Determining Earths Past Conditions

Question 1

What is Proxy Data?

Answer 1

Indirect data. Used to determine earths past conditions

Question 2

Pros and cons of historical written records.

Answer 2

Pros
Newspapers/ diary entries ships logs dated to that time
Cons
Could be subjective or biased

Question 3

Pros and cons of coral reefs in determining earths past conditions

Answer 3

Pros
-Coral shows additional skeletal growth similar to tree rings.
-Density of coral reef changes due to availability of carbon
Cons
-specific to where they can grow (not evenly)
-not well preserved as they are alkaline and therefore destroyed under acidic conditions

Question 4

Pros and cons of using pollen to determine earths past conditions

Answer 4

Pros
-Pollen grains determine plant type it came from
-plant types are associated with different climates
Cons
-pollinating plants are not located all over the world

Question 5

Pros and cons of using ice cores to determine earths past conditions

Answer 5

Pros
-can go back 10,000 years
-Ice builds up in layers annually
-thicker/lighter layers means more precipitation and warmer conditions as there is more evaporation
-thinner darker layers means less precipitation and cooler conditions as there is less evaporation
-analysis of trapped greenhouse gases. Higher amount=warmer lower =colder
-Oxygen isotope analysis. Changes in ratio of oxygen isotopes. 018 is heavier than 016 meaning that it is harder to evaporate (warmer climate)
Cons
-Ice cores arnt located in all areas of the Earth

Question 6

Pros and Cons dendrochronology (tree rings) to determine earths past conditions

Answer 6

Pros
-Wider the tree rings the warmer/wetter years
-Thinner the tree rings= colder/dryer years
-can go back a few 1000 years
-fossilised remains of trees if dated help to determine last climates
Cons
-damage of tree to obtain data
-trees do not grow in every area/ climate
-some trees have no rings and a low seasonality

Question 7

Pros and cons of ocean and lake sediments in determining earths past conditions

Answer 7

Pros
-Pollen and fossils can be found in sediment that can be associated with warmer climates
Cons
-Not dated

Question 8

What are the limitations of proxy data?

Answer 8

-Biased/subjective
-might have to cause damage to natural world to obtain data eg:Coral and trees

Question 9

What are some examples of modern methods of monitoring conditions on earth?

Answer 9

-Weather stations
-weather balloons
-Thermometers
-Satellites (measure ice cover)
-anemometer (wind speed)

Question 10

Modern methods Vs Proxy methods

Answer 10

MODERN
pros- more accurate less subjective and more factual more precise

Cons-only short history of modern data.
Cost of equipment such as satellites is expensive
PROXY
pros- can date back 100,000 years

Cons-biased/subjective/ damage nature

Conclusion: compare modern methods to proxy methods to see patterns