Sustainability
A. What is sustainability?
A1 The Laws of thermodynamics (which apply to
ALL CLOSED SYSTEMS - with no external inputs) underpin economic
(and
all other) systems. The first two laws are:
- Materials Balance Princple: Neither matter nor energy
can be
created
or destroyed: total mass-energy is fixed: all apparent changes
are
conversions of one form into others. So, the more matter and energy an
economy (people) uses, the more natural resource depletion and waste it
will generate.
- The Entropy Principle: where entropy is a measure of
disorder. In
a closed system, the use of mass-energy results in a one way
flow
from low entropy resources (mass-energy) to high entropy resources,
from
order to disorder. Perpetual motion is impossible - use of energy leads
to dissipation of energy into unusable forms (disorder), all we can do
is release order, and generate disorder. All closed systems tend to run
down and dissipate to disorder, towards maximum entropy. NO CLOSED
SYSTEM
IS ULTIMATELY SUSTAINABLE. (Though the earth is not closed - it
continually
receives energy from the sun - the solar system is (for practical
purposes),
closed, and the sun is runnning down.) So, any discussion of
sustainability
has to recognise that sustainability is a relative, not
absolute
concept. Are some processes and activities more or less sustainable
than
others?
A2. Ecology: Man is an Animal: whose
population
will expand to exhaust its local food supplies or life support systems,
and then contract (through disease, starvation etc, and, in the case of
man alone, wars and conflicts.) to a sustainable level, consistent with
the local environment - the Malthusian Principle. The world population
has grown from 0.5bn in 1600 to 1.6bn in 1900, to 6 bn. in 2000, and is
on track to grow to 9 billion or perhaps more by 2100, with the
population
explosion coinciding with the advent of the industrial revolution. It
has
achieved this through making massively more use of the planets
resources,
and creating more waste as a consequence. There must be a limit
to
the human carrying capacity of the planet - but where is this limit?
And to what extent does it depend on the state of technology - can
technological advance increase the carrying capcity of the planet
indefinitely?
A3. Economic Meaning of Sustainability?
- From a simple economist's perspective, sustainability
might be
taken
as the ability to maintain wealth, income, consumption and
lifestyles
indefinitely.
- Since the generation of income and wealth requires the use
(exploitation)
of both renewable and non-renewable natural and physical resources, and
also generates waste and pollution, while at least part of peoples
utility
and enjoyment derives from appreciation and use of the natural
environment
and physical character of the planet, sustainability requires that the damage
and depletion of the earth's natural resources and environment must be
made good somehow, otherwise the processes of income generation
will
eventually run down. A common way of expressing this requirement is
that
human activity should be organised as if the human race had a full
repairing
lease on the planet. See a recent paper by Arrow et al.
(2010) for the NIESR, which argues that a workable definition of
sustainability involves maintaining the stock of wealth available to
future generations (Sustainability
and the Measurement of Wealth).
- However, once stated in this way, most people (economists
included)
might
well wish to add that the present distribution of wealth,
income,
consumption and living standards (quality of life) leaves a lot to be
desired,
and hence is socially (even morally) unsustainable. So
sustainability
should also include the provision to improve welfare,
especially
of those currently less well-off.
- Once again, however, adding this proviso raises several more
practical
issues -
- raising the welfare of those less well-off either involves a
redistribution
of income and wealth from the rich to the poor, or increasing the
income
and wealth of the total population, or a combination of the two.
Since there is little evidence from either history or logic that the
rich
are willing to redistribute their wealth or incomes to generate an
acceptable
improvement in the welfare of the poor, it is practical to presume that
satisfaction of this social ambition necessarily requires continued
growth in income and wealth. Hence, the common (near ubiquitous)
ambitions
of most societies are expressed as both wealth creation and
welfare improvement.
- history strongly suggests that pursuit of wealth creation
increases,
rather
than reduces, the ecological and environmental footprint of man (and
woman)
on the planet, and generates greater depletion of and damage to
the planet's natural resources and environment.
