Transcript ENS501 Week 1

ENS501
Introduction to Environment
Week 1
Environment
• The environment is everything around us.
– “Environment is everything that isn’t me” – Albert
Einstein
• Environment includes all living and nonliving
things (air, water, and energy) with which an
organism interacts.
• We are dependent on the environment for clean air
and water, food, shelter, energy, and everything
else we need to stay alive and healthy.
Environmental Science
• Environmental science is an interdisciplinary
study of how humans interact with living and
nonliving parts of their environment.
– It integrates information and ideas from natural
sciences, social sciences and humanities.
• The three goals of environmental science:
– To learn how life on the earth has survived and thrived
– To understand how we interact with the environment
– To find ways to deal with environment problems and
live more sustainably.
Ecology
• Ecology – a key component of environmental
science
• Ecology is the biological science that studies how
organisms, or living things, interact with one
another and with their environment.
• Every organism is a member of certain species: a
group of organisms that have distinctive traits (or
characteristics) and, for sexually reproducing
organisms, can mate and produce fertile offspring.
Ecosystem
• An ecosystem is a set of organisms within a
defined area or volume interacting with one
another and with their environment of
nonliving matter and energy.
– For example, a forest ecosystem consists of
plants (especially trees), animals, and mostly tiny
micro-organisms that decompose organic
materials and recycle their chemicals, all
interacting with one another and with solar energy
and the chemicals in the forest’s air, water, and
soil.
Environmentalism
• Environmentalism is a social movement
dedicated to protecting the earth’s lifesupport systems for all forms of life.
• Environmentalism is practiced more in the
political and ethical arenas than in the realm
of science.
Sustainability
• Sustainability is the ability of the earth’s
various natural systems and human cultural
systems and economies to survive and adapt
to changing environmental conditions
indefinitely.
• Nature has sustained itself for billions of years.
The three over-arching science-based themes
to the long-term sustainability of life on this
planet: energy, biodiversity, & nutrient cycling.
Three Principles of
Sustainability
3 Principles of Sustainability
(or Lessons from Nature)
• Three principles of sustainability are solar
energy, biodiversity, and nutrient cycling.
• Solar energy warms the earth and provides
energy for plants to produce nutrients, or the
chemicals necessary for life. All life on earth
depends upon solar energy.
• Biodiversity (biological diversity) is the variety of
organisms, the natural systems in which they
live and the natural services that they provide.
3 Principles of Sustainability
(or Lessons from Nature)
• Nutrient cycling is the circulation of nutrients,
or chemicals from the environment (mostly
from soil and water) through organisms and
back to the environment is necessary for life.
• Natural processes keep this cycle going.
• This means there little waste in nature
because the wastes of organisms become
nutrient raw materials for other organisms.
Sustainability
- key components
• Natural capital—the natural resources and
natural services that keep us and other forms
of life alive and support our economies.
• Our lives and economies depend on energy
from the sun (solar capital) and natural
resources & natural services (natural capital)
provided by the earth.
• Natural capital = Natural Resources + Natural
Services
Natural Resources & Services
• Natural resources are materials and energy in
nature that are essential or useful to humans.
• These resources are often classified as
renewable (such as air, water, soil, plants,
and wind) or nonrenewable (such as copper,
oil, and coal).
• Natural services are processes in nature
such as purification of air and water, which
support life and human economies.
Solar
energy
Natural Capital
Natural Capital = Natural Resources + Natural Services
Air
Renewable
energy (sun,
wind, water
flows)
Air purification
Climate control
UV protection
(ozone layer)
Life
(biodiversity)
Population
control
Water
Water purification
Pest
control
Waste treatment
Soil
Nonrenewable
minerals
(iron, sand)
Soil renewal
Land
Food production
Nutrient
recycling
Nonrenewable
energy
(fossil fuels)
Natural resources
Natural services
Fig. 1-3, p. 9
Natural Service
(Nutrient cycling)
• One vital natural service is nutrient cycling.
• An important component of nutrient cycling is
topsoil – a vital natural resource that
provides food.
• Without nutrient cycling in topsoil, life could
not exist on the earth’s land.
Nutrient cycling
Natural Capital Degradation
• Many human activities can degrade natural
capital by using normally renewable
resources faster than nature can restore
them, and by overloading natural systems
with pollution and wastes.
• Natural capital degradation occurs when the
natural resources and services are hurt.
• Solutions are being found and implemented.
