4: The Atmosphere

Question 1

In what two ways are ocean currents created?

Answer 1

Wind
-surface currents are often created through winds ‘pulling’ the water in that direction.

Density differences

• Deep currents are usually created through differences in density, caused by temperature and salinity differences.
• increased salt concentration is caused by increased evaporation
• cool water in the north sinks, pulling warm, less dense water in from the south.

Question 2

What is El Nino?

Answer 2

It is a natural process by which warm surface water in the Pacific moves further east, causing a southward shift in the jet stream.

Normally, trade winds blow warm surface water from east to west across the Pacific, creating upwelling of cool water in the east.

However, during El Nino, this is reduced so the warm water moves back east, heating the ocean temperatures

Question 3

What is El Nina?

Answer 3

It is a natural process by which warm water moves further to the WEST pacific due to stronger trade winds.

This increases upwelling of cool water in the south.

Question 4

What are jet streams?

Answer 4

They are strong winds that blow from west to east in the upper troposphere.

Question 5

What cause jet streams, and what happens if they slow down?

Answer 5

They are caused by temperature and density differences, winds blow to equalise the pressure.

Increased temperature reduces the temperature differences and causes slower movements by the jet stream, meaning the weather remains the same for longer periods of time.

Question 6

What are two causes of sea level rise?

Answer 6

• Melting land ice

- increased temperature causing the water to expand.

Question 7

What are the effects of climate change on organisms?

Answer 7

• increased photosynthesis (until it reaches a limiting factor)
• habitat destruction
• changes to migration patterns
• reduced biodiversity
• increased pathogens

Question 8

Why is monitoring and predicting climate change difficult?

Answer 8

• average temperature and winds fluctuate
• some are human caused, so depends on how much we change
• difficult to predict far advance on a local scale as more sensitive to fluctuation.

Question 9

What is the IUCN?

Answer 9

The international union for conservation of nature, which aims to conserve a biodiversity..

Question 10

What positive feedback oops affect global temperatures?

Answer 10

• Rate of decomposition
• forest and peat fires
• land ice melting (albedo feedback loop)

Question 11

What is a tipping point?

Answer 11

When a postive feedback loop contiunes out of control, so that it cannot be reversed.

Question 12

Explain how methane stored in the permafrost is a positive feedback loop

Answer 12

The melting of the permafrost in some areas reveal peat bogs, which when thawed could release up to 70 billion tonnes of methane. The more the global temperatures, the more peat bogs are revealed, releasing more methane and further heating the earth.

Question 13

What are some ways we can reduce the release of methane?

Answer 13

• Reduce landfill waste
• reduce livestock production
• improved recovery of gas from mines

Question 14

What are some of the way we can reduce the relase of nitrogen into our atmosphere?

Answer 14

• increased use of public transport
• increased renewable energy use
• addition of urea in powerstation to react out nitrogen.

Question 15

What is carbon sequestion?

Answer 15

It is the storage of carbon dioxide in the form of either carbon capture of planting more vegetation

Question 16

What methods are there to control rising sea levels?

Answer 16

• Barriers to prevent flooding
• Coastal erosion control
• permeable urban surfaces + slowing surface run off
• river flow reduction

Question 17

what are the percentages of the main gasses that make up the atmosphere?

Answer 17

nitrogen: 78%
oxygen: 21%
rare gases: 1%
ozone: 0.000007

Question 18

What is the importance of stratospheric ozone?

Answer 18

It prevents most of the high energy UV solar radiation from the sun reaching the earths surface.

Question 19

What are the three different types of UV raditation?

Answer 19

UV-C (UV cant): The most powerfull form of UV with the shortest wavelength, but is totally absorbed by the atmospher, as it breaks bonds of ome of hte gasses when passing thorugh.

UV-B (UV bad):

• 90% absorbed by the atmosphere
• still strong so causes sunburn and other effects of UV

UV-A (UV allow):

• UV radiation which is very weak so is not damaging
• passes thorugh the atmosphere

Question 20

How does ozone naturally form?

Answer 20

1) UV radiation with wavelength between 100 and 240 nm causes oxygen to split into two oxygen atoms
2) The oxygen atom will join another unsplit, diatomic oxygen molecule to make 03, ozone.

Question 21

How is Ozone naturally depleated?

Answer 21

UV radiation with a wavelength 100 to 240 nm splits the ozone (03) into a ozygen molecule and an oxygen atom.

Question 22

What is the effect of UV-B on living organisms?

Answer 22

• SKin and DNA (mutations) damage
• Cateracts
• leaf tissue damage

Question 23

What makes chloroflurocarbons so useful?

Answer 23

• boiling point close to ambient temperatures so easy to store
• can dissolve grease and oil but not damage electrical components
• not flammable
• mainly non-toxic

Question 24

What is the Rowland Molina hypothesis?

Answer 24

That effect of CFCs stop the production of ozone.

This is because when UV passes through the atmosphere it breaks up the chloruoflurocarbons so that it releases a chlourine atom, which then binds to the oxygen atoms, so that the oxygen cannot join an oxygen molecule and fomr ozone.

Question 25

What is the dobson unit?

Answer 25

It estimates the total thickness of all ozone in the atmosphere as if it existed a s single layer of pure oxone at sea level

100 DU is equivalent to a 1mm thick ozone layer

Question 26

What were the main agreements of the montreal protocol?

Answer 26

• The manufacture and use of CFCs and other ozone depleting substances to be banned.
• The use of HCFCs to be phased out and banned by 2030

Question 27

what makes CFCs so harmful to ozone? (The Rowland-Molina hypothesis)

Answer 27

• Persistence of CFCs: CFCs are chemically stable so they remain in the atmosphere for long enough to be carried up to the atmosphere
• Dissociation by UV and the release of chlorine
• reaction of chlorine and oxygen

Question 28

What evidence for ozone depletion l?

Answer 28

• we measure ozone levels in DU (dobson units)
• detecting increased levels of UV at ground level
• satellites detecting increased UV reflected
• air samples collected found ozone depleting chemicals

Question 29

what are the different layers?

Answer 29

TSMT

Troposphere 
stratosphere
mesosphere
thermosphere
exosphere

Question 30

Why do we have difficulties in monitoring climate change?

Answer 30

• Short term changes may not link to a long term trend
• varies locally, regionally and globally, e.g. a local flood
• One change can have contrasting effects in different locations
• Changes in Jet stream may cause temperatures to rise
• Slowing of the north Atlantic conveyor my lower temperatures
• Variations in green house gas emission
• Natural fluctuations
• Delay between cause and effect

Question 31

How can we monitor past data on climate?

Answer 31

Proxy data:

• Width of tree rings to estimate growth rate and temperature
• Some coral produce growth rings
• pollen grains preserved (different species suited to different temperatures)

-Ice core data (radio isotope for age, measure different gas concentrations)

Question 32

How are satellites used to estimate ice cover?

Answer 32

GRACE satellites

• Low orbit technologies
• measure gravitational pull by increasing/decreasing height of orbit
• Radar altitude measurement
• Gravimeters