Fig. 2: Seasonal cycle of sea ice area and production in Control and increased CO₂ simulations.

Climatological monthly-mean (top; a–d) sea ice area (10³ km²) and (middle; e–h) sea ice production (10 km³) over the Prydz, Adélie, Ross, and Weddell polynyas simulated by (black) Control, (orange) 2×CO₂, and (red) 4×CO₂ experiments. The abscissa is the time (month). Sea ice production rates are calculated within the coastal polynya boundaries from the Control simulation (solid green lines Fig. 1c–f). (bottom; i–l) The areally-averaged winter sea ice productions (accumulated from June to September) for the i Prydz, j Adélie, k Ross, and l Weddell polynyas, simulated by the (black) Control, (orange) 2×CO₂, and (red) 4×CO₂ experiments. Shown in each box plot are the median (middle solid line), the 25th and 75th percentile (lower and upper hinge), and the 5th and 95th percentiles (whiskers). Changes in median sea ice production rates relative to the Control simulation are given in blue text.