HUMAN IMPACT ON THE ENVIRONMENT

Question 1

climate

Answer 1

refers to the long-term weather conditions of an area

Question 2

main gases that make up the atmosphere

Answer 2

1. nitrogen
2. oxygen
3. water vapour
4. greenhouse gases

Question 3

what are greenhouse gases

Answer 3

1. carbon dioxide
2. methane
3. nitrous oxide
4. ozone
5. chlorofluorocarbons(CFC’s)

Question 4

greenhouse effect

Answer 4

when greenhouse gases absorb infrared(long wave radiation) long wave radiation emitted from the earth and prevent it from escaping back into the atmosphere

Question 5

why is the greenhouse effect important

Answer 5

it keeps the earth warm so that life can be sustainable

Question 6

enhanced greenhouse effect

Answer 6

when there is an increase in the concentration of gases resulting in a significant rise in the average temperature of the surface of the earth over a period of time, also known as global warming

Question 7

what causes an increase in concentration of CO2 in the atmosphere

Answer 7

1. burning of fossil fuels for electricity, to power vehicles and for industrial purposes
2. deforestation by cutting trees and removing vegetation which decreases the amount of CO2 taken up by plants, therefore there is an increase in amount of CO2 available on the atmosphere

Question 8

what causes an increass in concentration of the methane in the atmosphere

Answer 8

1. increased number of landfills because decaying organic matter in waterlogged soils such as landfills releases methane
2. increased number of livestock because ruminants like cows release methane gas through digestive tracts
3. mining of coal

Question 9

what does increase in temperature lead to

Answer 9

1. more evaporation of water, leading to increased precipitation, therefore increasing potential for flooding
2. rising sea levels caused by melting of glaciers and ice caps which therefore increases the potential of flooding
3. increased wildfires therefore increasing the chances of soil erosion and eventually desertification
4. increased loss of biodiversity because the species are unable to cope with rapidly rising temperatures eventually leading to desertification
5. increased droughts in some areas leading to desertification and food insecurity

Question 10

carbon footprint

Answer 10

a measure of the total amount of carbon dioxide emissions of an individual, a defined population or a company per year

Question 11

strategies to reduce the carbon footprint

Answer 11

1. reuse and recycle therefore less fossil fuels burnt in the production of the material
2. drive less by using bicycles, walk or use public transportation
3. reduce the need for heating by insulating walls and build energy efficient homes
4. carbon offsetting by using alternative energy and reforestation to act as a carbon reservoir
5. technological developments to decrease the amount of energy needed for production/decreasing the dependency on carbon emitting fuels

Question 12

cause of the destruction of the ozone layer

Answer 12

chemicals called CFC’s released by refrigerators, aerosol sprays and fast food packaging

Question 13

what is the ozone

Answer 13

ozone(O2) is a greenhouse gas found at low concentrations and they absorbs the ultraviolet Ray’s from the sun

Question 14

impact of failing to reduce the destruction of ozone layer results in

Answer 14

1. there’ll be a significant increase in the number of skin cancer cases
2. uv Ray’s reaching the earth’s surface may cause a permanent damage to eyes

Question 15

factors that influence the availability of water

Answer 15

1. construction of dams
2. destruction of wetlands
3. water wastage
4. cost of water
5. poor farming practices
6. droughts and floods
7. boreholes and their effect on aquifers
8. water recycling
9. exotic plantations and depletion of the water table

Question 16

construction of dams

Answer 16

construction of dams increase the quantity of water stored

Question 17

why shouldn’t wetlands be destructed

Answer 17

1. because they influence both the availability and quality of water
2. they provided water for domestic and livestock use as well as for irrigation
3. vegetation in the wetlands also helps in purifying the water naturally

Question 18

how is water wasted

Answer 18

1. water used for irrigation is lost due to poor farming practices
2. wastage of water through leaking taps and toilets and faulty pipelines

Question 19

how can water wastage be reduced

Answer 19

1. it can be reduced by reducing the pressure in the pipes
2. by educating people to use water wisely
3. by maintaining all plumbing in good condition

Question 20

what is the cost of water influenced by

Answer 20

1. by the costs involved in increasing the availability and quality of water
2. cost per kilolitre of water increases with increased use if water which is meant to discourage over-use of water, thus allowing for sustained use
3. certain amount of water is available for free to all citizens to ensure that water is available to the poorest

Question 21

how do poor farming practices affect the availability of water?

Answer 21

1. fertilizers and pesticides decrease the amount of clean water available
2. over-grazing can lead to soil erosion

Question 22

how do droughts and foods affect the availability of water

Answer 22

1. water availability decreases

2. natural vegetation can hold back water from floods

Question 23

use if boreholes

Answer 23

1. they increase water availability in areas that do not have direct access to other sources of water

Question 24

what happens when you consistently use boreholes

Answer 24

it will eventually lead to the drying up of aquifers

Question 25

hiw do exotic plantations decrease the depth of water tables

Answer 25

1. some exotic plants she large quantity of water from the ground, therefore decreasing the level of the water table, making less water available

Question 26

how can we prevent the depletion of water availability

Answer 26

1. water recycling-where the existing water is used for more than one purpose and sewage can be treated and reused again, but not for human consumption

Question 27

factors that influence the quality of water

Answer 27

1. eutrophication and algal bloom 2. thermal pollution 3. pollution of water through domestic and agricultural use 4. mining 5. alien plants 6. water purification

Question 28

eutrophication and algal bloom effect on quality of water

Answer 28

1. water used for agriculture might contain pesticides and fertilizers which pollute the water in rivers and dams causing eutrophication 2. therefore there can be N increase in algal growth also known as algal bloom 3. thus depleting the oxygen level in the water, and therefore reducing the potential for life in such water

Question 29

thermal pollution effect on quality of water

Answer 29

1. heating of water is caused by the use of water in the cooling of power-stations andin industries 2. heated water has a lower oxygen content making it difficult to support life

Question 30

how is water polluted through domestic and agricultural use

Answer 30

1. domestic water may contain detergents and pathogenic bacteria which has to be treated before it can be used again 2. water that's used for industrial purposes may contain many heavy metals, oils, heat and fertilizers 3. fertilizers and pesticides may run off into rivers, ponds and dams and pollute water

Question 31

mining effect on quality of water

Answer 31

water near mines is generally acidic, toxic and hot and contribute to alien plants

Question 32

alien plants effect on quality of water

Answer 32

1. they block waterways, which reduces light for other aquatic plants resulting in decomposition 2. bacteria then deplete the oxygen supply in the water

Question 33

how can quality of water be restored

Answer 33

quality of water can be improved through purification methods of the water

Question 34

food security

Answer 34

access, by all people at all times, to adequate , safe and nutritious food for a healthy and productive life

Question 35

factors that influence food security

Answer 35

1. exponential growth of the human population 2. droughts and floods 3. poor farming practices 4. alien plants and reduction of agricultural land 5. loss of wild varieties and its impact on gene pools 6. genetically engineered food