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Fat Tails Part Deux: cost-benefit analysis and climate change; Weitzman replies to Nordhaus

February 13th, 2009 No comments

[Note:  Although the giant snakes I mentioned in my preceding post may have fat tails, I didn’t want my description of the discussion between Harvard`s Martin Weitzman and Yale`s William Nordhaus of the limits of cost-benefit analysis to be overlooked, so I have largely copied it below.  I’ve added an introduction, as well as a few links.]

“Fat tails” seem to be the rage these days, as Bill Safire noted last week in the NYT.  But what are “fat tails”?  Notes Safire,

To comprehend what fat tail is in
today’s media wringer, think of a bell curve, the line on a
statistician’s chart that reflects “normal distribution.” It is tall
and wide in the middle — where most people and things being studied
almost always tend to be — and drops and flattens out at the bottom,
where fewer are, making a shape on a graph resembling a bell. The
extremities at the bottom left and right are called the tails; when
they balloon instead of nearly vanishing as expected, the tails have
been designated “heavy” and, more recently, the more pejorative “fat.”
To a credit-agency statistician now living in a world of chagrin, the
alliterative definition of a fat tail is “an abnormal agglomeration of angst.”

In
an eye-popping Times Magazine article last month titled “Risk
Mismanagement
,” Joe Nocera, a business columnist for The Times, focused
on the passionate, prescient warnings of the former options trader
Nassim Nicholas Taleb, author of “The Black Swan” and “Fooled by
Randomness,”
who popularized the phrase now in vogue in its
financial-­statistics sense. Nocera wrote: “What will cause you to lose
billions instead of millions? Something rare, something you’ve never
considered a possibility. Taleb calls these events ‘fat tails
or ‘black swans,’
and he is convinced that they take place far more
frequently than most human beings are willing to contemplate.”

If I make quibble with Safire’s description; “fat” refers not to the probabilty distribution ballooning on either tail, but refers to the case that the tail probability does not decline quickly to zero (viz., probability approaches zero more slowly than exponentially).

*   *   *

The size of the giant snakes and the much higher temperatures (and GHG levels) at their time (60 million years ago) and shortly after during the PETM (a perod 56 million years ago temperatures shot up by 5° Celsius / 9° F in less than 10,000 years) tell us no simply that climate is sensitive
(on geological scales, sometimes rather short-term) to atmospheric
levels of carbon and methane, but  remind us that there is a “fat tail” of uncertain climate change risks
posed by mankind`s ramped up efforts to release as much as possible of
the CO2 that has been stored up in the form of fossil fuels, methane
and limestone over millions years.  

I have mentioned the issue of “fat tails” previously,
in connection with attempts at applying cost – benefit analysis (CBA)
to determine whether to tax CO2 emissions.  While economists like
Yale`s William Nordhaus who have applied CBA to climate policy have been saying for decades that taxing carbon makes sense on a net basis, our own Bob Murphy has criticized Nordhaus`s approach on rather narrow (and decidedly non-Austrian) grounds.

But Nordhaus has also been strongly criticized by economists such as Harvard`s Martin Weitzman,
who basically argue that Nordhaus has UNDERSOLD the case for carbon
pricing or that the results of such CBA imply a greater certainty of
knowledge (and complacency) than is deserved.  Weitzman points out
basic difficulties inherent in applying CBA to policies addressing
climate change, particularly where there seems to be a grave
possibility that we do not understand how drastically the climate might
respond to our influences.  Weitzman`s comments (scheduled to appear in
the February issue of The Review of Economics and Statistics) were the focus of the lead essay by Jim Manzi in Cato Unbound`s August 2008 issue, which I reviewed.

Nordhaus has since responded to Weitzman in a comment that became available in January; this time with Bob Murphy stepped in as a defender of CBA!  I note that Ron Bailey, science correspondent at Reason online, has just published a piece examining Weitzman’s paper last year and Nordhaus’s recent comments.

Weitzman has now replied to Nordhaus, and has kindly permitted me to
quote from a draft of his reply (which he has out for review).  It seems that Weitzman
provides a compelling statement of some the limits of CBA, as applied
to climate change.  (NB:  Weitzman`s draft response is a .pdf file that I cannot upload, though I have uploaded a version converted to .txt format.  I am happy to forward the .pdf to any interested readers.)

Weitzman`s criticisms of the limits of CBA ought to resonate with Austrian concerns about complexity, limits of knowledge and the difficulty of prediction — even as Weitzman (and Nordhaus and, indeed, Bob Murphy) completely fail to consider the fundamental problems of conflicting preferences in the absence of property rights and of the likelihood that rent-seeking with corrupt governmental policy responses.

 

The rest of the post sets those of Weitzman`s key points that I consider most salient to a discussion among laymen:

“there is enormous structural uncertainty about the economics of extreme climate change,
which, if not unique, is pretty rare. I will argue on intuitive grounds
that the way in which this deep structural uncertainty is
conceptualized and formalized should influence substantially the
outcomes of any reasonable CBA (or IAM) of climate change. Further, I
will argue that the seeming fact that this deep structural
uncertainty does not influence substantially outcomes from the
“standard” CBA hints at an implausible treatment of uncertainty.”

“The
pre-industrial-revolution level of atmospheric CO2 (about two centuries
ago) was

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false

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about280 parts per million (ppm). The ice-core data show that
carbon dioxide was within a range roughly between

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0

0
2

false
false
false

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180 and

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0

0
2

false
false
false

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280 ppm
during the last 800,000 years. Currently, CO2 is at

Normal
0

0
2

false
false
false

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385 ppm, and
climbing steeply. Methane was never higher than

Normal
0

0
2

false
false
false

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750 parts per billion
(ppb) in 800,000 years, but now this extremely potent GHG, which is
thirty times more powerful than CO2, is at

Normal
0

0
2

false
false
false

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1,780 ppb. The sum total of
all carbon-dioxide-equivalent (CO2-e) GHGs is currently at

Normal
0

0
2

false
false
false

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435 ppm.
Even more alarming in the 800,000-year record is the rate of change of
GHGs, with increases in CO2 being below (and typically well below)

Normal
0

0
2

false
false
false

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40
ppm within any past sub-period of ten thousand years, while now CO2 has
risen by

Normal
0

0
2

false
false
false

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40 ppm in just the last quarter century.

Thus, anthropogenic
activity has elevated atmospheric CO2 and CH4 to levels extraordinarily
far outside their natural range – and at a stupendously rapid rate. The
scale and speed of recent GHG increases makes predictions of future
climate change highly uncertain.  There is no analogue for anything
like this happening in the past geological record. Therefore, we do not
really know with much confidence what will happen next.”

“To keep atmospheric CO2 levels at twice pre-industrial-revolution levels would require not just stable but sharply declining emissions within a few decades from now. Forecasting
ahead a century or two, the levels of atmospheric GHGs that may
ultimately be attained (unless drastic measures are undertaken) have
likely not existed for tens of millions of years and the rate of change
will likely be unique on a time scale of hundreds of millions of years.

Remarkably,
the “standard”CBA of climate change takes essentially no account of the
extraordinary magnitude of the scale and speed of these unprecedented
changes in GHGs – and the extraordinary uncertainties they create for
any believable economic analysis of climate change.
Perhaps even
more astonishing is the fact that the “policy ramp” of gradually
tightening emissions, which emerges from the “standard” CBA, attains
stabilization at levels of CO2-e GHGs that approach

Normal
0

0
2

false
false
false

MicrosoftInternetExplorer4


700 ppm. The
“standard” CBA [of Nordhaus] thus recommends imposing an impulse or
shock to the Earth’s system by geologically-instantaneously jolting
atmospheric stocks of GHGs up to

Normal
0

0
2

false
false
false

MicrosoftInternetExplorer4


21/2 times their highest past level
over the last 800,000 years – without even mentioning what an
unprecedented planetary experiment such an “optimal” policy would
entail.”

