ess: chapter 1 - foundations

system

set of interactions, shows how it works together as a whole

transfer

change in location, not in state

transformation

change of state

model strengths

• predict and simplify system

• run simulations, see what happens

model weaknesses

• accuracy lost because of simplifying

• if assumptions are wrong, the model is wrong

• brings in bias from maker of model

ex: Rachel Carson's book Silent Spring (1962)

warned about devastating effects of DDT, led to investigation and JFK banned it

ex: Bhopal disaster

Indian city where 20 000 died from release of methyl isocyanate (MIC) in 1984

ex: Chernobyl

nuclear disaster, 1986

ex: Fukushima Daiichi

nuclear accident, 2011, demonstrations worldwide and governments shutting down nuclear plants and plans

ex: Deepwater Horizon oil spill

2010 in Gulf of Mexico, largest marine oil spill

1st law of thermodynamics

energy in an isolated system can be transformed but not created or destroyed

2nd law of thermodynamics

entropy of an isolated system not in equilibrium will tend to increase overtime

entropy

amount of disorder in a system (high entropy is high disorder; randomness)

steady-state equilibrium

continuous in- and outputs of energy and matter but system remains in constant state (eg. human ability to maintain body temperature)

static equilibrium

nothing changes; non-living system

stable equilibrium

system goes back to previous equilibrium after disturbance

ecological tipping point

reached when ecosystem experiences shift to new state, with almost irreversible change (eg. receding glaciers, eutrophication)

negative feedback

stabilising; reduces change and counters deviation

positive feedback

destabilising; amplifies changes and drives system to tipping point with new equilibrium

resilience

measure of the ability of an ecosystem to respond to disturbance, measures how quickly it recovers:

• either time it takes to return to stable state again

• or how well it can absorb change and keep same function and structure

the more complex ecosystem (species diversity, large habitat) the more resilient

resilience can be negative with invasive species, ex.

DDT

dichlorodiphenyltrichloroethane; a persistent organochlorine insecticide, banned by WHO in 1970

independent pressure groups, NGOs

influence the public which influences governments, eg: Greenpeace, WWF

ecocentric

ecology and nature central, self-sufficiency, rights of nature, holistic view of life (deep ecologists, self-reliant soft ecologists)

anthropocentric

humans must sustainably manage the global system, environmental legislation and regulation, nature is there to benefit humankind

technocentric

technological developments can provide solutions to environmental problems (environmental managers, cornucopians)

open system

both energy and matter exchanged across boundary

closed system

energy but not matter exchanged across boundary

isolated system

hypothetical concept, neither energy not matter exchanged across boundary

efficiency

• work or energy produced / energy consumed

• useful output / input

• can be percentage

natural capital

natural resources that can produce sustainable natural income of goods and services

environmental impact assessment (EIA)

report prepared before development project that will change use of land

ecological footprint (EF)

model used to estimate demands that human populations place on environment; accounts for area required to provide all resources needed by population

pollution

addition of substance or agent to environment by human activity, at a greater rate than it can be rendered harmless by environment

primary pollutant

active on emission (eg carbon monoxide from incomplete combustion of fossil fuels)

secondary pollutant

formed by primary pollutant undergoing physical or chemical changes (eg sulphuric acid forms when sulphur trioxide reacts with water)

non-point source pollution (NPS)

release of pollutant from numerous sources, combat by limiting all farmers or industries, eg

point source pollution (NP)

release of pollutant from single, identifiable source, usually easier to manage than NPS

persistent organic pollutants (POPs)

resistant pesticide

biodegradable pollutants

do not persist, break down quickly

pollution management strategies

• changing human activity which produces it

• regulating or preventing release of pollutant

• working to clean up or restore damaged ecosystem