- the only counteracting forces to this increase in damage and
depletion
appear to be:
- improved technologies (including, importantly, improved
management and
organisation and governance of human transactions and actitivies),
allowing
more to be produced (and consumed) for less - an improvement in the
efficiency of use of the life support system (the planet's natural
resources) - so developed economies now consume considerably less
energy
per pound (or dollar) of national income than they used to, for
instance.
- increased incomes and wealth appear to generate increased
values for
natural
environments and increased efforts to reduce pollution, at least in
specific
localities and for specific aspects of the environment, which leads to
an increased willingness to pay for environmental and resource
conservation.
- increased income and wealth, especially if associated with
increased
security (especially for the elderly) appears to be associated with
reduced
population growth rates (lower birth rates especially). Western Europe,
for instance, now has a declining population (except for inward
migration).
The general conclusion arising from these considerations is that
sustainability
is a problem of Market Failure, implying that some form of
government
intervention (social control) is necessary. Meanwhile, commerce remains
skeptical: a recent report in the Economist (19.11.04) concludes"The factors that
sustain long-term corporate returns are but vaguely understood. Some
research suggests a correlation between a company's stance on
environmental and social issues and its long-term performance, but none
yet shows a causal relationship between them. Until that can be
established, investors will be left wondering whether sustainability
analysis is more than a mere curiosity." This observation comes
at the end of an article about Al Gore's investment management company
which will “integrate
rigorous traditional fundamental equity analysis with sustainability
research to create a new approach to long-term investing”. Al Gore is
teaming up with David Blood (no kidding), previously a chief executive
with Goldman Sachs. "Mr Blood was
a
fund manager who saw a demand for long-term investment to take into
account his belief that “social, environmental and geopolitical issues
can materially impact a company's ability to sustain returns.”
Generation (the name of the Blood and Gore Management company) combines
Mr Gore's political savvy with Mr Blood's market
instinct."
B. Possibilities
for Sustainable
Land
(natural resource) Use?
Bi. Market Failures: The
critical
factors
giving rise to Market Failure problems are:
- Transactions Costs: for both externalities and public
goods,
the
negotiations necessary between suppliers and users/beneficiaries (or
sufferers
in the case of public bads or negative externalities) are complicated,
typically because there are many people affected, and the good or
activity
affects many different people in different ways. Because
transactions
are economic activities (they take time, effort and resources to do),
these
transactions are in competition with other uses for these resources,
time
and effort, and will not be undertaken unless the rewards from
successul
transactions more than outweigh the costs of making the
transaction.
In many cases, there have not been in the past sufficient rewards from
the solution to externality or public good problems for people to make
the effort to solve the transactions problems.
- Property Rights. Even when transaction cost problems can
be
overcome
economically, there is often a further factor giving rise to problems -
who owns the property rights - who has the right to expect benefits (or
expect reductions in damage or depletion)? Who owns the sea, or
the
atmosphere, or the view, or the natural environment? We all do -
which means everyone does, and anyone could represent these interests,
but since anyone could, no one actually does. It becomes a
problem
of governance - which is especially difficult for global externalities
and public goods, because we do not have a world government.
- Pricing & Valuation Problems: by definition,
externalities
and public goods are not freely traded between people, so no one has
any
experience of trading these effects, benefits etc. off against other
things.
In general people put value on things or effects for three major
reasons:
- Use Values - the thing or effect is valuable because it is
useful in
providing
either productive capacity or consumption benefits
- Option Values - things are valuable because they may become
useful
sometime
in the future (or in different circumstances) - so it worth having them
about as an insurance policy
- Existence Value - things are valuable in their own right - it
is nice
to
have them about.
None of these values can be infinite or invaluable - obtaining or
preserving
them always requires time, effort, inputs and resources, all of which
could
be used for other things - we have to make choices about what we do and
what we produce or preserve, we cannot do everything. Choice
automatically
implies an opportunity cost - what we might have done
instead.
It will only be worthwhile to provide these things if the opportunity
cost
of providing them are lower than their values.