“So-called
“climate sensitivity” (hereafter denoted S1) is a key macro-indicator
of the eventual temperature response to GHG changes. Climate
sensitivity is defi…ned as the global average surface warming following
a doubling of carbon dioxide concentrations. … the median upper 5%
probability level over all 22 climate-sensitivity studies cited in
IPCC-AR4 (2007) is 6.4° C – and this stylized fact alone is telling.
Glancing at Table 9.3 and Box 10.2 of IPCC-AR4, it is apparent that the
upper tails of these 22 PDFs tend to be sufficiently long and heavy
with probability that one is allowed from a simplistically-aggregated
PDF of these 22 studies the rough approximation P[S1>10° C]

Normal
0

0
2

false
false
false

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1%. The
actual empirical reason why these upper tails are long and heavy with
probability dovetails nicely with the theory of my paper: inductive
knowledge is always useful, of course, but simultaneously it is limited
in what it can tell us about extreme events outside the range of
experience – in which case one is forced back onto depending more than
one might wish upon the prior PDF, which of necessity is largely
subjective and relatively diffuse. As a recent Science commentary put
it: “Once the world has warmed by 4° C, conditions will be so
different from anything we can observe today (and still more different
from the last ice age) that it is inherently hard to say where the
warming will stop.”

“Exhibit C” concerns possibly disastrous releases over the long run of bad-feedback components
of the carbon cycle that are currently omitted from most general
circulation models. The chief worry here is a significant supplementary
component that conceptually should be added on to climate sensitivity
S1. This omitted component concerns the potentially powerful
self-amplification potential of greenhouse warming due to heat-induced
releases of sequestered carbon. … Over the long run, a CH4
outgassing-amplifier process could potentially precipitate a
cataclysmic strong-positive-feedback warming
. This real physical
basis for a highly unsure but truly catastrophic scenario is my Exhibit
C in the case that conventional CBAs and IAMs do not adequately cover
the deep structural uncertainties associated with possible
climate-change disasters.  Other examples of an actual real physical
basis for a catastrophic outcome could be cited, but this one will do
here.  The real physical possibility of endogenous heat-triggered
releases at high temperatures of the enormous amounts of
naturally-sequestered GHGs is a good example of indirect carbon-cycle
feedback effects that I think should be included in the abstract
interpretation of a concept of “climate sensitivity” that is relevant
here. What matters for the economics of climate change is the
reduced-form relationship between atmospheric stocks of
anthropogenically-injected CO2-e GHGs and temperature change. … When
fed into an economic analysis, the great open-ended uncertainty about
eventual mean planetary temperature change cascades into
yet-much-greater yet-much-more-open-ended uncertainty about eventual
changes in welfare.”

“Exhibit
D” concerns what I view as an unusually cavalier treatment of damages or
disutilities from extreme temperature changes. The “standard” CBA
treats high-temperature damages by a rather passive extrapolation of
whatever specification is assumed (typically arbitrarily) to be the
low-temperature “damages function.”  … Seemingly minor changes in
the specification of high-temperature damages can dramatically alter
the gradualist policy ramp outcomes recommended by the “standard” CBA.

Such fragility of policy to postulated forms of disutility functions
are my Exhibit D in making the case that the “standard” CBA does not
adequately cope with deep structural uncertainty – here structural
uncertainty about the specification of damages.”

“An
experiment without precedent is being performed on planet Earth by
subjecting the world to the shock of a geologically-instantaneous
injection of massive amounts of GHGs. Yet the “standard” CBA seems
almost oblivious to the extraordinarily uncertain consequences of
catastrophic climate change.”

“Almost
nothing in our world has a probability of exactly zero or exactly one.
What is worrisome is not the fact that extreme tails are long per se
(reflecting
the fact that a meaningful upper bound on disutility does not exist),
but that they are fat (with probability density). The critical
question is how fast does the probability of a catastrophe decline
relative to the welfare impact of the catastrophe. Other things being
equal, a thin-tailed PDF is of less concern because the probability of
the bad event declines exponentially (or faster). A fat-tailed
distribution, where the probability declines polynomially, can be much
more worrisome.
… To put a sharp point on this seemingly abstract issue, the
thin-tailed PDFs that Nordhaus requires implicitly to support his
gradualist “policy ramp” conclusions have some theoretical tendency to
morph into being fat tailed when he admits that he is fuzzy about the
functional forms or structural parameters of his assumed thin-tailed
PDFs
– at least for high temperatures. … When one combines fat
tails in the PDF of the logarithm of welfare-equivalent consumption
with a utility function that is sensitive to high damages from extreme
temperatures, it will tend to make the willingness to pay (WTP) to
avoid extreme climate changes very large.”

“Presumably
the PDF in the bad fat tail is thinned, or even truncated, perhaps from
considerations akin to what lies behind the value of a statistical life
(VSL). (After all, we would not pay an infinite amount to eliminate
altogether the fat tail of climate-change catastrophes.) Alas, in
whatever way the bad fat tail is thinned or truncated, a CBA based upon
it remains highly sensitive to the details of the thinning or
truncation mechanism, because the disutility of extreme climate change
has “essentially” unlimited liability.
In this sense climate change
is unique (or at least very rare) because the conclusions from a CBA
for such an unlimited-liability situation have some built-in tendency
to be non-robust to assumed tail fatness.”

“Reasonable
attempts to constrict the fatness of the “bad” tail can still leave us
with uncomfortably big numbers, whose exact value depends non-robustly
upon artificial constraints, functional forms, or parameters that we
really do not understand. The only legitimate way to avoid this
potential problem is when there exists strong a priori knowledge that
restrains the extent of total damages.
If a particular type of
idiosyncratic uncertainty affects only one small part of an
individual’s or a society’s overall portfolio of assets, exposure is
naturally limited to that specific component and bad-tail fatness is
not such a paramount concern. However, some very few but very
important real-world situations have potentially unlimited exposure due
to structural uncertainty about their potentially open-ended
catastrophic reach. Climate change potentially affects the whole
worldwide portfolio of utility by threatening to drive all of planetary
welfare to disastrously low levels in the most extreme scenarios.”

“Conclusions
from CBA [are] more fuzzy than we might prefer, because they are
dependent on essentially arbitrary decisions about how the fat tails
are expressed and about how the damages from high temperatures are
specified.
I would make a strong distinction between thin-tailed
CBA, where there is no reason in principle that outcomes should not be
robust, and fat-tailed CBA, where even in principle outcomes are
highly sensitive to functional forms and parameter values. For ordinary
run-of-the-mill limited exposure or thin-tailed situations, there is at
least the underlying theoretical reassurance that finite-cutoff-based
CBA might (at least in principle) be an arbitrarily-close approximation
to something that is accurate and objective. In fat-tailed unlimited
exposure situations, by contrast, there is no such theoretical
assurance underpinning the arbitrary cutoffs or attenuations – and
therefore CBA outcomes have a theoretical tendency to be sensitive to
fragile assumptions about the likelihood of extreme impacts and how
much disutility they cause.”

