Our environment is more then just our surroundings
Environment is the sum of our surroundings
It includes all of earths
o Biotic Components (Living Things)
Biotic Constituents（成分） = Animals, plants,
soil, forests, people occupying landscape
o Abiotic Components (Nonliving things)
Abiotic Constituents = Continents, oceans,
clouds, rivers, icecaps
In the most inclusive scene, our environment includes scientific,
political, ethical, economical, and social relationships &
It is the interactions that characterize environment.
Most people equated environment with wilderness.
Environment Canada is to preserve （保护）and enhance the
quality of Canada’s natural environment, conserve（保存）
our renewable resources and protect our water resources.
Environmental science explores interactions between humans
and the physical and biological world
We depend on the environment for air, water, food,
shelter, and everything else essential for living. Some actions have enriched our lives, bringing us longer
life spans, better health
o Some have damaged natural systems that sustain
Water & air pollution, soil erosion etc.
Environmental Science is the study of how the natural
world works, how our environment affects us, and how we
affect our environment.
o It is important to understand our interactions and our
role in the environment.
Natural resources are vital （重要的）to our survival
Islands are finite and have limitation in material resources
Renewable Natural Resources are natural resources that
are replenishable（可补充的） over short periods (wind,
wave energy, sunlight.
o Become non-renewable if we use them at a rate that
is faster at which they are renewed or replenished.
Resource Management is a strategic（战略上的）
decision making and planning aimed at balancing the use
of a resource with its protection and preservation.
o Balance the withdrawal from the stock with the rate
of renewal/regeneration （再生）
o Stock is the harvestable（收获的） portion of the
resource Stock-and-flow resources highlight the
importance of the balance
Non-Renewable Natural Resources are finite supply &
depletable（可耗减的） as they are formed much more
slowly (fossil fuels, mineral deposits.)
o Once we use them up they are no longer available.
o Fossil fuels & minerals are mined rather than
harvested therefore once extraction（提取）
becomes inefficient to be profitable they move on to
Management of non-renewable mineral
resources demands conservation, reuse &
o Other resources are truly non-renewable and
nonreplenishable (once a species has become extinct
it won’t return)
o A key question in managing resources is to look at the
resource of interest or to look at the environmental
system and how to avoid damaging the system and
sustain the availability of the resource in the long
Important to preserve for the future, recently
the consumption of natural resources has
increased greatly. Human population growth has shaped our resource use
Four significant periods of societal change appear to have
triggered（触发） remarkable increases in population
o 1. The paleolithic (stone age) period > humans
gained control of fire and began to shape and use
stones to modify their environment
o 2. Neolithic Period (agricultural revolution)
Transition from a nomadic（游牧的）, hunter-
gatherer lifestyle to a settled, agricultural way of life.
This change was 10000-12000 years ago.
o 3. Industrial Revolution began in mid-1700s, entailed
a shift from rural life（农村生活）, and
manufacturing by crafts（手工的） people, to an
urban society powered by fossil fuels. Life improved,
but marked the beginning of industrial-scale pollution
Air quality declined（下降） as of reliance（依
赖） on coal.
Water quantity declined
Workplace health and safety went under
o 4. Medical-Technological Revolution – Advances in
medicine and sanitation（ 卫生系统或设备 ）, communication technologies, shift to modern
agricultural practices (green revolution) allowed
people to live longer healthier lives.
Each major transition introduced technological
advancements that made life easier and resources more
available, effectively increasing the carrying capacity of the
environment for humans and allowing the human
population to increase dramatically.
Resource consumption exerts（表现出） social and
Population growth affects resource use and availability
> at the root of many environmental problems
I = P x A x T
This ‘IPAT’ model shows that the impact is a function of not
only population but of affluence（富裕） (which stands in for
‘level of consumption’) . Increase in number of people (P) has
impacts on increased consumption of natural resources and
manufactured goods by the world’s people (A), and the impacts
of new technologies (T) on the environment.
Carrying capacity and the ‘tragedy of the commons（平民百
姓）’ Carrying capacity refers to the biological productivity of a
system; it is a measure of the ability of a system to support
o Environmental scientists quantify（定量） carrying
capacity in terms of the number of individuals of a
particular species that can be sustained by the
biological productivity of a given area of land.
When the carrying capacity of the land or water
is exceeded（过渡的）, there are too many
individuals for the system to support.
This means the system will be altered,
damaged or depleted（耗尽的） or the
population of the species will decline（下
降） or collapse（倒塌）.
‘Tragedy of the Commons’
o Published by Garrett Hardin
o Illustrated this process while disputing（争论） the
economic theory that the unregulated（为受控制的）
exercise of individual self-interest serves the public
o Tragedy of The commons example is when each
person who puts animals to graze （吃草）on the
commons will be motivated（有目的的） by selfish
interests to increase the number of his or her animals in the pasture（牧场）, no one cares for the pasture
because no single person owns it.
