Ecology and the State: a global
lecture notes for International Studies
instructor. H. D. Maher Jr.
An absolutely huge topic!
study of interrelationships between organisms and their environment."
What makes us distinctly 'human', differentiates
us from other organisms?
Earth system science:
attempt to understand the mechanics and history of the earth as
a complex system. Renewed focus on because of the question whether
humanity through its collective action is changing the system.
Major components of the earth:
of renewed interest because of global climate change.
surface waters, critical component less is known about.
glaciers, represent a significant fraction of earth's system,
critical linkages with other components.
- biomes: (very large terrestrial ecosystems)
tropical rain forest, confierous forest, grasslands, savanna,
desert, tundra, estuaries, reefs, kelp forest, hydrothermal vents
- Gaia hypothesis
from the surface on down plate tectonics as a major framework.
- the hydrosphere and biosphere extend well
down into the lithosphere.
How can we attempt to understand complex
and open systems such as these?
- devising framework conceptual models of linkages
often known as cycles:
- hydrologic cycle.
- rock cycle: closed vs. open system models
- carbon cycle.
- food chain.
- components: reservoirs, transfer processes,
volumes, residence times,
- importance of feedback loops, and non-linear
- computer modeling.
- remote sensing and Geographic Information
- parallel processing.
- technology makes new science possible.
- collaborative science.
- mathematics of chaos, fractals and fuzzy
logic (new conceptual perspectives):
- initial conditions sensitivity: small change
leads to big long-term impact due to positive feedback loops.
- simple equations can generate very complex
- how do we deal with uncertainty? Partial
Population dynamics and ecologic
What is the significance of the human population
history and future from an ecologic and environmental perspective?
- determines resources use/depletion history.
- major factor in pollutant volume.
- determinant in disease vectors and spread.
- strong influence on ecosystem disruption.
- determines magnitude of fatalities and property
loss in natural disasters as influences population density.
What other populations are we interested in,
- insect populations (locust swarms).
- algal populations (toxic blooms, ecosystem
- fish (important food resource).
- most populations if understand the importance
of ecosystems and biodiversity.
- biodiversity: tool kit, the range of possibleof
responses to change.
Mathematical modeling of unrestrained
A specific case of doubling every generation. Take the case where every couple has 4 children which
survive to parenthood and repeat their parents history, a doubling
of population every generation. this would result in a sequence
like: 2 -> 4 -> 8 -> 16 -> 32 -> 64 -> 128 ->
256 -> 516 -> 1032 -> 2064 -> 4128 ...... The general
formula is y=2**t , where t is the number of generations
(in years the= average age of parent). This produces a J shape
curve, and the number 2 can be considered as a growth constant.
The general continuous case: We can describe an increment of growth with the following
sentence: population growth (N) = # of reproducing units (N(i))
* growth constant (k) * time increment (t). The shorthand for
this is below
N = N(i) * k * t
If you integrate then this changes into:
N(t) = N(0)* (e ** (k't )) or ln Nt = ln No + k't
where e=2.71 , where ln is the natural log
(base e), N(0)=initial population at time 0, N(t) = population
after time t. k' is a different growth rate. You can use this
equation in plug and chug mode to predict unrestrained constant
growth rate population histories (yet consider how likely is such
a history to occur?).
Extrapolating present growth rate - how long before there is
1 person for every square meter of long on the the earth?
Reiterative or incremental description. For successive generations imagine a series of numbers:
N(0) - N(1) - N(2) - N(3) - N(4) - N(5) - N(6) ...- N(n). If N(n)
is the population at present somewhere throughout this history,
then the population in the next cycle (generation), N(n+1), is
given by: N(n+1)=B*N(n) , where B is the equivalent of
k, a growth constant. Notice by the way that there is no reason
why B can't change with time.
Growth with a restraint term and
this way to chaos.
What will happen as the population begins to
reach a maximum population possible (N(max)) as determined by
the carrying capacity of the system? The growth constant must
decline in value. Verhulst in 1845 came up with
this equation for this situation:
N(n+1)=B*N(n)*(1- N(n)/N(max)) .
B is a inherent growth factor (reproduction
rate when restraining factors are not significant). How does the
last term behave as you approach or move away from N(max)? Simple
rearrangement of the forumula may better show this behavior.
N(n+1)=B'*N(n) , where B'=B*(1- N(n)/N(max))
In this formula the growth 'constant' actually
varies with time depending on how close or far away it is from
some maximum carrying capacity populations.
Summary of equation behavior:
- at low values you reach a steady equilibrium.
- at intermediate values the population regularly
fluctuates between two, then four, then eight levels.
- at high values (>3.5) the population fluctuates
- above 5 and the population can go extinct.
- exploring the equation using Excel.
