Evidence for Past Climate Change 7.2

Question 1

Changes in Rock Types?

Answer 1

Rock strata = evidence

• Shale layers from fine grained mud large lake or inland sea
• Above shale is compacted Loess from windblown deposits of fine grain clay & sand = wind blown from glacial area

Question 2

What the Ice cores reveal?

Answer 2

• Changes in snowfall > thickness of layers
• Storminess of the seasons > level of salt in ice
• Volcanic activity > amounts of microscopic particles of ash & dust in ice
• Ecosystems > plant pollen grains in ice cores
• Global warming > correlations between C02 levels & av global temps in past

Question 3

Dendrochology?

Answer 3

*Growth rings in trees > size determines climate of that time

Question 4

Limestone Cave Structures?

Answer 4

• The stalactites (upwards) and Stalagmites (downwards) of Limestone caves used for proxies for determining climate change in last 500 000 years
• Age of deposit measured from traces of Uranium Thorium radioisotopes
• growth rings show precipitations rates each year

Question 5

Human Instrumental Records?

Answer 5

• Meteorologists began serious recording of global temperatures in 1900’s
• Data shows BIG changed: concentrations of C01 is 25% higher than in 1960
• data also shows a strong correlation between C02 levels & rising dangers
• Also shows in last 2000 years graph goes from little changes up and down and then a massive leap in last century.