I'm working with the WWF ecoregions, which use the GCS_WGS_1984 geographic coordinate system. I have clipped the ecoregions with a species range (consisting of two polygons), but the new attribute table doesn't tell me the new 'clipped' ecoregion areas.
From reading around it seems I need a projected coordinate system to calculate these new areas. However the attribute table of the ecoregions contain area (km2) as well as shape area. Would these have been calculated using a projected coordinate system? If so, is there a way of finding out which one they used?
I am using ArcGIS 10.1 for Desktop.