources were going run out by the
year 2000 and civilisation was going to collapse?

Minimising impact on the environment seems very sensible, but if we had
always followed this rule we would still be hunter gatherers living in
caves. The invention of agriculture and the industrial revolution caused
significant environmental changes (what the environmentalists would call
damage) but also provide us with huge benefits.

It is also possible to be too cautious, environmentalists have already
killed off GM in Europe and now they have their sights on nano
technology. If concern for the environment means that we kill all new
technologies at birth then we are going to be in real trouble.


Dr David Corben
david@dsc-consulting.co.uk
jsterman@MIT.EDU
Junior Member
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Post by jsterman@MIT.EDU »

David Corben is right that there is an important conversation to
have about the proper role of the precautionary principle in guiding
policy for new technologies that affect human welfare. How much
evidence of safety and efficacy should be required before new and
untested substances or technologies are widely deployed? How are
costs and benefits to be assessed and traded off? These are difficult
and important issues, and there are many resources available to help.
However, for the conversation on this listserve to be productive, we
need to avoid unsubstantiated generalizations and caricatures. Contrary
to his assertion, responsible scientists and environmentalists (the
overwhelming majority) do not argue it would be better if we were still
""hunter-gatherers living in caves"" or that we should ""kill all new
technologies at birth."" Dr. Corben should provide references to
substantiate claims he makes and studies to which he alludes, such
as ""the one where all the resources were going run out by the year
2000 and civilisation was going to collapse.""

Posted by jsterman@MIT.EDU
No doubt there are some fundamental differences in values among those
on this list. These should not be glossed or censored. But hyperbole
and polarizing rhetoric ill serve what I presume to be our common goals:
learning more from and about one another; learning how to make wise
decisions in a world of immense and growing complexity.

John Sterman
Posted by jsterman@MIT.EDU
james.thompson@strath.ac.uk
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Post by james.thompson@strath.ac.uk »

Posted by james.thompson@strath.ac.uk
Dr. David Corben writes: ""I am afraid that the environmentalists
have cried wolf so many times that most people just switch off.
Does any one remember the hole in the ozone layer and all the
apocalyptic predictions the environmentalist were making 15 years
ago? It's still there by the way, but nobody seems that worried
about it anymore.""

As a consequence of understanding why the ozone layer was being
destroyed and reflecting appropriate concern, regulations to eliminate
the use of ozone-depleting chlorofluorocarbons were enacted on a global
scale. The forecasts were directionally correct and within tolerable
error limits. The global reaction was also appropriate, wouldn't you agree?

Dr. David Corben writes: ""What about the one where all the resources were
going run out by the year 2000 and civilisation was going to collapse?""

Forecasting is a risky business. Herbert Simon provided a special caution
for predictive models of social systems, the systems most likely to be modelled
in system dynamics. He observes that there are likely to be several entities
making guesses - rational expectations - about the future of such systems for t
he purpose of changing outcomes in those very systems.

In his article, Prediction and Prescription in Systems Modelling (Operations
Research, (1990) 38, 7-14), he notes that ""the feedback loops in social systems a
re not passive but predictive. Each of the participants may be trying to forecast
the behaviour of other actors and of the system in order to adapt his or her own
behaviour advantageously,"" (p. 10).

One construct of rational expectations implies that expectations are
amplified by outcomes. Another construct makes forecasting even harder;
it implies that expectations are supported by outcomes that in turn support
the predictions of the underlying theory. According to Simon, forecasting
under conditions of rational expectation feedback loops, ""it may be
impossible to obtain answers to our predictive questions, and we may be
well advised to ask a different set of questions instead,"" (p. 10). Simon
argues that the better question is Which combination of policies is more
robust and less prone to cause problems. In a nutshell, he argues in favour
of policy testing models when boundedly rational expectations are part of the
system to be modelled.

Jay Forrester made a compelling argument on the same point about 30 years
earlier. In Industrial Dynamics (1961, Pegasus Communications, Waltham, MA,
USA) he wrote, ""A successful model for predicting the future state of a business
or economic system cannot remain aloof from that system except to the extent that
the model fails. Should a model of proved ability to predict the specific future
course of a social system exist, it would defeat itself if it were put to use,"" (p. 127).

