An Overview of Methods for Estimating Urban Populations

Global Population Trends
implications and consequences
Paul Sutton
[email protected]
Department of Geography
University of Denver
Coming to grips with demographic history
Human Population Milestones
human population reaches
human population reaches
human population reaches
human population reaches
human population reaches
human population reaches
1 Billion
2 Billion
3 Billion
4 Billion
5 Billion
6 Billion
My father was born in 1926. Of these 6 milestones he saw
The world reach 2, 3, 4, 5, 6 and maybe 7 Billion
(6 of the 7 milestones in a single human lifetime)
The Graphical History of Human Population Growth
“Human beings – mammals of the 50 kilogram weight class and members of a group, the
primates, otherwise noted for scarcity – have become a hundred times more numerous than
any other land animal of comparable size in the history of life. By every conceivable measure,
humanity is ecologically abnormal. Our species appropriates between 20 and 40 per cent of the
solar energy captured in organic material by land plants. There is no way that we can draw upon
the resources of the planet to such a degree without drastically reducing the state of most other
E.O. Wilson’s book: “The Diversity of Life”
Basic Contemporary Population Reality
Some Introductory Questions:
~6.8 Billion
What is the annual Percentage Growth rate of the Planet? ~1.2%
1) How many people live on the Earth Right now?
3) If this rate remained constant, how long would it take for the
Earth’s population to double? (the rule of 69) ~58 Years
4) How many people are added to the Earth’s Population:
Every Year? ~80,000,000
Every Day?____________
Every Hour?__________
Every Second?__________
5) How many abortions happen every year?
What’s in store for future populations?
Is this graph possible?
What does zero population growth mean?
What does a sustainable economy look like?
What does the graph imply about total population?
Population Growth Rates are
going down but ……
Global rate over 2% in the early 1960’s
Global rate has dropped to ~1.2% today.
1.2% of 7 billion is: 84 million per year (today)
Whereas …
2.2% of 3 billion is: 66 million per year. (1960)
Did the 2005 Tsunami in Indonesia cause
negative growth in the global population?
Questions about Carrying
Capacity must be asked
The global human population that the earth can sustain indefinitely
• Most estimates of the world’s carrying capacity are in
the range of 4-15 billion people (how are they made?)
• In your lifetime, the earth already has, or soon will,
reach carrying capacity
• Population growth is THE major contributor to
concerns about Energy Supply, Housing Shortages,
Hunger, and Environmental Degradation…..
Inter-related Problems
• Population growth
puts stresses on
systems in interrelated ways. Think
of Food, Water, and
Energy. Think of
methanol in gasoline.
Corn as food becomes
corn as fuel. More
SUVs or more
The following slides describe 16 dimensions of the population problem
(adapted from World Watch paper #143)
1) Grain Production & Population
2) Fresh Water Supplies & Population
• Many rivers are dry or almost dry when they
reach the sea (Colorado, Yellow River, Nile)
• Many aquifers are being ‘mined’ for water.
• “As the growing demand for water collides with the
limits of supply, countries typically satisfy rising urban
and residential demands by diverting water from
irrigation. They then import grain to offset the loss of
irrigation water. Since it takes at least 1,000 tons of
water to produce a ton of grain.”
3) Biodiversity and Population
In the half a billion years of complex life, geology reveals five mass
extinctions. All were caused by the smash of big extraterrestrial bodies into
Earth or by stupendous geological forces. Biologists and conservationists call
today’s extinction the Sixth Great Extinction in light of its magnitude. This
extinction stands apart, though, because cosmic or geological forces do not
cause it. It has a biological cause. One species. Us.
Homo sapiens.
Due to its cause, and heeding our moral compass and sense of justice, perhaps
we should NOT call today’s ecological crisis the “Sixth Mass Extinction.”
Rather, we perhaps should call it the First Mass Murder of Life.
Never before has a single species escaped out of the confines of its ecosystems
to become a global, geological force and then to spread across Earth to
almost every ecosystem, and then remake and in many cases waste those
ecosystems. Never before has a single species consumed so much of the rest of
life into itself. Factoid: Homo Sapiens consumes 40% of NPP.
4) Climate Change and Population
The now famous CO2 graph
(global averages over time)
A map of the driving force
5) Oceanic Fish Catch and Population
Note: These declines are DESPITE vastly improved technology
• Source: The encyclopedia of the earth
6) Jobs and Population Growth
From article by Heidi Shierholz at Economic Policy Institute
Are we supposed to expect 10% unemployment now?
• Did the Black Plague cause the Renaissance?