“My
target is not CBA in general, but the particular false precision
conveyed by the misplaced concreteness of the “standard” CBA of climate
change. By all means plug in tail probabilities, plug in disutilities
of high impacts, plug in rates of pure time preference, and so forth,
and then see what emerges empirically. Only please do not be surprised
when outcomes from fat-tailed CBA are fragile to specifications
concerning catastrophic extremes.  The extraordinary magnitude of the
deep structural uncertainties involved in climate-change CBA, and the
implied limitations that prevent CBA from reaching robust conclusions,
are highly frustrating for most economists, and in my view may even
push some into a state of denial. After all, economists make a living
from plugging rough numbers into simple models and reaching specific
conclusions (more or less) on the basis of these numbers. What are we
supposed to tell policy makers and politicians if our conclusions are
ambiguous and fragile?”

“It is
threatening for economists to have to admit that the structural
uncertainties and unlimited liabilities of climate change run so deep
that gung-ho “can do” economics may be up against limits on the ability of quantitative analysis to give robust advice in such a grey area. But if this is the way things are with the economics of climate change, then this is the way things are – and non-robustness to subjective assumptions is an inconvenient truth to be lived with rather than a fact to be denied or evaded
just because it looks less scientif…cally objective in CBA. In my
opinion, we economists need to admit to the policy makers, the
politicians, and the public that CBA of climate change is unusual
in being especially fuzzy because it depends especially sensitively on
what is subjectively assumed about the high-temperature damages
function, along with subjective judgements about the fatness of the
extreme tails and/or where they have effectively been cut off
.
Policy makers and the public will just have to deal with the idea that
CBA of climate change is less crisp (maybe I should say even less
crisp) than CBAs of more conventional situations.”

“The
moral of the dismal theorem is that under extreme uncertainty,
seemingly casual decisions about functional forms, parameter values,
and tail thickness may be dominant. We economists should not pursue
a narrow, superficially precise, analysis by blowing away the
low-probability high-impact catastrophic scenarios as if this is a
necessary price we must pay for the worthy goal of giving crisp advice.
An artificial infatuation with precision is likely to make our analysis
go seriously askew and to undermine the credibility of what we say by
effectively marginalizing the very possibilities that make climate
change grave in the first place.

“The
issue of how to deal with the deep structural uncertainties in climate
change would be completely different and immensely simpler if systemic
inertias (like the time required for the system to naturally remove
extra atmospheric CO2) were short (as is the case for SO2;
particulates, and many other airborne pollutants). Then an important
part of an optimal strategy would presumably be along the lines of
“wait and see.” With strong reversibility, an optimal
climate-change policy should logically involve (among other elements)
waiting to see how far out on the bad fat tail the planet will end up,
followed by midcourse corrections if we seem to be headed for a
disaster. This is the ultimate backstop rebuttal of DT given by some
critics of fat-tailed reasoning, including Nordhaus. Alas, the problem
of climate change is characterized everywhere by immensely long
inertias – in atmospheric CO2 removal times, in the capacity of the
oceans to absorb heat (as well as CO2), and in many other relevant
physical and biological processes. Therefore, it is an open question
whether or not we could learn enough in sufficient time to make
politically feasible midcourse corrections. When the critics are
gambling on this midcourse-correction learning mechanism to undercut
the message of DT, they are relying more on an article of faith than on
any kind of evidence-based scientific argument.

“I
think the actual scientific facts behind the alleged feasibility of
“wait and see”policies are, if anything, additional evidence for the
importance of fat-tailed irreversible uncertainty about ultimate
climate change.

“The
relevance of “wait and see”policies is an important unresolved issue,
which in principle could decide the debate between me and Nordhaus, but
my own take right now would be that the built-in pipeline inertias
are so great that if and when we detect that we are heading for
unacceptable climate change, it will likely prove too late to do
anything much about it for centuries to come thereafter
(except,
possibly, for lowering temperatures by geoengineering the atmosphere to
reflect back incoming solar radiation). In any event, I see this whole
“wait and see” issue as yet another component of fat-tailed uncertainty
– rather than being a reliable backstop strategy for dealing with
excessive CO2 in the atmosphere.

Nordhaus
states that there are so many low-probability catastrophic-impact
scenarios around that ‘if we accept the Dismal Theorem, we would
probably dissolve in a sea of anxiety at the prospect of the infinity
of infinitely bad outcomes.’ This is rhetorical excess and, more to the
point here, it is fallacious. Most of the examples Nordhaus gives have
such miniscule thin-tailed probabilities that they can be written off.”

Nordhaus
summarizes his critique with the idea there are indeed deep
uncertainties about virtually every aspect of the natural and social
sciences of climate change – but these uncertainties can only be
resolved by continued careful analysis of data and theories. I heartily
endorse his constructive attitude about the necessity of further
research targeted toward a goal of resolving as much of the uncertainty
as it is humanly possible to resolve.
I would just add that we
should also recognize the reality that, for now and perhaps for some
time to come, the sheer magnitude of the deep structural uncertainties,
and the way we express them in our models, will likely dominate
plausible applications of CBA to the economics of climate change
.”

(emphasis added)

Let`s recreate the Paleocene! Giant snakes, "fat tails", cost-benefit analysis and climate change; Weitzman replies to Nordhaus

February 11th, 2009 1 comment

Giant snakes?  What could a few colossal bones found in Colombia have to do with us now?

1.  A recent paper in Nature about the discovery of several specimens of a giant snake (“Titanoboa”) that lived in Latin America 60 million years ago captured attention last week, including among climate change bloggers (yes, “skeptics” too).  Why?  Not only because the snakes were enormous (more than 40 feet and over a ton) – making anacondas look like garter snakes – but because their size appears to tell us something about the climate about during the Paleocene.  Based on existing knowledge of the size, metabolism and temperature tolerances of  snakes, scientists believe that the size of the snake appears to indicate that not only was the world overall quite warm during the Paleocene (with palms growing at the poles), but that average temperatures in the tropics would have been from 3° to 5° Celsius (5° to 9° F) warmer than they are today in order for such large snakes to  survive.

The period in which these snakes lived was followed a few million years later by the Paleocene – Eocene Thermal Maximum (PETM) in 56 million BC, when a pulse of CO2 and methane drove already warm temperatures sharply higher (by 5° Celsius / 9° F) in less than 10,000 years. During the PETM, CO2 levels rose to about 2000 ppm, or roughly 6 times  where they are now. The PETM resulted in a massive extinction of species.

The size of the snakes and the temperatures at their time and shortly after during the PETM also tell us that climate is sensitive (on geological scales, sometimes rather short-term) to atmospheric levels of carbon and methane – and remind us that there is a “fat tail” of uncertain climate change risks posed by mankind`s ramped up efforts to release as much as possible of the CO2 that has been stored up in the form of fossil fuels, methane and limestone over millions years.  

2.  I have mentioned the issue of “fat tails” previously, in connection with attempts at applying cost – benefit analysis (CBA) to determine whether to tax CO2 emissions.  While economists like Yale`s William Nordhaus who have applied CBA to climate policy have been saying for decades that taxing carbon makes sense on a net basis, our own Bob Murphy has criticized Nordhaus`s approach on rather narrow (and decidedly non-Austrian) grounds.

But Nordhaus has also been strongly criticized by economists such as Harvard`s Martin Weitzman, who basically argue that Nordhaus has UNDERSOLD the case for carbon pricing or that the results of such CBA imply a greater certainty of knowledge (and complacency) than is deserved.  Weitzman points out basic difficulties inherent in applying CBA to policies addressing climate change, particularly where there seems to be a grave possibility that we do not understand how drastically the climate might respond to our influences.  Weitzman`s comments (scheduled to appear in the February issue of The Review of Economics and Statistics) were the focus of the lead essay by Jim Manzi in Cato Unbound`s August 2008 issue, which I reviewed.

