Download ECOLOGY, POLLUTION AND ENVIRONMENTAL HEALTH

Global Warming
Greenhouse Gases and Climate
Is the climate becoming warmer and
warmer?
• According to the National Academy of Sciences, the Earth's surface
temperature has risen by about 1 degree Fahrenheit in the past
century, with accelerated warming during the past two decades.
There is new and stronger evidence that most of the warming over
the last 50 years is attributable to human activities. Human activities
have altered the chemical composition of the atmosphere through
the buildup of greenhouse gases – primarily carbon dioxide,
methane, and nitrous oxide. The heat-trapping property of these
gases is undisputed although uncertainties exist about exactly how
earth's climate responds to them.
(source:US-EPA)
Global temperature trend
Note that these are surface temperatures and mostly overland. The temperature in
upper levels may be different, even reversed.
What cause the temperature of the
atmosphere to go up?
• There are many possible mechanisms that can cause the
warming of the atmosphere, for example:
– Natural variation – the climate becomes warmer by internal chaotic dynamics
of the earth-atmosphere system (that is, no external influence).
– Solar activity – either direct increase of solar energy output or indirect
“trigger” mechanisms due to solar activity (though nobody knows how) may
cause the surface temperature to go up.
– Greenhouse effect – increasing “greenhouse” gases such as CO2, CH4, NO,
CFC,…etc. (actually H2O is very efficient, too, but at present it is assumed to be
in steady state).
• The last one is presently thought to be the most likely cause of the global
warming and hence we will examine it here in this chapter..
The real greenhouse
The (Atmospheric) Greenhouse Effect
Remember this chart?
•
•
Examples of greenhouse gases: H2O, CO2, CH4, CFC.
Currently, CO2 is the main suspect of causing the global warming since the
20th century because combustion of fossil fuel naturally injects CO2 into the
atmosphere and it has increased dramatically since last century.
Atmospheric Carbon Dioxide
•
This chart shows a steady increase of CO2 concentration in the last five
decades. Although this chart is based on Mauna Loa’s data, the same trend has
been found in many other places.
South Pole and Barrow, Alaska, show
the same trend as Hawaii
How is the CO2 increase connected to
the global warming?
• Physically, via the greenhouse effect.
• The connection is usually made via the use of a
climate model.
• Control run versus scenarios.
• If the scenario run results show warmer surface
condition than the control, then it is plausible to
suspect that the increasing CO2 concentration in the
atmosphere may cause warming.
Feedback Effect
• The climate system is very complicated. A change in one
component of the system may cause changes in other
components. Sometimes the changes in other components
enhance the initial change, then we say that these changes
have positive feedback to the system. If the changes result in
the reduction of the original change, then they have negative
feedback.
• Both positive and negative feedback processes may exist in
the climate system. In studying the global climatic change, we
cannot make conclusions based on intuition, but have to take
all such possible complicated effects into account. A good
climate model would have treated all of them realistically.
An example of positive feedback
• When the climate becomes warmer (either due to
the increase of CO2 in the atmosphere or other
unknown mechanisms), the ocean may also become
warmer. A warmer ocean has lower solubility of CO2
and hence will release more CO2 into the
atmosphere. This may cause the climate to become
even warmer than before. Thus the dependence of
solubility of CO2 on temperature has a positive
feedback on the climate system.
An example of negative feedback
• Consider a clear region over the ocean. Since there is no
cloud, the sun shines on the ocean surface, causing it to warm
up. This makes this part of the ocean warmer than other parts
and the air over it tends to rise (causing convection). As we
have learned before, rising air expands and cools, causing
clouds to form. The formation of clouds will block out the sun
and the solar heating of the ocean surface will cease. The
surface will start to cool down. Thus the cloud formation due
to surface heating and convection is a negative feedback to
the climate system.
How fast will the CO2 concentration increase?
• There are various estimates of the CO2 increasing rate. They are
different in the statistical models used (for example, linear vs.
nonlinear increase) and the future regulations.
Projection of future warming
Vertical distribution of temperature in radiativeconvective equilibrium for various values of
atmospheric CO2 concentration, i.e., 150, 300, and
600 ppm by volume. From Manabe and Wetherald
(8).
The degree of warming will not be uniform everywhere
higher latitudes are more sensitive
Source: IPCC
If temperature can change, so do other meteorological and
environmental variables.
• The change in
temperature may cause a
change in precipitation.