Natural Capital Degradation
• Solutions to natural degradation, such as
– reducing energy consumption
– reducing resource use and
– advocating a reduction in population growth,
• may require economic changes and lifestyle modifications.
• Sustainability begins at personal and local
levels.
Resources
• Humans depend on resources to meet our
needs.
• A resource is anything obtained from the
environment to meet our needs and wants.
– Solar energy, fresh air, fertile topsoil, wild edible
plants are directly available for use.
– Other resources such as petroleum, iron,
underground water, and cultivated crops become
useful to us only with some effort and technological
ingenuity.
Resource Types
• A perpetual resource is continuously
renewed and expected to last (e.g. solar
energy).
– Solar energy is called a perpetual resource
because it is renewed continuously and is
expected to last at least 6 billion years as the
sun completes its life cycle.
Renewable Resource
• A renewable resource is replenished in days
to several hundred years through natural
processes as long as it is not used up faster
than it is renewed.
– Examples include forests, grasslands, fish
populations, freshwater, fresh air, and fertile soil.
• Sustainable yield of a renewable resource is
the highest rate at which it can be used
indefinitely without reducing its available
supply.
Nonrenewable Resource
• Nonrenewable resources, such as coal and
oil, exist in a fixed quantity, or stock, in the
earth’s crust and take millions to billions of
years to renew.
• We can deplete these resources much faster
than nature can form them.
– Exhaustible energy (coal and oil).
– Metallic minerals (copper and aluminum).
– Nonmetallic minerals (salt and sand).
Sustainable Solutions
• Sustainable solutions: Reduce, reuse, recycle.
• Recycling involves collecting waste materials
and processing them into new materials, for
example cans that are collected and
reprocessed.
• Reuse means using a resource over and over
in the same form, for example glass bottles
that are collected, washed, and refilled many
times.
Sustainable Solutions
• Recycling nonrenewable metallic resources
uses much less energy, water, and other
resources and produces much less pollution
and environmental degradation than
exploiting virgin metallic resources.
• Reusing such resources has a lower
environmental impact than recycling.
• From an environmental and sustainability
viewpoint: Reduce, reuse, recycle.
Rich and poor countries have
different environmental impacts
• The United Nations classifies the world’s
countries as economically more developed or
less developed based primarily on their
average income per person.
– High-income countries include the United States,
Canada, Japan, Australia, New Zealand, and most
countries of Europe.
– Middle-income countries include China, India,
Brazil, Thailand, and Mexico.
– Low-income countries include Congo, Haiti,
Nigeria, and Nicaragua.
ECOLOGICAL
FOOTPRINTS
Environmental Degradation
• Also known as natural capital degradation
• It is occurring at an accelerating rate.
• Environmental degradation is when the use of
a renewable resource exceeds its natural
replacement rate, causing the available
supply to shrink.
– Examples include climate change, soil erosion,
aquifer depletion, decreased wildlife habitats,
species extinction, and declining ocean fisheries.
Natural Capital Degradation
Degradation of Normally Renewable Natural Resources
Climate
change
Shrinking
forests
Decreased
wildlife
habitats
Air pollution
Soil erosion
Species
extinction
Water
pollution
Aquifer
depletion
Declining
ocean fisheries
Fig. 1-5, p. 11
We are living unsustainably
• According to the 2005 UN Millenium
Ecosystem Assessment, about 60% of the
earth’s natural or ecosystem services have
been degraded.
• “Human activity is putting such a strain on the natural
functions of Earth that the ability of the planet’s
ecosystems to sustain future generations can no
longer be taken for granted”
– Summary statement of the Report
Pollution
• Pollution is contamination of the environment
by a chemical or other agent, such as noise or
heat, that is harmful to health, survival, or
activities of humans or other organisms.
Pollution Types
• Point sources are single, identifiable sources
– the smokestack of a coal-burning power or
industrial plant
– a factory drainpipe, or
– the exhaust pipe of an automobile
• Nonpoint sources are dispersed and often
difficult to identify.
– pesticides blown from the land into the air
– the runoff of fertilizers, pesticides, and trash from
the land into streams and lakes
Pollution Cleanup
• We can clean up pollution or prevent it.
• Pollution cleanup involves cleaning up or
diluting pollutants after they have been
produced
– for example, water filters used to clean
contaminated groundwater.
• Pollution cleanup is usually more expensive
and less effective.
Pollution Cleanup
Drawbacks
– It is only a temporary bandage as long as
population and consumption levels grow without
corresponding improvements in pollution control
technology.