Nordhaus has since responded to Weitzman, and this time with Bob Murphy stepped in as a defender of CBA.  Weitzman has now replied to Nordhaus, and has kindly permitted me to quote from the current draft of such reply.  It seems that Weitzman provides a compelling statement of some the limits of CBA, as applied to climate change. It seems to me that any Austrian ought to be sympathetic to Weitzman`s criticisms of the limits of CBA.

(NB:  Weitzman`s draft response is a .pdf file that I cannot upload, though I have uploaded a version convert to .txt format.  I am happy to forward the .pdf to any interested readers.)

The rest of the post sets out the most salient (for a layman) of Weitzman`s key points:

“there is enormous structural uncertainty about the economics of extreme climate change,
which, if not unique, is pretty rare. I will argue on intuitive grounds
that the way in which this deep structural uncertainty is
conceptualized and formalized should influence substantially the
outcomes of any reasonable CBA (or IAM) of climate change. Further, I
will argue that the seeming fact that this deep structural
uncertainty does not influence substantially outcomes from the
“standard” CBA hints at an implausible treatment of uncertainty.”

“The
pre-industrial-revolution level of atmospheric CO2 (about two centuries
ago) was

Normal
0

0
2

false
false
false

MicrosoftInternetExplorer4


about280 parts per million (ppm). The ice-core data show that
carbon dioxide was within a range roughly between

Normal
0

0
2

false
false
false

MicrosoftInternetExplorer4


180 and

Normal
0

0
2

false
false
false

MicrosoftInternetExplorer4


280 ppm
during the last 800,000 years. Currently, CO2 is at

Normal
0

0
2

false
false
false

MicrosoftInternetExplorer4


385 ppm, and
climbing steeply. Methane was never higher than

Normal
0

0
2

false
false
false

MicrosoftInternetExplorer4


750 parts per billion
(ppb) in 800,000 years, but now this extremely potent GHG, which is
thirty times more powerful than CO2, is at

Normal
0

0
2

false
false
false

MicrosoftInternetExplorer4


1,780 ppb. The sum total of
all carbon-dioxide-equivalent (CO2-e) GHGs is currently at

Normal
0

0
2

false
false
false

MicrosoftInternetExplorer4


435 ppm.
Even more alarming in the 800,000-year record is the rate of change of
GHGs, with increases in CO2 being below (and typically well below)

Normal
0

0
2

false
false
false

MicrosoftInternetExplorer4


40
ppm within any past sub-period of ten thousand years, while now CO2 has
risen by

Normal
0

0
2

false
false
false

MicrosoftInternetExplorer4


40 ppm in just the last quarter century.

Thus, anthropogenic
activity has elevated atmospheric CO2 and CH4 to levels extraordinarily
far outside their natural range – and at a stupendously rapid rate. The
scale and speed of recent GHG increases makes predictions of future
climate change highly uncertain.  There is no analogue for anything
like this happening in the past geological record. Therefore, we do not
really know with much confidence what will happen next.”

“To keep atmospheric CO2 levels at twice pre-industrial-revolution levels would require not just stable but sharply declining emissions within a few decades from now. Forecasting
ahead a century or two, the levels of atmospheric GHGs that may
ultimately be attained (unless drastic measures are undertaken) have
likely not existed for tens of millions of years and the rate of change
will likely be unique on a time scale of hundreds of millions of years.

Remarkably,
the “standard”CBA of climate change takes essentially no account of the
extraordinary magnitude of the scale and speed of these unprecedented
changes in GHGs – and the extraordinary uncertainties they create for
any believable economic analysis of climate change.
Perhaps even
more astonishing is the fact that the “policy ramp” of gradually
tightening emissions, which emerges from the “standard” CBA, attains
stabilization at levels of CO2-e GHGs that approach

Normal
0

0
2

false
false
false

MicrosoftInternetExplorer4


700 ppm. The
“standard” CBA [of Nordhaus] thus recommends imposing an impulse or
shock to the Earth’s system by geologically-instantaneously jolting
atmospheric stocks of GHGs up to

Normal
0

0
2

false
false
false

MicrosoftInternetExplorer4


21/2 times their highest past level
over the last 800,000 years – without even mentioning what an
unprecedented planetary experiment such an “optimal” policy would
entail.”

“So-called
“climate sensitivity” (hereafter denoted S1) is a key macro-indicator
of the eventual temperature response to GHG changes. Climate
sensitivity is defi…ned as the global average surface warming following
a doubling of carbon dioxide concentrations. … the median upper 5%
probability level over all 22 climate-sensitivity studies cited in
IPCC-AR4 (2007) is 6.4° C – and this stylized fact alone is telling.
Glancing at Table 9.3 and Box 10.2 of IPCC-AR4, it is apparent that the
upper tails of these 22 PDFs tend to be sufficiently long and heavy
with probability that one is allowed from a simplistically-aggregated
PDF of these 22 studies the rough approximation P[S1>10° C]

Normal
0

0
2

false
false
false

MicrosoftInternetExplorer4


1%. The
actual empirical reason why these upper tails are long and heavy with
probability dovetails nicely with the theory of my paper: inductive
knowledge is always useful, of course, but simultaneously it is limited
in what it can tell us about extreme events outside the range of
experience – in which case one is forced back onto depending more than
one might wish upon the prior PDF, which of necessity is largely
subjective and relatively diffuse. As a recent Science commentary put
it: “Once the world has warmed by 4° C, conditions will be so
different from anything we can observe today (and still more different
from the last ice age) that it is inherently hard to say where the
warming will stop.”

“Exhibit C” concerns possibly disastrous releases over the long run of bad-feedback components
of the carbon cycle that are currently omitted from most general
circulation models. The chief worry here is a significant supplementary
component that conceptually should be added on to climate sensitivity
S1. This omitted component concerns the potentially powerful
self-amplification potential of greenhouse warming due to heat-induced
releases of sequestered carbon. … Over the long run, a CH4
outgassing-amplifier process could potentially precipitate a
cataclysmic strong-positive-feedback warming
. This real physical
basis for a highly unsure but truly catastrophic scenario is my Exhibit
C in the case that conventional CBAs and IAMs do not adequately cover
the deep structural uncertainties associated with possible
climate-change disasters.  Other examples of an actual real physical
basis for a catastrophic outcome could be cited, but this one will do
here.  The real physical possibility of endogenous heat-triggered
releases at high temperatures of the enormous amounts of
naturally-sequestered GHGs is a good example of indirect carbon-cycle
feedback effects that I think should be included in the abstract
interpretation of a concept of “climate sensitivity” that is relevant
here. What matters for the economics of climate change is the
reduced-form relationship between atmospheric stocks of
anthropogenically-injected CO2-e GHGs and temperature change. … When
fed into an economic analysis, the great open-ended uncertainty about
eventual mean planetary temperature change cascades into
yet-much-greater yet-much-more-open-ended uncertainty about eventual
changes in welfare.”

“Exhibit
D” concerns what I view as an unusually cavalier treatment of damages or
disutilities from extreme temperature changes. The “standard” CBA
treats high-temperature damages by a rather passive extrapolation of
whatever specification is assumed (typically arbitrarily) to be the
low-temperature “damages function.”  … Seemingly minor changes in
the specification of high-temperature damages can dramatically alter
the gradualist policy ramp outcomes recommended by the “standard” CBA.

Such fragility of policy to postulated forms of disutility functions
are my Exhibit D in making the case that the “standard” CBA does not
adequately cope with deep structural uncertainty – here structural
uncertainty about the specification of damages.”

