human interaction chapter 12. “sustainability” is a popular idea these days. what does...
TRANSCRIPT
• “Sustainability” is a popular idea these days.
• What does “sustainability” in the ecosystem mean?
• What does “sustainability” in human communities mean?
WORK
TOGETHER
The term “ecological footprint” means:
1 2 3 4
25% 25%25%25%1. The ecological
services of a natural area.
2. The complete bio-capacity of Earth.
3. The land and water area needed to sustain humans.
4. The risk of a species to extinction.
Natural Communities• Natural, self-renewing communities
share several features:
• Stable populations at or below carrying capacity
• Biological diversity
• Recycling of all raw materials
• Reliance on sustainable energy (solar)
Human Communities
• How well does our community score on each of these four points?
• Stable populations at or below carrying capacity
• Biological diversity
• Recycling of all raw materials
• Reliance on sustainable energy
Human PopulationDate
Technical andcultural advances
Industrial andmedicaladvances
Agricultural advances
123
Billions Time to addeach billion(years)All of humanhistory
1312131433
1804
201219991987197419601927
1
234567*
*projected bubo
nic
plag
ue
billi
ons
of p
eopl
e
2012*
1830
1975
1960
1930
1987
19992006
We know that human population is increasing exponentially. Our resources are not.
Poll: The human species:
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33% 33%33%
1. Is approaching carrying capacity.
2. Has overshot carrying capacity.
3. Can never reach carrying capacity.
0
time
Consequences of exceeding K.
K(original)
K(reduced)
Populationovershootscarryingcapacity;environmentis damaged.
Extremedamage;populationdies out.
Low damage;resources recover,population fluctuates.
High damage;carrying capacitypermanently lowered.
The problem is, we don’t know for sure where we are on this graph.
When resources are highly limited, most individuals have access to only a small share
of those resources.
developed countries
2006: 6.5 billion
popu
latio
n (b
illio
ns)
year
developing countries
Presently, populations in developing nations are increasing, while developed nations are
stabilizing.
Developing countries average: 1.4%
Wor
ld r
egio
ns
natural increase per year (percent)
Europe: –0.1%
N. America: 0.6%
Developed countries average: 0.3%
China: 0.6%
Asia (excluding China): 1.6%
Latin America/Caribbean: 1.6%
Africa: 2.2%
World average: 1.2%
Breakdown of population increases in different parts of the world.
femalemale
Population pyramids for Mexico
percent
Mexico 2007
femalemale
percent
Population pyramids for Sweden
Sweden 2007
High birth rates increase population,
but also provide many young people to
support their elderly relatives.
Low birth rates reduce or level off the population,
but leave less support for the aging segment of the
population.
U.S
. po
pula
tion
(in m
illio
ns)
year
Even with a modest 0.6%
increase in the population each year, the U.S.
shows exponential growth.
In which area of Earth is the human population growing the fastest?
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25% 25%25%25%
1. North America2. Europe3. Africa4. Asia
On which continent are natural resources being used the
fastest?
1 2 3 4
25% 25%25%25%
1. North America2. Europe3. Asia4. Africa
While populations in developed nations are increasing slowly,
individuals in developed nations use many times the amount of
resources as individuals in developing nations.
What happens if developing nations adopt the U.S. lifestyle?
In some countries, such as the United States, population control is a highly controversial
issue.
This group promotes zero
population growth, birth control, and
social justice as means to
improve society.
This group rejects birth control, believes people should have as many children as possible, and
supports the rights of the individual.
In some developing
nations, women’s education
programs have taught women to read, write, and
run small businesses.
Where women are educated and
most people have meaningful work, birth rates slow down and the quality of life
improves.
Growth curves for the human population show that our species is
experiencing:
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25% 25%25%25%
1. Logistic growth2. S-shaped growth3. Exponential
growth4. Declining growth
Age structure diagrams show that human population is declining in which part of the
world?
1 2 3 4 5
20% 20% 20%20%20%
1. China2. Latin America3. United States4. Africa5. Europe
Humans affect natural populations
• We are living in the middle of a mass-extinction event, and we are the cause.
• We humans change our environment to meet our needs for food, shelter, and other resources. In doing so, we impact other species dramatically.
• The larger our population gets, the faster we use up limited resources.
Extinction Risks
• Specialization and resource partitioning increase diversity.
• However, the tradeoff is that organisms become more vulnerable to extinction if the environment drastically changes.
Localized Distribution
• By living in a limited area, a population avoids competition with other populations.
• The risk is that a natural disaster will destroy the limited habitat.
The Devil’s Hole Pupfish lives in a single waterhole
in Nevada.
Overspecialization• Organisms that
have specialized feeding habits reduce competition with other species.
• If the limited food source goes extinct, so does the species feeding on it.
Fender’s Blue Butterfly feeds only on Kinkaid’s
Lupine.
Interactions• Isolation reduces
competition and predation.
• If a new predator or competitor is introduced, a formerly isolated species may be hunted or out-competed to extinction.
