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 trendNote 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

• 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.

Remember this chart?

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 radiative-convective 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 everywherehigher 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

Ice shelves of the South Pole have partly separated and are collapsing. (NASA)

Receding high mountain glaciers

Melting ice and rising sea level

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 websitehttp://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 Have-Nots

By AMY WALDMANNew 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

Team who discovered the hole 1985. From left: Joe Farman, Brian Gardiner, and Jonathan Shanklin

British Atlantic Survey Research station, Holly Bay, Antarctic coast

• 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.

Artist's view of the QuikTOMS spacecraft (image credit: NASA)

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

Earth’s Atmosphere

•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.

The ozone layer

www.epcc.pref.osaka.jp/apec/ eng/earth/ozone_layer_depletion/susumu.html

• 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

Hole Formation Based on Two different mechanisms:

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)

• 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

(U.S.E.P.A. 1994)

www.epa.gov/air/airtrends/ aqtrnd95/stratoz.html

No DataNo Data

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:• 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 •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) …………….…………………………… PhotosensitivityNeoplasia (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

(last, 1993)

Aquatic Ecosystems

www.ciesin.org/docs/ 011-558/011-558.html

oceancolor.gsfc.nasa.gov/. ../phyto_zoo.jpg

Krill

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– 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

Bacterioplankton

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.

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

Can plants protect themselves against increased UV-B?

www.unep.ch/ozone/faq-env.shtml -

Amphibians

Global Decline Seen In Amphibians• Range of explanations as to why

amphibians are declining, which include:– 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

– 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 non-melanoma 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%

malignant

Non-malignant

www.ldeo.columbia.edu/.../ lectures/ozone_health/

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

www.ldeo.columbia.edu/.../ lectures/ozone_health

cornea is encountered first

then the lens

vitreous humor

• 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

• Causes pterygium– A wedge-shaped

growth over the central cornea

Over Exposure to UV-B….

Manifestations of…

Cataracts

Pterygium

Cancer

brought on by over exposure to UV-B

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 air-conditioning 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 ozone-depleting gases

– Satellite images show some slowing down of ozone lossHowever….

www.coolantarctica.com/. ../ozone_hole.htm

Recovery is slowAntarctica - Dec. 2005

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 ozone-

depleting 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?

BibliographyAllen, 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: 952-U.S. Environmental Protection Agency. Ozone Depletion Rules & Regulations www.epa.gov/ozone/enforce/index.htmlVan 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.gifwww.ntt.co.jp/.../ detail/detail_281.htmlwww.coolantarctica.com/. ../ozone_hole.htmwww.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 red-eared 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 controlIf 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 50Possible Solutions to Pollution, ozone depletion and global warming read from page 50 – 51 for self study

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