Eco Assignment 7 – Grade 12

Climate and weather

1) Explain in which way climate influences human activities such as
i) the kind of crops they grow,
ii) the way they dress,
iii) how they build their homes and
iv) where they go on vacation.
2) Global warming, by all present indications, will affect South Africa by causing temperatures to rise in summer and winter, rainfall may diminish, CO2 in the atmosphere may double and soil moisture will probable decrease. Discuss the following scenarios that may result as consequence:
• Variable agricultural yields (depletion of surface and ground water)
• Livestock production (poor and variable rangeland productivity and desertification)
• Afforestation (deficient rainfall)
• Unreliable hydro-electric power generation (dropping dam levels)
• Wildlife population decrease (droughts and expansion of human settlements)
3) Urban Heat Islands (UHI) refers to climatic conditions in urban areas that differ from neighboring rural areas. The causes are related to urban development as it hugely impacts on the area’s atmosphere. Discuss the phenomenon of Urban Heat Islands (UHI) by explaining the following:

i) Contributing factors:
• The role of buildings
o Heat capacity and thermal conductivity
o Urban canyoning effect with multiple absorption and reflective surfaces
o Blocking of wind and inhibiting cooling by means of convection
• The role of waste heat (cars, air conditioning, industry…)
• The role of air pollution
• The role of road infrastructure

ii)  Secondary effects:
• Longer growing seasons (increased rates of precipitation)
• Extreme heat (affecting air and water quality causing sickness and death to humans and ecosystems)
• Increased energy requirements (air conditioning, refrigeration…)

iii) Ways to lessen the impact
• Planting trees and shrubs
• Use light or reflective materials on houses, roofs, pavements and roads
Fluvial processes and landforms

1) The health of water bodies has a tremendous impact on the animals and plant life living in it as well as feeding from it. The clarity and purity of water bodies are greatly affected by erosion. Explain how the loss of vegetation and the use of chemicals in agriculture jeopardises the ecological role of water bodies.

2) The topography of the landscape plays a major part in the appearance of catchment areas (also known as drainage basins) Explain how drainage basins provides for healthy natural ecosystems by ensuring:
i) Convergence of surface water (topography) at single points (river, lake, reservoir, estuary, wetland, sea, or ocean)
ii) Manipulation of the amount of surface water reaching water bodies. Refer to the roles of factors such as the size of the catchment area, the type of soil and the land use.

3) Describe the significance of various human activities (such as agricultural practices and the building of dams) as it impacts on regulating the flow of water and its availability downstream.
4) From: Wikipedia, the free encyclopedia (

During the 17th and 18th centuries, Easter Island experienced severe erosion due to deforestation and unsustainable agricultural practices. The resulting loss of topsoil ultimately led to ecological collapse, causing mass starvation and the complete disintegration of the Easter Island civilization.

Due to the severity of its ecological effects, and the scale on which it is occurring, erosion constitutes one of the most significant global environmental problems we face today.

Land degradation: Water and wind erosion are now the two primary causes of land degradation; combined, they are responsible for 84% of degraded acreage.

Each year, about 75 billion tons of soil is eroded from the land—a rate that is about 13-40 times as fast as the natural rate of erosion. Approximately 40% of the world’s agricultural land is seriously degraded. According to the UN, an area of fertile soil the size of Ukraine is lost every year because of drought, deforestation and climate change. In Africa, if current trends of soil degradation continue, the continent might be able to feed just 25% of its population by 2025, according to UNU’s Ghana-based Institute for Natural Resources in Africa.

The loss of soil fertility due to erosion is further problematic because the response is often to apply chemical fertilizers, which leads to further water and soil pollution, rather than to allow the land to regenerate.

