Ecological Economics, Chapter 7 Review
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“How do we explain the unwavering devotion
to continuous economic growth by
economists, policy makers, and the general
public in the face of ecological and natural
resource limits?”
The laws of thermodynamics ensure that
there are limits to growth.
We must determine how close those limits
are.
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Exhaustion hardly seems imminent, we get
regular reports of increasing stocks.
We can extract at any rate, scarcity of flow is
the limiting issue.
Best estimate at current rates suggest
probable stocks will be exhausted in about
40 years.
Energy Information Administration estimates
that global demand will increase by 50% in
the next 20 years.
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New Discoveries and Production have peaked,
but consumption is still high.
A. Hubbert
Curve for Oil
Discovery
5 year
Intervals
1912 – 1992
The actual peak
was in 1970
A. Hubert curve for oil production
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Solar energy will require a great deal of time
to be developed as a viable substitute for
fossil fuels.
Without disrupting existing land use we could
only meet 20-50% of our current energy
needs in the US.
Food production in the US uses 3 times more
oil energy than it provides in carbohydrate
energy.
Using existing technology
◦ Less fossil fuel = less food
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The richest and most easily extracted ores
are used first.
These resources are growing more scarce.
Topsoil
◦ Depletion rates are currently 100
times that of formation in the US.
◦ Globally experts think 40% of
agricultural land is seriously degraded.
◦ In some areas this number is as
high as 75%.
◦ The current answer is
petroleum-based fertilizers.
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Global water consumption has tripled over
the last 50 years and continues to climb.
Although climate change may lead to more
rain it is thought that is may lead to increased
periods of aridness followed by intense
downpours.
We likely face greater risk of flooding and
drought.
70% of water is used for agriculture
◦ So hunger will arrive before thirst
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1.2Billion people without access to potable
water.
Less than 1/3 of the world has access to
abundant water supplies.
It is possible that in 2025 50% of the world’s
population could be living in water shortage
areas, according to some studies.
Current use patterns are drying up existing
sources faster than they can be replenished.
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The future is uncertain:
◦ We lack adequate data.
◦ Consumption patterns and technology can alter the
demand.
◦ Climate change could have drastic impacts on the
hydrologic cycle, but it is unclear exactly what
those impacts will be.
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For the most part extraction of renewable
stocks of significance is presently limited by
resource scarcity, not lack of infrastructure.
A shortage of fish is caused by inadequate
supply, not lack of fishing boats.
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Presently, if we deplete one species of fish we
simply switch to another.
Economists cite this ability to substitute as
evidence that the limits are boundless.
However, the fishing fleets are already in
place ready to deplete the next stock.
We run the risk of harvesting substitute
species to extinction before we can even
determine the sustainable yields.
Cod
Orange Roughy
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Ecosystem services are destroyed by the
harvest of their structural components (i.e.
the renewable resources of which they are
composed)
This may be worse than the danger of raw
materials depletion
In poor countries forest cover is being
depleted at ~140,000km2/year
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We understand marine ecosystems less well
than terrestrial ecosystems.
However, it seems highly likely that fish
populations are crucial to the system and the
services it provides.
We know oysters filter entire estuaries and
have seen this service decline in the
Chesapeake Bay.
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All economic activity produces waste:
◦ Accumulation of toxins impact humans
◦ Toxins also impact ecosystems and can degrade
their services.
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Evidence suggest we are overwhelming the
waste absorption capacity of the planet.
CO2 is accumulating in the atmosphere.
◦ This has led to international discussions, but so far
no clear movement or participation by the US
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Heavy Metals
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Nuclear Waste
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Halogenated Hydrocarbons
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Persistent Organic Pollutants
◦ Remain indefinitely
◦ Bioaccumulation – not released when ingested and
passed along the food chain
◦ Break down but not on a human time frame
◦ Would need to be sequestered for 50 times as long as
civilization has existed
◦ Ozone depletion
◦ Capable of affecting reproductive capacity of many
species
◦ Will persist in the environment for long periods of time
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A recent study found a 3km thick layer of
pollution over South Asia.
It is reducing solar energy throughout by 15%
in the region.
It is preventing heat from escaping.
Risk of thousands of premature deaths.
Likely to increase monsoon flooding in some
areas.
Could reduce precipitation by up to 40% in
some areas.
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Sink filling faster than sources are being
emptied.
This makes sense as anyone can use the sink.
◦ Rival and non-excludable
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Sources are typically rival and excludable
resources
◦ Typically they are privately or publicly owned and
managed.
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A rapid assessment of resources suggests we
are in a full world.
Continued physical expansion of the
economy threatens to impose unacceptable
costs.
Typically people are worried about the
sources, but it seems we should really be
worried about the sink .
We are far exceeding the waste
absorption capacity of the planet.