The font’s design is based on data from the National Snow and Ice Data Center (https://nsidc.org) and predictions provided by the IPCC (https://www.ipcc.ch/srocc/). The heaviest font weight represents the minimum extent of the Arctic sea ice in the year 1979, when satellite measuring began. The lightest weight represents IPCC’s 2050 forecast, when the Arctic sea ice minimum is expected to have shrunk to only 30 % of the 1979 extent.