• Vegetation may also
change in response to
temperature and
precipitation changes.
• And there will be changes
in the animal and human
world in response to
these environmental
changes.
Source: NOAA
Melting ice and
rising sea level
Receding high mountain glaciers
Ice shelves of the South Pole have
partly separated and are collapsing.
(NASA)
Of course the physical environmental
change will lead to changes in the
biosphere – including our society.
Not everybody is convinced of the greenhouse
gases - global warming theory
•
•
•
At this point, it appears that the
warming itself is real – the surface
temperature indeed becomes higher
in the last few decades.
The question is – Is the warming
caused by the greenhouse gases
(especially CO2)?
Some groups, especially the IPCC
members argue strongly for it. But
there are other groups that are not
convinced. The summary to the right
is from Robinson et al. (1998).
Summary
World leaders gathered in Kyoto, Japan, in
December 1997 to consider a world treaty
restricting emissions of ''greenhouse gases,''
chiefly carbon dioxide (CO2), that are
thought to cause ''global warming'' severe
increases in Earth's atmospheric and
surface temperatures, with disastrous
environmental consequences. Predictions of
global warming are based on computer
climate modeling, a branch of science still in
its infancy. The empirical evidence actual
measurements of Earth's temperature
shows no man-made warming trend. Indeed,
over the past two decades, when CO2 levels
have been at their highest, global average
temperatures have actually cooled slightly.
You can get this from the following website
http://www.oism.org/pproject/review.pdf
You can get IPCC reports at http://www.ipcc.ch/
Some examples of criticisms
•
•
There are evidence showing that
the current temperature isn’t really
that warm compared to what was
two to three thousand years ago.
The figure to the right shows that
the temperature of Sagaso Sea
fluctuates in a range of ~ 3.6°C.
Also the “trend” depends on the
data sets and the section of data
you select to examine – see the
lower chart. By using a different
data set (here the satellite
microwave sounding) and selecting
a suitable section (for example,
1978-1998) you can actually show
that there was a cooling, not
warming.
Source: Robinson et al. (1998)
There are also evidence showing that the solar activity seems to
have some influence on atmospheric temperature. But there are
many questions here. Especially on how and how much.
Global Warming: More than a scientific problem - Aside from
scientific problems, there are political problems as well.
At Climate Meeting, Unlikely Ally for HaveNots
By AMY WALDMAN
New York Times 1 Nov 2002
NEW DELHI, Friday, Nov. 1 — When
India's prime minister, Atal Bihari Vajpayee,
finished speaking at the international
conference on climate here on Wednesday,
the fissure between richer and poorer
countries over how best to tackle global
warming could no longer be papered over.
In his speech, he argued that poorer
countries could not be expected to invest
money in tackling the causes of global
warming. They bear little responsibility, he
said, producing fewer greenhouse gases
than industrialized countries, and yet have
been hit harder by the natural calamities,
from drought to floods, caused by climate
changes. They have weaker economies,
and with pressing needs in everything from
health to education, can little afford to invest
in clean-air technologies.
His speech articulated sentiments —
resentments, in some cases — widely
shared among developing nations. So while
it produced little new of substance, the
conference, the eighth since the United
Nations Framework Convention on Climate
Change was adopted in 1992, illuminated
the challenges in crafting a global response
to global warming.
It highlighted a divide between north and
south, between the industrialized and
developing worlds, over who should bear the
obligations and burdens of trying to reduce
the emissions that cause global warming.
But on several points, the south found itself
with an unlikely ally: the United States,
which under the Bush administration has
also blanched at joining efforts to reduce
emissions.
Instead, the United States joined India and
other developing countries in encouraging a
focus on developing the technology and
finding the resources to adapt to climate
change.
You can go back even further…
• Back even further in
time, the CO2 level in
the atmosphere
fluctuated
considerably and
sometimes the
concentration might
be much greater than
it is now.
Crowley & Berner, Science 2001;292(5518);870–872.
Ultimately
• The problem really is that we don’t know how the climate machine
works, hence it is difficult at present to say that the warming is due
to the increase of greenhouse gases and not the results of natural
fluctuation of the global climate system.
• Recently, there seems to be increasing evidence showing the
connection between the global warming and industrial injection of
greenhouse gases. However, the extent is still not clear.
• Hopefully, with more research we can say more definitely in the
near future.
