This is a slightly updated set of Urban Ecology slides that I am sharing with my Soil and Water Conservation class

1. Why should we care about cities?
http://exploredia.com/world-population-2011/

2. Throughout human history, most humans have NOT lived in cities.

3. In 1800, only 3 percent of the global population lived in
cities and only 1 city had more than 1 million people.
http://worldkit.org/population/

4. By 1900, ~14 percent of the global population lived in
cities and ~ 15 cities had > 1 million people.
http://worldkit.org/population/

5. In 1950, 30 percent of the world's population lived in
cities and the number of cities with over 1 million
people had grown to 83.
http://worldkit.org/population/

6. In 2008, for the first time, the world's population was
evenly split between urban and rural areas and there were
more than 400 cities with over 1 million people.

7. Distribution of the world’s urbanites in 2008
53% lived in cities with < 500,000 people
38% lived in cities with > 1 million people.
15% lived in cities > 5 million people
http://www.prb.org/Educators/TeachersGuides/HumanPopulation/Urbanization.aspx

8. (Grimm et al., 2008)

9. Today, 74 % of people in industrialized
countries live in urban areas and 44
percent of people in developing countries
live in urban areas.
It is expected that world population will
be 70 percent urban by 2050.
http://www.prb.org/Educators/TeachersGuides/HumanPopulation/Urbanization.aspx

10. Megacities in 2002

11. There are currently ~ 26 megacities with more than 10 million people!

12. http://en.wikipedia.org/wiki/Megacity

13. http://www.nationsonline.org/oneworld/most_pop_cities_usa.htm

14. 1) NY City
3) Chicago metro area metro area
9.4 million 18.7 million
Seattle 4) Philadelphia
metro area
5.8 million
2) LA metro Puerto
area 12.9 Rico
million Honolulu
5) Dallas-Fort
Worth metro area
5.8 million
Only 8 % of Americans live in 0 100 10,000
people per sq. mile
cities with populations > 1 million
http://i.bnet.com/blogs/usa-population-time-2006-joe-lertola-edit.jpg

15. WHICH ARE THE LARGEST? WHY PUBLISHED POPULATIONS
FOR MAJOR WORLD URBAN AREAS VARY SO GREATLY
RL Forstall, RP Greene and JB Pick
Abstract:
Lists of the world’s largest urban areas according to
population size are surprisingly inconsistent in standard
reference sources. These even disagree about which area is
the world’s largest. In this paper we first review the
differences found in the population reporting of the twenty
largest world urban areas by several unofficial sources and by
the United Nations. We then demonstrate that variations in
the populations and rankings stem primarily from differences
in concepts and definitions, not from bad census counts or
lack of basic information about the individual urban areas.
http://www.uic.edu/cuppa/cityfutures/papers/webpapers/cityfuturespapers/session3_4/3_4whicharethe.pdf

16. 3 terms used to define urban areas
city proper = an incorporated administrative district
with specific boundaries beyond which urban
development has often overflowed
urban agglomeration = a central city (or cities)
surrounded by continuous urban areas
metropolitan area = a large urban nucleus
together with adjacent areas with a high degree of
economic and social integration

17. http://www.uic.edu/cuppa/cityfutures/papers/webpapers/cityfuturespapers/session3_4/3_4whicharethe.pdf

18. More than 95% of the net increase in global population
during the 21st century is projected to occur in cities in
developing countries
http://maps.grida.no/go/graphic/urban_population_status_and_trends

19. Almost 40 percent of city dwellers in developing
countries (~ 1 billion people) live in slums

20. Variation in urban population density

21. If all the people on planet Earth lived in one city,
http://marcgawley.com/
how large would that city be?

22. Urban areas depend on the productive and
assimilative capacities of ecosystems well
beyond their formal boundaries, i.e., land tens
to hundreds of times larger than the area a
city physically occupies is required to produce
the energy, material goods, and nonmaterial
services (including waste absorption) that
sustain the city.
(Grimm et al., 2008)

23. Human appropriation of net primary production (NPP), as a per cent
of total NPP. The local consumption rate of NPP is compared to the
local production rate of NPP. Highly populated areas (yellow and red)
consume up to 300 times their local production.
Source: Imhoff and others 2004
http://www.unep.org/yearbook/2004/010b.htm

24. Historians speculate that excessive resource
demands (especially by elites) led to
degradation of surrounding landscapes and
eventual collapse of many ancient cities.
Angkor Babylon
Tikal

25. During the 18th and 19th centuries demand by European
cities for wood deforested colonial lands and more
recently, demand for beef by Western cities has
transformed New World tropical rainforests into pastures.