It's difficult to say to which 'one' Corben refers. It seems that 30 years ago,
there were many forecasts of depleted resources. Entrepreneurs who took note of
those forecasts developed fertilisers, seeds, and alternative means of doing things
(e.g. fibre optics instead of copper wire) helped to avert the medium term threats
seen in many of those models. Governments adopted policies to maintain and improve t
he quality of air, soil and water. One can ask whether these actions were taken
because of, in spite of, or merely along side the forecasts. But it is reasonable
to say that the forecasts played a role in attracting attention to problems that
people converted into opportunities that defeated the forecasts.

Jim Thompson
james.thompson@strath.ac.uk
Posted by james.thompson@strath.ac.uk
Tom Fiddaman
Senior Member
Posts: 55
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Post by Tom Fiddaman »

Posted by Tom Fiddaman <tom@vensim.com>
""The environmentalists"" are as handy a punching bag as ""economists."" Yet
the image of wild-eyed greenies running around predicting the apocalypse
and monkeywrenching the economy has little to do with the mainstream of
environmentalism, the substance of the global warming debate, or the
history of environmental modeling.

At 04:01 AM 12/30/2004, Dr. David Corben wrote:

>>If you want people to adopt a precautionary principle then you need to
>>have some degree of credibility based upon a track record of getting it
>>right. I am afraid that the environmentalists have cried wolf so many
>>times that most people just switch off.


One might accuse modelers on all sides of the same problem. How many
nontrivial economic forecasts come true? According to The Economist,
forecasts by panels of professional economists are worse than random. Yet
economists are still widely listened to. Everything gets amplified in the
press, not just the claims of environmentalists. Crying wolf is clearly not
optimal, but neither is blanket disregard for all things environmental
because of past excesses. To select a management principle exclusively by
track record is to explicitly ignore the possibility of delays and shifting
loop dominance, and instead rely on the assumption that technology can
outpace physical limits forever.


>>Does any one remember the hole in the ozone layer and all the
>>apocalyptic predictions the environmentalist were making 15 years ago?
>>It's still there by the way, but nobody seems that worried about it
>>anymore.


Seems to me that the scientific understanding of the problem was right,
though incomplete and uncertain at the time, and that all the noise
achieved a useful goal - getting policies in place that led to a peak in
emissions a few years ago and will result in a gradual improvement of the
situation this century. It seems absurd to conclude that there never was a
problem when (1) the problem would not yet have become acute and symptoms
would not be easily observable due to the long time constants involved and
(2) understanding of the problem led to corrective action.

There are lots of ozone links (mostly research institutions) at
http://www.theozonehole.com/ozonelinks.htm
and the WMO 2002 assessment at
http://www.al.noaa.gov/WWWHD/pubdocs/Assessment02.html

>>What about the one where all the resources were going run out by the
>>year 2000 and civilisation was going to collapse?


I'll hazard a guess that this refers to an incorrect but oft-repeated
criticism of the Limits to Growth (LTG) report. Therefore I will respond
nonspecifically to the many critics of LTG.

The basic critique runs, as above, ""LTG predicted the end of the world in
year XXXX, and it didn't happen."" Usually the year XXXX is chosen, not from
one of the World3 runs, but from a table of resource lifetime indices in
the chapter on nonrenewable resources, which were not forecasts at all. If
you flip through a copy of LTG, you won't find any runs where industrial
output peaks before about 2010, and you will find a number of comments to
the effect of ""this is a choice, not a forecast"" or ""more study is needed.""
The plots in the book deliberately used a minimally-labeled time axis to
highlight the fact that output was meant to illustrate generic behaviors of
a system with rapid growth, long delays, and limits, rather than point
predictions of future conditions.