Can you think of some species whose populations
show chaotic and/or large fluctations, and whether their inherent
growth rate is high or low? Remember that this is a model,
and if it has a sound theoretical basis it informs of possibilities,
Populations that show dramatic fluctuations:
insects, lemmings, algal blooms, rabbits in Australia.
The lesson is simply in how such systems can
behave, and that small differences can have big long term results.
causes changes in growth 'constant', and also determines global
- medical and agricultural technology, disease,
environmental toxins, warfare, behavior, space availability,
change in critical resource base (food, water, energy).
- Now trying ranking them in order of likely
- Bongaarts (1994) - perhaps possible to feed
10 billion people in 2050. But if doubling time 50 years how
about in 2100?
Global scale ongoing ecologic/environmental
Some examples of ongoing global scale changes.
- deforestation (mainly rainforests).
- desertification and salinization.
- ozone depletion.
- dramatic increase in extinction rates.
- fishery collapses.
- changes in sedimentation patterns.
- global climate change.
- local anoxic events in oceans due to nutrient
Global climate change: We will focus on this because of the obvious importance
to ecosystems and to the states.
The best predictor of future behavior is past
- Vendian Glaciation Snowball earth: new hypothesis that around 600 Ma oceans frozen
- Cretaceous super greenhouse: at around 100 Ma earth much warmer than today, interior
of continents flooded, and much more.
A model for the myriad of ways global climate
can change is given below.
Some of the myriad of ways to change global
- increase upper atmosphere backscatter:
- by injection of volcanic sulfur aerosols
and ash high into atmosphere (residence time of several years)
- nuclear winter, large asteroid impacts.
- change surface albedo (water, bare land,
vegetated land and ice as main surface categories):
- increase in ice/snow cover and positive feedback
cycle (Icebox earth around 600 Ma).
- change in sea level (interesting feedback
- deforestation and change in albedo
- change in greenhouse gas composition in atmosphere:
- burning of fossil fuels.
- exchange with oceanic reservoirs.
- biologic extraction and preservation in geologic
- volcanic contributions out of the ordinary.
- consistent change in cloud cover extent (difficult
- change in heat exchange between oceans and
- Gaian component - the role of the biosphere.
The basic idea is that the biosphere influences conditions on
the planet so that stay favorable to life; i.e. it is homeostatic.
Effects of present global warming?
- Possible change in circulation patterns in
the oceans and attendant changes in weather patterns. One model
suggests that global warming may cause local cooling in Europe.
- Increase in sea level as ice melts and water
- Change in large storm frequency.
- Increase locally in desertification.
- Ecosystem shifts, especially in polar regions.
- Hard to predict because of complexity of
the system. Some may be beneficial to humans, some deleterious.
- Important to remember that population densityhighs
often along coasts.
Influence of environmental
issues on matters of the state?
Rwanda - one example.
- 1950-1994 pop. went from 2.5 to 8.8 million,
1992 average number of children per woman = 8.
- 1960s->1990s grain production overall
increased, but per person decreased by 50%
- freshwater supply, classified as one of the
world's 27 water scarce countries.
- information source: Brown, 1995, State of
- other factors contributed to intense social
chaos and genocide, but these played some role.
Gulf War: I will
leave as self explantory.
in Tigres-Euphrates area: sudden collapse at 4170+/-150 yr B.P.Coincides
with a sudden (with a sudden aridity episode 300 years long).
Local climatic shift. Cullen et al., 2000, Climate change and
the collapse of the Akkadian empire: Evidence from the deep sea;
Geology, vol. 28, p. 379-382.
Many more examples. History courses often doesn't
deal with them, but environmental issues have been a major factor
in human history.
Present political framework of environmental
- over 170 environmental treaties (most ineffective).
- Montreal Protocol
- controls CFC s and ozone releases. Partially successful. 1.3
billion kg in 1988 to .510 billion kg release in 1993.
- U. N. Conference on Environment and Development
- Agenda 21 (also known as Rio Summit). Much discussion on contribution
of fossil fuel combustion to global warming. Also Kyoto conference.
- Law of the Sea, 1994, recognizes EEZs. U.S.
refuses to sign.
Changing economic perspective on environmental
- short vs. long term perspective.
- material capital, information capital, social
capital, aesthetic capital(?): basic recognition of worth of
non-material entities. In addition, there is a redefinition of
material capital to include things such as the cleansing benefits
- ecotourism a budding discipline.
Closing statement: Humanity has at least two challenges ahead
of us. First, to understand the complexity of systems that make
up the earth, and how we affect and are affected by them. Second,
to act appropriately with this knowledge. We have addressed a
small bit of the first challenge. I leave the second challenge
up to you. Those who argue that we are destined to survive has
little appreciation for the character of history or the ways of
nature, and are wearing blinders. We will ultimately have to act
with collective wisdom if we are to survive as an advanced civilization.
© Harmon D. Maher Jr.. This
page may be used for non-profit educational purposes. For any
other use please contact me.
Harmon's home page.