Table 1 Reference subpopulation extents (km²) based on mean sea ice extent in March between 1979–1988 for two different values of sea ice concentration used to define sea ice extent (i.e., < 15% or < 30% sea ice concentration) and two different definitions of the threshold used to define an ice-free day (IFD; i.e., < 15% or < 30% of 10-year March average sea ice concentration).

From: Model sensitivity limits attribution of greenhouse gas emissions to polar bear demographic rates