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BIO 141 Last Lecture John Byrd, Cynthia Dott


By 2050 Africa will grow from 900 million to almost 2 billion. ... Andorra 83.5 Years. Japan 81.25. US 77.85. Swaziland 32.62. Botswana 33.74 ... – PowerPoint PPT presentation

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Title: BIO 141 Last Lecture John Byrd, Cynthia Dott

BIO 141 Last Lecture John Byrd, Cynthia Dott
Dick Grossman
  • Review and Final Exam Preparation

  • World population - 6.6 billion - increasing by 77
    million per year.
  • In 2050 world population will be 9.4 billion.
  • US population 300 million.
  • Most growth in developing countries. By 2050
    Africa will grow from 900 million to almost 2
  • Europes population will fall from 730 million to
    660 million in 2050.

US Population Challenges
  • Population problem in most industrialized
    countries is an aging population that will
    require support by decreased number of workers.
  • In the US Social Security and Medicare will
    require more outlays (or smaller distributions)
    as Baby Boomers retire.
  • By 2030 the ratio of working age people to those
    sixty-five and older will fall from five-to-one
    to about three-to-one.

Inter-generational Equity
  • By saving more today, we can reduce the future
    burden of demographic change. Saving more
    requires that we consume less or work more.
    Either case entails some sacrifice on the part of
    the current generation. We can mitigate the
    adverse effect of the aging population on future
    generations but only by foregoing consumption or
    leisure today.
  • Federal Reserve Board Chair, Ben S. Bernanke

Population Concepts
  • Total Fertility Rate (TFR)
  • The average number of children a woman will have
    during her childbearing years.
  • A TFR of about 2.1 implies no population growth.
  • TFR Niger 7.46 Hong Kong 0.95 US2.09 (all 2006

Population Momentum
  • Population momentum refers to the tendency of a
    population to continue to grow beyond the time
    when replacement levels of fertility are
    achieved. TFR for population stability is about

Infant Mortality Rate
  • IMR is the number of babies that die before their
    first birthday per 1,000 live births.
  • In the US infant mortality among African
    Americans in 2000 was 14.1 compared to the
    national average of 6.9.
  • Angola 185 US 6.4 Sweden 2.8

IMR and Water Quality
  • Water-related diseases are a growing human
    tragedy, killing more than 5 million people each
    year - 10 times the number of people killed in
    wars. Some 60 of all infant mortality worldwide
    is linked to infectious and parasitic diseases,
    most of them water-related.
  • In China, India and Indonesia, twice as many
    people die from diarrhoeal diseases as from
  • http//

Reasons for large families
  • Religion
  • Culture
  • Economics
  • Lack of contraception

Demographic Transition
Life Expectancy
  • Andorra 83.5 Years
  • Japan 81.25
  • US 77.85
  • Swaziland 32.62
  • Botswana 33.74

Population Poverty and the Environment
  • Hydrologic cycle - Global water circulates
  • Less than 1 of all water on Earth is available
    for plants and animals.
  • Conflicts over water.
  • Egypt, Sudan, Ethiopia - Nile River
  • Turkey, Iraq, Syria - Tigris-Euphrates River
  • US, states and Mexico - Colorado River

Water Scarcity
Scarcity Definitions
  • Physical water scarcity More than 75 of river
    flows are allocated to agriculture, industries or
    domestic purposes
  • Approaching physical water scarcity More than
    60 of river flows are allocated.
  • Economic water scarcity Water resources are
    abundant, but malnutrition exists.
  • Little or no water scarcity Abundant water
    resources relative to use. Less than 25 of water
    from rivers is withdrawn for human purposes.

  • The aggregate food supply in 2000 provided 3,800
    calories per person per day,
  • Roughly 1,100 calories were lost to spoilage,
    plate waste, and cooking and other losses,
    putting dietary intake of calories in 2000 at
    just under 2,700 calories per person per day.
  • (http//

Food Hunger
  • Even so, there are over 800 million malnourished
    people in the developing countries. In the
    developing world one out of every five persons
    does not have enough food to meet daily
  • A universal cause of hunger is dire poverty,
    sometimes worsened by war, political upheaval and
    natural disasters.

