This document provides an overview of key concepts in environmental science, including: 1) The interrelated nature of environmental factors and how changes can impact ecosystems. 2) How population growth contributes to environmental issues by increasing resource usage and degrading habitats. 3) The links between environmental quality, food security, and human health, particularly for vulnerable populations. 4) The importance of sustainable development and management of natural resources to support both the environment and human well-being into the future.

1. April
2020
Lesson 1
Environmental interrelationship

2. Objective of the
lesson:
• Recognize that the field of environmental science is
multidisciplinary
• Describe the interrelated nature of environmental
science
• Recognize that human population growth
contributes to environmental problems
• Understand sustainability concept
• Recognize that people rely on the ecosystem
services
• Understand that food security is an issue for the less
developed world
• Recognize that the quality of the environment has an
important impact on human health
2

3. Contents
1. The Interrelatedness of the
environment
2. Population growth & Environmental
issues
3. Food security in the less developed
world
4. Environmental quality & human health
5. Sustainability Concept
3

4. The Nature of
Environmental Science
4
What is environment?
 Environment is everything that affect organisms;
=> Environmental Science is therefore an interdisciplinary
field; It is the study of living organism and factor affecting their
lives;
 Environmental Science deal with the natural environment
and other things that affect human development such as
politics, social organization, economics, ethics, and
philosophy;
 Environmental decisions often involve compromise.
• A decision that may be supportable from a scientific economic point of view
may not be supportable from a political point of view without modification.
• Often political decisions relating to the environment may not be supported by
economic analysis.
1. Interrelatedness
of the environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health
5. Sustainability Concept
Environmental Interrelationships

5. Interrelatedness Is a Core Concept
5
The absence of wolves led to an increase in elk and coyotes
but to a decrease in beaver, streamside stands of willow and
cottonwood, and habitat for some birds. Reintroduce of
wolves to the community reverse the situation!
=> Conflict idea between Rancher and
Environmentalist/biologist on Wolf should be reintroduced to
the park!
1. Interrelatedness
of the environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health
5. Sustainability Concept
Tug on anything at all and you’ll find it
connected to everything else in the universe
(John Muir )
The study of environmental science is
so interesting, frustrating, and
challenging because of the
interrelatedness among seeming
unrelated factors.
Wolves population in Yellowstone National park affect park
biodiversity and also affect the social, economic, and
political realms of human society!

6. An Ecosystem Approach
6
1. Interrelatedness
of the environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health
5. Sustainability Concept
An ecosystem is a region in which the organisms and
the physical environment form an interacting unit;
The interaction among abiotic and biotic
environment in an ecosystem is very complex.
Three type of interaction:
(1) Abiotic-Biotic
(2) Biotic – Biotic
(3) Abiotic-Abiotic
Weather &
soil
Plant
growth
Impact on
insects
Insect
spread
plant seed
More plan
growth
Evaporatio
n & plant
biomass Interaction
among
different
components of
an ecosystem
Interaction in a forest ecosystem

7. An Ecosystem Approach
7
1. Interrelatedness
of the environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health
5. Sustainability Concept
Part of Koh Rong coastal ecosystem
(Image source: traveldestinationguide.net)
What relationship can
you tell from this
picture?

8. An Ecosystem Approach
8
1. Interrelatedness
of the environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health
5. Sustainability Concept
What is an “ecosystem approach”?
 Ecosystem approach is a ecosystem-
based management approach to deal
with environmental concerns.
 It is needed to recognize and
understand the natural interactions that
take place in an ecosystem, and to
integrate them with the uses humans
must make of the natural world
ecosystem;
Tonle Sap Basin Ecosystem
 It is crucial to keep balance of global
ecosystem!

9. Emerging Global Issues
9
 No region is free from environmental problem;
 Environmental problems are complex and
interrelated with issues specific to a given region
1. Interrelatedness of the
environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health
5. Sustainability Concept
In today world, people are facing
more global environmental
challenges than ever due to
climate change!
People cause tremendous change to
the earth climate system, which result is
many unfavorable situation i.e., global
warming, drought, sever flooding and
storm, sea level rise………..

10. Population growth and Environmental Issues
10
 Current world population is app. 7.5
billions
 People can control the number of
children they will have but for cultural
and economic reason they often have
large families;
 Population growth rate for most of the
developed nations is stable or falling;
 Population continues to grow rapidly,
especially in poor countries;
1. Interrelatedness of the
environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health
5. Sustainability Concept
2020

11. Population growth and Environmental Issues
11
But, what matter with more population?
 Population Growth puts pressure on resources and
leads to the degrading of the environment
=> often locks people in a cycle of poverty
1. Interrelatedness of the
environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health
5. Sustainability Concept
Trapang Seh Poor community, Siem Reap, Sept,
2018
Poverty is often linked to poor health
because of malnutrition and lack of
access to affordable health care!

