enviromental threats to the planet

Question 1

how do ice cores allow us to measure past climates?

Answer 1

1) scientists use a machine to drill 1 meter into the ice.

2) scientists determine how old the ice is by examining how many layers the ice has (1 layer is 1 season).

3) to test the past climate they examine the trapped oxegen isotopes in the ice.

4) these are usually taken from antartica or greenland.

Question 2

how do tree rings allow us to measure past climates?

Answer 2

1) the best trees to use are trees that are struggling for life, this is because a small change in the atmosphere will affect them more than healthy trees.

2) each ring is a diffrent year and the size of that ring can tell us how well the tree grew that year informing us of the overall climate

3) finally we can look for things like scaring from forest fires. which will tell us how hot the climate was

Question 3

how can we use sailors log books as a proxy for climate change?

Answer 3

1) Sailors usually record any small changes in the course of the weather and climate and record the date of when this happened.

2) we can then record the frequency of these things being said from a sailor 10 years later and compare it. therefore telling us if the climate has changed at all in the 10 years.

Question 4

what is a ‘proxy’

Answer 4

a proxy is the term which describes preserved physical features of the enviroment.

Question 5

what happens when solar output increases

Answer 5

more watts are able to reach the earths surface and increase temp in the atmosphere.

Question 6

does a bigger or smaller tilt mean a warmer tempreture

Answer 6

1) a smaller tilt means less noticeable change of seasons. this means more ice and snow will form because there is no summer melt

2) tempretures will decrease on average with a smaller tilt

Question 7

what are sunspots?

Answer 7

1) sunspots are regions on the surface of the sun that are on average 1500 dgrs C less than he rest of the surface.

2) this means slightly less watts are emitted to earth decreasing the tempreture by about 0.1 degrees C

Question 8

give 1 example of a volcanic eruption that changed global temps

Answer 8

Pinatubo
(VEI 6)
temps decrease by 0.5 d c globally for 3 months

Question 9

what is the structure for describe questions?

Answer 9

O - overall patterns (global pattern)

B - breakdown (continent by continent then region by region)

E - evidence (use evidence from the map or data you have been given)

Question 10

are the tropic of cancer and Capricorn, low or high pressure zones

Answer 10

1) both are high pressure zones because there is sinking air and low precipitation

2) equator is low pressure because warm air rises and high precipitation

Question 11

explain how the global circulation of the atmosphere creates extreme weather events

Answer 11

1) the hadley cell:
at the equator the air is heated, the air then rises and goes north and south. when the air moves north and south it condenses forming storm clouds. when the condensed air reaches 30 degrees N and S it sinks creating a high pressure zone.

2) the feral cell :
air on the surface is pulled further towards the poles. these winds pick up moisture going over the oceans. simply the colder moist air and warmer meet and form unstable weather conditions.

3) at the poles the cool air sinks forming high pressure.it then flows towards the lower latitudes. At about 60 degrees N and S, the cold polar air mixes with warmer tropical air and rises upwards, creating a zone of low pressure called the subpolar low. The boundary between the warm and cold air is called the polar front. It accounts for a great deal of the unstable weather experienced in these latitudes.

Question 12

what is El Nino ?

Answer 12

An irregularity across the equatorial Pacific region that occurs every 2-7 years, lasting about 9-12 months. This phenomenon involves unusually warm water concentrating off the coast of South America which reverses wind patterns across the Pacific.

Question 13

what were the causes of the big dry?

Answer 13

• Weather patterns were unusual - these broke records
  
  • El Nino was present - this doesn’t always happen
  • A growing population put pressure on the land - but AC population growth is fairly slow so this is not a new pressure
  • The basin was mismanaged - but it’s always been poorly managed
  • The area was agriculturally dependent - but it has been for a while
  • CONCLUSION - the real change were the top two - based on the reduced SUPPLY of water

Question 14

what are the causes of el nino

Answer 14

> the weakening of trade winds across the pacific ocean.

> this tends to make the thermo cline increase in the west (Australia) increasing tempretures and makes it decrease in the east (SA) causing mass rainfall.