Producing More Food
  • Most improvements in food availability have been
    from local production
  • How can more food be made available?
  • Use more land - Best land being used
  • Use land more intensely - Risk is soil
  • Irrigate - Water scarcity could limit irrigation
  • Fertilize - Expensive
  • Higher yield varieties - Expensive, limited
    increases available

Climate Change
  • Greenhouse effect - much of the Suns energy
    penetrates the atmosphere and warms the Earths
  • Because of a wave length change most of this
    energy is trapped in the Earths atmosphere.
  • Without heat-trapping gases the Earth would be
    about 0 F.

The Main Greenhouse Gas
  • Carbon dioxide has had the greatest effect on
    changing the climate. During the 1980's humans
    released 5.5 billion tons of carbon dioxide into
    the atmosphere annually by burning fossil fuels
    (coal, oil, natural gas) for heat,
    transportation, and electricity. An additional
    1.6 billion tons was released from anthropogenic
    (human-induced) changes in land-use (i.e.
    clearing land for agriculture, pastures, etc.)
    mostly through deforestation in the tropics.

Rising Temperatures
  • The average surface temperature of the earth has
    increased by about 1F in the past century.
  • In 1816 atmospheric ash from a volcanic eruption
    in Southeast Asia decreased solar radiation
    reaching the earth's surface, lowering the global
    mean temperature by 1F. As a result, frost
    occurred in July in New England and crop failures
    occurred throughout the world. (Stommel et al.

Sea Level Rise
  • Increasing global temperatures causes the thermal
    expansion of sea water and the melting of icecaps
    which will result in rising sea level.
  • Sea level has risen 4 to 10 this century.
  • Sea level rise increases the vulnerability of
    coastal populations to flooding and causes land
    to be lost to erosion.
  • A 1 meter increase in sea level will be enough
    to flood 1 of Egypt, 6 of the Netherlands and
    17.5 of Bangladesh.

Intensification of the Hydrologic Cycle
  • Warming will likely result in an increase in the
    amount of water exchanged among the oceans,
    atmosphere, and land. Increasing rates of
    evaporation will likely result in drier soils. An
    accelerated hydrologic cycle means greater
    amounts of precipitation in some areas and will
    probably result in more frequent and severe
    droughts and floods.

Health Effects
  • Warming will reduce "killing" frosts. As a
    result, there will likely be an increase in the
    geographical range of vector-borne (e.g. mosquito
    carried) diseases such as malaria, dengue, yellow
    fever, and encephalitis.
  • Today, 45 of the world's population is within
    the malaria zone. With warming, there will be an
    additional 50 to 80 million cases of malaria
    worldwide, bringing 60 of world's people within
    the susceptible zone.

Effect on Eco-systems
  • Forests
  • Deserts
  • Glaciers and Icepacks
  • Mountain Regions
  • Lakes, Streams, Wetlands
  • Coastal Systems
  • Oceans
  • Fisheries

Food Production
  • Total global food production is not expected to
    change substantially, but production will
    probably change dramatically regionally.
  • Some areas will have increasing crop yields.
    Others will decline, especially in tropical and
    subtropical regions.
  • Developed countries may be able to adapt to these
    circumstances. Developing countries that
    currently struggle with these issues will suffer
    even more.

  • "..development that meets the needs of the
    present without compromising the ability of
    future generations to meet their own needs"
    Brundtland Report
  • Sustainability is equity over time ... think
    of it as extending the Golden rule through time
    .. Do unto future generations as you would have
    them do unto you. Robert Gilman

  • Leave the world better than you found it, take no
    more than you need, try not to harm life or the
    environment, make amends if you do. Paul Hawken
  • A sustainable society is one that lives within
    the self-perpetuating limits of its environment.
    That society is not a "no growth" society - it
    is, rather a society that recognizes the limits
    of growth and looks for alternative ways of
    growing. James Coomer

Fish Banks
  • Tragedy of the Commons - over use of an open
    access resource.
  • Other open access resources - atmosphere, rivers,
    aquifers, forests.
  • We almost all use the atmosphere to dispose of
    emissions from driving.