12. Population growth and Environmental Issues
12
How does population growth
affect the environment?
 For socioeconomic development,
people make use of natural
resources;
More people = more
natural resources being
exploited and degraded!!!
1. Interrelatedness of the
environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health
5. Sustainability Concept

13. Population growth and Environmental Issues
13
Human make use of natural resources and affect ecosystem service!
“Ecosystem services is direct and indirect benefit that human being can obtain from natural
environment”
1. Interrelatedness of the
environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health
5. Sustainability Concept
Ecosystem Services include:
1. Provisioning services, such as food, minerals,
renewable energy, and water;
2. Regulating services, such as waste
decomposition,
pollination, purification of water and air, and
pest and disease control;
3. Cultural services, such as spiritual,
recreational, and cultural benefits;
4. Supporting services, such as nutrient cycling,
photosynthesis, and soil formation.
Provision service:
food and medicine,
income source:
honey, bee
larvae,……
Pollination service to
increase species diversity,
help plant growth, and
increase habitat………
Recreational service:
Bee help diversify
flowering specie, some
people just keep bee as
hobby…….
Cultural service:
Honey brew is special
beverage for some
culture, bee is also
use as defend
weapon for some
ethnic group……

14. Population growth and Environmental Issues
14
1. Interrelatedness of the
environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health
5. Sustainability Concept
Rice field in Siem
Reap (Shutter Stock image)
Removing trees from forest
area make farmland/ other
landuse types cause habitat
lose for wild animal and some
species go extinct!
Example: lost of wolf population is
Yellowstone park cause change
plant species and reduce
biodiversity of the park.
 When a species of organism goes extinct, its loss
has a ripple effect throughout its ecosystem =>
existent ecosystem service will be alter as a
consequence.
 Environmental changes that alter these
services affect human security.
• Food security
• Health impacts
 All people rely on ecosystem services, but the
world’s poorest people are especially
dependent on environmental goods and services
for their livelihoods, which makes them
particularly sensitive and vulnerable to
environmental changes.
Stone quarry for
construction material in Kep
Province
The mountain is
disappearing and entire
mountain ecosystem is
altered!

15. Food security in the less developed world
15
1. Interrelatedness of the
environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health
5. Sustainability Concept
 The amount of food produced in the world is currently
enough to feet able to feed the world population; but,
food shortage, is still a critical concern for world poor
population.
“Food security exists when all
people, at all times, have
access to sufficient, safe and
nutritious food that meets their
dietary needs and food
preferences for an active and
healthy life”.
(World Food Summit, 1996)
What is food security?
Do we have enough food to feed the world?

16. Food security in the less developed world
16
1. Interrelatedness of the
environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health 5. Sustainability Concept
A local resident in Chnok Tru Floating
community is preparing her food (Oct 2017)
Fishery resource in the Tole Sap Lake is the
only source of income for this household
The poor of the world are often subsistence
farmers who rely on the food they grow to feed
their families or people who relied entirely on
Natural resource!
Environmental disasters such as droughts,
floods, or outbreaks of disease in their
animals or crops often result in a lack of food
and malnutrition.
To secure the world food supplies we have to
secure our environment!

17. Environmental quality & human health
17
1. Interrelatedness of the
environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health
5. Sustainability
Concept
Change in natural environment negatively affect
human health!
Water pollution
Diarrhea that results from
contaminated drinking water
causes dehydration and
malnutrition and leads to
nearly 2 million deaths per
year.
Air pollution
Common diseases related
to air pollution are
pneumonia, emphysema,
and bronchitis, which are
responsible for about 6
million deaths per year.
Disease associated with environmental changes:
• Malaria is caused by a protozoan parasite
carried by mosquitos => breed in poor
environment area.
• Cancer and coronary heart disease
commonly associated with exposure to
cigarette smoke, exposure to ultraviolet light,
and the kinds and amounts of foods eaten;
• Emerging diseases result from new organisms
or those that become a problem because of
environmental changes;

18. Sustainability Concept
18
1. Interrelatedness of the
environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health
5. Sustainability Concept
“The concept of sustainability requires that we consider future generations when we
make decisions about how to use resources”
 Will our decedent could access to
the natural resource for their socio-
economic development as much as
we can now?
 Can we continue our development
without consuming natural resource
or without altering the natural
environment?
buschdesign.com

19. Sustainability Concept
19
 We can not completely stop
using natural resource or avoid
altering natural environment;
But, we can use them in
a more sustainable
way!
“Without maintaining
good environment
human development is
not sustainable”
The SDGs
2015-2030
1. Interrelatedness of the
environment
2. Population growth &
Environmental issues
3. Food security in the less
developed world
4. Environmental quality &
human health
5. Sustainability Concept

20. Summary
20
• Environment is everything that affect organism;
• Environment include living and non-living thing that are interrelated either directly or
indirectly;
• Environmental Science is multidisciplinary field; it involve science, economics, ethics,
and politics; Environmental problem solving often need to be compromise among
different fields;
• Population growth put more pressure on the environment by increasing natural
resource consumption, degrading and altering natural ecosystem;
• Environmental disaster link to insecurity of food supply; poor people such farmer and
people who relies solely on natural resource, especially in less developed countries are
the most affected;
• Environmental change negatively affect human health and is the cause of millions
deaths every year;
• Without maintaining good environment human development can not be sustained;

21. THANK YOU!
Danet HAK, PhD
Phone
012 867 507
Email
Hakdanet.fmse@puc.edu.kh