global climate change

Question 1

define the difference between the green house effect and the enhanced greenhouse effect

Answer 1

1) the presence of natural atmospheric gases which absorb infrared radiation and warm the atmosphere
2) changes to the composition of the atmosphere due to human activates which increase the presence of green house gases so more infra red is absorbed and warm the atmosphere further

Question 2

list human activities which increase CO2, methane, oxides of nitrogen

Answer 2

1) combustion of fossil fuels, ploughing of soils, drainage of marshes and bogs
2) anaerobic respiration of bacteria in paddy fields, livestock gut and land fill
3) the reaction of oxygen and nitrogen at high temps in locations such as engines and power stations

Question 3

what are the consequences of global climate change

Answer 3

1) ecological changes
2) changes in climatic processes
3) changes in the cryosphere
4) ocean changes

Question 4

outline ecological changes as a result of global climate change

Answer 4

1) increased photosynthesis= increased plant growth= more food for herbivores species
2) precipitation changes cause the enlarging or shrinking of wetland habitats
3) disruption of species- changes in temp may affect which area of colonization are suitable- instructions to interconnected species and food chains
4) smaller gene pool

Question 5

what are the climatic changes as a result of GCC

Answer 5

1) changes in wind patterns

2) changes in rain fall

Question 6

outline changes in wind patterns as a result of GCC

Answer 6

• jet streams are strong winds that blow west to east in the upper troposphere caused by changes in temp and density between 2 air masses
• winds blow from high to low pressures causing a spiral pattern
• as polar regions warm faster than areas near the equator the temp differences creating jet streams decrease and jet streams are getting smaller
• this decreases the movement of weather systems so weather becomes more intense in one area

Question 7

outline changes in rainfall as a result of GCC

Answer 7

1) increased temp causes more evaporation
2) this means more precipitation
3) higher temps the air will have to move further t0 reach cooler areas where it can condense into rain
4) therefore new areas will receive more rainfall and other areas will receive none

Question 8

list changes in the cryosphere as a result of GCC

Answer 8

1) reduced snow cover
2) changes in speed and movement of land ice
3) loss of ice shelves
4) changes in the thickness of ice

Question 9

what are the effects of reduced snow cover

Answer 9

1) decreased albedo
2) less sunlight reflected more absorbed
3) therefore more infrared emitted
4) more absorbed by GHG
5) increased temp

Question 10

why have there been changes in the movements of glaciers

Answer 10

1) as ice moves to lower altitudes it melts, it may reach the ocean before this occurs forming icebergs etc
2) increased temps cause melting to occur earlier so the front end of the glacier is melting faster than it moves forward so ice fronts retreat
3) increased melting may find its way to the base of the glacier acting as a lubricant and increasing speed

Question 11

outline ocean changes as a result of GCC

Answer 11

1) increased sea level

2) changes in water current

Question 12

why has sea level risen

Answer 12

1) thermal expansion- as temps increase seawater expands causing sea levels to rise - this takes a very long time as water volume is massive and has a high specific heat
2) melting of land ice- increased ice causes ice on land to melt and flow into water bodies causing increased volume and sea rise

Question 13

outline changes to the gulf stream

Answer 13

1) moves warm tropical water from the Atlantic ocean to north-west Europe allowing the warmer temp
2) cold salty water is denser and moves towards south America, warm less salty water is less dense creating a current towards Europe = separate currents
3) melting of land ice dilutes salinity and warms water so dense slaty water currents rise and disrupt the warmer currents slowing them down as they push against each other
4) slower current rate may cause Europe to become colder

Question 14

outline normal ocean currents before an El Nino event

Answer 14

1) trade winds blow from South America to the east coast of Australia
2) this causes cold water to be driven upwards and westwards carrying nutrients
3) as the water moves from South America towards Australia water warms up providing Austria with warm ocean currents

Question 15

outline an El Nino event

Answer 15

1) occurs every 5-7 years
2) a change in wind pattern changes the direction of ocean currents from east to west to the west to east
3) this causes colder water to be drawn up around Australia increasing rainfall and flooding and carries warmer currents to South America which will cause increased evaporation and droughts

Question 16

how has GCC impacted El Nino events

Answer 16

increased frequency

Question 17

what is the impact of the loss of ice shelves,

Answer 17

1) if ice sheets are grounded they block the forward’s movement of ice on land
2) if they are gone or broken up glaciers behind may flow more rapidly into the sea causing rising sea levels