– Cleanup often removes a pollutant from one part
of the environment only to cause pollution in
another. For example, we can collect garbage.
– Once pollutants become dispersed into the
environment at harmful levels, it usually costs
too much to reduce them to acceptable levels.
Pollution Prevention
• Pollution prevention reduces or eliminates
the production of pollutants
– for example, air purifying technologies used on
smoke stacks for cleaner exhaust.
• But we need both pollution prevention (frontof-the-pipe) and pollution cleanup (end-of-thepipe) solutions.
• Pollution prevention is another key to a more
sustainable future.
The tragedy of the commons
overexploiting shared renewable resources
• Many open-access renewable resources have
been environmentally degraded
– Atmosphere
– Open Ocean & its fish population
• In 1968, the biologist Garrett Hardin called the
degradation of openly shared resources the
tragedy of the commons.
The tragedy of the commons
overexploiting shared renewable resources
• Possible solutions:
• Use a shared renewable resource at a rate
well below its estimated sustainable yield
– by using less of the resource
– regulating access to the resource, or both.
• To convert open-access renewable resources
to private ownership
– This is not practical for global resources such as
the atmosphere and the oceans.
Ecological footprints
our environmental impacts
• Ecological footprint is the amount of
biologically productive land and water needed
to supply a person or country with renewable
resources and to recycle the waste and
pollution produced by such resource use.
• Per capita ecological footprint is the
average ecological footprint of an individual in
a given country or area.
Ecological footprints
our environmental impacts
• Ecological deficit means the ecological
footprint is larger than the biological capacity to
replenish its renewable resources and absorb
the resulting wastes and pollution.
• Humanity is living unsustainably
– By depleting their natural capital instead of living
off the renewable supply or income provided by it.
• Footprints can also be expressed as number of
Earths it would take to support consumption.
Total Ecological Footprint (million
hectares) and Share of Global
Biological Capacity (%)
United
States
2,160 (19%) European Union
United States
2,810 (25%)
European Union
China
India
Japan
Per Capita Ecological
Footprint (hectares per
person)
China
2,050 (18%)
780 (7%)
India
9.7
4.7
1.6
0.8
Japan
540 (5%)
4.8
Number of Earths
2.5
Unsustainable living
2.0
1.5
Projected footprint
1.0
Ecological
footprint
0.5
0
1961
1970
1980
1990
2000
Sustainable living
2010
2020
2030
2040
2050
Year
Fig. 1-8, p. 14
Ecological footprints
our environmental impacts
Country
Total
Ecological
Footprint
(million ha)
Share of Global
Per Capita
Ecological
Ecological
Capacity
Footprint
(%)
(ha per person)
United States
2810
25
9.7
Europe
2160
19
4.7
China
2050
18
1.6
India
780
7
0.8
Japan
540
5
4.8
Ecological footprints
our environmental impacts
• Per Capita Ecological Footprint (ha per
person) in the US is 9.7 and in China is 1.6.
• On average each person in the U.S. consumes
a lot more than someone in China.
• To indefinitely sustain the resource use of the
current human population, we would need the
equivalent of 1.3 planet earths. If we continue
on our current path, by around 2035 we will
need 2 planet earths.
IPAT
environmental impact model
• In the early 1970s, scientists Paul Ehrlich and
John Holdren developed the IPAT model.
• It is a simple model showing how population
size (P), affluence or resource consumption
per person (A), and the beneficial and harmful
environmental effects of technologies (T) help
to determine the environmental impact (I) of
human activities.
• I=PxAxT
I=PxAxT
IPAT
environmental impact model
• Some forms of technology increase
environmental impact by raising the T factor
– Polluting factories, coal-burning power plants, and
gas-guzzling motor vehicles
• Some other technologies reduce
environmental impact by decreasing T factor
– Pollution control and prevention technologies,
wind turbines and solar cells that generate
electricity without polluting, and fuel-efficient cars.
IPAT
environmental impact model
• While the ecological footprint model
emphasizes the use of renewable resources,
this model includes the per capita use of both
renewable and nonrenewable resources.
• In most developing countries, the key factors
in total environmental impact are population
size and the degradation of renewable
resources as a growing number of poor people
struggle to stay alive.
IPAT
environmental impact model
• In more-developed countries, high rates of per
capita resource use and the resulting high per
capita levels of pollution and resource
depletion and degradation usually are the key
factors determining overall environmental
impact.