As an example, Bjorn Lomborg writes in The Skeptical Environmentalist (pg.
121 of my edition), ""Along with numerous other resources, Limits to Growth
showed us that we would have run out of oil before 1992."" What he refers to
is a table on pg. 58 of LTG showing static reserve life indices (SRLI) and
their dynamic equivalents for a variety of resources. If you read the
accompanying text, it's clear that the table has little to do with
forecasting exhaustion. Instead it simply makes the point that the static
index (=reserves/current use) is a poor measure of the true lifetime of a
resource with exponentially growing use. LTG also recognizes the
distinction between reserves and resources, and includes a second column of
dynamic indices at arbitrary 5x reserves, to make the point that even large
increases in reserves can be overwhelmed quickly by growth. For oil, this
yields a dynamic lifetime of 50 years (again, not a forecast and not
model-based, but implying exhaustion in 2022, not 1992). Lomborg happily
ignores these subtleties and publishes a table of updated SRLIs a few pages
later.

While there are valid things to criticize about LTG, I get the sense that
most critics haven't actually read the book; they're just repeating
something they heard about it years ago, probably from someone who also
didn't read it.


>>Minimising impact on the environment seems very sensible, but if we had
>>always followed this rule we would still be hunter gatherers living in
>>caves.


This is a rather heroic leap of logic. Few environmentalists are proposing
we return to the cave, though a long day at the mall sometimes makes this
seem like an attractive alternative. No one thinks a $50/ton carbon tax
would return us to the stone age.


>>The invention of agriculture and the industrial revolution caused
>>significant environmental changes (what the environmentalists would call
>>damage) but also provide us with huge benefits.


If this is the case (and it likely is - I wouldn't trade my life for any in
the 10th century) then a well-formulated environmental policy would not
have obstructed those innovations.


>>It is also possible to be too cautious, environmentalists have already
>>killed off GM in Europe and now they have their sights on nano
>>technology. If concern for the environment means that we kill all new
>>technologies at birth then we are going to be in real trouble.


The private sector's track record on environmental prognostication is no
better, and more infused with self-interest, than that of
environmentalists. In the case of GM, a sensible thing to do might be to
internalize externalities like cross-pollination, provide choice, and let
the market decide. Industry efforts to prevent that choice, and its
apparent greater interest in intellectual property than social welfare
(e.g. the terminator gene) likely contributed to the public's distrust of
the whole affair. Collateral damage from cross-Atlantic trade disputes
likely played a large role as well. The history of technology suggests that
most major innovations take decades from invention to market, so GM isn't
really off track. In any case, I think most environmentalists aren't
looking to kill technology; they want a different mix of technologies,
through recognition of potential side effects, not just private gain.


It's important to remember that there are actually two components to each
debate: a set of objective questions of causality (does CO2 warm the
atmosphere, and will that wipe out polar bears?) and a set of subjective
valuations (what's more important to you, polar bears or a snowmobile?).
Some we call Luddites are misinformed about the causality of technology in
the economy, and some really would prefer to live in a cave. For this
reason, I think many would agree, looking back a few decades, that they
underestimated the ability of technology to sustain growth in the face of
declining resource quality, and at the same time argue that the apocalypse
is well underway for nonhuman species or other environmental amenities they
enjoy.

Models can't help much with the subjective component, but they make it
easier to solve problems by making the objective component as clear as
possible, so interested parties with different values can at least
negotiate an efficient solution. The problem is that the subjective
component is complex, and parties on both sides of the debate sometimes
resort to disinformation to confuse the issue rather than addressing the
fundamental questions of values and distribution of costs and benefits. The
challenge for us as modelers is how to get at the truth and be heard in a
polluted information environment.

Tom



****************************************************
Tom Fiddaman
Ventana Systems, Inc. http://www.vensim.com
PO Box 153 Tel (406) 578 2168
Wilsall MT 59086 Fax (406) 578 2254
Tom@Vensim.com http://www.sd3.info
****************************************************
Posted by Tom Fiddaman <tom@vensim.com>
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Post by »

Posted by <heffron@hialoha.net>
First of all, labeling people ""environmentalists"" or ""non-environmentalists""
(i.e., implied: ""realists"") is -if not unnecessary- just plain dumb. Really,
really dumb. Especially for people who claim to be ""systems thinkers."" (!)

I hereby label everybody who labels people ""environmentalists"" and (implied)
""realists"" or ""non-environmentalists""-- ""dumb."" No offense intended. Irony
intended.

Fellow systems thinkers, as an experiment for several months why don't we
skip the simplistic labels and just say what is on our minds?