Effects of Ozone Depletion
The Discovery
• In 1985, using satellites, balloons, and surface
stations, a team of researchers had discovered a
balding patch of ozone in the upper stratosphere,
the size of the United States, over Antarctica.
British Atlantic Survey Research station, Holly Bay, Antarctic coast
Team who discovered the hole 1985.
From left: Joe Farman, Brian Gardiner, and Jonathan Shanklin
Total Ozone Mapping Spectrometer (TOMS)
• Used by NASA to measure ozone
concentrations
• TOMS – a satellite-borne
instrument
• TOMS launched in 1996 – makes
35 measurements every 8 seconds
• Levels of ozone are measured in
Dobson units (DU), where 100 DU
is equivalent to a 1 millimeter
thick layer of pure ozone
Artist's view of the QuikTOMS spacecraft (image credit:
NASA)
Earth’s Atmosphere
The ozone layer
•Ozone is a triatomic form of
oxygen (O3) found in Earth’s upper
and lower atmosphere.
•The ozone layer, situated in the
stratosphere about 15 to 30 km
above the earth's surface.
•Ozone protects living organisms by
absorbing harmful ultraviolet
radiation (UVB) from the sun.
•The ozone layer is being destroyed
by CFCs and other substances.
• Ozone depletion progressing
globally except in the tropical zone.
www.epcc.pref.osaka.jp/apec/ eng/earth/ozone_layer_depletion/susumu.html
Hole Formation Based on Two different mechanisms:
• Meteorological
mechanism
– Movement of air from
one place to another in
the upper stratosphere
– Cold temperature in the
upper atmosphere
causes nitric acid to
freeze into crystals
forming wispy pink
clouds
– Forms a vortex of
tightly twisted winds
thus forming a hole in
the upper atmosphere
Chemical Mechanism
• Different chemicals are responsible for the destruction of the ozone
layer
• Topping the list :
– chlorofluorocarbons (CFC’s)
– man-made, non-toxic and inert in the troposphere
– In the stratosphere are photolysed, releasing reactive chlorine
atoms that catalytically destroy ozone
A combination of low temperatures and elevated chlorine
and bromine concentrations are responsible for the
destruction of ozone in the upper stratosphere thus
forming a “hole”. (Kerr, 1987)
www.met.sjsu.edu/~cordero/ education/education.htm
Ozone levels over North America (USEPA, March 1994)
No Data
No Data
www.epa.gov/air/airtrends/ aqtrnd95/stratoz.html
• Comparing
the colors of the bands over a particular city, such as
Seattle, shows lower ozone levels in 1994 than in 1979
• Over
the U.S., stratospheric ozone levels are about 5 percent below
normal in the summer and 10 percent below normal in the winter
Stratospheric Ozone and Ultraviolet Radiation (UVR)
• Ultra-violet radiation (UVR) high energy electromagnetic wave emitted from the
sun. It is made up of wavelengths ranging from 100nm to 400nm.
• UV radiation includes UV-A, the least dangerous form of UV radiation, with a
wavelength range between 315nm to 400nm, UV-B with a wavelength range
between 280nm to 315nm, and UV-C which is the most dangerous between 100nm
to 280nm. UV-C is unable to reach Earth’s surface due to stratospheric ozone’s
ability to absorb it. (Last, 2006)
Too much ultra-violet light can result in:
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Skin cancer
Eye damage such as cataracts
Immune system damage
Reduction in phytoplankton
Damage to the DNA in various life-forms
– this has been as observed in Antarctic ice-fish that lack
pigments to shield them from the ultra-violet light (they've
never needed them before)
• Possibly other things too that we don't know about at
the moment
Effects of UV radiation on biological organisms
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•
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DNA damage ………………………….. Maximum effect on small and single cell
organisms
Impaired growth and photosynthesis ...poor crop yields
Phytoplankton: ………………………...Reduced uptake of CO2
…………………………………………..mortality
…………………………………………..Impaired reproductive capacity
Nitrogen-fixing soil bacteria…………. Reduced, damaged
Human health effects:
Suppressed immune system……………..Enhanced susceptibility to infection
