evidence: Ice cores are generally sliced into segments up to a meter long for transport and storage. Ice core storage requires specialized facilities. The National Science Foundation Ice Core Facility (NSF-ICF) houses ice cores from Greenland, Antarctica, and North America. The NSF-ICF’s main freezer provides 1,600 cubic meters (55,000 cubic feet) of storage space, kept at a frigid -36°C (-33°F). Although the facility has an on-site examination room, most ice analysis is performed offsite, after ice samples have been shipped to other research facilities. [...] As the NSF states, ice cores show lower carbon dioxide amounts over the past 400,000 years, but ice cores reach back even further in time. According to the NSF-ICF, cores extracted from the Greenland Ice Sheet preserve 130,000 years of climate history. Cores from the Antarctic Ice Sheet preserve up to 800,000 years. Researchers continually strive to extract older ice, so these ice-core-age limits will likely increase.