Stories in the Ice
by Peter Tyson
Online Producer, NOVA
Nature's Time Machine
How would you like to have a time machine that could take you back anywhere over the past 300,000 years? You could see what the world was like when ice sheets a thousand feet thick blanketed Canada and northern Europe, or when the Indonesian volcano Toba blew its top in the largest volcanic eruption of the last half million years.
Well, scientists have such a time machine. It's called an ice core. Scientists collect ice cores by driving a hollow tube deep into the miles-thick ice sheets of Antarctica and Greenland (and in glaciers elsewhere). The long cylinders of ancient ice that they retrieve provide a dazzlingly detailed record of what was happening in the world over the past several ice ages. That's because each layer of ice in a core corresponds to a single year—or sometimes even a single season—and most everything that fell in the snow that year remains behind, including wind-blown dust, ash, atmospheric gases, even radioactivity.
Indeed, fallout from the Chernobyl nuclear accident has turned up in ice cores, as has dust from violent desert storms countless millennia ago. Collectively, these frozen archives give scientists unprecedented views of global climate over the eons. More important, the records allow researchers to predict the impact of significant events—from volcanic eruptions to global warming—that could strike us today.
Ice Core Timeline
Special thanks to Mark Twickler, University of New Hampshire
Stories in the Ice | Antarctic Almanac | Water World | Live and Breathe Antarctica
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