Many Hawai’ian birds were driven to extinction by introduced predators.
Habitat Loss
• The greatest cause of extinction is habitat loss.
• Organisms with highly specialized habitat needs may avoid competition, but risk extinction if their habitat is threatened.
Tropical rain forests are being logged at an alarming rate, mostly for grazing cattle.
“HIPPO” and Extinctions
• Humans activity can contribute greatly to species extinction.
• The acronym “HIPPO” can help us remember the major contributors to human-caused extinctions.
Habitat destruction
Humans plow up land for farms and
housing developments, strip soil from
mountains to mine minerals, damage
ocean bottoms with deep-water
nets, and cut down forests for wood products. All of
these are habitats for wildlife.
H
Invasive Species
Humans have introduced
species into areas where they have
no natural predators.
Without natural controls, the
invasive species overpopulate
rapidly, crowing out native species.
Kudzu – there’s a house under there.
Ivy
Purple Loosestrife
Starling
I
Pollution
Debris, oil spills, and toxic chemicals pollute
waterways, air, and soil. Pesticides and herbicides used on
farms, lawns gardens, and golf courses
contribute to local pollution.
P
Population
Human population has increased
exponentially and is still climbing.
Large populations need large amounts of
resources, but at the same time
occupy land that might otherwise have supplied
resources.
P
Overharvest
Ancient bison in North American may have been hunted to extinction. The dodo,
the passenger pigeon, and the
Great Auk have all gone extinct due to
overhunting.
O
Of the five HIPPO factors, which causes extinctions the fastest?
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20% 20% 20%20%20%
1. Habitat destruction
2. Invasive species3. Population
(human)4. Pollution5. Overharvest
So why don’t people…
• …simply stop polluting, reproducing excessively, and start using resources wisely?
• The “Tragedy of the Commons” scenario helps explain the human mindset that interferes with this “simple” solution.
Common Pool Resources
These are resource that:
1) are available in limited supply (either they do not renew, or
renew more slowly than they are being
used)
2) are openly available for use, and
3) it is costly to prevent people from using the resources.
When it comes to Common Pool
Resources:
It is in the community’s best
interest to control how the resource is used so that the resource will not be depleted and will be available
for all.
It is in the individual’s best interest to get as much of the resource
as possible.
Part of the problem is that nations all over the world have economies that rely on a linear system
of resource extraction and disposal. Our linear system relies on over-exploitation of common pool
resources.
Linear systems are not sustainable. Material
extraction MUST be tied to material recovery and re-
use, just like a natural ecosystem, to be
sustainable.
The current situation was no accident. In the
1950s, the U.S. made a deliberate move from
being a nation of producers to being a
nation of consumers in order to grow the
economy.
It has been estimated that if everyone in the world lived as people do in Western nations, we would need about 4 Earths to sustain us.
We don’t have these.We only
have this.
In 2013, Earth Overshoot Day fell on August 20 – the day when the
world has used as much of Earth’s resources as Earth can replace in
one year.
Victor Lebow, U.S. economist under Eisenhower.
This is the definition of “overshooting carrying
capacity.”
Is it hopeless?• Never in the history of the Earth has
one species had such an enormous effect.
• However, unlike other organisms, humans have choices about how they live and how they use resources.
• Our past decisions have gotten us into this mess. Our future decisions can solve the problem.
Lessons from Nature• Remember the features of a
renewable, self-sustaining natural community:
• Stable populations at or below carrying capacity
• Biological diversity
• Recycling of all raw materials
• Reliance on sustainable energy (solar)
Stable populations at or below carrying capacity
Humans, unlike other organisms, have the
ability to choose whether to reproduce or not. Some societies have
created laws to regulate populations. Others have relied on incentives, or have left the issue to
individual choice.
The issue becomes complex if a society depends on a large
number of young people to support the aged.
Okay, not like this.
What are some
unexpected effects of
small families?
Biological diversity
Preserving biological diversity in nature, in agriculture, and even
in our human communities is
becoming increasingly important.
Ecosystem services
Indirect, beneficial services• maintaining soil fertility• pollination• seed dispersal• waste decomposition• regulation of local climate• flood control• erosion control• pollution control• pest control• wildlife habitat• repository of genes
Directly used substances• food plants and animals• building materials• fiber and fabric materials• fuel• medicinal plants• oxygen replenishment
“Ecosystem services” are direct and indirect benefits humans receive from the
environment.
Natural rivers meander, creating a richly diverse wetland ecosystem.
Humans also benefit indirectly from intact, diverse ecosystems.
Channelizing rivers, reducing wetlands, and
cutting down trees along rivers changes the
ecosystem.
Loss of wetland diversity means loss of species. Sediments that would be deposited along the
river system and in islands around the
mouth of the river flows straight out to sea.
New Orleans was once protected by
the many islands in the Mississippi
Delta.
Much of the sediment that built those islands now
runs out to the sea. The islands have
eroded, leaving less protection against
hurricanes.
