3-year mean time series of observed and simulated Arctic SIA for 1979–2019 for each calendar month (shading), and their linear trends (bars) and 5–95% ranges (gray dashed lines or error bars) estimated from the preindustrial control (CTL) simulations. Three observations (OBS) from OSISAF, NASATeam, and Bootstrap are compared with Coupled Model Intercomparison Project Phase 6 (CMIP6) multi-model simulations from historical (ALL; anthropogenic plus natural forcing), hist-GHG (GHG; well-mixed greenhouse gas only forcing), hist-aer (AER; anthropogenic aerosol-only forcing) and hist-nat (NAT; natural only forcing) experiments. The residual GHG distribution (GHG + ) obtained by All–AER–NAT is displayed. SIA anomalies are obtained by computing non-overlapping 3-year averages (2-year averages for 2018–2019) relative to the 1979–2019 means. ALL runs are extended by using Shared Socioeconomic Pathway (SSP) 2–4.5 scenario runs since 2015.
