The Medieval Warm Period (MWP) refers to a time interval between
AD 900 and 1300 in which some Northern Hemisphere regions were
warmer than during the period known as the Little Ice Age that
followed it, and also warmer than the period of glacial advance
preceding the MWP. There is clear evidence in parts of the
Northern Hemisphere for dating the Medieval Warming Period, both
through glacial geologic dating and through recorded human
exploration and history; however, there is some debate over the
geographic comprehensiveness of the MWP; for example the
presence of this period of warming on the Colorado Plateau is
not clearly defined. Large extents of Iceland were farmed in the
10th century AD. At this time, Norse Vikings colonised
Greenland, while a reduction of sea ice allowed regular voyages
at these northern latitudes. There was a certain spatial
inhomogeneity regarding the precise onset of the MWP, based upon
different positions around the globe as Jansen et al have
pointed out; the warmest conditions occ