####Geophysical Research Letters | Izumi and Bartlein 
The inverse-modeling through iterative-forward-modeling (IMIFM) approach was used to reconstruct last glacial maximum (LGM) climates from North American fossil-pollen data. The approach was validated using modern pollen data and observed climate data. While the large-scale LGM temperature IMIFM reconstructions are similar to those calculated using conventional statistical approaches, the reconstructions of moisture variables differ between the two approaches. We used two vegetation models, BIOME4 and BIOME5-beta, with the IMIFM approach to evaluate the effects on the LGM climate reconstruction of differences in water-use efficiency, carbon-use efficiency, and atmospheric CO2 concentrations. Although lower atmospheric CO2 concentrations influence pollen-based LGM moisture reconstructions, they do not significantly affect temperature reconstructions over most of North America. This study implies that the LGM climate was very cold but not very much drier than present over North America, which is inconsistent with previous studies.
Full text can be found [here](http://onlinelibrary.wiley.com/doi/10.1002/2016GL070152/epdf)