I had a brief email exchange with Professor
This is fascinating. I had no idea these emails were in the public domain.
In general Steve has gotten most of this right. There really is a problem
with the trees not being sensitive to temperature after about 1950. My
current best guess is that the higher CO2 since then has caused greater
warming at night (which is corroborated by minimum temperature trends,
since minimum temperatures usually occur at night). Trees respire more
at higher temperature, so they lose carbon when nights are warmer
than average. So their ring width has not increased as much as it would
have if the warming had been uniformly distributed over the diurnal cycle.
I think this is all published now so it should be possible to set the whole
record straight. But I did indeed feel at the time that Mike Mann had not
given me a straight answer. So if there is a response written, it won’t be
one defending Mike.