Download McKibben: A Special Moment In History

McKibben: A Special Moment In
History
What are the limits of human development and
overpopulation?
Is this a special time? What is unprecedented about
the current period?
An unprecedented historical change
 We have taken ‘more’ as progress.
 Growth, both technological and population has accelerated.
 We’ve increased the population fourfold in 150 years.
 Q: Is it necessary for humans to limit their fecundity (e.g., to
have only one child)?
 China has many policies to make things more difficult for
those with larger families but other people are also chooses
to limit the number of children they have.
Population growth seems to be slowing
 However, population has grown so much this cannot happen
too soon.
 Human population has grown more since 1950 than it did
during the previous 4 million years.
 We know some of the reasons it great but are less sure of the
reasons it is slowing. Is it development, empowerment of
women. McKibben: It is personal choice.
 Even if population growth dropped to 2.5 children per
woman the population in 150 years would reach 28 billion.
How Big Are We?
 The real question is not how many we are but how much we
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consume.
A hunter-gatherer uses 2,500 calories per day, almost all of it
food. The daily intake of a dolphin.
Modern human uses 31,000 calories, most in the form of fossil
fuels. It is the equivalent of a pilot whale.
We have geographical space to fit each person but each modern
person consumes resources that need thousands of acres. We are
‘giants.’ 1.7 million people require 21.5 million acres of land to
support them.
Like being followed by a Macy’s balloon.
Person in Manhattan is like someone on the Mir space station in
their dependence on distant resources.
Development & overdevelopment
 Developing nations also increase demand for resources.
China slaughters more pigs than any nation.
 Developing economies would have to be 5-10 times larger to
move poor to an acceptable standard of living.
Carrying capacity
 Issue of carrying capacity: The number of a population an
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environment can support.
This seems to change. Ancient philosophers worried about
population outstripping food supply but it has not.
Malthus—geometric population would outstrip food supply.
Many books in 1970s predicted dire catastrophes.
Each new Malthusian prediction has been wrong.
Optimism v. Pessimism
 Increase in population increases standard of living.
 If we run out of copper, this will just prompt someone to
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build a substitute.
Pimentel—We are already in trouble. Iceberg lettuce is 50
calories to eat but 1,800 calories to ship.
The soil is eroding. Chinese soil is found in the air in the
South Pacific.
Fresh water is becoming more scarce. Water sources are
drying up. Only 2% of the Nile makes it to the ocean.
Our technology cannot seem to get around the water needs
of plants for photosynthesis.
Agricultural development
 The ‘green revolution’ and ‘miracle rice’ made it possible for
crop yields to more than double in poor countries. Thus crop
yields were always increasing. However, lately they have
leveled off or decreased. There is less interest in agricultural
breakthroughs than there was.
 The capacity to produce food may not be infinite.
 It’s very hard to predict how many people the earth can
support. From 5.9-40 million. The median is 12, which is
what the population of the earth will be in the next century.
Earth 2
 Through 10,000 years of recorded human history, the planet
has been a stable place (even if there are constant disasters).
However, climate change is making weather so unpredictable
insurers don’t know how to predict risk anymore.
 We are ¼ the way into full global warming & we don’t know
what the future holds.
 However, worse storms are appearing and this poses a threat
to agriculture.
 Large scale changes in climate on the horizon.
We can’t wait
 “Nature may still meet us halfway (regarding climate change)
but halfway is a long way from where we are now.
 …This is a timed test like the SAT: Two or three decades and
we lay our pencils down. It’s *the* test for our generations
and population is part of the answer.