I have a new paper on climate variability and how it affects our estimates of climate sensitivity. It breaks the "pattern effect" into two terms. This paper will be appearing in J. Climate.
drive.google.com/file/d/1m0LIg6…
drive.google.com/file/d/1m0LIg6…
The first term is the unforced pattern effect, which is due to internal variability over the 20th century. The second is the forced pattern effect, due to the fact that the surface warming pattern during transient warming is not the same as the pattern at equilibrium.
Together, they could bias ECS measured over the 20th century low by about 0.5 K.
Combined with other sources of error, such as masking and blending errors in the observational record, which could be another 0.5 K, we can explain most of the disagreement between models and ECS derived from the 20th century.