However, unless we actually require people to put their money (or their
own time and effort) where their mouth is, we will frequently get very
silly (inconsistent and incoherent) answers to apparently simple
questions
about how much a landscape, or a particular ecology is worth. If we
think
someone else will pay, it makes sense for us to pretend or imagine that
the thing is very valuable indeed, whereas once we are required to pay
up to the value we think we place on the thing, we become very much
more realistic
about its worth in relative terms to the other things commanding our
attention,
resources and income. - see here from some
brief
notes on the approaches used to determine social willingness to pay
for non-market goods and services.
Economics (the market) cannot resolve these
problems,
except in very special circumstances. Solution requires collective
action
- governance - the long arm of the law is necessarily attached to
the
invisible hand of the market, not just to correct for market
failure,
but also to police the market system (outlaw theft, establish and
policy
property rights and the laws of contract, and make judgements about
relative
equity of market outcomes (changing these as seem fit).
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Bii. Problems of Substitution
between physical
(man-made)
and natural capital -> valuation problems again
Sustainability implies at least a constant stock of Capital
(both
natural (Kn) and physical (man-made, Kk)). In the limit, maintaining a
constant stock of natural capital denies the possibility of using any
non-renewable
resources (coal, oil, natural gas), and also denies the possibility of
creating any waste. This strict form of capital sustainability is
clearly
unworkable (socially unsustainable). Some substitution of man-made
capital
(wind farms, solar energy panels, water power etc.) for natural capital
is necessary for human systems to be termed sustainable. It must be
possible
to compensate for the loss of natural resources by building up stocks
of
physical (man-made) capital, otherwise human existence is inherently
unsustainable
above a very low level (perhaps 0.5 bn. people at subsistence levels of
existence).
As stocks of Kn are used up, so they will become scarcer, and thus
more
valuable (more expensive) - which will both encourage more efficient
and
economical use of the remaining stock, and encourage the search for and
use of alternatives (renewables). We are already seeing some of these
natural
reactions, as renewable energy sources and energy efficiency measures
become
more attractive (energy use per £ of GDP is now considerably
lower
than it was 20 years ago), while we are becoming more concerned about
waste
disposal as the costs of damage become more obvious and the value of
the
natural environment increases (less of it per £ of GDP). However,
there are 2 major problems with this natural (market) reaction to
depletion
of natural capital, each of which can compromise the resiliance
of market systems to cope with unforseen catastrophes.
- uncertainty and technological lags: Increasing man
made capital
(Kk) is investing in the future - providing increased capacity to
produce
and consume at future dates. The future is uncertain. The more
uncertain
it is, the lower the incentive to invest, since the probabilities of
sufficient
returns being generated to repay the investments are lower.
Furthermore,
the greater the technical problems of developing alternatives, the
longer
the lag between recognising the need to invest and the provision of the
alternative, and thus the greater the uncertainty and the lower the
incentive. Long
lead times, and large technological gaps mitigate against simply
rational investment decisions - where simply rational means relying
on probabilities of outcomes, and treating beneficial outcomes with the
same weights as detrimental outcomes. We end up doing too little too
late,
because we are myopic, except that we don't always.
- irreversibility: the simple economic mechanisms tend to
assume that
economic processes are reversible - if we make mistakes, we can rectify
them later. Burning up fossil fuel reserves which took 300 million
years
to accumulate in 300 years or so is nearly certain to have significant
effects on global carbon balances and hence on global climate. But what
will be the effects? We remain uncertain, and we certainly don't
know that they will be all bad, though there will be some bad
effects.
It is tempting to suppose that we can make good, or at least make do
and
mend, if we fail to make the appropriate decisions now to limit (or
even
reduce) carbon emissions - that we can live with our mistakes. But this
may turn out to be impossible, or impossibly expensive. So surely
it is more sensible to be cautious now - to adopt the precautionary
principle (PP): if we don't know what the effects of certain
actions
will be, better to avoid them altogether, especially if the possible
effects
include serious and irreversible damage. But universal adoption
of
this principle would eliminate many innovations and many experiments
(trials
by error), and limit our ability to cope with the future. In the
end, regardless of whether we are economists or not, we take decisions
based on guesses about the relative merits - a balance between some
guess
about the possible benefits versus the possible costs. The PP really
only
amounts to the identification of those cases where the possible
costs
sufficiently exceed the possible benefits as to make the case
(decision)
daft. Deciding on these cases necesarily involves judgements about
relative
values of costs and benefits.