Second of all, folks may be off with respect to WHEN we will run out of
resources, but not IF we will. The simple laws of physics and principles of
ecology, made clearer -hopefully- through systems thinking, tell us that
there is no way to have infinite growth of anything. Something ALWAYS has to
give. There ARE ""limits to growth."" There are even examples of what has
happened to human societies in the past when they exceeded the capacity of
their environment to sustain them (they took over other lands, or they
become extinct). Thus the Earth's carrying capacity and our net
consumption -and despoiling- of the environment that sustains us are simply
a reality, regardless of whether one is a ""environmentalist"" or a
""non-environmentalist/realist.""

Thirdly, as physics and ecology have shown consistently at all known
scales -universe to sub-atomic particles- most phenomena do not behave
forever linearly, but rather build up steam/momentum, and then PULSE! (See
earthquakes, tsunamis, revolutions, procreation, and so on.) Thus there is
at least the possibility that once a few screws (ecological, social,
economic) become loose beyond a certain, unknown, point, a lot of things
could change quite suddenly and on a large scale.

If you don't believe me, look at the various systems models that have been
produced the past 40 years. (One of my personal favorites is, ""A Systems
Model of Global Development,"" in ""Maximum Power: The Ideas and Applications
of H.T.Odum,"" Charles A.S. Hall, Editor, ISBN 0-87081-362-5, pages 168-169.)
And if you don't like the models already out there, while being at least
somewhat faithful to the principles of physics and ecology (see for example,
Senge's and Richmond's systems archetypes), try creating your own model, and
see what you get. And please share your model with the rest of us so that we
can get away from mere words and get a feel for -and offer our
ideas/opinions on- those critical stock and flow relationships, feedbacks,
and delays.

That reminds me, as the Odums (both generations); the Meadows and Jorgen
Randers; Barry Richmond; Peter Senge, and other systems thinkers have been
trying to convey to the rest of us...we NEED the language of systems
thinking (especially, in my opinion, those diagrams and models produced by
heterogeneous groups of people) to help us understand and to make plain our
assumptions. Once we get the systems language down a little better, maybe we
can make a more effective contribution to more sustainable
social-economic-environmental policies, which would help give us not
infinite time, but more time.

Thank you -environmentalist and realists- for considering these neutral
thoughts.

Aloha,
-Peter

Peter Heffron
heffron@hialoha.net
Posted by <heffron@hialoha.net>
Corey Lofdahl clofdahl bos.saic.
Junior Member
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Post by Corey Lofdahl clofdahl bos.saic. »

Posted by ""Corey Lofdahl"" <clofdahl@bos.saic.com>

A couple of amplifying observations to Peter's post. System dynamics is
indeed
an excellent way to look at the slow build-up and pulse behavior of systems.

This behavior is called ""punctuated equilibrium"" after the evolutionary
theory put
forth by Niles Eldredge and Stephen Jay Gould. I became aware of punctuated

equilibrium in the management sphere through Connie Gersick's Academy
Management
Review Article, and Anjali Sastry wrote about it from a system dynamics
perspective.

The theory of punctuated equilibrium is controversial, and those who take
the
opposite position support slow, gradual change called phyletic gradualism.
The Economist (http://www.economist.com/displaystory.c ... id=3500219)
taught me recently that those who support punctuated equilibrium are ""jerks""
and
those who support phyletic gradualism, ""creeps"".

Finally, an observation on the promise of system dynamics to contribute to
or
resolve such arguments. Last spring I heard a talk by James Bailey, most
famously of Thinking Machines Corp., who talked about the history of
understanding. He broke it into three levels: religious, logical, and
complex. Religious understanding attributes causality to supernatural
powers, and people
described this in books. Logical, scientific, or enlightenment
understanding
attributes causality to articulable laws, logics, and mathematical
relationships
that once again can be described linearly in books. While such descriptions

have great power and have enjoyed great success, our understanding of
complex
systems and our ability to express such systems computationally, according
to
Bailey, have outstripped our ability to express or describe them in book.
This is another way of saying that it is hard to make a complex
systems-based
argument in a logical, linear, or convincing fashion. I thought this was a
pretty smart observation, and it says something about social, economic, and
environmental policy formation. Namely, as Galileo experienced, it's one
thing
to make a true argument supported by observations and evidence, it's quite
another to make a convincing argument that will carry political weight.

