3. Definition of Environmental Change
• Environmental change is defined as a change or
disturbance of the environment caused by human
influences or natural ecological processes.
5. Global temperature has increased 0.5-1.0°F since the
late 19th century.
The snow cover in the Northern Hemisphere and floating ice
in the Arctic Ocean have decreased.
6. 5 main global environmental changes
The five main global environmental changes which are currently
on the agenda:
• Climate change
• Ozone depletion
• Loss of biodiversity
• Fresh water supplies
• Persistent organic pollutants
8. 1- Climate change
• What is climate change?
• What are the environmental consequences?
• What does it mean for human health?
9. Definition of climate change:
Refers to a long-term change
(usually an increase) in global
temperatures
The greatest challenge facing the world at the beginning of
the last century.” the average global temperature has risen by
0.75 degrees
“the most important long-term issue which we face as a
global community”.
13. Earth With An Atmosphere That
Includes Greenhouse Gases
Partly
Greenhouse Gases Make the Earth Warmer by Slowing the Loss of Infrared Radiation
(infrared)
16. The real greenhouse
Greenhouses work by
trapping heat from the sun
Glass let in light short
waves
But
Keep in heat ( infrared
long)waves from escaping
17. What is the Greenhouse effect?
• The greenhouse effect is the rise in the Earth average
temperature because certain gases in the atmosphere trap
heat from the Sun’s rays.
18. Importance of greenhouse effect
1- Existence of life: heating effect of greenhouse gases makes
existence of life is possible in earth.
2- Maintains ecosystem:
Protects the plants and gives them new lives and along with
maintaining earth’s average temperature it also protects the
existing bio-diversity.
3- Melting of ice and snow
4- Evaporation of water
20. Causes of global warming
Manmade causes
1- Air pollution due to
a. burning fossil fuel
b. industrialization
c. coal mining
2- Deforestation
Natural causes
1- volcanic eruption
2- release of methane gas
from arctic tundra and
wetland
Global warming is caused by a build-up of greenhouses gases,
which leads to an increase in the Earth’s temperature.
Enhanced greenhouse effect may lead to significant climate change.
21. Greenhouse gases and effect
Key greenhouses gases include:
carbon dioxide (CO2)
methane (CH4)
water vapour (H2O)
nitrous oxide (N2O)
Carbon dioxide is one of the most important
greenhouse gases because atmospheric
concentrations have risen dramatically over
the past century.
25. Direct effects on human health
Extreme weather conditions:
• Temperature-related effects heat stress.
• Storms accidents and loss of housing.
• Droughts limited access to water and food
• Floods accidents and loss of housing.
Heat wave
26. Temperature
Heat-wave related mortality and morbidity
• Heat waves can cause death directly
through causing illnesses.
• Aggravation of pre-existing heat-sensitive
medical conditions.
• Stress from extreme heat can cause
myocardial infarction, sudden cardiac
death
29. Floods in Egypt 2006
Floods in Italy 2008
Floods in Saudi Arabia 2013
Floods in Denmark 2010
30. Flood-related diseases
• Floods disrupt basic sanitation systems
diarrheal disease outbreaks via fecal-oral route.
• Contamination of drinking water and facilities with
pathogens from human or animal sewage
water-borne diseases such as
dysentery,
hepatitis A,
cholera,
typhoid fever.
31. Indirect effects on human health
Vector-borne diseases (change in vector distribution).
Water-borne diseases (quantity, quality).
Food-related diseases (availability, quality).
Health effects related to changes in air quality.
(e.g pollen allergies).
Melting of ice-sheets in the Arctic.
32. Vector-borne diseases
Malaria
Transmitted by mosquitoes
Occurs in 97 counties
207 million people infected
in 2012 (90% in sub-saharan
Africa)
627 000 deaths (482 000
among children under five)
35. Vector-borne diseases
Schistosomiasis
Transmitted by snails
Snails breed in fresh water
Occurs in 78 counties
249 million people required
treatment in 2012 (90 % in sub-Saharan Africa)
http://news.ku.dk
37. Melting ice and rising sea level
Global warming causes the polar
ice sheets melt. It increases the
sea-level. It will possibly rise 18 cm
by 2030 and 58 cm by 2090.
Flooding will probably occur in
lowlands.
Many cities along the coast may be
under sea water.
The loss of polar ice will have a
profound effect on animal habitats.
39. Population displacement
Rising sea levels
Increase the risk of coastal flooding
Necessitate population displacement
• More than half of the world's population now lives within
60km of the sea.
Destruction of island communities
Relocations of populations
42. 2- Ozone depletion
Stratospheric ozone layer is protective
absorbs UV radiation and thus prevents it from
reaching the surface of the earth where it would
damage the DNA of plants and animals (acts as
a protective radiation shield).