7) Cropland and Population Growth
In October of 2009 the United Nations Food and Agriculture Organization held a high
level expert forum titled “How To Feed The World in 2050”
( ). The forum reviewed projections of
population and economic growth to the year 2050. Population numbers are expected to
rise to 9 billion by 2050, with 70% of the population living in urban areas. Incomes are
expected to continue to rise, leading to more protein consumption. It is also anticipated
that there will be growth in the use of crops for biofuels. Based on these projections the
forum members came to the following conclusions :
The 2050 demand for food and agricultural products will rise by 70% compared to 2009.
To meet this demand, 70 million hectares of new cropland will be needed.
50 million hectares of cropland will be lost in developed countries, primarily due to urbanization.
• Big Key Point: Growth in Population and Standard
of Living will require a DOUBLING of Global
agricultural land area by 2050 – Really ?
8) Forests and Population Growth
Population growth (Blue)
Forest Loss (Red) in major
World regions 1990 to Present
Deforestation in the Amazon
Is visible from Space
9) Housing and Population Growth
Pictures are worth 1,000 words
What do you think the water and sewer systems are like in the world
Right now? Add 3 Billion people by 2050. Will they get better?
Please tell us how?
10) Energy and Population Growth
Food production has been
Dependent on Oil Energy.
Future water production via
Desalinization will require
Lots of energy.
Oil is going away.
Population growth continues.
Facts of Discovery and production
to the year 2000
How related do you think the oil
Production curve and the population
Growth rate curve really are?
Scary rhetorical figure?
11) Urbanization and Population Growth
New World Order
In 1950 there was just one city with a
population of more than ten millionNew York. In 2015 there will be 21,
and the number of urban areas with
population between five and ten
million will shoot from 7 to 37. This
growth will occur mainly in
developing countries, those least
equipped to provide transportation,
housing, water, and sewers. Asia and
Africa, now more than 2/3 rural, will
be half urban by 2025. Never have
urban populations expanded so fast.
“Humanity has not been down this
road before”, write urbanists Peter
Hall and Ulrich Pfeiffer. “there are
no precedents, no guideposts”
Image Taken from National Geographic Magazine
Special issue on Cities of the World
12) Natural Recreation Areas and
Population Growth
Here in the U.S. we have to
Reserve campsites and often
Deal with crowding in our
National Parks. In other
Countries people harvest
Plants and animals out of their
‘protected’ areas for their own
Ahhh… The serenity of being back to
Nature at Yellowstone NP……..
13) Education and Population Growth
Even here in the United States
(arguably the wealthiest nation
in the world) we can’t seem to
maintain an effective education
Imagine trying to establish one
in a poor developing country
with A rapidly growing
14) Waste and Population Growth
We have created massive
Oceanic patches of garbage
That we were until recently
Unaware of. The atmosphere
Is hosting our waste CO2 with
Potentially devastating
Great Pacific Plastic Garbage Gyre (above)
Consequences. The waste we
Do deal with going into landfills
And sewage systems is getting
Increasingly expensive to handle.
How will this get better with
3 billion more people in the next
40 years?
Other oceanic garbage gyres
15) Meat and Population Growth
Global carrying Capacity is
Higher if we all become
Increasing meat Consumption
Accelerates extensification of
Agricultural land.
Over 1/3 of all grain goes to
Feeding poultry and livestock.
Do YOU want to become a vegetarian to
make room for a larger population?
16) Income and Population Growth
Are there limits to growth?
Is our global economy outgrowing our global ecosystems
Ability to support it?
To what extent does ‘Zero Sum Game’ apply to human life and
Resources on the earth?
What happened after the Black Plague?
(e.g. when population declined)
Rising Wages
Land Reform
Technological Innovation
Higher Incomes
Overpopulation – Talk about it
Peter Alcorn on the world in 2200 (TED Talk)
Beneficial Economic Effects of the U.N.’s projected declining global population
Predicts the future will be better then. But skips over why the world’s global population
Will drop. You could make the same argument about how much better it is on Easter
Island since the collapse of its population. The transition was no fun.
“If we can make it through the next 150 years…….”
Well that’s the hard question isn’t it. How to make it through the next 150 years.
Those are the years you and I and our children will have to live through. I don’t
Want them to look like the Plague.
Talking about and then addressing the very real and fundamental problems of
Population growth is essential to avoid that.
Overpopulation is a taboo topic of conversation. End the taboo.
A better talk on Population Challenges by Hans Rosling (TED talk)
Policy Observation
Carbon Sequestration and Population Growth
The $7 cost of abating a ton of CO2 using family planning
compares with $24 for wind power, $51 for solar,
$57-83 for coal plants with carbon capture and storage,
$92 for plug-in hybrid vehicles and $131 for electric vehicles
The “Tech” solutions to Carbon Sequestration do nothing for
Agricultural land expansion, biodiversity preservation, urbanization
Problems, water shortages, etc.
The family planning approach helps in all dimensions.
What are we waiting for?

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