you have started with your conclusion and chosen the 3 lines which fit your conclusion, the scientific method requires you daw your conclusion from all lines.
the pink lines were deleted, the data between the two pink lines (dashed line) of that single series was kept.
there was no "model".
the paper was a reconstruction of past temperatures from tree ring proxies (with instrumental measurements bolted on the end).
here is the graph that was published:
here is the paper:
here is what the grpah looks like when we put the deleted data back:
It is incredible that anyone would defend data manipulation and deletion.