5.3.2 - Evidence For The Causes Of Climate Change

Question 1

What Types Of Things Can Be Used For Evidence Of Climate Change?
(4 Points)

Answer 1

~ Records of carbon dioxide levels.

~ Temperature records.

~ Pollen in peat bogs.

~ Dendrochronology.

Question 2

What Have Caused Atmospheric Carbon Dioxide Levels To Fluctuate Through Earths History?
(2 Points)

Answer 2

~ Volcanic eruptions.

~ Weathering of limestone rocks.

Question 3

How Do Scientists Know That Atmospheric Carbon Dioxide Levels Have Fluctuated Throughout Earths History?

Answer 3

Due to analysis of gas compositions of bubbles formed in ancient ice cores.

Question 4

Describe ‘Record Of Carbon Dioxide Levels’ As Evidence For Climate Change
(2 Points)

Answer 4

~ Increasing levels of CO2 in the atmosphere, are believed to contribute towards climate change.

~ As CO2 is a greenhouse gas and is involved in the greenhouse effect.

Question 5

Describe ‘Temperature Records’ As Evidence For Climate Change
(2 Points)

Answer 5

~ Since the 1850s temperature has been measured around the world using thermometers.

~ This gives a reliable but short-term record of global temperature change.

Question 6

Describe ‘Pollen In Peat Bogs’ As Evidence For Climate Change
(3 Points)

Answer 6

~ Pollen is often preserved in peat bogs.

~ Peat bogs accumulate in layers, age of the preserved pollen increases with depth.

~ Peat cores can be taken from a bog and the layers can be analysed to assess the pollen grains.

Question 7

What Type Of Conditions Are There In Peat Bogs?
(4 Points)

Answer 7

~ Waterlogged soil, creating anaerobic conditions.

~ Low oxygen levels due to the waterlogged nature leads to slow decomposition.

~ Acidic environments, low pH levels.

~ Cold temperatures, leads to slow decomposition.

Question 8

How Can Scientists Determine The Climates In The Past By Analysing Peat Bogs?
(2 Points)

Answer 8

~ Only fully grown plant species produce pollen, so the samples only show the species that were successful at that time.

~ Different plant species grow under different climatic conditions, plant present at different times can be used to measure the climate of that time.

Question 9

What Is Dendrochronology?

Answer 9

Method for figuring out how old a tree is using tree rings.

Question 10

Describe ‘Dendrochronology’ As Evidence For Climate Change
(3 Points)

Answer 10

~ Tree trunks grow in diameter each growing season as they produce more vascular tissue, which grows in a ring.

~ Trees grow faster in warmer conditions and slower in colder conditions.

~ Scientists can take cores through tree trunks, then date each ring by counting them back from when the core was taken.

Question 11

‘Trees Grow Faster In Warmer Conditions’ How Does Dendrochronology Show This?
(2 Points)

Answer 11

~ The thicker the ring, the warmer the climate was. Vice versa.

~ Lighter colour rings are produced by fast growth during warmer conditions. Vice versa.