Based on the facts mentioned in the paragraph above, explain the importance to preserve and restore soil. You may use the following headings to guide your answer:
• The effects of soil erosion (loss of agricultural fertility, desertification, loss of habitat, additional sedimentation, ecological collapse)
• The causes of soil erosion (removal of vegetation, wrong farming methods, urbanization and roads, climate change)
• The types of erosion (sheet-, rill-, gully- and riparian erosion; soil leaching and wind erosion)
• Preventative measures (increase of vegetation, crop rotation, reforestation, strip cropping, restoring soil fertility, control of grazing, terracing, wind-breakers.
People and Places: Rural and Urban settlement

1) Discuss the effects that urbanization and overcrowding of cities have on the environment. You can refer to the list below.
• Inadequate fresh water (drinking, sewerage treatment, effluent discharge)
• Depletion of natural resources
• Increased levels of air pollution, water pollution, soil contamination and noise pollution
• Deforestation and loss of ecosystems
• Changes in atmospheric composition and consequent global
• Irreversible loss of arable land and increase of desertification
• Mass species extinction from reduced habitat
• Intensive factory farming to support large populations

2) Discuss the effects that urbanization and overcrowding of cities have on human health.
• Increased chance of the emergence of new epidemics and pandemics
• Starvation and malnutrition
• Unhygienic living conditions
• Elevated crime rate
• Conflict over scarce resources and crowding
• Less personal freedom and more restrictive laws.
3) South Africa’s Urbanization rate is 65% compared to the world rate of 55%. The main reason for this increasing trend is that work opportunities are more plentiful and pays better in towns and cities than in the most rural areas. The rural areas thus experience an exodus of young talent while the cities are unable to cater for the huge influx of people.

Explain why the following conditions prevail in the majority of rural areas:
• The population of old people increase in rural areas
• Restricted development of provinces with extensive rural areas – as it is often restricted by its contribution to the country’s annual GDP
• Extra high population of children to take care off in the face of limited resources and little economic support from government
• A high population of senior citizens (over the age of 65) at the mercy of a decreasing younger generation
• Only a small percentage of the state budget that goes to public health, shifting the burden to the public sector

4) 70% of South Africa’s ultra-poor live in rural areas.

i) Describe the general survival strategies of the extreme poor in rural areas and the challenges that it presents:
• Subsistence farming (requires land, water, seed, fertilizer, equipment) and fishing (burdened by permits, quotas and seasonality)
• Pensions or social grants
• Remittances
• Child labour (assisting parents or work on commercial farms)
• Bearing more children
• Limited education

ii) Explain some of the causes of rural poverty and misery
• Limited economic opportunities in rural areas
o Lack of transport infrastructure
o Remote location
o Limitations in capacity
o Low product demand
o Small market leads to higher prices on services and products
• Limited education and training opportunities
• Lack of access to proper health-care
o Lack of willingness for professionals to serve in rural areas
o The effects and causes of HIV and Tuberculosis
• Lack of arable land
People and Needs:  Economic Activities
The role of decision-makers is important as they will decide on the location of:
• industries – if these are near residential areas, those residents may suffer bad health
• informal settlements – the presence of informal settlements my influence the value of nearby residential areas
• agriculture / livestock – due to the increased uncertainty in the pricing and delivery of various products and services are moving many to consider  subsistence farming as well as raising chickens and growing vegetables from home.

Discuss your own view and offer probable solutions for the future of especially low-income groups.

1) Unlike other renewable resources as the sun, wind and tide, freshwater is not plentiful. South Africa is a water-scarce country and is experiencing ever-increasing demands to supply water. Causes for these challenges can be grouped under the three headings, Natural causes; Human activities and Socio-political causes. Please discuss.


• Looming climate change
o prolonged droughts
o more severe flooding

Human activity

• Population growth
o bigger agricultural demands (food security
o greater effects on environment (chemicals
• Land-use
o Poor land management
 Wrong techniques
 Little understanding of soil/water interface
 Developing water-thirsty crops in catchment areas – water scarcity downstream
o Reduction of vegetation cover
o Greater run-off – reduce water infiltration (water-table and soil fertility)
o Storage capacity of dams decrease – siltation
o ‘Water-thirsty crops’ in catchment areas – run-off reduced

• Pollution
o Agricultural return flow, industry, domestic use
o Reduced availability for use
o Affects groundwater
o Affects humans and living organisms depending on it for life sustenance
o Affects coping methods of river – harder when river environment is degraded

• Biodiversity and habitat destruction
o Reduction of vegetation cover – lan degradation and erosion
o Deforestation and drainage of wetlands – upsetting micro climates

Socio political

• Ineffective legislation to:
o Reduce demand for water
o Enforce greater efficiency of use
o Enforce water conservation methods
• Ineffective staff to deal with
o Integrated approach required
o Communication with local authorities
• Wrong general conception
o There is plenty of water in Southern Africa
o Only hindrance – to get it to the right places at the right times
2) Discuss some possible solutions by which the looming water crisis might be treated on a practical level, theoretically and from a governance point of view.

