Projected changes in sea ice extent in the northern hemisphere in September

Note: Changes in sea ice extent in the northern hemisphere in September were simulated using the fifth phase of the World Climate Research Programme's Coupled Model Intercomparison Project (CMIP5) models over the 21st century under different emission scenarios (RCPs). Sea ice extent is defined as the total ocean area in which the sea ice concentration exceeds 15 % and is calculated based on the original model grids.
The solid curves show the 5-year running mean under emission scenarios RCP2.6 (blue) and RCP8.5 (red) based on those models that most closely reproduce the climatological mean state and the 1979-2012 trend in Arctic sea ice. The shading denotes the uncertainty range. The mean and associated uncertainties averaged over the period 2081-2100 are shown for all RCP scenarios as coloured vertical bars.
For completeness, the CMIP5 multi-model mean for RCP2.6 and RCP8.5 is indicated with dotted lines.
The dashed line represents nearly ice-free conditions.
Adapted from Figure SPM7(b) in the Working Group I contribution to the IPCC Fifth Assessment Report.