Underlying these difficulties are three more fundamental problems: the
problem of valuation; the
problem of capital; the
problem of equity.
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Biii. Identification and
Valuation of non-market
goods
and services
This
picture represents the typical problem of commerical farming
(especially
if subsidised) - that it uses land too intensively to be sustainable.
Intensity of Production (essentially the yields of biomass production
per hectare, increased by the application of increased inputs) is
measured
along the horizontal axis. The value of the effects of land use
is
measured on the vertical axis.
The Private (supported) Value of Biomass curve represents the net value
(revenues minus all costs except land costs) of the subsidised
production
of biomass (food and fibre) on this particular hectare of land. It
reaches
a maximum value at intensity level B.
However, if we were to remove all the subsidies from this production,
the net value curve would shift, so as to produce a maximum at
intensity
level P, the subsidies result in increased intensity of land
use
(and higher values to land under biomass production).
The remaining curves represent the values of other attributes and
characteristics
of the land use as intensity changes. (we might add a curve
representing
sporting rights and benefits as well, which would conflict with some
other
elements (wildlife) and complement others (other bits of wildlife).
The total social value of land curve is the vertical sum of
each of the component curves (removing the subsidy from biomass
production).
This total value reaches a maximum at point S.
Is this point (S) the sustainable point of intensity?
Identification of this point requires that the following critical
components be identified:
- The biophysical consequences of particular land use
decisions
and
practices for the rural environment ? the shapes and locations of the
various
curves (relationships) in physical terms as intensity is increased (and
as production practices are changed).
- The behaviour of land managers and users in response to
market
or
policy signals - showing what they will do under different market and
policy
conditions, and the decisions they will make about land use.
- The social valuations of the care (conservation,
amenity,
recreation and environmental) goods and services themselves - these are
typically non-market goods and services, and it is difficult, but not
impossible,
to estimate peoples willingness to pay for these attributes and
services.
Providing that we:
- get the price of biomass “right” (without distorting and
supporting it,
which shifts the biomass curve upwards and to the right);
- “properly” reflect the public or social values of the care goods
(including
pollution) back to the landowners and users.
Then can we expect market forces and a properly liberalised market to
encourage
land users to operate at the socially optimal level of intensity and
multifunctionality
at point S. Then we can regard this land use as sustainable -
in
the sense that we are properly accounting for the depletion of natural
resources used in the production of food and fibre and properly
accounting
for the other competing and complimentary attributes of this land use.
Notice, however, that this characterisation of the problem is:
- Spatially heterogenous - there will be different curves
(relationships)
for different parcels of land
- Temporarly dynamic - these relationships will change
through
time
as new techologies appear and as preferences and social valuations
change
- Behaviourally heterogeneous - different people, as land
onwers and
land users, will respond differently to the same market and policy
signals.
It is a complex system - which is not formally capable of prediction,
but
does generate replicating patterns and structures within certain
boundary
conditions.
See here for an article exploring the
implications
of this sort of analysis for the appropriate response to quests for a
genuinely
Multifunctional Agriculture.
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Biv. Capital: Choices between
now and the future
(the
tyranny of the discount rate)
As if the previous section were not complicated enough, dealing with
the
heterogenity across space and current behaviours, there
is
also an all important time dimension. Consider a policy to try
and
improve the sustainability of a particular land use (choose whatever
example
you like). Suppose that we have all the necessary information
(referred
to above) to identify the costs and benefits of various forms of land
use
and their effects, and their social values. This information will
be contingent on current preferences, and on current technolgies,
and
on current capacities (land qualities, buildings, plant and equipment
etc.
in short on current capital stocks, both man made and natural).
But, we will discover that the biophysical attributes of the
environment
will be changed according to which land use we choose - the natural
capital
stock will change through time. So, too will the values people attach
to
these attributes (both individually and collectively). And, we may
imagine,
we could do better if we had and used different technologies. In
short, if we did things differently NOW, we would live in a different
world
in the FUTURE. But, in order to decide whether or not we should
do things differently now, we need to be able to compare the value
of the different future conditions we generate with the costs
of
doing things differently now. Furthermore, the future is a
stream
of (annual) net benefits or costs, while NOW is a single value.
