A hundred people gathering, analyzing, correcting or adjusting thousands of temperature data points for variances, etc. and «filling in the gaps» where there are no data points, is no better than these hundred people, the thermometers themselves and their environment (i.e. has urbanization occurred, is the thermometer next to an AC exhaust, building or asphalt parking lot, etc..) (judithcurry.com)
I've also added the two most recent GISP2 temperature data points (for 1847 and 1855, red crosses). (skepticalscience.com)
I've also shown on the graph the well - established age of the Younger Dryas — note that the Shakun et al. global temperature data points show a dip in temperature (presumably the Younger Dryas) that is considerably younger. (wattsupwiththat.com)