“An
experiment without precedent is being performed on planet Earth by
subjecting the world to the shock of a geologically-instantaneous
injection of massive amounts of GHGs. Yet the “standard” CBA seems
almost oblivious to the extraordinarily uncertain consequences of
catastrophic climate change.”

“Almost
nothing in our world has a probability of exactly zero or exactly one.
What is worrisome is not the fact that extreme tails are long per se
(reflecting
the fact that a meaningful upper bound on disutility does not exist),
but that they are fat (with probability density). The critical
question is how fast does the probability of a catastrophe decline
relative to the welfare impact of the catastrophe. Other things being
equal, a thin-tailed PDF is of less concern because the probability of
the bad event declines exponentially (or faster). A fat-tailed
distribution, where the probability declines polynomially, can be much
more worrisome.
… To put a sharp point on this seemingly abstract issue, the
thin-tailed PDFs that Nordhaus requires implicitly to support his
gradualist “policy ramp” conclusions have some theoretical tendency to
morph into being fat tailed when he admits that he is fuzzy about the
functional forms or structural parameters of his assumed thin-tailed
PDFs
– at least for high temperatures. … When one combines fat
tails in the PDF of the logarithm of welfare-equivalent consumption
with a utility function that is sensitive to high damages from extreme
temperatures, it will tend to make the willingness to pay (WTP) to
avoid extreme climate changes very large.”

“Presumably
the PDF in the bad fat tail is thinned, or even truncated, perhaps from
considerations akin to what lies behind the value of a statistical life
(VSL). (After all, we would not pay an infinite amount to eliminate
altogether the fat tail of climate-change catastrophes.) Alas, in
whatever way the bad fat tail is thinned or truncated, a CBA based upon
it remains highly sensitive to the details of the thinning or
truncation mechanism, because the disutility of extreme climate change
has “essentially” unlimited liability.
In this sense climate change
is unique (or at least very rare) because the conclusions from a CBA
for such an unlimited-liability situation have some built-in tendency
to be non-robust to assumed tail fatness.”

“Reasonable
attempts to constrict the fatness of the “bad” tail can still leave us
with uncomfortably big numbers, whose exact value depends non-robustly
upon artificial constraints, functional forms, or parameters that we
really do not understand. The only legitimate way to avoid this
potential problem is when there exists strong a priori knowledge that
restrains the extent of total damages.
If a particular type of
idiosyncratic uncertainty affects only one small part of an
individual’s or a society’s overall portfolio of assets, exposure is
naturally limited to that specific component and bad-tail fatness is
not such a paramount concern. However, some very few but very
important real-world situations have potentially unlimited exposure due
to structural uncertainty about their potentially open-ended
catastrophic reach. Climate change potentially affects the whole
worldwide portfolio of utility by threatening to drive all of planetary
welfare to disastrously low levels in the most extreme scenarios.”

“Conclusions
from CBA [are] more fuzzy than we might prefer, because they are
dependent on essentially arbitrary decisions about how the fat tails
are expressed and about how the damages from high temperatures are
specified.
I would make a strong distinction between thin-tailed
CBA, where there is no reason in principle that outcomes should not be
robust, and fat-tailed CBA, where even in principle outcomes are
highly sensitive to functional forms and parameter values. For ordinary
run-of-the-mill limited exposure or thin-tailed situations, there is at
least the underlying theoretical reassurance that finite-cutoff-based
CBA might (at least in principle) be an arbitrarily-close approximation
to something that is accurate and objective. In fat-tailed unlimited
exposure situations, by contrast, there is no such theoretical
assurance underpinning the arbitrary cutoffs or attenuations – and
therefore CBA outcomes have a theoretical tendency to be sensitive to
fragile assumptions about the likelihood of extreme impacts and how
much disutility they cause.”

“My
target is not CBA in general, but the particular false precision
conveyed by the misplaced concreteness of the “standard” CBA of climate
change. By all means plug in tail probabilities, plug in disutilities
of high impacts, plug in rates of pure time preference, and so forth,
and then see what emerges empirically. Only please do not be surprised
when outcomes from fat-tailed CBA are fragile to specifications
concerning catastrophic extremes.  The extraordinary magnitude of the
deep structural uncertainties involved in climate-change CBA, and the
implied limitations that prevent CBA from reaching robust conclusions,
are highly frustrating for most economists, and in my view may even
push some into a state of denial. After all, economists make a living
from plugging rough numbers into simple models and reaching specific
conclusions (more or less) on the basis of these numbers. What are we
supposed to tell policy makers and politicians if our conclusions are
ambiguous and fragile?”

“It is
threatening for economists to have to admit that the structural
uncertainties and unlimited liabilities of climate change run so deep
that gung-ho “can do” economics may be up against limits on the ability of quantitative analysis to give robust advice in such a grey area. But if this is the way things are with the economics of climate change, then this is the way things are – and non-robustness to subjective assumptions is an inconvenient truth to be lived with rather than a fact to be denied or evaded
just because it looks less scientif…cally objective in CBA. In my
opinion, we economists need to admit to the policy makers, the
politicians, and the public that CBA of climate change is unusual
in being especially fuzzy because it depends especially sensitively on
what is subjectively assumed about the high-temperature damages
function, along with subjective judgements about the fatness of the
extreme tails and/or where they have effectively been cut off
.
Policy makers and the public will just have to deal with the idea that
CBA of climate change is less crisp (maybe I should say even less
crisp) than CBAs of more conventional situations.”

“The
moral of the dismal theorem is that under extreme uncertainty,
seemingly casual decisions about functional forms, parameter values,
and tail thickness may be dominant. We economists should not pursue
a narrow, superficially precise, analysis by blowing away the
low-probability high-impact catastrophic scenarios as if this is a
necessary price we must pay for the worthy goal of giving crisp advice.
An artificial infatuation with precision is likely to make our analysis
go seriously askew and to undermine the credibility of what we say by
effectively marginalizing the very possibilities that make climate
change grave in the first place.

“The
issue of how to deal with the deep structural uncertainties in climate
change would be completely different and immensely simpler if systemic
inertias (like the time required for the system to naturally remove
extra atmospheric CO2) were short (as is the case for SO2;
particulates, and many other airborne pollutants). Then an important
part of an optimal strategy would presumably be along the lines of
“wait and see.” With strong reversibility, an optimal
climate-change policy should logically involve (among other elements)
waiting to see how far out on the bad fat tail the planet will end up,
followed by midcourse corrections if we seem to be headed for a
disaster. This is the ultimate backstop rebuttal of DT given by some
critics of fat-tailed reasoning, including Nordhaus. Alas, the problem
of climate change is characterized everywhere by immensely long
inertias – in atmospheric CO2 removal times, in the capacity of the
oceans to absorb heat (as well as CO2), and in many other relevant
physical and biological processes. Therefore, it is an open question
whether or not we could learn enough in sufficient time to make
politically feasible midcourse corrections. When the critics are
gambling on this midcourse-correction learning mechanism to undercut
the message of DT, they are relying more on an article of faith than on
any kind of evidence-based scientific argument.

“I
think the actual scientific facts behind the alleged feasibility of
“wait and see”policies are, if anything, additional evidence for the
importance of fat-tailed irreversible uncertainty about ultimate
climate change.

“The
relevance of “wait and see”policies is an important unresolved issue,
which in principle could decide the debate between me and Nordhaus, but
my own take right now would be that the built-in pipeline inertias
are so great that if and when we detect that we are heading for
unacceptable climate change, it will likely prove too late to do
anything much about it for centuries to come thereafter
(except,
possibly, for lowering temperatures by geoengineering the atmosphere to
reflect back incoming solar radiation). In any event, I see this whole
“wait and see” issue as yet another component of fat-tailed uncertainty
– rather than being a reliable backstop strategy for dealing with
excessive CO2 in the atmosphere.

