Global climate change

Question 1

Evidence for climatic change is taken from a variety of sources. What are they (8)?

Answer 1

1. Pollen analysis- If pollen falls in spots with no oxygen then they show what type of plants lived in a location at a time.
2. Dendrochronology- The analysis of tree rings, wide band = warm and wet year, narrow ring= cold and dry
3. Ice-core analysis- carbon dioxide levels trapped in air bubbles. Lower levels during cooler periods
4. Sea floor analysis
5. Radiocarbon dating
6. Coleoptera- beetle deposits
7. Changing sea levels- Shown by rias and fjords
8. Glacial deposits- evidence of growth and retreat.

Question 2

What are the possible causes of climate change?

Answer 2

Meteorite impact
Variation in solar activities (e.g: Sunspots)
Volcanic activity increasing the amount of dust in the atmosphere
Changes on ocean circulation
Change in tilt of the Earth’s axis
Changed in atmospheric composition (e.g: more CO2)

Question 3

What are the main effect so global warming?

Answer 3

Rising sea-levels –> 1.5cm in the twentieth century if continued –> flooding
Climatic change, average temperature increases –> more desert like places in places previously good for agriculture
Extreme events –> Heatwaves, floods, droughts and storms will last longer and be more intense (global weirding)