Corey Lofdahl
SAIC
Posted by ""Corey Lofdahl"" <clofdahl@bos.saic.com>
Jean-Jacques Laublé jean-jacques
Senior Member
Posts: 68
Joined: Fri Mar 29, 2002 3:39 am

Models and Science

Post by Jean-Jacques Laublé jean-jacques »

Posted by =?iso-8859-1?Q?Jean-Jacques_Laubl=E9?= <jean-jacques.lauble@wanadoo.fr>
Hi everybody.


These debates about effective use of modelling must be as old as the

World.

One remark that follows the last paragraph of Tom Fiddaman about objective
and subjective components to the debate.



Whether models or environmentalists are wrong or right is of course
important but what is important too is what kind of decision will come out
of this knowledge, wrong or right, and why?



Examples:

Jim Thompson writes about the CFC interdiction some years ago that had
probably a good impact on the ozone problem.

Why was that decision taken?

Was it pure good intention or more down to earth economical interests or
whatever one can imagine?

In this world it is more and more difficult to trace the origin of
decisions, especially in big organisations. So instead of concentrating all
the efforts on having models right or wrong, it would be worthwhile spending
some time understanding and clarifying how organisations take decisions and
by the way how they react to modelling. This would too help fill the huge
gap that exists between the common electors in our democracies and the
people in charge of public affairs.



Before the Roman Empire collapsed, and when there was still some
possibilities to avoid this destiny, many learned and powerful Roman people
had the knowledge of the possibility of their extinction.

This knowledge did not change probably their faith and certainly not their
destiny. Why?

The question is obviously more important than knowing if things could
improve if nothing was changed.



Regards.

J.J. Laublé Allocar rent a car business.

Strasbourg France
Posted by =?iso-8859-1?Q?Jean-Jacques_Laubl=E9?= <jean-jacques.lauble@wanadoo.fr>
Jay Forrest systems jayforrest.c
Junior Member
Posts: 7
Joined: Fri Mar 29, 2002 3:39 am

Models and Science

Post by Jay Forrest systems jayforrest.c »

Posted by ""Jay Forrest"" <systems@jayforrest.com>
Great comments, Corey!

My personal experiences have led me to embrace both punctuated and phyletic
gradualism for I believe they both are operative and each has a place
dependent upon the conditions in which the evolution occurs.

I would suggest that an important consideration that affects the
feasibility, potential impact, and even value of either approach lies in the
nature of the fitness landscape in which the evolution occurs. Stuart
Kauffman of the Santa Fe Institute has done extensive experimentation in NK
fitness landscapes. Greatly simplified, his findings are that as the number
of ""genes"" or factors determining fitness, the more complex and fragmented
the fitness landscape becomes. As the fitness landscape grows more
fragmented, there are more localized peaks. Phyletic gradualism can only
creep up to a local peak. Leaps (i.e major mutations) are necessary to leap
from one localized peak to another (the ""jerk""). Once on the slope of a new
localized peak, phyletic gradualism can move toward the new peak. If that
peak is higher, the new ""solution"" should be able to thrive - possibly
replacing the former ""solution"" if they compete. If the peak is lower, one
can expect less success.

I would suggest we see this in many facets of modern business, politics,
etc. Globalization is increasing the number of factors affecting ""fitness.""
It is also leading to increased numbers of perturbations of the landscape
(as disturbances ripple through interdependencies around the world). These
disturbances cause the fitness landscape to shift (also supported by
Kauffman's work.) In the business world this results in disorientation and
confusion. Old reductionist thinking and incremental solutions don't work
well or for long. Leaping is dangerous. But the alternative is possibly
sticking to your historic formula and finding yourself in a fitness pit -
and that can be fatal.

I feel system dynamics has a great deal to contribute to reacting
productively to the forces I describe. Good, rigorous ST rooted in SD can
IMO do a great deal to help clarify where opportunities lie and how to
achieve them.

