Transcript Philosophical Debates, IPAT Equation

Philosophy of Sustainability
Scott Matthews
12-712 / 19-622
Lecture 3
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Administrative Issues
HW 1 Due Today
Few came to office hours – keep same times
HW 2 Given Out, Due Next Wednesday
Lecture 1:
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Rise of “Sustainable
Development” as a Thought
Last reading – plenty of history on early
efforts and recognition of managing
resources (and the consequences of
failing to do so)
Efforts achieving / failing “triumph over
nature”
BY and large, technological progress over
time has come at the expense of nature
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Anti – Tech / Pro-Environment
Europe mostly civilized (i.e. developed) by
1800s. US mostly unspoiled land
Arguments of Manifest Destiny
Goal to develop/inhabit the west like Europe
had done
Thoreau / Emerson promoted the virtues
of an unspoiled wilderness as escape
from civilization, technology, etc.
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20th century
Massive technological progress – car,
electricity, war efforts/production
New recognitions of natural limits
Florman: technology did not cause
problems. Seeking comforts is human
nature (free will). Blame humans not the
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technology
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Brief commentary on utility
Utility = economic measure of well being
E.g., “I get more utility by consuming more”
or “I get twice as much happiness drinking 2
beers as I do drinking one”
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Define: Carrying capacity
Supportable population given demand for
food or resources and the supply of those
resources, without degrading future
generations
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Tragedy of the Commons
Hardin, 1968 (partly a retelling of an
example by old British economist lloyd
from 1800s).
Argument against “invisible hand” of Smith
Picture a pasture open to all.
Each herdsman will try to keep as many
cattle as possible on the commons.
May work reasonably satisfactorily for
centuries because tribal wars, poaching, and
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disease keep the numbers of both man and
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Each herdsman seeks to maximize his gain.
Asks "What is the utility to me of adding one
more animal to my herd?”. Two components
Positive component is a function of the increment of
one animal. Since the herdsman receives all the
proceeds from the sale of the additional animal, the
positive utility is ~ + 1.
Negative is a function of the additional overgrazing
created by one more animal. Since, however, the
effects of overgrazing are shared by all the
herdsmen, the negative utility for any particular
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decisionmaking herdsman is only a fraction of - 1.
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The Tragedy
Taken as a big series of indivudal “one more
animal?” decisions there is no noticeable effect
But the sum of the negatives from all of the
additional animals is enormous
And eventually the sum of the small parts leads
to the ruin of the commons
The commons is nature. By taking action
without regard to impact, we ruin the commons
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Link to Population
Little tragedy of commons when
population density (or population) is low
Brings us to IPAT – simple equation
Environmental Impact = Population ×
Affluence × Technology
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IPAT – originally about T
Orginally pushed that I was mostly a
function of T
Observation that impacts of new technology
increase over time more than the rate of
benefit that come with them
Over 20 years, consumption of beer only up
slightly but nonreturnable bottles up 600%
Bottles as technology? Need to replace bottles
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Ehrlich et al: Independent P,A,T
Hard to dissociate population in variables
Effect of population underestimated
Leaded gasoline: Pop up 41%, VMT
doubled (affluence), emissions up 83%
IPAT = 5.16, 416% increase (compared to
1.0)
Without population, only 3.66 (266% inc)
Popultion effect a clear multiplier
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IPAT-like equations for climate
change
Energy use =Pop *
(GDP/person)*Energy/GDP
Same for carbon emissions (carbon/GDP)
IE master equation:
Env Impact = Pop * GDP/Person * Env
Impact/per-capita GDP
is only definable for each impact separately
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(without weighting methods)
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More from Chertow paper
Sample problems?
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Julian Simon
Ingenuity is the ultimate resource
Somehow we have survived despite
challenges
Distinction between definitions of reources
Economic – do not exist until discovered, can be
created (almost infinite supply of these)
Physical
Scarcity causes us to find alternatives to physical
We depend more on economics resources
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Simon
Natural limits and carrying capacity do
nott exist (we’ve always found solutions to
shortages). Claims of running out always
false
For a resource: time to depletion
Quantity available in reserves / rate of use
Market will solve any problems,
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sustainability not an issue
Simon-Ehrlich Wager (1980)
Ehrlich was author of population book.
Central premise was that population growth was
outstripping our ability to provide food –
catastrophe (Simon disagrees)
As evidence, they made a wager (food data too
easily manipulated) that resource prices would
decrease.
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Wager continued
Simon: resource prices will not rise in long run
Simon told Ehrlich he could pick any commodity
he wanted, select any date in the future (1+
year)
Ehrlich chose 5 metals: copper, chromoum,
nickel, tin, tungsten (Ehrlich up, Simon down).
On paper bought $200 of each
Payoff date 9/29/90. Inflation adjusted prices
Winner paid loser net gain or loss
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Results of Wager
Over that 10 years:
Population increased by 800 million (largest
one decade increase in history)
3/5 decreased in absolute terms, all 5 with
inflation (some 50% less)
Ehrlich mailed a check for $576 to Simon
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Bjorn Lomborg – Skeptical
ENvironmentalist
Environmental dangers overstated
Shows stats that refute popularly stated
beliefs and conclusions about environment
Summary:
Big picture is global improvement in humanity
Pollution/environmental problems have peaked
No sign of reaching carrying capacity soon, that
we have exhausted our resources, or that we
have irreparably harmed nature
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His evidence
Crop yields, food prouction per capita
increased (50-100 yrs), so has life
expectancy and personal income
He says (fairly) that environmentalists
inject their bias into their work by using
poor or misleading data, then similarly
make bad visuals
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Recent: Al Gore hockey stick
chart
Graph that shows arctic warming and
relates it to ice melting
But in previous warming periouds,
inconsistent melting showed up in data
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