Melting isn’t an possibility 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 saved at 50 °C under zero. The oldest ice on the very backside of the core will likely 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 section referred to as clathrate.

“On the very backside, we count on 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 present ice core document.

The brand new technique Krauss and Fischer are growing is known as deepSLice. (A pizza menu is taped to the facet of the gadget proper beneath the laser warning labels, a present from a pizzeria in Australia with the identical identify.) DeepSLice has two elements. The Laser-Induced Sublimation Extraction Gadget, or LISE, fills half a room within the group’s lab house. LISE goals a near-infrared laser repeatedly at a 10-centimeter slice of ice core in order that it turns straight from strong to gasoline beneath extraordinarily low stress 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 expertise, which shoots photons by way of 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 study, during which scientists measured methane by melting ice (it doesn’t dissolve into water) and measured carbon dioxide by grinding ice.

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