In simple terms, the value of the future might seem to be simply the
sum of all the annual net benefits (NB(t), for each year t in
the
future) from a particular course of action, which can be compared with
the current costs (K) of achieving this net benefit stream,
where
K
is the investment necessary to achieve the future benefit stream.
But, for how long in the future - for ever? Then any positive net
benefit stream, however small the future benefits, will always outweigh
the current costs, however large these may be, simply because the sum
of
an infinite stream is infinite. So this is clearly quite impractical as
a guide to decision making.
It is also socially unsustainable - we do not behave as if the
future
were of exactly equivalent value as the present.
- We only save (invest) if we think the extra returns will pay us
to wait
(will pay us to curb our natural impatience) - we need to be rewarded
for
saving - we express a personal time preference rate (p)
as
the rate of return (5% say, so p = 0.05) we are willing to accept to
delay
our consumption and enjoyment.
- Furthermore, we (as banks, or pension funds etc.) will only lend
our
own
income to finance such investments (incurring costs now for some future
benefit) if we are promised repayments which include a reward for
waiting
- and at least match the returns we could earn by investing in
something
else. The returns we could earn by investing in something else is
the opportunity cost of capital - r. So, if we invest
£100
in the bank now, at an interest rate of 5%, (r = 0.05) we will get back
£105 next year, with the £5 being both our reward for
waiting,
and the return we get for lending our income to the bank (who then lend
it on to someone else to use now). If we could earn a higher rate
of return by lending to someone else (a local small business, or
investing
in the stock market) then we would be wise to do so. This opportunity
cost
of capital then represents the returns to be earned on alterntive forms
of investment - the returns we get from incurring present costs to do
something
else rather than the current object of our investigation - the project
under consideration.
- But, of course, there is a risk associated with these
alternatives
- we may not get the return we expect or hope for, we may even suffer a
loss. So, we will demand a risk premium (m) to
compensate
us for this uncertainty. The higher the uncertainty about a
future
return, the greater the risk premium we demand. {If we expect inflation
in the future, we will also require our future return to compensate for
the loss in value of the money caused byn inflation}. The
opportunity
cost of capital will therefore include approariate adjustments for the
risk associated with alternative investments.
So long as the Capital Markets are working reasonably competitively
(which
they mostly do), these markets will balance personal time preference
rates
with the opportunity costs of capital to generate a interest rate
- i.
Now we can compare current costs (K) with a future stream of
net benefits (NBt). NB1 - the net benefit we expect to get
by the end of year 1, will need to be greater than our cost of securing
this benefit now by at least the rate of interest, to make the current
investment worthwhile. So, if we invest £100 now, we need
to
be sure that our NB1 is at least £105 at a 5% interest rate (=
£100
*(1.05)). In other words, the Present Value (PV)
(£100)
is equivalent to a Future Value (FV) of £105)
So: FV1 = PV(1+i); or PV = FV1/(1+i). This is the principle
of discounting, where the interest rate is used as a discount rate -
discounting
the future value to its equivalent present value. Repeating
the
same logic for year 2 gives FV2 = [PV(1+i)](1+i)] = PV(1+i2),
so for year 2, PV = FV2/(1+i2), and so on as t increases.
The further into the future, the lower is the
present
value of the future benefit. This discounting of the future
is even more severe if there is any uncertainty about our future
return,
since this uncertainty adds a risk premium to the discount rate.
The greater the uncertainty, the higher the risk premium. Our
behaviour is necessarily myopic - we could not make decisions over time
unless this were the case.
Most modern mixed economies operate at a base interest rate
(excluding
inflation) of about 3 to 6%. Simple arithmetic - the tyranny of
discounting
- quickly reduces anticipated future benefits to rather low present
value
at these rates of interest. For instance, £1000 in 30 years time
is only worth £167 today, at a 5% discount or interest rate, and
is only worth £333 today at a 2% discount rate.