Thanks for reading! Look forward to your comments!
Jay Forrest
Posted by ""Jay Forrest"" <systems@jayforrest.com>
George Richardson gpr albany.edu
Junior Member
Posts: 6
Joined: Fri Mar 29, 2002 3:39 am

Models and Science

Post by George Richardson gpr albany.edu »

Posted by George Richardson <gpr@albany.edu>


>> Posted by <heffron@hialoha.net>
>> First of all, labeling people ""environmentalists"" or ""non-environmentalists""
>> (i.e., implied: ""realists"") is -if not unnecessary- just plain dumb. Really,
>> really dumb. Especially for people who claim to be ""systems thinkers."" (!)
>>
>> I hereby label everybody who labels people ""environmentalists"" and (implied)
>> ""realists"" or ""non-environmentalists""-- ""dumb."" No offense intended. Irony
>> intended.


Reminds me of the wisdom of the great biologist and ecologist E. O.
Wilson, Professor and Curator of Entomology at the Museum of
Comparative Zoology at Harvard University, who said that where the
environment was concerned there were two (only two) kinds of people:
environmentalists and exceptionalists. In that second group go all the
people who think the laws of ecosystems don't apply to humans.

..George

George P. Richardson
Chair of public administration and policy
Rockefeller College of Public Affairs and Policy
University at Albany - SUNY, Albany, NY 12222
gpr@albany.edu *518-442-5258 *http://www.albany.edu/~gpr




Posted by George Richardson <gpr@albany.edu>
posting date Tue, 18 Jan 2005 13:51:36 -0500
Tom Fiddaman tom vensim.com
Junior Member
Posts: 2
Joined: Fri Mar 29, 2002 3:39 am

Models and Science

Post by Tom Fiddaman tom vensim.com »

Posted by Tom Fiddaman <tom@vensim.com>
I'm sure at least a few of you hoped this thread would die, but here's
another gasp. If you recall, it was sparked by Myron Ebell's claim that
""modeling is not science,"" quoted in the Washington Post. There's an
extensive critique of that point of view at http://www.realclimate.org/ -
see the Jan. 12 2005 entry. The comments at the end are also worthwhile,
particularly #12 and follow-ons, which address a question we're familiar
with - can a model with lots of parameters be overtuned?

On another note, an inquiry from Mike Wallace pointed out an absurdity in
something I said:


>>It's a gross overstatement to claim that GHG emissions reductions will
>>keep billions of people in poverty. The energy sector is not that big in
>>the economy - even a ""ruinous"" total elimination of emissions in the DICE
>>model doesn't cause a decline in global GDP/capita; it just requires
>>foregoing a couple of years of growth.


The absurdity is not mine, but that of the DICE model, which permits
instantaneous variation in the carbon intensity of the model without
penalty. For a permanent reduction in GDP of about 7% (plus or minus a bit
due to changes in the optimal savings rate), the economy can be moved from
current emissions to a carbon free state. In the short run this is
obviously impossible due to the momentum of capital stocks. In the long run
it's also likely wrong, as an eventual transition to alternate energy
sources is inevitable anyway. On balance, I think the model understates the
cost of abatement at the high end. At the low end though - i.e. the first
30% of emissions reductions - it's probably reasonable, and Nordhaus has
been extensively criticized for excluding negative-cost reductions
available according to some engineering estimates.

On balance it would seem that the excess flexibility in DICE would favor
emissions reductions, but when uncertainty is considered it does the
opposite. Because the DICE economy is so flexible, it's better to wait and
see, and act when necessary. A refinement of DICE, recently reported in
Science by Gary Yohe, limits the rate of emissions reductions to 1.5%/year
and finds that there is significant value to climate insurance - i.e.
acting now in case we have to act later.

R&D into alternative energy paths provides another form of insurance. In
fact, this is the principal policy favored by the Bush administration. The
problem is that, without corresponding price signals, R&D lowers the
effective cost of energy services, and the resulting rebound in demand eats
up the potential gains. Meanwhile, capital stocks and settlement patterns
continue to embody the assumption of a cheap energy world, delaying the
date at which the economic supertanker begins to turn.

Ultimately the do-nothing approach to energy policy rests on some
combination of the following assumptions (or perhaps a few similar ones I
haven't thought of):
- climate is insensitive to GHG forcing (essentially Richard Lindzen's
argument, but you have to be 100% certain, or think it's as likely to go
down as up)
- warming and CO2 fertilization are as likely to result in benefits as
costs (the greening earth argument)
- other externalities related to fossil fuel use are zero with 100%
certainty, or at least symmetrically distributed as above
To borrow a line from Clint Eastwood, ""... you've got to ask yourself one
question: Do I feel lucky? Well, do ya punk?""

