Unit 4.4 - Climate Change

Question 1

Greenhouse gases

Answer 1

• Carbon dioxide
• Water vapor
• Methane
• Nitrogen oxides
• Absorb and re-emit this infrared radiation as heat

Question 2

Most significant greenhouse gases

Answer 2

Water vapor and carbon dioxide

Question 3

Greenhouse gases impact

Answer 3

Depend on their concentration and ability to absorb IR radiation

Question 4

Greenhouse effect

Answer 4

• Natural process that increases average temperatures:
  • Incoming radiation from the sun includes short-wave ultraviolet (UV) radiation
  • This radiation may be emitted by the Earth as long-wave infrared (IR) radiation

Question 5

Carbon fluxes

Answer 5

Describe the amount of carbon transferred between various carbon pools
(e.g. lithosphere → atmosphere)

Question 6

Carbon dioxide concentrations

Answer 6

Are increasing within the atmosphere due to a number of human-induced activities:
•  Industrial practices 
(i.e. combustion of fossil fuels)
•  Deforestation 
(less CO2 transferred to the biosphere)
•  Agriculture 
(land clearing and methane production)

Question 7

Global temperatures and climate patterns

Answer 7

• Influenced by greenhouse gases
• Increasing CO2 concentrations may be causing global climate change (enhanced greenhouse effect)
• Positive correlation between rising CO2 levels (since industrial revolution) and average global temperature

Question 8

Oceans

Answer 8

Major carbon sink
(i.e. stores CO2 from the atmosphere)
• Some of the CO2 remains dissolved, but most of it is chemically converted
• CO2 is converted into carbonic acid, which dissociates to release H+ ions

Question 9

This conversion

Answer 9

Impacts marine organisms (such as coral) in a number of ways:

• It increases ocean acidity, which can stress coral survival (⬆ H+ = ⬇ pH)
• It lowers carbonate levels, which is required for shells and exoskeletons
• These conditions can cause coral to expel mutualistic algae (coral bleaching)

Question 10

Is current climate change natural?

Answer 10

Past changes were not as abrupt Ocean levels are rising, pH decreasing

Question 11

Are greenhouse gases the cause?

Answer 11

Climate changes don’t match sun activity CO2 levels are highest ever recorded

Question 12

Are climate models reliable?

Answer 12

All the climate models are predicting a temperature increase by 2100 (~2–6C)