This is what
makes paleoreconstructions possible, and what makes it possible to initialize global numerical weather prediction models with so few observations.)
We have more confidence in our present - day (interglacial) result since it is based on fits to direct observations rather than on more
uncertain paleoreconstructions, and we find it unlikely that glacial sensitivities were much lower than 2.5 K, given ice albedo feedbacks (47, 48).
First, Montford's book clarifies three weaknesses in
the paleoreconstructions, from MBH 98/99 through Mann et al 08.