…………………………………………..Increase risk of Cancer
Dermatology (skin)……………………...Sunburn
…………….………………………….....Loss of skin elasticity (Premature aging)
…………….…………………………… Photosensitivity
Neoplasia (cancer)……………………....Melanocytic (malignant melanoma)
…………….………………………….....Squamous cell skin – cancer
…………….……………………………Basal skin – cancer
Still questionable if causes lip cancer or cancer of
the salivary glands
Oculur (Eye)….…………………….......Cataract
…………….…………………………....Pterygium
Aquatic Ecosystems
oceancolor.gsfc.nasa.gov/. ../phyto_zoo.jpg
Krill
www.ciesin.org/docs/ 011-558/011-558.html
Phytoplankton
• UV-B penetrates water columns to depths of 30m
• Increased UV-B exposure
– Reduces productivity by interfering with processes of photosynthesis
– Damages DNA
– Alters nitrogen metabolism
– Inhibits mobility
• Studies (1993) conducted in the Weddle Sea
– Evaluated effects of photosynthesis to UV exposure in the presence of vertical
mixing, found:
• photosynthesis by phytoplankton was strongly inhibited near the surface of
the water
• rapid mixing, photic zone is extended, severe inhibition of photosynthesis
•
Play critical role in aquatic system
Bacterioplankton
– Decomposers - absorb dissolved organic carbon and recycle it back into the
environment
– Primary producers – found at the center of food web
•
Prone to UV-B stress
– Inhibits growth
– Interferes with mechanisms for nitrogen fixation and carbon dioxide fixation
– High mortality
•
Effects dependent on:
– Where found in the water column
– Amount of exposure
– Amount of protection when moving from one mixing layer to another
•
Adaptive Strategy:
– Pigmentation – absorb more than 90% of UV-B before it penetrates to the genetic
material
– Form external filaments which protect them from excess UV-B
Macroalgae and Seagrasses
• Are sessile and restricted to growth site
• Have diverse habitats
– Above tidal zones
– Intertidal zones
– Some never exposed to air
• Have adapted to varying solar exposure
– Able to protect themselves from excessive radiation using
mechanisms of phototinhibition
• mechanisms (electron transport) decrease photosynthesis during
excessive radiation
Plants
The influence of the UV-B radiation on plant process.
Environmental Effects of Ozone Depletion: 1994 Assessment
DNA & UV-B
•
DNA absorbs UV-B radiation
• Changes shape in DNA
– Changes in the DNA molecule mean that
enzymes cannot “read” the DNA code
– Results in mutated cells or the cells die
• Cells have developed the ability to
repair DNA
– A special enzyme arrives at the damage
site
– removes the damaged section of DNA
– replaces it with the proper components
• This makes DNA somewhat resilient
to damage by UV-B
•
Higher
Plants
Experiments were done to determine if
increased UV-B is a threat to terrestrial
vegetation:
– Found
• High UV-B exposure does induce
some inhibition of photosynthesis
However….
•
Studies found no significant effects on
photosynthetic productivity
•
Some researchers have concluded that
ozone depletion and increase of UV-B
not a direct threat to photosynthetic
productivity of crops and natural
vegetation (Allen, 1998)
Difficult to Unmask UV-B Effects
• Limitations in controlled and field studies include:
– Large differences in temperature, precipitation, soil types
from year to year and in different locations
– UV-B radiation masked by other stresses of land plants
such as drought
• Drought produces large reductions in photosynthesis
and growth masking the effects of UV-B
• Water stressed plants produce a high concentration of
leaf flavonoids (for pigmentation) providing greater
UV-B protection
Environmental Effects of Ozone Depletion: 1994 Assessment
Flowering
• UV-B radiation can alter both the
time of flowering as well as the
number of flowers in certain
species.
• Differences in timing of
flowering may have important
consequences for the availability
of pollinators.
• The reproductive parts of plants,
such as pollen and ovules are
well shielded from solar UV-B
radiation.
Can plants protect themselves against increased UV-B?
