What do ice core samples have to do with Global Warming?
They do not have any causitive relationship whatsoever. But just like a core of rock, a core of ice gives us samples of material representing past time. By studying the chemistry of the ice and its inclusions, we can learn how the atmosphere and oceans have varied over geologically relatively short time frames (thousands to hundreds of thousands of years, primarily), and there really aren’t a lot of good ways to get that information. Not like there was anyone around writing a weather diary during that time. In the absence of ice cores, we would have a very very poor understanding of climatic variations during the “ice age” of the past couple million years.