Practical Solutions
• Underground aquifers when rainfall is scarce
• Use storage tanks and rain harvesting techniques
• Conserve soil moisture and structure
• Use drought-tolerant crops

Theoretical Solutions
• Richer countries can make a ‘water-footprint’ measure compulsory on all products
• Water should be priced – not just the water-supply infrastructure

Governance Solutions
• Effective coordination between various departments dealing with water issues, pulling together both human and environmental needs.
• Avoid ‘land-grabs’ from vulnerable people who rely on the land for sustenance
• Taking serious the UN General Assembly recognition in July 2010 – “the right to safe and clean drinking water and sanitation as a human right.”
• A cohesive strategy for climate change, biodiversity, desertification and water-management on international level

Discuss the theory of evolution as understood by Jean Baptiste de Lamarck and Darwin and offer some arguments against evolution for example the age of the earth and nature’s tendency to disorderliness.

Extinction happens when a species is no longer able to survive or reproduce in its environment and cannot move to a new environment where it can do so. Realising that species extinction was in the increase, Sir Peter Scot from the World Conservation Union in 1963, published the first Red Data Book which has been updated regularly since. South Africa’s Red List indicates that nearly 20% of our mammal species are either critically endangered, endangered, or vulnerable.

The species that are critically endangered are the five species of the golden mole, 2 species of bats, the black rhino, riverine rabbit and Ngoye red squirrel (10 animals in total). These animals face extinction and there is very little chance that of these animals being seen in the wild. Eighteen of South Africa’s species are endangered and there is a high risk of them becoming extinct. Twenty-nine of our species are vulnerable. And intervention is required to ensure their continued existence. Species that my fall in one of the categories mentioned in the near future are near-threatened or threatened. In regard to the survival of species they may also be referred to as data deficient or ‘least concern.’
1) Discuss what the possible consequences might be for the animal, organisms and ecosystems when they appear on Red Data lists by referring to the pointers below.

• Functional extinction
• Local extinction (expiration and replacement or reintroduction)
• Extinct in the wild
• Chains of extinction (keystone species, co-extinction)
2) Offer reasons why species are disappearing directly due to human activities.
• Habitat Destruction (agriculture, mining and logging)
• Overharvesting and-hunting (poaching and bottom trawling)
• Urban sprawl
• Pollution (toxicity contaminating or sterilizing fauna or flora)
3) Discuss reasons for loss in biodiversity due to factors that could indirectly be attributed to humans, such as:
• Global Warming (some species able to expand and others not able to adapt and becoming vulnerable)
• Introduction of ‘foreign’ species (new competitor could find himself lucky with no natural predators, but he could also become a threat to the native creatures of the particular ecosystem)
South Africa has a huge variety of biotic natural resources such as plants, animals and fish. We also have generous quantities of a-biotic mineral resources such as gold, iron and coal and land. However, with population numbers increasing and consumerism demanding the processing of more resources, their availability is under strain.

Present possible solutions to:
• preservation of our fauna and flora in South Africa
• our fish stock
• suitable land for our live-stock and crops
• the demands on our mineral reserves

1) Pollution happens when something is added to the ecosystem that has a detrimental effect on it. One may not notice small amounts of pollution, but as waste builds up in the natural environment, it becomes more noticeable as impacts increase. Pollution takes place in the three main areas of the environment air, water and soil.

Air pollution happens when substances accumulate in the air to such a degree that human health suffers or the natural environment deteriorates as a result. The main causes of air pollution are the generation of power and heat, the burning of solid wastes, industrial processes and modern transportation.

Water pollution occurs when material (chemical, physical or biological) is introduced to water (rivers, dams or oceans) in quantities that degrade the quality of the water source and negatively affect the organisms living in it. Activities could range from households washing dissolved or suspended liquids down the drain to industries discharging toxic pollutants (pesticides, heavy metals, bio-accumulative and chemical compounds) directly into rivers and other natural sources.