Sustainable Harvest
  • If the population is at an appropriate level
    sustainable harvest would be the catch that can
    be maintained forever. This is NOT equal to the
    reproduction rate.
  • Catching the number of fish equal to the number
    produced means a reduction in species biomass
    (older, larger fish are replaced by younger,
    smaller fish). There is also natural mortality
    contributing to the loss of fish, so the
    sustainable catch is always less than the
    reproduction rate.

Sustainable Harvest
  • If population is below the desired level then the
    optimal harvest rate is below the sustainable
    rate, which allows the population to grow. The
    optimal population depends on the carrying
    capacity of the eco-system
  • This applies to the target species. Must reduce
    by-catch (non-targeted species caught with
    targeted fish).

Fishery Depletion
  • A study published in November 2006 in the journal
    Science found that about one-third of all fishing
    stocks worldwide have collapsed (with a collapse
    being defined as a decline to less than 10 of
    their maximum observed abundance), and that if
    current trends continue all fish stocks worldwide
    will collapse within fifty years.
  • One solution to the tragedy of the commons is
    privatization via ITQs.

Non-renewable Resources
  • Sustainability in renewable resources is simple
    compared with non-renewable resources (e.g.
    energy, minerals). Non-renewable resources such
    as fossil fuels and minerals are created by very
    slow geological processes, so slow in human terms
    that their use diminishes the available stocks.

Peak Oil
  • There is growing evidence that global oil
    supplies will not continue to grow.
  • We also know demand is growing. India and China
    both have growing populations that want private
  • Economic growth depends on energy, so demand for
    oil is unlikely to decrease.

Post-Carbon World
  • Consider three questions as oil supplies
  • How will we transition to lower oil use?
  • What opportunities will the change create?
  • What personal decisions should consider oil use
    (House, job, etc.)?

Green Design Building
  • Buildings use significant amounts of energy,
    water and materials, and 1 producer of CO2
  • Thoughtful design and construction can reduce
    this demand.
  • It can also improve the interior health of the
    building for users.

Green Design
  • When 3 of the building costs have been spent
    about 80 of the total costs have been
  • The design phase is where savings (or waste) are
    built into the future of a building.
  • Careful design saves costs over the 30, 40 or 50
    year life of a building.

Types of Capital
  • Natural Capital Traditional natural resources,
    including minerals and natural assets.
  • Built Physical Capital Physical, produced
    assets that are assigned monetary value and
    traded in markets.
  • Human Capital The health, well-being, and
    productive potential of individuals.
  • Social Capital The status, functioning, and
    resilience of social institutions.

Sustainable Use
  • Maintain the net amount of natural, built, human,
    and social capital, to yield constant or
    increasing opportunities for satisfying human
    needs and wants generation after generation.
  • Lower consumption rates can extend the life of
    finite resources.
  • Technological improvements - more efficient use
    of minerals and/or the development of renewable
    substitutes - can help society achieve
    sustainable use of non-renewable resources.

  • We have been focusing on resources but
    sustainability has a human dimension too.
  • For example, wages need to be high enough for a
    person or family to maintain a stable, healthy
    household. There must be institutions that
    assure the security, safety, and education for

Liberal Arts Education
  • Education should help you address the big,
    important questions
  • What constitutes a good life?
  • What are our obligations to others - family,
    friends, future others and distant others?
  • What legacy do I want to leave?
  • How do I balance personal, family and community?

Where to from here?
  • The are significant challenges ahead, but there
    are also lots of smart people working on
  • Lots of examples of individual action making the
    world better.