Each individual withdraws whatever benefits are
available for the common property as quickly as
possible until the resource becomes overused or
Calculating our ecological footprints
Ecological footprint is a tool that can be used to express
the environmental impact of an individual or population
o Calculated in terms of the amount of biologically
productive land and water required to provide the
raw materials that the population consumers and to
absorb or recycle the waste produced.
o Gives the surface area ‘used’ by a given population
after all the direct & indirect impacts are totalled.
o It is the inverse of carrying capacity
Measure of land required to sustain an individual
rather than the number of individuals that can
be sustained by area of land or water.
o Our species is using 39% more resources than are
We are not only exceeding the carrying capacity
but also depleting renewable resources 39%
faster than they are being replenished. o Ecological footprint for average Canadian is
approximately 7.6 hectares (2-4 city blocks)
If the （属于居住的） land was among 6.7
billion people alive it would be less than 1 city
If all of the worlds people consumed resources
at the rate of North Americans we would need
greater or = to 2 additional planet earths.
Environmental Science can help us avoid mistakes made in the
There is evidence that civilizations can crumble（衰落）
when pressures from population and consumption
overwhelm（压倒） resource availability.
Jared Diamond identified five critical factors that
determine the survival of civilizations:
o Climate change
o Hostile（怀有敌意的） neighbours
o Trade partners
o Environmental problems
o Society’s response to environmental problems
The only one which is controllable is
society’s response to environmental
The Nature of Environmental Science Environmental scientists aim to comprehend（理解）
how earth’s natural systems function, how humans are
influenced by those system, and how we are influencing
The solutions (such as new technologies, policy decisions)
are applications of environmental science, and these
solutions are in turn also part of environmental science
Environmental Science is an interdisciplinary（各学科间的）
Environmental science is an interdisciplinary field – one
that employs concepts and techniques from numerous
disciplines and brings research results from these figures
in a broad synthesis.
Environmental science is broad because it encompasses
o Natural sciences (study the natural world)
o Social sciences (human interactions and institutions)
Most environmental science programs
focus more on natural sciences as they
pertain （属于）to environmental issues.
Programs heavily on social sciences prefer
the term environmental studies People differ in their perception（认识） of environmental
Environmental problem is any undesirable（不受大家欢
迎的） change in the environment
o Although a perception of what an undesirable change
is may vary from one person to another
o Information about environmental health risks reaches
wealth people more readily （容易的）than poor
Therefore, who you are, where you live, what
you do, your income, gender, and
socioeconomic status can have a huge effect on
how you perceive your environment.
Environmental Science is not the same as Environmentalism
Environmental science is not the same as
environmentalism or environmental activism（激进主义）
o Environmental Science is the pursuit（职业） of
knowledge about the workings of the environment
and our interactions with it.
o Environmentalism Is a social movement dedicated to
protecting the natural world, and humans from
undesirable changes brought about by human
choices. o Canadian Environmental Perspectives are in each
chapter of the book and contain brief profiles of
Canadian environmental scientists who contribute to
the understanding, protection, management and
sustainable use of the natural environment.
All of them have made a difference , some are
Scientists and writers
Scientists or filmmakers
Gardeners, politicians, or musicians
o Many of them are also
David Suzuki – scientist, activist &
The Nature of Science
Science is a systematic process for learning about the
world and testing our understanding of it.
o Term is used to refer to the accumulated body of
knowledge that arises from this dynamic process of
observation, testing and discovery
o Most important applications of science are its use in
developing technologies and its use in informing
policy and management decisions.
Why does science matter? o Late astronomer Carl Sagan wrote ‘The demon-
haunted world: science as a candle in the dark’
Everything depends on science
agriculture, medicine, education,
entertainment, protecting the environment,
Scientists test ideas by critically examining evidence
Scientists examine ideas about how the world works by
designing tests to determine whether these ideas are
supported by evidence. The scientific method is a key element of science
Scientific Method is a process that scientists generally
o Theme with variations, scientists persue their work in
many different waves.
o Scientists from different fields approach their work
Chemist will conduct research differently from a
Science is a broad sense to include
o Natural science
o Social science
Scientific Method relies on the following assumptions:
o The universe functions in accordance（一致） with
fixed natural laws that do not change from time to
time or place to place
o All events arise from some cause and lead to other
o We can use our senses and reasoning abilities to
detect and describe natural laws that underlie the
cause and effect relationships we observe in nature.
Researchers do the steps below o Make observations （观察）(set the scientific
method in motion and function throughout the
o Ask questions. Scientists are naturally curious. (why
are certain plants or animals less common today than
they once were?)
o Develop a hypothesis. Hypothesis is an educated
guess that explains a phenomenon or answers a
Eg. A scientist investigating the question of why
algae are growing excessively in local ponds
might observe chemical fertilizers being applied
on farm fields nearby.
The scientist than makes hypothesis:
o ‘Agricultural fertilizers running into
ponds cause the algae in the ponds to
A null hypothesis is a statement that the scientist
is expecting no relationship between variables.
Such as between fertilizer and algael growth in a
o Make Predictions
Scientist uses the hypothesis to generate（生成）
predictions which are specific statements that
can be tested. In the algae example, a prediction might be
‘If agricultural fertilizers are added to a
pont, the quantity of algae will increase’
o A null hypothesis can also lead to
predictions; for example, scientist
might predict that adding agricultural
fertilizer to a pond will cause no
change in the amount of algae growing
in the pond.
o Test the predictions
Tested one at a time by gathering evidence that
can disprove the hypothesis
Evidence comes from experiment which is a
activity designed to test the validity of a
Involves manipulating（利用） variables
(conditions that change)
o Algae example > a scientist could test
the hypothesis linking algal growth to
fertilizer by selecting two identical
ponds and adding fertilizer to one
while leaving the other in its natural
In this example Independent variable is
fertilizer input, which is a
variable the scientist