Human Influences on the Environment

Question 1

What are natural causes of nitrous oxides and sulphur dioxide?

Answer 1

Volcanic eruptions and lighting

Question 2

What is a human cause of sulphur dioxide and nitrous oxides?

Answer 2

Burning fossil fuels

Question 3

What do sulphur dioxide and nitrous oxides combine with to form sulphuric and nitric acids?

Answer 3

Water vapour in clouds

Question 4

What do sulphuric and nitric acids combine with to form acid rain?

Answer 4

Rain

Question 5

What are the consequences of acid rain?

Answer 5

• Death of conifers
• Acidification of soil (leaching of ions into lakes kills fish; root hairs less effective at absorbing minerals so slowed tree growth)
• Acidification of lakes (death of bacteria and algae; death of fish and amphibian eggs; change in ecosystem)

Question 6

What are some examples of GHGs?

Answer 6

Water vapour, carbon dioxide, nitrous oxides, methane and ChloroFluoroCarbons

Question 7

How has human activity contributed to GHGs?

Answer 7

• Burning of fossil fuels, such as coil, oil and natural gas, as well as petrol and diesel in vehicle engines
• Deforestation - tress absorb carbon dioxide and produce oxygen, less trees => less absorption
• Landfill sites - decomposition of waste buried in the ground by microorganisms
• Fermentation by microorganisms in the rumen (stomachs) of cattle and other ruminants
• Fermentation by bacteria in rice fields

Question 8

What are the effects of pollution of water by untreated sewage?

Answer 8

• Aerobic bacteria in sewage use up dissolved oxygen in the water, killing larger animals e.g. fish
• Contains pathogenic bacteria, which are a danger to human health

Question 9

What are the effects of deforestation?

Answer 9

• Global warming - burning trees produces carbon dioxide
• Global warming - less trees means less carbon dioxide absorbed
• Destruction of habitats and loss of biodiversity
• Reduced soil quality - no tree roots to hold soil together so rain washes minerals out resulting in leaching
• Soil erosion due to exposure to wind and lack of roots to stabilise soil
• Disturbs water cycle and evapotranspiration
• Loss of medical drugs along with biodiversity

Question 10

What happens after leached minerals from fertiliser stimulates the growth of plants, usually first seen as rapid growth of algae called an algal bloom?

Answer 10

The algae will soon start to die and be decomposed by aerobic bacteria in the water using up oxygen resulting in fish and other aerobic animals dying. In addition algae blocks sunlight from reaching other underwater plants

Question 11

What happens after short-wavelength IR radiation from the sun strikes Earth and is partially absorbed and re-emitted as longer-wavelength radiation?

Answer 11

Some long-wavelength IR radiation from Earth escapes into space and some is absorbed by GHGs and re-emitted back to Earth. Therefore more GHGs, more re-emitted radiation