What are proxies

Stomata

O isotope used in climate research

how O-18 is used

standard for Oxygen

What chemical used to estimate O-18/O-16

How does O get in shells

how are shells collected

When is Holocene epoch

what epoch did the ice age occur

What 'caused' high temps 250mya

CO2 55mya(compared to today)

glacier

evidence for extent of glacial coverage

# of times glaciers advanced and receded over last 500,000years

how does rock weathering remove CO2

MilanKovitch Cyles

eccentricity

temperature anomaly

why not average temps to get global avg