Predecitions
of general catastrophy in 50 years time, coupled with a considerable
amount
of uncertainty surrounding the nature of this catastrophe, does not
appear to warrent
very large investments NOW. Try getting people to pay for
avoiding
them, and see both the logic and the evidence of this.
However, the converse also applies: to get £1000 in 30
years
time,
so long as there is no risk or uncertainty, we only have to invest
£167
now, at 5%. At 2% return, we will need to invest £333
now.
A little spent now might generate
considerable returns in the future.
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Bv. Problems of Efficiency
versus Equity (choices
between
us and them) (markets versus democracy)
There is a further complication to the assessment of costs and benefits
- the distribution. Who pays the costs and who
gets
the benefits also matters. The market accords weight to those with
the income and wealth - the more £s you have, the greater your
votes
in the market place for what you want in competition with everyone
else.
Thus, those who own the resources get most of the say in what is
produced
and how, and for whom, and how much.
However, as humane societies, we also worry about caring for the
less
well off, at least some of the time, and expect our governments (and
NGOs)
to look after the poor on our behalf. We might, therefore, be
prepared
to weight the interests of the poor (the benefits they miay get) rather
more highly than the interests of the rich? Similarly, we may
want
to count the costs more highly if they are suffered by the poor rather
than by the rich. To do so requires that we use our governments,
through democracy, to exercise these social and caring judgements on
our
behalf.
Does this mean that we should count future generations welfare at a
higher level than our own? Won't they be richer than us,
providing
our recent history of economic growth can be sustained? Won't
they
be cleverer than us?
Does this mean that we should care more about the very poor, who
live
a long way away from us, than we care about the relatively poor on our
own doorstep?
Questions of sustainability also raise these uncomfortable
questions,
which cannot be resolved through the market place, but need to be
resolved
through our governments.
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C. Conclusions and lessons learned?
THE PRINCIPLE CONCLUSIONS TO BE DRAWN FROM THESE CONSIDERATIONS CAN BE
GROUPED UNDER TWO MAJOR HEADINGS: ECONOMICS AND SYSTEMS THEORY.
ECONOMICS: THERE IS NO SUCH THING AS A FREE LUNCH
|
SYSTEMS THEORY: SUSTAINABILITY IS RELATIVE:
|
Treating the natural environment as if it were a free lunch
is reckless,
and potentially suicidal. The environment, and all its components, have
a price. |
No closed system is absolutely sustainable except in a state
of
maximum entropy
(complete chaos). |
The human condition involves making choices. |
System persistence depends on buffering feedbacks which
constrain explosive
or implosive tendencies. |
Making choices automatically implies a relative valuation of
or judgement
about outcomes versus inputs. |
But too much buffering prevents adaptation and response to
changing
conditions, and lowers resiliance to external (or unforseen) shocks. |
There is no such thing as an invaluable asset - there is
always a price
at which people (as communities) will be willing to seek an alternative. |
Systems persist if they balance opposing forces and
tendencies,
oscillating as a means of preserving these balances. |
Valuations are critical, and are an expression of social
choices |
To do so, they require a continual source of energy of some
sort. Perpetual
motion is impossible in a closed system. |
The ways in which social choices are made are thus critical |
Human systems are no different, in principle, from
biophysical systems. |
The market is only one, albeit fundamental, way in which
society makes
choices |
Living systems (at least) evolve: they mind and respond,
and so adapt to seek best fits with their biophysical environments. |
The ways in which society learns to live with the natural
processes
of market transactions are critical to human sustainability. |
Human systems care and reply, as well as minding and
responding, and
thus learn (exhibiting Lamarkian adaptations: nurture breeds as well as
grows new natures, which in turn replicate and evolve) |
Social science is at least as important as natural science in
making
our systems more sustainable. In fact, if sustainability means
sustaining
human existence, social science has to be fundamental. Technology and
Natural
Science is not enough - these are simply tools. The rules and
reasons
of use are more fundamentally important. |
Social Science needs to grow up, and breed a coherence and
consistency
which is currently lacking - this is the biggest challenge facing the
Human
race. See here for a possible beginning to this
quest (as submitted to Ecological Economics) |
Further Reading: The
Stern Review on the Economics of Climate Change. In summary (From
the Economist, Nov. 2. 2006 -
my emphasis added) : "Sir Nicholas has tried to assess the future costs
of climate change—drought in Africa, floods in Europe, hurricanes in
America, rising sea levels around the world—and has set them against
the costs of cutting fossil-fuel usage enough to stabilise
carbon-dioxide concentrations in the atmosphere. His answer to the
second part of this calculation is fairly uncontroversial. The costs of
switching away from carbon should not be huge because of the rise in
fossil-fuel prices and the fall in alternative energy prices. Sir
Nicholas reckons that the world could stabilise concentrations at a
reasonable level at a cost of 1% of GDP by 2050. Many other
economists have looked at the matter, and most agree with Sir Nicholas.
