I can only go where the data leads.
Think how much amplified feedback is required to make the
1.1 C of 2XCO2 forced warming to become the 3 C of projections?
The formula is simple, output divided by input 3/1.1=2.72.
Now look at how that 2.72 factor works using the GISS's numbers and Hansen's latency of 37.5 years for ECS.
Within the GISS data we have .2 C of warming that occurred before 1940, that is two of Hansen's cycles ago.
So cycle 1: .2 X 2.72= .544 C, cycle 2: .544 X 2.72= 1.47 C.
Now since we have not warmed by 1.47 C since 1940, we can rule out the 2.72 feedback factor (and the 3 C where it came from) as possible.
What do we really have to work with?
It turns out not much!
If we subtract the 1950 forcing from the 2011 forcing, we get 1.72 Wm-2 or .516 C from forcing.
The decade average difference between the GISS 1950 to 2011 is .602 C
So the total unknown possible, including the amplified feedbacks from the aforementioned .2 C pre 1940 warming,
is less than .086 C. Even if all of the unknown were from amplified feedbacks, they still would not amount to much.