43. What damages the ozone layer?
CFCs are used in:
fridges and freezers,
air conditioners,
aerosol spray cans,
and packaging materials such
as polystyrene.
Chlorofluorocarbons (CFCs), which contain the elements
carbon, hydrogen, chlorine and fluorine.
44. Ozone Depletion process
(CFCs), enter the upper atmosphere and break down
ozone molecules.
When ozone breaks down, the ozone layer thins,
Depletion of ozone layer leads to increase in harmful UV
rays reach Earth.
45. Ozone Hole
These images of the ozone hole
were taken by NASA between
September 1981 and September
1999.
First identified in 1985 over
Antarctica
Areas of major ozone thinning,
called ozone holes, appear
regularly over Antarctica
47. Effects of Ozone Depletion
• Higher levels of UV-radiation
hitting the earth
– Skin cancer
– Eye cataracts
– Weakened immunity
• May disrupt ecosystems
• May damage crops and forests
48. Recovery of Ozone Layer
• The Vienna Convention for the protection of the Ozone layer 1985
• Montreal Protocol (1987)
– Reduction of CFCs
– Phase out of all ozone destroying chemicals is underway
globally
• The production and use of CFCs is now banned in many countries
and could be worldwide in a few years.
• spray cans no longer contain CFC propellants.
• Satellite pictures in 2000 indicated that ozone layer was recovering
• Full recovery will not occur until 2050
51. What does biodiversity mean?
Biodiversity refers to the variability of species . Necessary for
healthy ecosystem functioning
52. Loss of biodiversity
As a result of human activities, especially the destruction of
tropical rain forests and other habitats.
Plants and animals are becoming extinct at a faster rate than
the planet has ever previously experienced.
53. Causes of Loss of biodiversity
Pollution
(e.g.
Eradication
or
malformatio
n)
Habitat loss
(e.g. Snail
vector of
schistosomias
is)
Biotic change
(e.g. Change
in life
cycles/transmi
ssion cycles)
57. Reduced availability of drinking water.
Reduced possibilities of washing, hygiene
and sanitation.
Impact on intestinal infectious diseases
(e.g., Cholera).
Scarcity in food supplies.
Tensions and armed conflicts in the
struggle for water supplies (e.g. Ethiopia
and Sudan due to the need of irrigation).
Consequences
59. Water-borne diseases
Diarrhea
Typhoid
Hepatitis
Dysentery
Giardiasis
Cholera
Caused by fecal contamination of drinking water
”Water-borne diseases are likely to emerge in areas experiencing
warmer weather and water scarcity such as tropical zones
and the Arabian Peninsula”.
Report N° 64635 – MNA. October 2011. World Bank –Sustainable Development Department- Middle East
and North Africal Region: Adaptation to a Changing Climate in the Arab Countries, MNA Flagship Report, Chapter
7
61. A- Malnutrition & Famine
• Climate change affects the agricultural sector and food
production
• Less water available for irrigation will reduce crop yields.
70. 5- Persistent organic pollutants (POP’s)
• Lead and other heavy metals have become widely
distributed in the world environment.
• The worst pollutants are synthetic chemicals,
particularly the persistant organic (POP’s) including
polychlorinated biphenyls (PCB’s).
• Highly toxic in the environment, do not break
down, and accumulate in the food chain.
71. Persistence
Toxins can either degrade quickly or remain unaltered and
persist for decades
Rates of degradation depends on temperature, moisture,
and sun exposure
Breakdown products = toxicants degrade into simpler
products. May be more or less harmful than the original
substance
DDT degrades into DDE, which is also highly persistent
72. Bioaccumulation
It is the Process leading to higher
concentrations in organisms than the
surrounding environment
• Fat-soluble ones lipophilic substances
are stored.
• DDT is persistent and fat soluble,
so builds up in tissues: bioaccumulation.
73. • Poisons move up the food chain
• The increased concentration of toxic
chemicals in the tissues of organisms
that are at higher levels in food webs
• Diagram is example of
biomagnification of DDT
• toxicants concentrate in top predators
• At each trophic level, chemical concentration
increases.
• DDT concentrations increase from plankton to fish
to fish-eating birds.
Biomagnifications
74. POP’s affect the human immune system.
Increases susceptibilty to respiratory infetions.
Exposure to low concentrations from the environment can
pose chronic health risks (e.g. cancer).
Consequences
76. 6- Desertification
Overgrazing and developing of
grasslands that border deserts transform
the grasslands into deserts.
As a result:
agricultural output decreases,
habitats available to native species are
lost.
78. 7- Deforestation
Clear-cutting of forests causes erosion,
flooding, and changes in weather patterns.
The burn method of clearing tropical rain
forests for agriculture increases atmospheric
CO2, which contributes to the greenhouse
effect.
Because most of the nutrients in a tropical
rain forest are stored in the vegetation,
burning the forest destroys the nutrients.