Nordhaus
states that there are so many low-probability catastrophic-impact
scenarios around that ‘if we accept the Dismal Theorem, we would
probably dissolve in a sea of anxiety at the prospect of the infinity
of infinitely bad outcomes.’ This is rhetorical excess and, more to the
point here, it is fallacious. Most of the examples Nordhaus gives have
such miniscule thin-tailed probabilities that they can be written off.”

Nordhaus
summarizes his critique with the idea there are indeed deep
uncertainties about virtually every aspect of the natural and social
sciences of climate change – but these uncertainties can only be
resolved by continued careful analysis of data and theories. I heartily
endorse his constructive attitude about the necessity of further
research targeted toward a goal of resolving as much of the uncertainty
as it is humanly possible to resolve.
I would just add that we
should also recognize the reality that, for now and perhaps for some
time to come, the sheer magnitude of the deep structural uncertainties,
and the way we express them in our models, will likely dominate
plausible applications of CBA to the economics of climate change
.”

(emphasis added)

Bob Murphy – fan of cost-benefit analysis (in the face of climate risks)!

February 4th, 2009 3 comments

Austrian-leaning economist Bob Murphy, whose efforts last year to discount the work of Yale’s William Nordhaus on how cost-benefit analysis merits current action on climate change I previously examined, is back with more, this time defending Nordhaus’ work from the criticism that I alerted him to by Martin Weitzman with respect to limits on the usefulness of CBA in the event of uncertainty (‘fat tails”). 

Bob, in a post on MasterResource, explains that Nordhaus has reviewed Weitzman’s work and found limits to it.  But he fails both to address most of the points I raised previously, including whether CBA is consistent with Austrian perspectives, and to note that Nordhaus still supports action now to price carbon.

I left the following comment with Bob at the MasterResource thread:

Bob, while you’re shoring up “cost-benefit analysis” – the tool of states and bureaucrats everywhere – perhaps you may care to address the point that, under traditional libertarian analysis, if anyone can demonstrate that others’ GHG emissions negatively affect his property (by altering temperatures, rainfall or causing flooding), he has the right to enjoin ALL such activities (and is not compelled to suffer them, subject to whatever compensation he can collect)?

Perhaps the “excitableness” of the “alarmists” may have something to do with the problems of collective action and public choice – viz., in circumstances where pollution laws and regulations provide effective “rights to pollute”, and where emissions are worldwide, how does one deal with existing rent-seekers and move the state, and do it in a meaningful way? There are plenty of private initiatives underway, and even though Austrians dissaprove of efforts to use the state, surely they can understand calls to group action, and that many of the “alarmists” sincerely believe that a fight over the wheel of government is inescapable.

Fundamental Austrian analysis straigthforwardly discussed the problems of conflicting preferences in the absence of property rights and where states are involved, but your lack of understanding or sympathy is rather striking. Why you think it helpful to label one side – a huge swath of people and organizations including Exxon and the Catholic Church – as “alarmists” while ignoring not only the institutional problem but those who profit from the status quo is rather beyond me.

Also, why so little interest in exploring policy options that you would support, like allowing immediate depreciation of capital investment and further public utility deregulation?

 Roger Koppl, another commenter, raised similar questions:

How do you square Nordhaus’s CBA with “Austrian” (or computable economics) arguments about complexity and the difficulty of prediction? Why shouldn’t we chastise Nordhaus for hubris? The pretense of knowledge and all that.

More later.

Categories: Bob Murphy, carbon pricing, Nordhaus, Weizman Tags:

Jim Manzi/Cato on climate: with flabby "libertariarian sinews", he advocates no panic, but domestic climate science and technology investments

August 18th, 2008 4 comments

[UPDATE:  See my follow-up post.]

Cato Unbound’s new climate issue features a lead essay by Jim Manzi, who is an MIT- and Wharton-trained statistician and CEO of Applied Predictive Technologies (which uses pattern recognition and optimization models for sales and marketing).

Manzi is a newcomer to the climate commentary scene, but has made a splash in conservatives circles over the past year or so through a series of articles in the National Review and The American Scene.  Manzi’s bio at Cato states that Manzi’s position is that “global warming, while real, is a problem of limited magnitude, deserving a proportional response, not overreaction“.

Manzi’s essay at Cato is a polished rehashing of points that he has made elsewhere, tweaked shamelessly to appeal to libertarians, as in this lead-off paragraph:

“The danger of potentially catastrophic global warming is an almost paradigmatic case of decisionmaking under conditions of extreme uncertainty.  Of course, this is just another way of saying that many of the intellectual sinews of libertarianism are central to thinking through this problem.” (emphasis added)

While the essay is worth consideration, aside from this initial mention, it is painfully evident that Manzi’s “libertarian sinews” are rather flimsy; indeed, Manzi:

  •  makes no mention of basic Lockean-based libertarian principles (rights to property in one’s own person, in the fruits of one’s own labor, and in resources taken from nature when mixed with one’s own labor; and duties to abstain from harming others, from taking property of others, and to leave enough and as good for others when taking from the commons) that are relevant to environmental and public policy issues (see Rothbard; Edwin Dolan has laid an application of Lockean principles to climate change here; );

  • fails to acknowledge “environmental” problems as cases where resources are not clearly or effectively owned, either individually or on a community basis, so that some economic actors do not bear the costs or risks of their actions, which costs or risks are shifted to others against their will (see Cordato; Jon Adler makes similar points here); and

  • provides only a rudimentary discussion of public choice issues that, while noting both the difficulties of reaching a global agreement and that government policies to prepare for climate change may be both inefficient and hijacked special interests, disregards the possibilities that effective international steps can be taken by just a few countries and completely fails to consider the role that special interests have played to date in manipulating government policies and in protecting the “GHG emissions/risk-shifting is free” status quo.

Rather, Manzi:

(1) argues that the estimates for future damages that the IPPC derives from models appear rather modest,

(2) downplays the widespread agreement by economists (like Nordhaus) and others that standard cost-benefit analysis provides ample support for carbon pricing (particularly in the form of carbon taxes) now,

(3) argues that we cannot adequately gauge the “massive uncertainties” regarding the “danger of potentially catastrophic global warming” (addressing but failing to mention Weitzman),

(4) argues that the US should not adopt “insanely expensive” measures to “force massive change in the economy” via “rapid, aggressive emissions reductions”,

(5) lumps climate change in with other, external risks (like pandemics and rogues states, which risks, oddly, we actually try to manage), and

(6) and tones down his earlier pieces by presenting an artificially weakened case that,

if there is a real, though unquantifiably small, possibility of catastrophic climate change, and if we would ideally want some technological hedges as insurance against this unlikely scenario, and if raising the price of carbon to induce private economic actors to develop the technologies would be an enormously more expensive means of accomplishing this than would be advisable,” (emphasis added)

THEN the government might be justified in investing in “improved global climate prediction capability, visionary biotechnology to capture and recycle carbon dioxide emissions, or geo-engineering projects to change the albedo of the earth’s surface or atmosphere”.

Manzi concludes with a mix of a case for a surprisingly large government climate program (even if “rife with inefficiencies”) and a bashing of the worst case, while ignoring the middle ground:

“But consider that its costs would be on the order of 1/100th of the costs of imposing a large U.S. carbon tax. It could be massively inefficient and we would still be far better off in actually developing the long–lead-time technologies that we would want if faced with a currently unanticipated emergency.

