The number of Posts appearing was not defined and as a result the total number of Posts attributed to an Author are not displayed; instead it stops at 10 Posts.

https://dev.p4.greenpeace.org/international/author/greenpeace-international/

In lieu of not having a UX designer - let's just do this:
for all screen sizes, show 10 Posts, Display a Load More button and when clicked on 10 more stories will appear, regardless of screen size.