(4.12-4.18B) Human impacts

What does sulphur dioxide pollution lead to? How?

SO₂ combines with water vapour → acid rain

increases pH of bodies of water, killing animals + plants

What does carbon monoxide pollution lead to?

Binds to haemoglobin, reducing its capacity to carry oxygen through the body.

can lead to suffocation and death in high concentrations

What is a greenhouse gas?

A gas that absorbs and traps Sun’s infrared radiation in Earth’s atmosphere, retaining heat.

Name the greenhouse gases.

water vapor

carbon dioxide

nitrous oxide

methane

CFCs

How have human activities impacted greenhouse gas emissions?

Combustion of fossil fuel → carbon dioxide

Cattle → methane

Describe the enhanced greenhouse effect.

increasing greenhouse gases

reduce the amount of energy reflected back to space

increasing the amount trapped within Earth’s atmosphere

raising global temperatures above normal

global warming!

What are the consequences of global warming?

• Higher ocean temperatures

  • sea levels rising

  • ice caps melting

• increasing temperatures

  • extreme weather events

• changes/losses of habitat

• decreased biodiversity

What is leaching?

when heavy rainfall dissolves nutrients in soil and transports them downwards

What is eutrophication?

overgrowth of aquatic plants and algae at the surface

due to nitrogen in fertilisers stimulating growth

plants below surface die due to limited light

decomposers break down dead material

oxygen levels decrease as increased number of decomposers respire

water no longer contains enough oxygen to support other organisms so many die

How does sewage pollution affect environments?

cause an increased growth of aerobic bacteria which feed on waste

they reduce oxygen availability

organisms that are sensitive to oxygen levels die

decrease in biodiversity as only organisms that can survive at low concentrations remain

What are the effects of deforestation?

leaching

soil erosion

disturbance of evapotranspiration

disturbance of the carbon cycle

change to balance of atmospheric gases

How does deforestation affect leaching?

soil minerals that would have been taken up by trees are swept away into bodies of water

How does deforestation affect soil erosion?

soil is not held together by tree roots

more likely to be washed/blown away

How does deforestation affect evapotranspiration?

reduction of water vapour release via transpiration

reduced clouds + rainfall

How does deforestation affect the carbon cycle?

less carbon removed from the atmosphere and stored in plant tissues during photosynthesis

How does deforestation affect atmospheric gases?

combustion of trees increases release of carbon dioxide into the atmosphere.