Plant adaptation:
– Have UV shielding
– Only a small proportion of the UV-B radiation striking leaf
penetrates into the inner tissues
– When exposed to increasing amounts of UV-B, many species
of plants can increase the UV-absorbing pigments in their
tissues
Other adaptations include:
– Increased thickness of leaves reducing the proportion of
inner tissues exposed to UV-B radiation
– Have repair mechanisms in plants
– includes repair systems for DNA damage
www.unep.ch/ozone/faq-env.shtml -
Amphibians
Global Decline Seen In Amphibians
• Range of explanations as to why
amphibians are declining, which
include:
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–
–
Habitat destruction
Disease
Parasites
Introduction of exotic species
Environmental contaminants and other aspects
of global climate change
UV-B radiation is still high on the list for the
decline in amphibians seen around the world
• Causes damage to many species of amphibians at
every stage of their life cycle, from egg to adult
• Affects growth and development in larvae
• Causes
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–
–
–
Changes in behavior
Deformities
Make amphibians more vulnerable to disease and death
In adults, causes retinal damage and blindness
UV-B Effects on Human Effects
Effects on Human Health
• Over exposure may:
– Increase risk of nonmelanoma and malignant
melanoma skin cancer
• Higher risks of
malignant melanoma
from severe
sunburns –
especially in
childhood
• Risk of malignant
melanoma has
increased 10%
• Risk of
nonmalignant
melanoma has
increased 26%
www.ldeo.columbia.edu/.../ lectures/ozone_health/
Non-malignant
malignant
Over Exposure
– Suppress immune system
– Accelerate aging of skin due high exposure
– Cause an outbreak of rash in fair skinned people
due to photo allergy – can be severe
dermis.multimedica.de/.../ en/13007/image.htm
Skin Protection
• Protect the skin against the solar radiation
using skin creams with SPF
– The greater the numerical value of the SPF the
greater the protection
• Use lip balm with SPF
• Cover up
Over Exposure to UV-B….
• Increases the risk of
cataracts
– Induces type of protein
that provokes cleaving
(splitting) in the lens
– Leading cause of
blindness
– The prevalence of
cataract after age 30 is
doubling each decade
vitreous humor
then the lens
• Causes pterygium
– A wedge-shaped
growth over the central
cornea
www.ldeo.columbia.edu/.../ lectures/ozone_health
cornea is encountered first
Manifestations of…
Cancer
Cataracts
brought on by
over exposure to
UV-B
Pterygium
Protection
•
•
•
•
Sunglasses with 100% UV block
Wrap around sunglasses
Eye protection for children
Hats
What Is Being Done to Counter the Effects of Ozone
Depletion?
• Montreal Protocol (adopted in 1987) – panel
of experts was formed to investigate substances
responsible for hole formation
– Established policies that prevent future use of
certain types of chemicals
– Stipulated that the production and consumption of
compounds contributing towards depletion of
ozone in the stratosphere were to be phased out by
the year 2000 (2005 for methylchloroform)
The Environmental Protection Agency (EPA)
• Responsible for enforcing the Montreal
Protocol within the U.S.
– The EPA has several programs in place;
• Regulating and enforcing on-road car and truck airconditioning systems
• Regulating most air-conditioning and refrigeration
appliances
• Technician certification
• Service equipment
Signs of Recovery???
There have been some signs of recovery
– 1997 satellite showed a decline of several known ozonedepleting gases
– Satellite images show some slowing down of ozone loss
However….
Antarctica - Dec. 2005
Recovery is slow
www.coolantarctica.com/. ../ozone_hole.htm
Images of Antarctica Taken Indicate A Slow
Recovery
Understanding the future
Researchers would like to see:
• Stations that measure levels of ozone and surface radiation
changes in relation to incidence rate of skin cancer and cataracts
- installed in urban areas and in remote regions far from
populations
• More studies to determine biological effects (including human)
on UVR exposure
• Research on protective creams and ointments and their
efficiency in preventing skin cancer and malignant melanoma
• More surveillance of UV-related damage to other species living
in high latitudes for example…..
Reports of Sheep in Iceland developing eye
disease – no research to support
(Last, 1993)
Future Evolution of Ozone
• Remains unclear
– Current models are unable to reproduce ozone variability
accurately
– Rates of future increases in greenhouse gases are not yet
established
– Interactions between ozone depletion and climate change
not yet fully understood
• Continued monitoring of ozone and ozone-depleting
substances is essential
– Ozone layer recovery expected by 2050
– Hinges on the complete elimination of atmospheric ozonedepleting substances
– Replacements for HCFCs, methyl bromide, and halons are still
being sought, and studies of the new compounds must continue
(U.N.E..P. Progress Report, 2003)
Summing It All Up
• The Ozone is Earth’s only defense against harmful UVR
• Studies indicate ozone thinning throughout the globe due to 2
mechanisms:
– Meteorological
– Chemical
• Research indicates microorganisms, are extremely sensitive to
increasing UV-B levels
• There is a lot of uncertainty and debate among researchers as to the
degree in which land plants are affected by UV-B
• There is debate in the scientific community in the role UV-B radiation
plays on the decline of amphibians seen globally
• In the last decade, there has been an increase in skin cancer and
cataracts all related to increase UV-B exposure
Efforts Need to Be Continued
• Create reliable models
– To gain a better understanding of the effects ozone
depletion has on organisms living within different
ecosystems
• Enforcement of Montreal Protocol
– To reduce concentrations of chemicals responsible for
ozone depletion
• Monitoring chemicals being emitted
• Gain a better overall understanding on just how ozone
depletion is affecting our planet
...