But Sir Nicholas dissents from the general view on the costs of climate
change itself. Most economists who have looked at the matter up
to now reckon that, if greenhouse-gas emissions continue on their
current path, the costs of climate change would be between zero
(where the benefits of warming to cold countries balances out the
costs) and 3% of global output over the next 100 years. Sir Nicholas
thinks they would be a massive 5-20% over the next century or
two: in other words, world output could be up to a fifth lower,
as a result of climate change, than it otherwise would have been.
He justifies these high numbers on two main grounds. First, he says,
the earlier estimates were based on temperature increases of
2-3°C by the end of this century. But the science has moved on. A
better understanding of feedback loops in the climate, such as the
melting of Arctic ice, which increases the region's tendency to
absorb sunlight and therefore reinforces warming, means that, although
2-3°C remains the likeliest increase, scientists now think that
warming of 5-6°C is a real possibility. That would be a massive
jump: 5°C is the difference between the temperature now and in the
last ice age.
Second, he points out, most economists have fed only the likeliest
climate-change scenario into their models and ignored the outlying
possibilities of catastrophe. Sir Nicholas has received plenty of
support from economists (four Nobel prize-winners have endorsed the
report) and a certain amount of criticism. One complaint is that he has
selected the most pessimistic research and ignored more conservative
work. Richard Tol, a professor at Hamburg University and a big noise in
this field, describes the report as “alarmist and incompetent”. Another
criticism is that figures on the economic costs of climate change are
bound to be nonsense because they are based on a cascade of
uncertainties. Nobody knows just how much carbon dioxide the world is
going to produce in future. Nobody knows just what it will do to the
temperature. Nobody knows just how temperature rises will affect the
world economy. These numbers are therefore too uncertain to act on. Sir
Nicholas may well err on the gloomy side. And it is certainly
impossible to predict precisely what effect climate change will have
had on the world economy in a century's time. But neither point
invalidates Sir Nicholas's central perception—that governments should
act not on the basis of the likeliest outcome from climate change but
on the risk of something really catastrophic (such as the melting of
Greenland's ice sheet, which would raise sea levels by six to seven
metres). Just as people spend a small slice of their incomes on
buying insurance on the off-chance that their house might burn down,
and nations use a slice of taxpayers' money to pay for standing armies
just in case a rival power might try to invade them, so the world
should invest a small proportion of its resources in trying to avert
the risk of boiling the planet. The costs are not huge.
The dangers are."
See Stern Report: Executive Summary;
and a Review, and a Critique,
and a rejoinder by Ken Arrow (one of the
greatest), and the latest (Nov. 2007) IPCC report on
climate change
See, also: World
Economics, 7 (2),
April/June 2006:
Nicholas Stern: "What is the ecoonomics of climate change? (1 - 11)
Ian Byatt et al.: "The Stern Review 'OXONIA' Papers: a critique", (145
152)
Nicholas Stern: "Reply to Byatt et al.", (153 - 158).
Also, a critique by Bjorn
Lomborg (author of "The
Sceptical Environmentalist"), published by the Wall Street Journal
- as expected, a clear alternative view. I am afraid you will
have to make up your own mind on this!
See, also, IFPRI, recent policy brief on
Sustainable Land Management: Lessons from the East African
Highlands <>by John Pender, Frank Place, and Simeon Ehui,
February
2006, for a review of the practical difficulties and possible solutions
in areas of high deprivation and low economic development.
Comments and Suggestions??
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