27. Almost 900 of these giant stone sculptures were carved
and transported - some weighing over 80 tons
Pollen analysis has now established that Easter Island
was almost totally forested until 1200 CE. The tree
pollen disappeared from the record by 1650, and the
statues stopped being made around that time
http://www.nomadicminds.org/blogs/2010/06
/

28. The unprecedented rates of urban population
growth over the past century have occurred
on <3% of the global terrestrial surface, yet
the impact has been global, with 78% of
carbon emissions, 60% of residential water
use, and 76% of wood used for industrial
purposes attributed to cities.
Land use change directly associated with
building cities as well as supporting the
demands of urban populations drives many
other types of environmental change.
(Grimm et al., 2008)

29. In China alone, 300 million rural people are likely move to
cities in the next few decades transforming their home
landscapes and driving onward unprecedented rates of
urban construction. .
Shortages of construction materials such as metals, coal,
cement, and timber are likely to constrain China’s
urbanization in the long term, and exert pressure on urban
infrastructure development worldwide
(Grimm et al., 2008)

30. For most of the 20th century, most ecologists ignored
urban areas with the result that ecological knowledge
contributed little to solving urban environmental
problems.
Recently, however, ecologists have begun collaborating
with other scientists, planners, and engineers to
understand and even redesign urban ecosystems.
With the advent 10 years ago of National Science
Foundation–funded urban research programs in the
United States, urban ecology also has begun to change
the discipline of ecology.
(Grimm et al., 2008)

31. http://caplter.asu.edu/

32. Residential landscapes are a critical ecological feature of the urban
ecosystem because they are widespread and are made up of highly-
designed and managed combinations of plants (e.g. landscaping)
and animals (e.g. pets). As Phoenix has urbanized, native Sonoran
desert ecosystems have been replaced by an “urban oasis” that
includes both lush, watered lawns and carefully-managed desert-like
landscapes. CAP’s socio-ecological research has delved into the
household decision-making, perceptions, and priorities that result in
particular residential landscapes.

33. ~32 million acres of lawn!

34. Some stats to consider
Residential lawns occupy ~ 20 million acres in the US.
US lawn care industry annual revenue exceeds $40 billion.
> $ 5 billion is spent on fertilizer for U.S. lawns.
A typical power lawnmower pollutes as much in one hour as driving
an automobile for 20 miles.
60 to 70 thousand severe accidents, some fatal, result from
lawnmower use, as well as significant damage to human hearing.
~ 70 million pounds of pesticides are used each year on lawns

36. Bring written answers to the following questions to class tomorrow.
1) The review of Gimme Green at the following link:
http://www.gimmegreen.com/media%20articles/Newsleader.htm
includes an interesting quote towards the end – “Some documentaries “fall on the
preachy side (and) turn people off… Others antagonize and attempt to make people
look foolish. That’s not my style at all”. What do you think? Does the film avoid
getting preachy? Does the film avoid antagonizing/making people look foolish?
2) Overall, do you think this review does a good job of capturing the essence of the
film? Discuss your answer.
3) Spend a little time looking at the Gimme Green website http://www.gimmegreen.com/
Describe a few interesting things you learned specifically from the website.

37. 4) Did you think the film was humorous? If so, comment on some of the
more humorous moments in the film.
5) Do you know anyone who is obsessed with their lawn or at least is very
committed to maintaining a nice looking lawn? If so, briefly discuss this
person's relationship with their lawn and how you think they would
respond if they watched the film Gimme Green. If not, describe how you
think one of the specific people interviewed in the film would react to the
film.
6) Considering the negative environmental impact of intensively managed
lawns, do you think there should be public policies to discourage lawns or
encourage alternatives to lawns?
7) Has your perspective on lawns changed at all as a result of watching
the film? Explain.

