Proxy data Our knowledge of past climate is based on analysis of “proxy” records, or natural histories that are preserved & are sensitive to climate Ice cores - examples Pollen from sediments Tree rings Fossils Social/anthropologic records

Ice cores & climate

Ice coring locations

Antarctica

Antarctic ice coring

Ice coring in Greenland:

GISP2 Berthing in tents

GISP2 camp

GISP2 Work areas in weatherports

GISP2 deep ice core: drilling dome & tower

GISP2: inside drilling dome

GISP2 Recovering & examining 6-m long section of ice core

GISP2 Cutting core w/ saw Dark bands indicate annual dust layers

Shallow ice coring in Greenland

Undergraduate student Tiffany House saws ice core to 2 x 2 x 100 cm pieces, then loads onto melter for analysis

Continuous flow analysis (CFA) Spectroscopic & spectrofluorometric methods Depth resolution ~2 cm

Comparison of annual markers, NASA-U core 1 Anklin et al., JGR 1998 Depth, m

Ice core analysis Result is a record of the Earth’s atmosphere & climate over the past 500,000 years Year-by-year record for past 20,000-50,000 years Century-by-century record for past 200,000 years Millenial scale record for past 500,000 years