Question 15

what are the impacts and causes of modern climate change ?

Answer 15

causes:
1) green house gas effect - gas is trapped in our atmosphere, this traps the heat in instead of letting it escape.

Question 16

how do high temps make droughts worse ?

Answer 16

• any rain is evaporated quickly
• evaporates water sources like reservoirs
• can increase chances of other natural disasters like forest fires

Question 17

what is the Murray darling basin responsible for producing?

Answer 17

• 40% of Australia’s agricultural produce
• makes up 70% of Australia’s crop land
• the Basin is struggling in drought with little water because people are having to take water out to use on the crops and it is badly managed across the 4 territories

Question 18

what affects did the big dry have on farmers?

Answer 18

• severe mental health decline because farmers were having too shoot cattle.
• lots of farmers were also having to make very long journeys away from home to collect feed for the cattle (1000km - 2000km)

Question 19

facts about impacts of the big dry

Answer 19

• Hey, seed and crop all doubled in price
• to save up for the feed farmers would not buy themselves things like prescriptions
• many had to sell their farms
• CWA distributed care packages to farmers
• in 2018 only 1/4 of the usual yield was harvested in crop
• there was 43% less of rivers flowing
• water supplies in sydney decreased by 30%

Question 20

how can future droughts be minimised?

Answer 20

• move reservoirs underground meaning less evaporation (very costly)
• desalination plants can be made along the coast turning sea water into drinking water and then using pipes to transport it. (very costly 6 billion dollars and very energy intensive)
• Aussie helpers, good for farmers mental health’s (short term strategy and not really combatting the issue)

Question 21

glacial and interglacial climates

Answer 21

Glacial:
- lower tempretures
- lower sea level
- land bridges created
- not much vegetation
- less rainfall, dry weather

Interglacial:
- more humid weather
- higher temps
- more vegetation
- higher sea levels

Question 22

what is the Milankovitch cycle

Answer 22

• when the Earth has a fairly circular orbit around the sun, earths tempreture is at its hottest. this is because the distance from the earth to the sun is constant.

over time the earths orbit has become more egg shaped meaning for certain parts of the year we are closer to the sun. when the orbit is egg shaped (elliptical) the tempretures on average are colder because we spend more time further from the sun.

Question 23

what is the greenhouse gas effect?

Answer 23

it is when heat from the suns waves is trapped in earths atmosphere by greenhouse gases like methane and CO2.

Question 24

what is the layer that stops gases from leaving the atmosphere?

Answer 24

tropopause layer

Question 25

name 3 consequences of climate change

Answer 25

1. wild fires
2. sea level rise
3. heavier rainfall causing flooding
4. drought
5. storms

Question 26

explain the cells

Answer 26

the Hadley cell - at the equator the warmer less dense air rises. the warm air then spreads out towards each pole. it then gradually cools and sinks as it moves. it descends to the surface and goes back to the equator.

The Polar cells - cold dense air flows along the ground to about 65 degrees north or south. as it is warmed it rises and cools down returning to the surface at the poles.

Ferrel cells - not based on tempreture, simply transfer air from the equator to the poles and bring it back.

Question 27

low and high pressure zones

Answer 27

low pressure - the equator and between Polar and Ferrel cells ( the most rainforests are found on the equator in the low pressure zone and all low pressure zones have a fairly wet climate.

high pressure - where air descends (poles and tropics of cap and cancer) this is where there is little rainfall so most desserts from there.

Question 28

tropical storms

Answer 28

• oceans need to be more than 60m deep and 26 degrees to cerate a hurricane.
• tropical storms form between 8 - 20 degrees north or south
• tropical storms form in these areas because of the high trade winds and the low pressure belt

Question 29

how is a tropical storm made?

Answer 29

1. warm oceans of 27 degrees, lots of water is evaporated
2. winds converge close to the oceans surface forcing the wind in an upwards direction
3. the wind rises rapidly because of the unstable air and it causes a thunderstorm .
4. warm rising air condenses to form storm clouds.
5. high pressure in the upper atmosphere removes heat from the rising air which pulls warm air from below
6. high wind speeds keep the storm constant