38. What is urban metabolism?
A key concept within the discipline of urban ecology is
urban metabolism which compares the flows of
energy and materials in and out of cities and the
transformation and accumulation of energy and
materials within cities to biological metabolism.
Some scientists debate the appropriateness of the
metabolism analogy but interest in urban metabolism
has led to informative analysis of long-term trends in
the flow of energy, paper, plastics, metals and
food stuffs in, out and within cities.

40. Fresh water consumption
Fresh water consumption and waste water production by cities
waste water production
150
(gal/day/person)
75
The Changing Metabolism of Cities (Kennedy et al., 2007)

41. Throughout history, cities have sprung up along rivers,
because of the available water.
Within cities, water is intricately linked to not only
domestic use but also industrial processes,
transportation, sanitation, and natural disasters (floods,
hurricanes, and tsunamis). Thus, humans have
modified hydrosystems to meet a large array of often
conflicting goals.
Designed or altered streams, rivers, flood channels,
canals and other hydrosystems serving urban areas
neither replicate the aquatic ecosystems they replace
nor preserve the ecosystem services lost.

42. Stormwater is conveyed separately from sewage in cities
with relatively new infrastructure but are mixed in older
European and American cities, creating acute pollution
events every time large rainfall events occur.
Low flow-discharge from cities also contribute to
pollution downstream in the form of automotive
chemicals, pesticides, pet wastes, persistent
organic pollutants...

43. How much gasoline do you consume per day?
(Gigajoules/year/person)
1 gallon of gasoline per day
Adapted from (Newman and Kenworthy, 1991)

44. Many factors influence the metabolism of cities
Sprawled, low-density cities have higher per capita
transportation energy requirements than compact cities.
Cities with interior continental climates expend more energy
on winter heating and summer cooling than those with more
temperate climates. Application of technology, appropriate
use of vegetation and the costs of energy influence energy
consumption.
Public policies (e.g., building codes and recycling programs)
and social attitudes impact material and energy flows.
Lastly, the age of a city, its overall infrastructure, and its stage
of industrial development impact its urban metabolism.

47. The City Solution
Why cities are the best cure for our planet's growing pains
December 2011
Seoul, Korea

48. Large cities are concentrations of human
ingenuity and efficiency and generally require
far fewer resources on a per capita basis than
small towns or rural areas.

50. “Possibly the most exciting book on ecology or environmentalism
to be published in several years, David Owen's Green Metropolis:
Why Living Smaller, Living Closer, and Driving Less Are the Keys to
Sustainability challenges the conventional wisdom of the
environmental movement and uses Ney York City (not Portland
Oregon or rural Vermont) as a model of true sustainability.
Owen's seemingly counter-intuitive argument is supported by the
data: New Yorkers have the lowest per capita energy consumption
and smallest per capita carbon footprint of anyone in the United
States. The key to this isn't that New Yorkers are morally superior
or ideologically predisposed to environmentalism, but simply the
structure of the city: “Manhattan's density is approximately
67,000 people per square mile, or more than eight hundred times
that of the nation as a whole and roughly thirty times that of Los
Angeles.”
http://nefac.net/greenmetro

51. City dwellers tread more lightly in many ways,
David Owen explains in Green Metropolis. Their
roads, sewers, and power lines are shorter and so
use fewer resources. Their apartments take less
energy to heat, cool, and light than do houses.
Most important, people in dense cities drive less.
Their destinations are close enough to walk to, and
enough people are going to the same places to
make public transit practical. In cities like New
York, per capita energy use and carbon emissions
are much lower than the national average.

52. The high cost of suburban living is subsidized by the
rest of the population in the form of highway
construction, extension of water and sewer lines, and
running electricity to new subdivisions at taxpayer
expense.
If the true cost of sprawl were borne by developers
and suburban home-buyers, in the form of increased
housing prices, higher property taxes, infrastructure
recovery costs included in utility bills, and tolls placed
on highways used primarily by commuters, the
suburbs would look much less attractive.

56. City Hall, Chicago

59. With an ever-increasing fraction of humans living in cities,
encounters with urban nature have supplanted experiences
with natural biodiversity for many people.
Positive human experiences with nonnative, global
“homogenizers”, such as pigeons, may be essential for
convincing urbanites of the importance of conserving
global biodiversity.

60. If what you value most is nature, cities look
like concentrated piles of damage—until
you consider the alternative, which is
spreading the damage.
Cities allow half of humanity to live on
around 4 percent of the arable land, leaving
more space for nature.