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How do we know about the climate from thousands of years ago?

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Lesson Plan 4 – Day 1

Ice Core Slides

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Climate Readings Over Time

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DATA: Petit, J.R., et al., 2001;

NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.

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Measuring Devices

  • Thermometers were not invented until 1724.

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  • Other climate measuring devices were not invented until much later.

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  • How can we make long-term climate graphs?

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Ice Cores!

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Ice Cores

  • Drilling into glacial ice allows us to see back in time.

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  • Each winter new snow fall packs on top of previous snow. This creates a new band each year.

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Dating Ice Cores

  • Ice cores are like tree rings
  • Summer ice appears light
  • Winter ice appears dark
  • How many years do you see?

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Dating Ice Cores

This ice core shows 12 years

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Air Bubbles

  • Air bubbles in the ice trap pollen and the atmosphere which is made of gases.

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  • These help scientists know what the climate was like thousands of years ago.

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The Vostok Ice Core

  • The Vostok Ice Core is a Russian Station near the South Pole.

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  • Their ice cores have produced climate data for the past 420,000 years!

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Analyzing the Data:�Isn’t Heating and Cooling Just a Natural Cycle of the Earth?

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Vostok Ice Core Data�Beginning & Ending Temp. Data

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Age of Ice

(years)

Temperature Difference

(Degrees Celsius)

0

0

17

0

35

0

53

0

72

0

419095

0.94

419682

0.51

420281

0.54

420888

0.32

421507

0.15

422135

0.08

422766

0.23

Top of Core

Bottom of Core

DATA: Petit, J.R., et al., 2001;

NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.

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Vostok Ice Core Data�

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DATA: Petit, J.R., et al., 2001;

NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.

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Ice Core Data�Sample Carbon Dioxide Data

Gas age (yrs)

CO2 (ppmv)

2342

284.7

3634

272.8

3833

268.1

6220

262.2

7327

254.6

8113

259.6

10123

261.6

11013

263.7

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In what year does this data begin?

DATA: Petit, J.R., et al., 2001;

NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.

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Vostok Ice Core Data�

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DATA: Petit, J.R., et al., 2001;

NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.

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Climate Readings to the Present

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DATA: Petit, J.R., et al., 2001;

NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.

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Ice Core Conclusions

  • The Earth has been this hot before, but it was far different than the conditions we have today. For example, there were no ice caps at the poles.

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  • The carbon dioxide level has not been this high in the last 420,000 years although it had been much higher millions of years ago.

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  • If CO2 keeps increasing, temperatures are virtually certain to surpass highs of the past 420,000 years.

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