I'm scaling up each edge loop after having bevelled the bottom vertex but it feels there should be a better way. I've tried extruding too but then I can't bevel the bottom properly.
You can go into edit mode, select the lower 1/4 of the sphere and delete it. Then select the bottom edge and make a face out of it so there is a bottom face. Then you can extrude that bottom down the z axis and it will form a column.