Hedging against the risk to future generations of potential unanticipated impacts from global warming is a legitimate job for the U.S. government. Ideally, it would be tackled by the governments of the small number of countries with a sophisticated technology development capability acting in some kind of coordinated fashion. A massive carbon tax, a cap-and-trade rationing system, and the attempt to use the government to control the evolution of the energy sector of the economy are all billed as prudent reactions to this risk, but each is the opposite: an impractical, panicky reaction unworthy of a serious government.

I hope to address later various aspects of Manzi’s piece, but I think it is fair to conclude initially that it is not libertarian nor, ultimately, a balanced discussion, but rather a somewhat strange conservative position that we ought to worry about climate change and so the government should throw even MORE money at it, while refusing to harness markets to accomplish the research tasks Manzi wishes to fund or to ask those who are generating climate risks to internalize or shoulder any of the burden.

While this stance might please fossil fuel interests and their defenders, it’s hard to see what, exactly, in Manzi’s analysis – other than his opposition to “massive” carbon taxes – will appeal to libertarians.

Can Pigovian taxes be Coasean bargains? – The case of climate negotiations

July 14th, 2008 1 comment

David Zetland’s libertarian-environmental blog, Aguanomics, has recently been carrying on some excellent discussions on resource and environmental economics, with interlocutors like Bob Murphy, Gene Callahan and others.  In the context of two recent posts on government approaches to climate change, I commented on one thread (An Ounce of Prevention…) that

As for the setting the level of carbon taxes, you and Gene keep assuming that there is a global government that sets taxes in a vacuum. Instead, we have a multi-player game, where any politically sustainably prices are set at levels that the chief emitters are willing to agree to.

This is analogous to ranchers, lobstermen or shrimpers deciding to close a range or fishery. No single one of them is setting a price.

On an earlier thread (Pigouvian Libertarians), I noted to the effect that:

Bob, the standard objections to Pigovian taxes don`t apply to climate change, as there is no single government administering the world. Rather, we are engaged in multi-player negotiations as to how to regulate a commons.  The taxes (or other schemes) that individual governments may impose will ultimately be coordinated, and much more resemble a Coasean trade among nations with respect to a shared resource.

David has kindly made this point the subject of a new post:  How to Set a Carbon Tax.

Allow me to elaborate my point.  A C Pigou, is often trotted out by supporters of government economic regulation, for the proposition that governments should regulate or impose taxes in order to force economic actors to internalize the “external costs” of their actions (costs that are imposed on others outside of that transaction without their consent).  This use of Pigou is a bit unfair, as Pigou himself noted that taxing authorities would always lack the information needed to determine the correct tax, but nevertheless the perception that externalities are ubiquitous has helped to justify a wide range of governmental regulatory interventions.

Other objections to Pigou can of course be raised, as Ronald Coase prominently did when he argued that, when trade in an externality is possible and there are no transaction costs, bargaining will lead to an efficient outcome regardless of the initial distribution of property rights.  Pigou and those using him did not consider the real world dynamics of self-help among economic actors, and many ignored Pigou’s acknowledgment that governments are seldom positioned to calculate external costs.  Coase noted that because transaction costs are NOT zero, many bargains would not be reachable, so that the initial distribution of property rights would affect ultimate outcomes in resource allocation.  Coase properly turned the focus of the debate over “externalities” towards a focus on the use of bargaining between parties to accommodate differences in personal objectives, and to fruitful discussions of how property rights and bargains are defined and enforced and whether information and transaction costs can be lowered.  Austrians have further criticisms of Pigou and Coase, but those can be set aside for the moment.

In ongoing discussions over at Aguanomics, Bob Murphy and others have trotted out that standard Coasean attacks on the proposals by economists (such as Robert Nordhaus and other members of Gregory Mankiw’s “Pigovian Club”) for carbon taxes, i.e., that government can’t know at what level to set carbon taxes, that such carbon taxes will prevent private transactions among parties that might fully address climate concerns at less costs, etc.

In the context of this discussion, I ask that people step back from the theoretical and observe the pragmatic – that we are in the midst of a multi-decade multinational negotiation of a GLOBAL resource that no one nation controls, in which there are no private property rights or common legal systems and in which transaction costs for private transactions are enormous and swamp individual economic benefits that may be achieved by them, and that in this context, our governments are essentially our negotiating proxies who can more efficiently negotiate for us and come to terms with others than can any private entities or groups.  Given these circumstances, even though our governments are all subject to domestic rent-seeking pressures, because no effective approach to climate change can be reached without the voluntary agreement of all major emitters, is it not the case that the discussions that our governments conduct – including the possibility of coordinated Pigovian taxes at the national level for implementation purposes – ARE efforts at Coasean bargaining?

Any thoughts?

Comment to Bob Murphy on whether "Cap and Trade" is a "market solution"

June 5th, 2008 1 comment

I copy below comments I made on June 11 (Tokyo time) on Bob Murphy‘s June 4 blog post, Cap and Trade Is Not a “Market Solution”, that have apparently been held up for moderator approval (perhaps because my three links triggered the blog’s spam defenses?):

Bob, I thank you for posting your piece from IER, which has stimulated a relatively even-tempered and productive discussion.

But allow me to express a little disappointment.  Even as I agree fully with the gist of your post (the largely self-evident and unsurprising point that politicians prefer, as an alternative the more honest, open and politically less-palatable approach of direct Pigouvian taxes of the type supported by a wide range of mainstream economists, to address the concerns of scientists, economists, business leaders and others about man’s contribution to ongoing climate change by dressing up such taxes as a “market approach” involving a cap and trade program), I think that:

(1) you unfairly conclude that, since it will be government that will be implicitly pricing carbon emissions, such pricing “won’t reflect genuine economic scarcity” at all, when Austrian approaches do not deny that lack of property rights will result in economic actors ignoring external costs, but simply indicate the government pricing of resources can only imperfectly reflect economic factors;

(2) you’ve gone to a bit of unjustified rhetorical excess with your statements that:

“[t]his is no more a “market price” than if the government decided to sell people permits giving them permission to sneeze”:  rather, it’s more like the government trying to price grazing rights, resources extraction rights or other user fees on “public lands”– yes, such prices are not market prices (and are perhaps more likely to be underpriced rather than overpriced), but that does not mean that they do not represent or at all reflect valuable resources.

“Cap and trade is not a market-based solution” – while not a true market solution, a cap and trade approach is clearly one that makes use of markets.

– “Cap and trade … can therefore be justly viewed as a tax, stealthy or otherwise, on energy – the lifeblood of our economy” – this not only overbroad, as it would only tax certain types of energy, and overdramatic, it completely ignores the point that certain activities (a wide array not limited to combustion of fossil fuels, including release of other GHGs) are perceived as adversely affecting (now and in the continuing future) many within the country as a result of externalities involving an open-access and unowned and unmanaged commons, which is precisely what expressly motivates (actually or allegedly) so many – including many in your profession – to support Pigouvian approaches;

(3)  surprisingly, you failed to take the opportunity to add to the discussion by informing your readers of Austrian concerns, including the following:

– the calculation problem;

– whether, as you note it posting here, there is any reasonable basis to “trust governments around the world to implement the scheme ‘properly'” (by exploring problems with rent-seeking and bureaucratic incentives);

– whether it is desirable for the government to presume that it should act as the owner of the atmosphere in creating emissions rights (as opposed to citizens generally or long-standing/homesteading users of fossil fuels), and the related ethical issue of creating rights to emit that cut off those who may be harmed from any direct remedy (such as a share of the proceeds of the sale of rights); and

– the underlying institutional problem of lack of clear or enforceable property rights (for which past interferences by government have some responsibility); and

– whether growing concerns (and private responses) regarding the shared global issue (affecting nations with different circumstances and legal systems than ours) of increasing GHG emissions might be addressed less expensively and more rapidly by voluntary actions and national and international litigation rather than by coordinated action by various governments and implemented by individual nations.