Questions
• What are the 2 mechanisms responsible for ozone
depletion? Explain each mechanism.
• Explain 4 effects of ozone depletion.
• What efforts have been implemented to counter the
effects of ozone depletion? Are there any signs that
these efforts are working?
• What are some things scientist would like to see done in
order to gain a better understanding on the effects of
ozone depletion?
Bibliography
Allen, D.J., S. Nogues, and N. Baker. 1998. Ozone depletion and increased UV-B radiation: is there a real
threat to photosynthesis? Journal of Experimental Botany. Vol. 49, No. 328, pp. 1775 – 1788.
Executive: summary: Scientific Assessment of Ozone Depletion: 1994, World Meteorological Organization, Geneva,
[World Meteorological Organization Global Ozone Research and Monitoring Project – Report No. 37]
Antarctic Ozone Bulletin: 2005, World Meteorological Organization, 2006. [Antarctic Ozone Bulletin No 8/2005
Winter/spring summary]
Bojkov, R.D., V.E. Fioletov. 1996. Total ozone variations in the tropical belt: An application for quality of ground
based measurements. Meteorology and Atmospheric Physics, - Springer
Britt, A.B.2000. Plant Biology: An unbearable beating by light? Nature. 406, 30 – 31.
Descamps, F.J., E. Martens, P. Proost, S. Starckx, P. E. VandenSteen, J.VanDamme and G. Opdenakker. 2005.
Gelatinase B/matrixmetalloproteinase-9 provokes cataract by cleaving lens BB1 Crystallin. The FASEB
Journal. 19:29-35.
Environmental effects of ozone depletion and its interactions with climate change: Progress Report 2003; United
Nations Environmental Programme, Environmental Effects Assessment Panel 2003. [The Royal Society of
Chemistry and Owner Societies 2004] Photochemistry and Photobiology Science 2004, 3, 1 – 5.
Hader D.P., H.D. Kumar, R.C. Smith, and R.C. Worrest. 1998. Effects on aquatic ecosystems. Journal of
Photochemistry and Photobiology. B: Biology 46: 53 – 68.
Kerr, R. 1987. Winds, pollutants drive ozone hole. Science. 238: 156 – 159.
Last, J.M. 1993. Global change: Ozone depletion, greenhouse warming and public health. Annual Review
of
Public Health. 14: 115-36.
M.M. Caldwell (USA), A.H. Teramura (USA), M. Tevini (FRG ), J.F. Bornman (Sweden),
L.O. Björn (Sweden), and G. Kulandaivelu (India). EFFECTS OF INCREASED SOLAR
ULTRAVIOLET RADIATION ON TERRESTRIAL PLANTS . Environmental Effects of Ozone
Depletion: 1994 Assessment
Neale P. J., R. Davis, and J. Cullen. 1998. Interactive effects of ozone depletion and vertical mixing on
photosynthesis of Antarctic phytoplankton. Nature. 392, 585 – 589.
Randal, W.J. and F.Wu. 1999. Cooling of Artic and Antarctic Polar Stratosphere due to depletion. Journal
Climate. 12; 1467 – 1479.
Shell, E.R. 1988. Solarflights into the ozone hole reveal its causes. Smithsonian.
Smith, R. C., B. B. Prezelin, K. S. Baker, R R. Bidigare, N. P. Boucher, T. Coley, D. Karentz, S. MacIntyre, H. A. Matlick, D.
Menzies, M. Ondrusek, Z. Wan, and K. J. Waters. 1992. Ozone depletion: Ultraviolet
radiation and phytoplankton biology in Antarctic waters. Science 255: 952U.S. Environmental Protection Agency. Ozone Depletion Rules & Regulations
www.epa.gov/ozone/enforce/index.html
Van Der Mei, I.A., A.L. Ponsonby, T. Dwyer, L. Blizzard, R. Simmons, B.V. Taylor, H. Butzkueven and T. Kilpatrick. Past
exposure to sun, skin phenotype and risk of multiple sclerosis: case-control
study. British Medical Journal, 2003, 327, 316 – 322.
