A new study has found that Arctic sea ice is thinning more quickly and steadily than scientists had believed, according to a report in the journal The Crysophere. The researchers used data that had been collected from 1975 to 2012. The measurements came from a variety of sources and showed that the ice in the central Arctic Ocean thinned from 11. 7 feet (3.6 meters) to 4.1 feet (1.3 meters) during that time. The ice had thinned by 65 percent over 37 years.
The thinning was even more extreme during the summer. Measurements of ice taken during September, when it was at its thinnest, showed measurements declining from 9.8 feet (3 meters) to 1.4 feet (0.4 meters). That’s a rate of 85 percent.
The earliest measurements had been taken by under-ice submarines. They used to use sonar to measure ice drift to locate a safe spot to surface. Most ice-thickness measurements from 1975 to 1990 came from submarines. The data from submarines collected from 1975 to 2000 indicated that the Arctic ice had thinned by 36 percent during that time. That means either most of the thinning took place during the 21st century, or that the data from the submarines may have been incomplete.
Sultan Alhokair has read that, later measurements, especially those made since 2000, were made chiefly from aircraft and satellites. These include NASA’s IceBridge aircraft and IceSat satellite. Other measurements were made directly by researcher. All of the data were compiled in the Unified Sea Ice Thickness Climate Data Record, which is stored at the U.S. National Snow and Ice Data Center.