None of these points is easily addressed, but they would help to provide a Austrian framework that may be useful to your readers. 

(4)  Finally, it is disappointing that you completely failed to take on any of your mainstream colleagues (such as those in Gregg Mankiw’sPigou Club”  http://en.wikipedia.org/wiki/Pigou_Club) who support either carbon taxes or cap and trade approaches. 

I understand that you’ve got a paper in the works addressing Nordhaus, but he’s hardly the only one writing specifically on climate change; I hope you will also be looking at Marty Weitzman at Harvard, Richard Tol and a few others noted here and here:

http://mises.org/Community/blogs/tokyotom/archive/2007/12/16/the-social-cost-of-ignoring-carbon.aspx
http://mises.org/Community/blogs/tokyotom/archive/2007/10/17/reason-congratulations-to-al-gore.aspx

Sincerely,

TT

"Heroic" contrarians, proven wrong on AGW, make another slick cry for relevance at Bali

December 14th, 2007 No comments

On the main blog, Sean Corrigan posts the latest missive of what he considers the brave dissenting voices on climate science. http://blog.mises.org/archives/007541.asp.

The letter nods briefly at the concerns summarized by the IPCC reports about warming and the role of human economic activity, and raises good issues about how global society should react, including the respective merits of public policy and private measures directed towards mitigation and adaptation.

But Sean does not examine any of these issues, but simply (i) touts the supposed “heroism” of the dissenters, (ii) complains about the supposed unfairness of the Bali conference sponsors (the 180+ states that are party to the UN Framework Convention on Climate Change) for not providing them a soapbox, (iii) cries about the supposed hysteria of the UN Secretary General (Mr. “Barking-at-the” Moon”!) [okay, points for being clever, anyway] and (iv) finally, for good measure, tries to sweep away the undeniable and rapid climate change in the Arctic with a link that tells us about a possible localized factor but nothing about the wider scale changes, which just MIGHT be due to the fact that air temperatures over the Greenland ice sheet have increased by about seven degrees Fahrenheit since 1991
http://www.sciencedaily.com/releases/2007/12/071211233433.htm.

Interestingly, while Corrigan seems to think his ongoing rants on “carbolic socialism” helps to clarify the issues and the interests of all parties, he constantly fails to note how a large and powerful group of rent-seekers packages the items that he swallows whole. In this case, only a modicum of research shows that these brave dissenters have been smoothly packaged by yet another new “grassroots” organization established to influence policy for the benefit of energy interests.

The whole issue deserves much better discussion, but it seems that many Miseseans are fundamentally not interested, either in conducting a serious analysis or even in being taken seriously.  Instead, they would rather be taken in, either by one group of rent-seekers or by themselves, by swallowing all manner of uninformed science (see my preceding post; http://mises.org/Community/blogs/tokyotom/archive/2007/12/14/who-knows-climate-science-the-mises-blog.aspx).  This kind of cantankerous self-delusion and naivete is hardly the best way to show the strengths of Austrian analysis to the world.

I`m getting tired of what I see as the Mises blog fundamentally counterproductive approach to this and related problems – which surely will NOT go away until some sort of management regimes are extended to important global and regional open-access “commons”.

Below is a copy of my initial response on Wrong-Way Corrigan`s thread: [snark on]

Heroes, Sean? Really?

This is an eclectic group (weighted towards social sciences and others outside of climate science) but still more like a bunch of grumpy emerituses who have been wrong time and again over the past thirty years (and don`t even agree with each other) but now wish to assert relevance by reluctantly conceding that change is in the cards and arguing that, given our long delay, sunk costs in current infrastructure and long lead times to change changes, our best course is to simply start getting ready for the ride.

Well, if even these folks think we need to start getting ready, then perhaps even the most skeptical should admit some slight concern. (I note that climate science “skeptics” John Christy and Pat Michaels didn`t sign on; can you guess why?)

 – Our most respected scientific bodies have been stating unequivocally that global warming is occurring, and that human economic activity is a significant factor. The U.S. National Academy of Sciences, which in 2005 the White House called “the gold standard of objective scientific assessment,” issued a joint statement with 10 other National Academies of Science saying “the scientific understanding of climate change is now sufficiently clear to justify nations taking prompt action. It is vital that all nations identify cost-effective steps that they can take now, to contribute to substantial and long-term reduction in net global greenhouse gas emissions.” (Joint Statement of Science Academies: Global Response to Climate Change [PDF], 2005); http://nationalacademies.org/onpi/06072005.pdf

I know; they and all of the other scientists who participated in the IPCC process are all hysterical misanthropes, whom freedom-loving rationalists can sweep away, in favor of this hero`s lot, who are now clearly changing tactics to argue adaptation instead of mitigation. (The lack of stomach in this second group is enough to make one wonder whether we might be better off without ALL scientists, isn`t it?)

– You and others are good at pointing out evil and rent-seeking motives on the part of everyone you disagree with – practically everyone now, it seems – but do you ever to trouble to notice how you`re being played by this letter? Like a string of others (this is the fourth in the past five years), it was started in Canada, organized and pushed by smooth PR professionals via a sophisticated vehicle (that are designed to provide “balance” while conducting “grassroots” campaigns) that clearly has significant backing from energy interests; this campaign differs in that it was perhaps more polished – for example, though the core signers remain the same over all four letters, this one was “by invitation only”: http://www.nrsp.com/articles/07.12.13-open%20letter%20to%20the%20un%20secretary%20general.html; http://www.nrsp.com/articles/07.12.13-open%20letter%20signatories-independent%20experts.html; http://tinyurl.com/2fpnsg; http://www.desmogblog.com/nrsp-not-really-science-peoplehttp://www.desmogblog.com/nrsp-controlled-by-energy-lobbyists.

While energy firms have entirely legitimate interests, they too are rent-seekers and it behooves one to note that when they speak they certainly have their own interests in mind. Even more so when they try to hide who they are and pretend to be impartial, grassroots groups concerned only about the pubic interest.

– The letter itself argues that we’d be better off adapting to/managing the effects of climate change rather than trying to prevent it. This is no slam dunk, but clearly there are more iummediate returns from investments in adaptation than in trying to mitigate future climate change. But serious standard cost-benefit analysis has clearly shifted in the past two years to the conclusion that investments in mitigation also make sense:

Nordhaus/Yale: http://www.reason.com/news/show/121926.html

http://www.desmogblog.com/research-the-new-economy-of-global-warming

Marty Weitzman/Harvard: “On Modeling and Interpreting the Economics of Catastrophic Climate Change”, December 5, 2007; http://www.economics.harvard.edu/faculty/weitzman/files/modeling.pdf

Richard Tol: “THE SOCIAL COST OF CARBON: TRENDS, OUTLIERS AND CATASTROPHES”, August 9, 2007; http://www.fnu.zmaw.de/fileadmin/fnu-files/publication/working-papers/margcostmetawp.pdf; Yohe, G.W. and R.S.J. Tol (2007), Precaution and a Dismal Theorem: Implications for Climate Policy and Climate Research, http://www.fnu.zmaw.de/fileadmin/fnu-files/publication/working-papers/dismaltheoremwp.pdf.

These are the papers that the policy crowd is reading.