The insurance question reminds me of another possibly apocryphal Forrester
comment, to the effect that globalization allows all regions to reach all
limits at once. It seems that we are collectively optimizing the world for
more or less current conditions, while what we really need is a real
options world, optimized for a diverse set of uncertain futures.

Tom




****************************************************
Tom Fiddaman
Ventana Systems, Inc. http://www.vensim.com
PO Box 153 Tel (406) 578 2168
Wilsall MT 59086 Fax (406) 578 2254
Tom@Vensim.com http://www.sd3.info
****************************************************
Posted by Tom Fiddaman <tom@vensim.com>
posting date Mon, 21 Feb 2005 19:40:55 -0700
Tom Fiddaman tom vensim.com
Junior Member
Posts: 2
Joined: Fri Mar 29, 2002 3:39 am

Models and Science

Post by Tom Fiddaman tom vensim.com »

Posted by Tom Fiddaman <tom@vensim.com>
Over the last few days I spent some time attending climate tracks at the
AAAS meeting. That's prompted some further reflections on models, science,
and climate. Hope it's of some general interest.


>>>>Ebell has been looking a lot more closely than the poster might suspect,
>>>>and that is precisely why he (and I) believe that there are no good GCM's
>>>>yet. The modelers are trying to crawl (by concentrating on the last 20
>>>>years) before they walk, and they are nowhere near to running. Their
>>>>efforts are commendable, but what is completely irresponsible is to use
>>>>their primitive results for purposes of public policy (e.g., the Kyoto
>>>>Treaty).


The symposia underscored the fact that modelers are using far more than the
last 20 years of data, and that the information content of even recent data
is much greater than skeptics let on. Greenhouse skeptics have focused
largely on global average temperature, but in fact models are tested
against regional and seasonal variations. More interestingly, different
forcings (i.e. gases, aerosols, solar variability, ...) have different
geographic and altitude signatures, which models do a decent job of
replicating. For examples, aerosols have a short residence time in the
atmosphere, so they mainly affect the industrial Northern Hemisphere.
Models also do a good job replicating transient forcing effects (from the
Pinatubo eruption, for example). So, the criticism (often leveled against
SD models) that GCMs have zillions of parameters and could fit anything is
rather overstated given the breadth of data available for verification, not
to mention the technical difficulty of tuning to reach a deliberately
biased result. Models are still far from perfect, but at the end of the day
they can replicate recent history better when anthropogenic forcings are
included.

One of the challenges is that, while models do a decent job of replicating
recent history, recent history doesn't constrain the uncertainty about the
climate sensitivity to 2x CO2 very well. This is due substantially to the
question of aerosol masking (aerosols lead to cooling, which has offset a
significant but uncertain fraction of recent warming). A variety of
combinations of aerosol forcing, cloud physics and climate sensitivity are
plausible given the recent temperature record. However, much of the
uncertainty falls on the side of high sensitivity, as illustrated by the
recent climateprediction.net results which showed that parameter
combinations consistent with recent history could lead to climate
sensitivity as high as 11 degrees C (the press seemed to like the word
""scorching"" as a descriptor for that and generally didn't mention the low
side of 2 degrees C - about the same as past estimates).

Modelers and paleoclimatologists I heard don't find the high numbers
plausible; they simply can't be excluded based on recent history alone.
Paleo researchers are busy working on a number of reconstructions of past
climates, including a complete 3D gridded dataset from the middle pliocene
(3 million years ago). This will provide an extremely useful check;
modelers have already explored many paleoclimatic scenarios, but using more
limited data, mostly from the quaternary (<2m years ago). The trouble is
that we are headed for CO2 concentrations well beyond that - not seen since
20 million or more years in the past, where data are even harder to come
by. The surprising (to me) experience so far is that ""hundreds of GCM runs
have been made and none underestimates past climatic conditions,"" leading
one presenter to suggest (to murmurs of affirmation by colleagues in the
audience) that there may be poorly understood amplifying mechanisms in
climate (ice and solar/orbital variability are not likely candidates).