Whitehead R. F. S.de Mora, and S. Demers. 2000. Enhanced UV radiation – a new problem for the marine
environment. Cambridge Environmental Chemistry Series (No. 10)
World Meteorological Organization, Geneva, 2003. Executive: summary: Scientific Assessment of Ozone
Depletion: 2002. [Reprinted from Scientific Assessment of Ozone Depletion: 2002, Global Ozone
Research and
Monitoring Project – Report No. 47, 498 pp., World Meteorological organization,
Geneva, 2003.]
www.cmdl.noaa.gov/.../ wmobro/graphics/fig9m.gif
www.ntt.co.jp/.../ detail/detail_281.html
www.coolantarctica.com/. ../ozone_hole.htm
www.dermis.multimedica.de/.../ en/13007/image.htm
www.epa.gov/air/airtrends/ aqtrnd95/stratoz.html
www.ldeo.columbia.edu/.../ lectures/ozone_health/
www.met.sjsu.edu/~cordero/ education/education.htm
www.unep.ch/ozone/faq-env.shtml
Alien plant and Animal invasion
•
•
•
Alien plants have been introduced in
SA from South America and Australia
as dune stabilizers (Hakea),
ornamental trees (Jacarandas),
edible plants (prickle pear),
ornamerntals (jointed cactus, parrots
feather), firewood (Hakea) and
furniture wood (Acacia).
These aliens are now choking the
local rivers and dams (water
hyacinth), crowding out Fynbos in the
South Western Cape (Hakea) and
encroaching on pastures in the EC
(Nasella tussock grass, jointed
cactus).
Other examples check table 3, page
42 of your guide.
•
•
Gumtrees grow faster in southern
Africa than in their native Australia.
Alien plant natural parasites or
predators are not in SA. Atleast 314
plant species have invaded SA nature
reserves. Introducing their predators
such as weevils, which consume the
seeds of Hakea and Kariba weed, can
effectively control certain plant
species. Biological control is only part
of the answer.
Five species of birds and the redeared terrapin, among others are
animal invaded SA. They are
aggressive species and threatened
indigenous animals occupying the
same ecological niche.
The Traditional Healer and the Ecology
•
•
•
Traditional healers use plant and
animal materials for medicinal
purposes. Some use raw materials
derived from threatened plant and
animal species.
These include pangolin scales, tissue
from vultures, bateleurs and pythons,
lion fat, rhinoceros horn and
crocodile skins etc. Large trees are
often killed by being ring barked.
Solutions offered: coveted animal
found dead channelled towards
them, plants specially grown for
them e.g. Natal parks board, SANBI.
Education play a major part.
•
Efforts to eradicate the trade by the
substitution of Western medicine are
not considered appropriate by
experts. What is your opinion about
it?
Arthropod Pests and Pesticide Use
•
•
The arthropods are by far the most
successful phylum of animals, both in
diversity of distribution and in
numbers of species and individuals.
They have adapted successfully to life
in water, on land and in the air.
About 80% of all known animal
species belong to the Arthropod about 800,000 species have been
described, and recent estimates put
the total number of species in the
phylum at about 6 million.
•
Arthropods are found in a greater
variety of habitats than any other
animal group; on top of mountains,
at great depths in the ocean and in
the icy wilderness of Antarctica. They
can survive great extremes of
temperature, toxicity, acidity and
salinity.
Harmful effects of arthropods
1.
Direct harm
a. Annoyance-flies interfere with your work and rest.
b. Venom-stings of scorpions and spiders may even cause death.
c.
Parasites-Fly larvae may cause myiasis, scabies and mange are caused
by Sarcoptes scabiei.
2. Transmission of diseases: Mechanical transmission; Biological transmission.
Pathogens spend a part of their life cycle in the arthropods. The stages are
Propagative, Cyclopropagative, Cyclodevelopmental and or Transovarian.
•
•
•
b) Cyclopropagative-The pathogenic organisms undergo a developmental
cycle in the arthropod with multiplication and change in form. Plasmodium
sp. In anopheline mosquitoes.
c) Cyclodevelopmental- The pathogenic organisms undergo a change in
form without multiplication. Filaria in mosquitoes.
Note: Read further at page 43 for more arthropods species in South Africa and
problems caused by insecticides.
