evidence: UN Says Melting Arctic Ice is a Key Indicator of Climate Change—But It's Not Melting "Questioning the data. [...] The National Oceanic and Atmospheric Administration (NOAA) uses NSIDC data to record Arctic sea ice yearly minimums in September, at the end of the summer melt season. The measurement is based on sea ice extent, which is the square mileage of ice covering the Arctic Ocean during a specified time. [...] "The sharp decrease in Arctic Sea ice extent before 2007, when the Nobel Prize was delivered to IPCC and Al Gore, was supposed to continue forever. In that light, the predictions were fair," he said.