Land pollution takes place when the land surface or the soil beneath is degraded. It can be done by poor agricultural practices, mineral exploitation and industrial waste dumping. It also includes certain methods used to dispose of  urban wastes, such as littering and burying substances.

i) Discuss the following methods of air pollution:
• Exhaust gasses of vehicles
• Combustion of coal and other fossil fuels
• Acid Rain
• Noise pollution
• Tobacco smoke

ii) Discuss the following methods of water pollution:
• Mining and agricultural waste
• Industrial effluents
• Sewerage disposal and domestic wastes

iii) Discuss the following methods of land pollution:
• Soil pollution (herbicides (weed killers) and pesticides as well as litter)
• Waste disposal (encouraging unhygienic conditions and pests)
2) On an individual level, the best way to prevent land pollution is to recycle. The number one way to prevent air pollution is to walk or bike more and drive less. The best way to prevent water pollution is to not throw trash and other harmful chemicals into our water supplies. Discuss if these suggestions and the ones below are practical, or present other ways in which pollution could be minimized.

• The kind of fuel one uses in his car
• Use energy and water wisely
• Discourage littering by being a role model (land-pollution)
• Recycle paper, plastic, metal and glass (land-pollution)
• Reuse any items that you can (land-pollution)
• Buy biodegradable products (land-pollution)
• Store all liquid chemicals and waste in spill-proof containers (land-pollution)
• Eat organic foods that are grown without pesticides (land-pollution)
• Don’t use pesticides (land-pollution)
• Use a drip tray to collect engine oil (land-pollution)
• Buy products that have little packaging (land-pollution)
• Don’t dump motor oil on the ground (land-pollution)
• Carpool or join a ride share with friends and co-workers (air-pollution)
• Don’t smoke (air-pollution)
• Keep your car maintenance up-to-date (air-pollution)
• If you have to drive, do your errands at one time (air-pollution)
• Don’t buy products that come in aerosol spray cans (air-pollution)
• Avoid using lighter fluid when barbecuing outside (air-pollution)
• When you drive accelerate slowly and use cruise control (air-pollution)
• Always replace your car’s air filter (air-pollution)
• Use a push or electric lawnmower rather than a gas-powered one (air-pollution)
• Don’t use harsh chemical cleaners that can emit fumes (air-pollution)
• Inspect your gas appliances and heaters regularly (air-pollution)
• Wash your car far away from any storm water drains (water-pollution)
• Don’t throw trash, chemicals or solvents into sewer drains (water-pollution)
• Inspect your septic system every 3-5 years (water-pollution)
• Avoid using pesticides and fertilizers that can run off into water systems (water-pollution)
• Sweep your driveway instead of hosing it down (water-pollution)
• Always pump your waste-holding tanks on your boat (water-pollution)
• Use non-toxic cleaning materials (water-pollution)
• Clean up oil and other liquid spills with kitty litter and sweet them up (water-pollution)
• Don’t wash paint brushes in the sink
3) Add to the list below and discuss control measures that governments and industry could put in place to lessen their contribution to pollution of the environment.
• Legislation
o establishing smokeless zones
o make industry liable for their impact on the environment via special taxes
o enforce strict fines for illegal dumping of any waste
• Developing ‘clean’ alternatives for energy generation

4) Landfill sites are becoming increasingly problematic in that it is poisoning the air, ground and surface water as well as the usefulness of the land. It does so as certain waste products that are being dumped there release various toxins. The components of products such as electronics and fluorescent lights contain various hazardous substances such as mercury, arsenic, cadmium, PVC, solvents, acids and lead that is detrimental to the environment in high dosages. As waste breaks down it also releases a liquid referred to as leachate that enters the soil beneath. When organic matter is compacted underground, the break-down process happens without the presence of oxygen and as a result methane, a gas more that 20 times potent than CO2, is released. It is also dangerous as it is highly flammable.

5) Discuss the three important environmental problems that are associated with landfill sites, namely toxins, leatchate and greenhouse gasses. Point to the effects it has on the atmosphere, ground-and surface water and on soil quality.  Mention possible ways in which the accumulation of these items and substances at land-fill sites could be prevented via personal action; measures taken by landfill site authorities and legislation. Consider the:
• Recycling of plastic, glass, Styrofoam, batteries, aluminium.
• Recovering of methane fuels
• Recovering substances used in electronics
• Composting – private and industrial
• Not buying products that could harm the environment when their usefulness expires
• Landfill levies