Evidence for climate change

Question 1

What are temperature records?

Answer 1

Reliable but short term measured by thermometer

Equipment wasn’t as accurate as it used to be

Question 2

Describe peat bogs

Answer 2

Peat is an accumulation of partially decayed organic matter
Peat bog is anaerobic and acidic, the decay rate is slowed
Pollen is preserved well in peat

Question 3

Why is pollen useful for reconstructing past climates?

Answer 3

Plants producing lots of pollen
Pollen grains have a tough outer layer that’s resistant to decay
Each species has a distinctive type of pollen
Peats form in layers - deeper peat =older, c14 dating allows age of layer to be established
Each species has a certain set of ecological conditions in which it grows best

Question 4

Describe dendrochronology

Answer 4

Trees produce a new layer of xylem vessels by mitosis
Diameter of xylem varies according to theseason wide=spring, narrow = summer
Take core of the trunk and date it

Question 5

Describe combining data

Answer 5

Trees study back hundreds of years, pollen around 20,000 years, ice cored used before this
Combining builds a picture over lsat 400,000 years