Researchers at the University of Ottawa Laboratory for Paleoclimatology and Climatology have reconstructed temperature for the for the last 2,000 years in North America using 748 pollen sites from the North American pollen database.
The researchers found that the Medieval Warm Period (MWP) (800-1200 AD) and Little Ice Age (LIA) (1400-1850 AD) were both cooler than present (1961-1990 average).
[See Figure 2 - top and middle panels).
The MWP was warmer than the LIA over much of the continent.
[See Figure 2 – bottom panel).