Arthropods Pests
Bedbugs, Cockroaches, Ticks, Mites, Lice, Mosquito, Termites
Symptoms of Insecticide Poisoning
Over-stimulation of the nervous system is the most common symptom
of insecticide poisoning. Symptoms include excessive salivation,
uneasiness and a change in personality. As the condition progresses,
muscle tremors, change in pupil size (contracted pupils), vomiting and
diarrhoea occurs. Eventually if poisoning is severe, stiffness, paralysis,
and seizures are common. Death occurs from cardiovascular and
respiratory failure. Clinical symptoms generally progress rapidly and
persist for days and even weeks.
•
Steps to minimize the Hazards of pesticides to humans (page 45 -46) self-study and
for assessment purposes.
RODENTS
Any of various mammals of the order Rodentia, such as a mouse, rat, squirrel, or
beaver, characterized by large incisors adapted for gnawing or nibbling.
Rodents have the following health adverse and other negative effects of man:
 They destroy food crops and other food during cultivation, transport or storage,
amounting to millions of rand
 They damage piping, electric wiring, scaffolding, packaging and almost any other
substance
 They pollute the man-inhabited environment through urine, faeces and nesting
material
 They kill or injure domestic such as chickens, other birds, even cats and dogs. Even
babies have been attacked e.g. Alexandra Township, Gauteng.
 They can cause fires by gnawing through electric wiring or containers filled with
flammable substances
 They act as reservoirs of many diseases such as plaque, tick bite fever, rat
tapeworm, leptospirosis, murine typhus and endemic relapsing fever.
Economic Uses of Rodents
• These include:  Rodents are an excellent source of cheap protein. Many local
people consider the larger cane rat and the giant rat
delicacies.
 In India they are revered and cared for in special temples.
They also serve as totems for some African tribes.
 The make engaging pets and serve a socialization purpose in
this manner.
 They are used as diagnostic laboratory animals for certain
diseases e.g. haemorrhagic fever in laboratories
 They serve as a primary food source for many non-domestic
animals of ecological importance.
Control of Rodents
• Rodents can be controlled by some of the following methods:  Biological control by means of members of the Mustelidae, Viverridae and
small cats, including domestic cats.
 Spring traps
 Trapdoor cage trap
 Box traps
 Poison bait
 Fumigation
 Rat proofing.
For more information on the different controls see notes in page 47 – 48.
Sanitation in the Control of Arthropods and
Rodents
• The presence of vectors such as arthropods (flies, mosquitoes,
fleas, cockroaches, lice, mites, ticks and bedbugs) and rodents (rats
and mice0 in a house premises result from neglect of basic
cleanliness.
• Rodents and arthropods are vectors of disease and cause injury to
humans. In many cases, rats and mice, or insects and other
arthropods may not necessarily pose an immediate disease threat.
• Their numbers increase rapidly as standards of cleanliness and
maintenance decline.
• Pesticides (insecticides and rodenticides) may produce temp pest
control reduction, only permanent techniques such as sanitation
and pest proofing bring about long-term control.
Domestic Rats and Mice
• Rodent problems are common to most urban and most severe in
areas of substandard housing and urban blight.
• Rats and mice are responsible for spread of a number of diseases,
either directly, as by contamination of human food with their urine
or faeces, or indirectly by way of fleas and mites.
• The more common rodent-borne diseases are rat-bite fever,
leptospirosis, salmonellosis, trichinosis, murine typhus fever, and
plague. Rickettsialpox is transmitted from the house mouse to man
by the bite of the mouse mite.
• Control of rats and mice requires (a) sanitation to eliminate their
food and harbourage, (b) effective rodent proofing, and (c) efficient
supplemental killing programs.
Vertebrate Pests and Problem Animals
•
Regarding vertebrate pests and problematic animals read through page 49.
Legal alternatives for animal control
If problem animals become a nuisance there are legal, effective control methods
available. Assistance can be provided from the Poison Working Group or Provincial
Nature Conservation authority. A representative can provide specifics on the
following:
 Information on the species responsible for damage
 Proven methods to reduce or eliminate damage
 Sources for recommended animal control equipment , chemicals or suppiles.
Measure of Ecosystems Health ( read through page 50
Possible Solutions to Pollution, ozone depletion and global warming read from page
50 – 51 for self study
THE END…
I THANK YOU
GOOD LUCK ON YOUR CAREER
DREAMS
HOPE WE MEET AGAIN.
CHEERS