The paleo data contains at least one interesting analog of today's
greenhouse gas experiment, the paleocene-eocene thermal maximum (PETM), 55
million years ago. In deep time CO2 data it looks like a vertical line,
from an episode in which on the order of 3000 gigatons of carbon entered
the atmosphere/ocean system in a short time - an amount similar to fossil
resources. Recent sediment cores have illuminated what may have happened at
the time. A favored explanation is that ocean sediments released a vast
amount of methane into the atmosphere. Methane hydrates in the ocean are
potentially unstable, as warming triggers positive feedbacks (warming ->
release of methane bubbles -> destabilization of sediments -> release of
more methane -> more warming). Methane is a strong greenhouse gas and
oxidizes to CO2, a process which becomes nonlinear at high concentration as
hydroxyl radicals in the atmosphere (which normally act as scrubbers) are
depleted. The high GHG concentrations led to rapid warming and diminished
ocean circulation. As a result the deep oceans likely became anoxic and
eutrophic, making a transition to sulfur metabolism and potentially toxic
upwellings of hydrogen sulfide, which may have been responsible for mass
extinctions during the PETM. Acidification from carbon chemistry in the
ocean wiped out corals and diatoms, an outcome also considered possible
today. With the system saturated, carbon levels took on the order of 40k
years to recover (current policy models assume carbon storage with a time
constant on the order of a century, so there are evidently nonlinearities).
Interestingly, temperatures took on the order of 100k years to recover, so
clearly some irreversibility was triggered.

As skeptics have focused on a limited subset of model results, they have
focused on a limited set of recent temperature measurements, particularly
the land surface and satellite records. In fact a much wider range of
indicators now suggest that warming is underway. Northern hemisphere polar
ice has thinned dramatically, to an extent now considered to be emerging
from the variability of decadal oscillations. Ocean heat content is
increasing. Meta analyses of plants and animals show that their ranges have
shifted poleward and that the timing of behaviors has shifted seasonally. A
study about to be published indicates that these shifts can be explained
better using GCM results including anthropogenic greenhouse gas forcings
than by runs using natural forcings alone. Mid-latitude mountain glaciers
are losing volume to the tune of 7% per decade. Glaciers are highly
temperature sensitive. While individually they have their own dynamics,
collectively they are regarded as an integrator of temperature. They have
fairly short time constants, so the observed behavior is not a residual of
the end of the little ice age. Continental ice shelves are thinning and
recent observations have established that loss of ocean ice leads to
acceleration of glacial flow; an ice-free Greenland (causing 7 meters of
sea level rise) is plausible in less than a millenium.

Paleo cryosphere researcher Richard Alley summed the glacier situation up
as, ""we don't know enough to scare real people, but we can't reassure them
either."" That seemed to characterize the feeling of many individual
disciplines, and the collective picture is stronger. A speaker from Munich
Re was more outspoken, declaring that ""we need to stop this dangerous
experiment humankind is conducting on the earth's atmosphere"". In the Q&A
at the end of several sessions, one participant promoted a perpetual motion
scheme to generate electricity using wind turbines on moving vehicles. To
me, the greenhouse skeptics are looking increasingly like they are in the
same sort of denial. Regrettably none showed up to stir the debate.

In spite of the fact that the administration's stated climate policy is to
wait and do lots of science so we can figure out what's going on, the 2006
budget request cuts climate change science. Worse, changes in priorities (a
shift towards homeland security and human space exploration) erode the
ability to monitor climate on many fronts - USGS stream guages, maintenance
of surface temperature monitoring networks, and remote sensing will all
suffer. Deep-time paleoclimate research is historically badly underfunded
given the critical information it could provide for model verification.

Tom


****************************************************
Tom Fiddaman
Ventana Systems, Inc. http://www.vensim.com
PO Box 153 Tel (406) 578 2168
Wilsall MT 59086 Fax (406) 578 2254
Tom@Vensim.com http://www.sd3.info
****************************************************
Posted by Tom Fiddaman <tom@vensim.com>
posting date Fri, 25 Feb 2005 15:22:34 -0700
Locked