Proxy RecordsProxy Records

Ice CoresIce CoresDendrochronologyDendrochronologySediment recordsSediment records

Agricultural recordsAgricultural records

Proxy Records: Natural Information that is Proxy Records: Natural Information that is measurable which reveals information on measurable which reveals information on

past climates.past climates.

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Ice CoresIce Cores

Glaciers are remains of previous ice Glaciers are remains of previous ice ages when ice covered 32% of land up ages when ice covered 32% of land up to 2 km thick. to 2 km thick.

Some formed between Some formed between 60-120 00060-120 000 years ago during last glacialyears ago during last glacial

Some are remains from earlier glacialsSome are remains from earlier glacials

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Ice CoresIce Cores

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Other GasesOther Gases Trapped Air Trapped Air

– picture of atmosphere picture of atmosphere as snow compressedas snow compressed

– Relative % of each gasRelative % of each gas

– COCO2 2 in ice suggests in ice suggests

warmer temps as it warmer temps as it dissolves out of dissolves out of oceans.oceans.

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Ice CoresIce Cores Vostok AntarcticaVostok Antarctica

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Other substances in iceOther substances in iceSolid Particles Solid Particles

– ash from volcanoes/fires, ash from volcanoes/fires, – dust & rock from meteorite impacts,dust & rock from meteorite impacts,– pollen reveals health of vegetationpollen reveals health of vegetation

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Materials in Ice CoresMaterials in Ice Cores

http://www.ulapland.fi/home/hkunta/jmoore/johnice.html

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Sediment SamplesSediment 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

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Sediment SamplesSediment 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

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Sediment SamplesSediment Samples Oxygen Oxygen

incorporated in incorporated in marine shells marine shells formed under formed under cold conditions cold conditions will have elevated will have elevated levels of levels of 1818OO

organisms thrive organisms thrive in different in different temperaturestemperatures

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Coral ReefsCoral 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