In this manner, Hansen and Sato use climate models to help them estimate past radiative forcings and surface temperature changes using
paleoclimate data without influencing their climate sensitivity estimates.
Just a quick note to say that the
paleoclimate data for earlier warm periods 125,000 years ago and even 8 - 10,000 years ago in northern Alaska (
paleoclimate warmer than now, [from] different forcings) document the northward advance of the treeline from Nome to Barrow, Alaska, and the Canadian border at different times of change in Earth's orbital parameters (
without a significant change in CO2).