Proxy records Ice Cores What Is a Proxy

Proxy records – Ice Cores

What Is a “Proxy Record”? • A proxy record is historical record of different and various substances relating to climate obtained through the examination of a tree, ice core, rocks, etc…

What is an “Ice core”?

Definition: • An ice core is a sample which is removed from a large body of ice, such as an ice sheet or a glacier.

But what exactly do we do with the sample? !

• Large masses of ice have a feature similar to trees. Instead of rings, they have layers. Similar to a tree, these layers form annually. These layers can be used to look at gas concentrations corresponding to specific years. These gas concentrations can then be used to check for climate changes. These ice cores can let us go back as far as 800, 000 years.

HINT! PPM = Parts Per Million PPB = Parts Per Billion

Carbon Dioxide (ppm)

Nitrogen (ppb)

Methane (ppb)

What Causes Gas Concentration Increase? • Mining • Burning Fossil Fuels

What Do the increases in gas concentration mean? Increased levels effect gas cycles, which then misbalances natural levels of gasses. This allows the green house effect to occur on a larger scale, which heats up the earth.

Year 250 500 750 1000 1250 1500 1750 2000 Carbon Dioxide 280 275 280 285 290 295 280 340 Methane 620 630 620 640 680 700 720 1440 Nitrogen 260 260 265 270 275 280 300

Summary • Ice in Greenland, Antarctica contain ice bubbles • Air bubbles have been trapped for thousands of centuris • The ice is drilled into and cylinders of ice (ice cores) are extracted • They are cut up into slices • The gasses in the air bubble are examined • Nitrous Oxide, Methane, and Carbon dioxide concentrations are established in PPM and PPB • Allows us to check ice concentrations up to 800, 000 years back and allows us to compare concentrations of various years