Climate Change - Evidence

- Ice sheets are made up of layers of ice, one layer is formed each year

- Scientists drill into ice sheets to get long cores of ice

- By analysing gases trapped in the layers of ice, they can tell what the temperature was each year

- The remains of organisms found in cores taken from ocean sediments can also be analysed.

- Since the 1850s global temps have been measured using thermometers. This is reliable but short term

- Historical records e.g. harvest dates, newspaper weather reports can extend a bit further back

- As trees grow, they form a new ring each year

- Rings are thicker in warm, wet conditions

- The thickness of the ring tells us what the climate was like

- Tree rings are reliabe for the past 10,000 years