BIO 141 Last Lecture John Byrd, Cynthia Dott

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BIO 141 Last LectureJohn Byrd, Cynthia Dott
Dick Grossman

• Review and Final Exam Preparation

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Population

• 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
  billion.
• Europes population will fall from 730 million to
  660 million in 2050.

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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.

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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

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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
  estimates)

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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
  2.1.

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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

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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
  HIV/AIDS.
• http//www.wateryear2003.org/

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Reasons for large families

• Religion
• Culture
• Economics
• Lack of contraception

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Demographic Transition
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Life Expectancy

• Andorra 83.5 Years
• Japan 81.25
• US 77.85
• Swaziland 32.62
• Botswana 33.74

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Population Poverty and the Environment
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Water

• Hydrologic cycle - Global water circulates
  constantly
• 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

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Water Scarcity
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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.

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Food

• 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//www.usda.gov/factbook/chapter2.htm)

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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
  requirements.
• A universal cause of hunger is dire poverty,
  sometimes worsened by war, political upheaval and
  natural disasters.

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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
  degradation
• Irrigate - Water scarcity could limit irrigation
• Fertilize - Expensive
• Higher yield varieties - Expensive, limited
  increases available

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Climate Change

• Greenhouse effect - much of the Suns energy
  penetrates the atmosphere and warms the Earths
  surface.
• 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.

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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.

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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.
  1979).

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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.

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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.

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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.

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Effect on Eco-systems

• Forests
• Deserts
• Glaciers and Icepacks
• Mountain Regions
• Lakes, Streams, Wetlands
• Coastal Systems
• Oceans
• Fisheries

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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.

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Sustainability

• "..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

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Sustainability

• 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

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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.

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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.

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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).

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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.

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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.

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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
  cars.
• Economic growth depends on energy, so demand for
  oil is unlikely to decrease.

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Post-Carbon World

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

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Green Design Building

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

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Green Design

• When 3 of the building costs have been spent
  about 80 of the total costs have been
  determined.
• 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.

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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.

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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.

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Sustainability

• 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
  citizens.

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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?

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Where to from here?

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