The Ice at the End of the World: An Epic Journey into Greenland’s Buried Past and Our Perilous Future
IPCC Special Report on the Ocean and Cryosphere in a Changing Climate
The Hindu Kush Himalaya Assessment: Mountains, Climate Change, Sustainability and People
There is a house-sized boulder in the woods near where I live. I can see it through my window, perched at the top of a steep slope. It seems as though it were set there by a giant’s hand; in a sense, it was. The great rock was deposited by the Laurentide Ice Sheet, which blanketed the northern half of North America roughly 20,000 years ago. By 12,000 years ago, the Laurentide had retreated from my corner of northern New England, leaving Lake Champlain and a scoured, striated landscape in its wake. Around that time, the earth’s temperature spiked rapidly.
We know this thanks to samples, known as ice cores, extracted from Greenland’s two-mile-thick ice sheet, parts of which are almost a million years old. There is a huge variety of information locked in its layers—isotopes of oxygen, trapped bubbles of methane, traces of pollutants—from which entire ancient worlds can be inferred and their climates reconstructed.
In his new book, The Ice at the End of the World, the journalist Jon Gertner chronicles the labors of the scientists who drilled and studied those cores in frigid trenches dug out of the ice sheet itself, occasionally pausing to marvel at layers formed from snow that had fallen when Marcus Aurelius invaded Germany, or that contained traces of volcanic dust from an eruption during Caesar’s reign.
Gertner visited the storage facility in Colorado that now houses the cores. Joan Fitzpatrick, the US Geological Survey scientist who runs the facility, showed him one that dates to 11,700 years ago. “Boom. All of a sudden they get tighter here,” she said, pointing to a sharp transition in the layers of ice that marks a warming spike of about 10 degrees Celsius—the same increase that caused the Laurentide to melt. “Ice age here. Not ice age there. We think this was in the space of a few years. And the whole point is, we all once thought it would take thousands of years.”
There are mounting signs that we are living through a similarly wrenching transition in the global climate—one of our own making. But there may be no clearer signal of the scope and speed of this transformation than the accelerating melting of the cryosphere, the frozen realms of our planet. The cryosphere encompasses glaciers, permafrost, sea ice, snow fields, ice shelves floating on the sea, and ice sheets made from snow piled up over thousands and millions of years. Around 10 percent of Earth’s land is covered by glaciers or ice sheets, which hold 69 percent of the world’s fresh water. Arctic ice helps drive the temperature difference between the poles and lower latitudes…
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