The ice cores that may allow us to look 1.5-million-years into the previous


Melting isn’t an choice as a result of carbon dioxide simply dissolves into water. Historically, scientists have used mechanical extraction strategies, grinding up samples of particular person layers of ice to free the air. However grinding wouldn’t be efficient for the Past EPICA ice within the college’s storage freezer, which is stored at 50 °C under zero. The oldest ice on the very backside of the core will probably be so compressed, and the person annual layers so skinny, that bubbles received’t be seen—they’ll have been pressed into the lattice of ice crystals, forming a brand new part referred to as clathrate.

“On the very backside, we anticipate 20,000 years of local weather historical past compressed in just one meter of ice,” says Hubertus Fischer, head of the previous local weather and ice core science group at Bern. That’s a hundredth the thickness of any current ice core file.

The brand new technique Krauss and Fischer are growing known as deepSLice. (A pizza menu is taped to the facet of the system proper underneath the laser warning labels, a present from a pizzeria in Australia with the identical title.) DeepSLice has two elements. The Laser-Induced Sublimation Extraction Gadget, or LISE, fills half a room within the workforce’s lab area. LISE goals a near-infrared laser constantly at a 10-centimeter slice of ice core in order that it turns immediately from stable to gasoline underneath extraordinarily low strain and temperature. The sublimated gasoline then freezes into six steel dip tubes cooled to fifteen Okay (-258 °C), every containing the air from one centimeter of ice core. Lastly the samples are loaded right into a custom-made absorption spectrometer primarily based on quantum cascade laser know-how, which shoots photons by the gasoline pattern to measure concentrations of carbon dioxide, methane, and nitrous oxide concurrently. One other large benefit of this method is that it takes loads much less ice (and work) than the previous technique of research, through which scientists measured methane by melting ice (it doesn’t dissolve into water) and measured carbon dioxide by grinding ice.

DeepSLice presents “a singular functionality that no person else has,” says Christo Buizert, an ice core scientist on the College of Oregon and the ice evaluation lead for COLDEX (the Heart for Oldest Ice Exploration)—the US equal of Past EPICA, which is at present in a “pleasant race” with the Europeans to drill a steady core all the way down to 1.5-million-­year-old ice.

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