The term “ecosystem services” refers to:
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33% 33%33%
1. Direct and indirect benefits humans receive from the ecosystem.
2. How the ecosystem supplies our needs even when we extract resources at a high rate.
3. When humans do service projects to help restore ecosystems.
YellowstoneNational Park
On a large scale, National Parks, the wildlife refuge system, and public lands can contribute to the preservation of habitat and biodiversity.
transitionarea
Allows developments andtourism, as well as sustainablefishing, forestry and agriculture.
Allows experimental research,education, training, tourism,and low impact development.
Protected; may allowanimal monitoring andlow impact development.core
reserve
bufferzone
Biologists are studying how biological reserves can co-exist with human communities and
allow for multiple uses.
buffer zones
core reserve
core reserve
corridors
smallreserve
Connecting reserves with
wildlife corridors vastly increases
the value of individual reserves.
Animals can make use of a much larger area of land,
which benefits top carnivores that need large
territories.
Wildlife preserves in our current Wildlife Refuge system can be
considered:
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1. Corridors2. Core reserves3. Buffer zones
Routes that are maintained between preserved habitat are
called:
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1. Core zones2. Preserves3. Corridors4. Transits
Modern agriculture relies on vast monocultures of crop plants; the exact opposite of diversity. Monocultures are easier to harvest, but more vulnerable to
diseases and pests than mixed crops.
Sustainable agricultural practices help preserve topsoil, reduce the need for pesticides and
fertilizers, and can help support natural diversity as well.
Most sustainable agriculture is currently practiced on a small scale, but sustainably-
grown food can be found at farmer’s markets, “U-pick” farms, and from Community Supported
Agriculture (CSA) farms.
Permaculture and mixed-crop
agriculture supports a diverse soil food web,
which supports the crops. These methods
tend to be more labor-intensive.
A good place to buy sustainably grown food is:
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25% 25%25%25%
1. McDonald’s2. A major grocery
store3. A farmer’s market4. A mall
Recycling of all raw materials
In nature, all materials are
recycled. Humans can also recycle raw materials. Making new products from recycled materials
uses much less energy than making products from raw
materials from nature. BUT
recycling only works if there is a market
for recycled products.
Besides recycling to conserve natural
resources, reusing items, repairing items, and
reducing overall consumption are
important: Reduce, Reuse, Repair, then
Recycle.
“Use it up, wear it out, make it do, or do
without”
Not buying stuff in the first place helps reduce material consumption and resource over-exploitation. When you shop for gifts or are thinking of what to do
with the weekend, think of “doing” rather than “consuming.”
Movie or concert tickets
Zoo or museum memberships
Take someone outdoors and do something fun.
Help someone with their cleaning or
gardening.
Reliance on sustainable energy
Wind, solar, and geothermal energy are available from nature in unlimited supply. Using these in a sustainable way means developing energy-harvesting methods that are
efficient, cost-effective, have a low
impact in nature, and produce far
more energy than the energy required
to manufacture them.
New material technologies make alternative energy more reliable, accessible, and feasible. Solar glass and roof tiles, for example, integrate solar energy
collection into building design, turning entire structures into electricity generators.
And hey… Solar freakin’ roadways!
Real change requires more than just recycling your pop cans. Real change requires a change in
thinking – from “More is better” to “Better is better.” Better stuff rather than more stuff.
Better energy sources rather than more energy use. Better, more active living rather than more
shopping.
What can I do?You may hear: “It’s impossible to be a ‘locavore’ and eat only locally-grown
food. Give it up and just eat ‘regular’
food.”
But you can think, “I can eat some
locally-grown food. I can commit to
buying a pound of produce each week
at the farmer’s market.”
You may hear: “Organic food and recycled products are too expensive. You should save
money.”
But you can think, “I can save money lots of ways. And I
can buy some organic food and
recycled products.”
You may think: “I live in an
apartment. There’s no way I can install solar panels and go
solar.”
But you can think: “But hey, here’s this really
cool crowd-funded project for a green
company I’m interested in.”
You may hear: “Money talks.
Lobbyists have the money, and
politicians listen to them.”
But you can think: “I can write to my representatives, and join a group working on an
issue, until they DO hear us.”
There is always something you can do, no matter how small.
Lots of small actions add up to a big effect.
Do what you can, with what you have, where
you are, right now.
Jane Goodall
Jane Goodall makes the point that to save the environment, we must also help the people who
depend on that environment.
Jane Goodall talk on the TED site
• Discuss and list specific ways in which your community contributes to:
• Preservation of biodiversity
• Recycling materials (also, Reduce, Reuse, Repair)
• Using renewable energy
• Which of these have you participated in?
WORK
TOGETHER
Recap• Humans as a species have a huge
and devastating effect on biodiversity worldwide.
• The “Tragedy of the Commons” scenario pits long-term benefits to the community against short-term benefits to the individual.
• Humans can make conscious choices. We can choose to contribute or not contribute to environmental destruction.