1. Proxy Records Ice Cores Dendrochronology Sediment records
Agricultural records
Proxy Records: Natural Information that is measurable which reveals information on past climates.
Table of contents

2. Ice Cores
Glaciers are remains of previous ice ages when ice covered 32% of land up to 2 km thick.
Some formed between years ago during last glacial
Some are remains from earlier glacials
Glaciers are the remains of the last ice age, when glaciers covered 32% of the land and 30% of the oceans. Glaciers are the result of many years of snowfall, each year's snow piling on top of the previous year’s snow. The heavy snow on top exerts pressure on the snow beneath turning it into firn and eventually into ice. Ice cores are long tubes of ice obtained by drilling down into glacial ice.

3. Ice Cores
DESCRIPTION FROM -
The uppermost portions of an ice core have a layered structure that show yearly variation. Extreme pressure crushes the deeper ice layers together so tightly that individual years cannot be distinguished, though lower resolution climate variations can still be discerned. Typically, in ice samples from Polar Regions, the upper layers of ice have alternating light and dark layers. Light bands correspond to the relatively fresh, clean snows that fall in the summer when warmer conditions bring more moisture (and thus more precipitation) to these high-latitude locales. Dark bands mark the polar winter season, when little new snow falls on these frigid deserts and blowing snow is mixed with dust, discoloring the white snow. In many samples, the alternating light and dark layering is visible to the naked eye; in others, the layers can only be found by looking through polarized filters or via chemical analysis

4. Other Gases Trapped Air picture of atmosphere as snow compressed
Relative % of each gas
CO2 in ice suggests warmer temps as it dissolves out of oceans.
Air Bubbles – Air in glacial ice represents the atmospheric composition of a time just after the deposition of the snow, once there was sufficient mass above the snow to compress it into ice. These air bubbles are like tiny snapshots, revealing the relative percentages of the various gases in the atmosphere (O2, CO2, NO2, CFC’s, CH4 etc).
GRAPH - The percentage of carbon dioxide and methane in the atmosphere above Antarctica for the last 150,000 years has been measured in air bubbles enclosed in a long Antarctica ice core.
Variations of GHG’s have closely paralleled the temperature record. For example, during the Holocene interglacial CO2 concentrations have varied between 200 and 300 ppmv (parts per million unit volume). and during the Isotope Stage 5e Eemian/Sangamon interglacial 125,000 years ago CO2 concentrations were around 280 ppmv.
The Russian Antarctic ice-core data indicates that during the last glacial maximum CO2 concentrations were around 180 ppmv. As this data indicates the level of CO2 in the atmosphere is highly variable. 4 4

5. Ice Cores
Vostok Antarctica

6. Other substances in ice
Solid Particles
ash from volcanoes/fires,
dust & rock from meteorite impacts,
pollen reveals health of vegetation
Other Ions – Sodium, Chloride and Sulphate ions all indicate various climatic conditions
Air Bubbles – Air in glacial ice represents the atmospheric composition of a time just after the deposition of the snow, once there was sufficient mass above the snow to compress it into ice. These air bubbles are like tiny snapshots, revealing the relative percentages of the various gases in the atmosphere (O2, CO2, NO2, CFC’s, CH4 etc).
Solid Particles – ash, dust & pollen reveal information about volcanic eruptions and vegetation health of the time when the snow was first deposited.

7. Materials in Ice Cores 7 7

8. Sediment Samples
Type of rock that is formed by the deposition of sediment
In aquatic environments change based on the amount of rainfall bringing sediment into the basin
the thickness and types of material in each layer provides information.
Provide evidence of climate from more than one million years
Type of pollen = plants present = temperature
Microscopic organisms in sediment cores from lakes and oceans = isotopes of oxygen present in shells = temperature of water
Sedimentology is another important proxy record. Sediment layers in lake and ocean beds change based on the amount of rainfall bringing sediment into the basin, so the thickness and types of material in each layer provides information.
Even more important are the organisms preserved in each layer. Microscopic organisms hold evidence of the climatic conditions during their lifetime. The oxygen isotopes in their shells reflect the temperature as O-18 is more readily available than O-16 during colder periods. The pattern in their shells reveals temperature conditions as does the types of organisms present, with some thriving in colder waters and some in warmer waters. Studying the percentages of organisms in waters today with known temperatures gives paleo-climatologists an excellent profile for what relative numbers suggest about past environments. 8 8

9. Sediment Samples
Annual sedimentary layers produce alternating light and dark-coloured sediments
Summer
thick deposits of coarse light-coloured sediments = meltwater washes sediments into lakes
Winter
fine, dark-coloured sediments
Sedimentology is another important proxy record. Sediment layers in lake and ocean beds change based on the amount of rainfall bringing sediment into the basin, so the thickness and types of material in each layer provides information.
Even more important are the organisms preserved in each layer. Microscopic organisms hold evidence of the climatic conditions during their lifetime. The oxygen isotopes in their shells reflect the temperature as O-18 is more readily available than O-16 during colder periods. The pattern in their shells reveals temperature conditions as does the types of organisms present, with some thriving in colder waters and some in warmer waters. Studying the percentages of organisms in waters today with known temperatures gives paleo-climatologists an excellent profile for what relative numbers suggest about past environments. 9 9

10. Sediment Samples
Oxygen incorporated in marine shells formed under cold conditions will have elevated levels of 18O
organisms thrive in different temperatures
Sedimentology is another important proxy record. Sediment layers in lake and ocean beds change based on the amount of rainfall bringing sediment into the basin, so the thickness and types of material in each layer provides information.
Even more important are the organisms preserved in each layer. Microscopic organisms hold evidence of the climatic conditions during their lifetime. The oxygen isotopes in their shells reflect the temperature as O-18 is more readily available than O-16 during colder periods. The pattern in their shells reveals temperature conditions as does the types of organisms present, with some thriving in colder waters and some in warmer waters. Studying the percentages of organisms in waters today with known temperatures gives paleo-climatologists an excellent profile for what relative numbers suggest about past environments.

11. Coral Reefs Corals add layers of growth each season
Studied by drilling cylinders
Temperature of surface water is obtained as coral growth depends on water temperature 11 11