Büntgen, U., Raible, C.C., Frank, D., Helama, S., Cunningham, L., Hofer, D., Nievergelt, D., Verstege, A., Timonen, M., Stenseth, N.C. and Esper, J. 2011. Causes and consequences of past and projected Scandinavian summer temperatures, 500-2100 AD. PLoS ONE 6: 10.1371/journal.pone.0025133.
Buntgen et al. combined five previously-published reconstructions of summer (July-August) temperatures of the northern Scandinavia region to produce a single mean temperature history spanning the period AD 500-2000+. This record indicates that there were four periods of time - peaking at about AD 760, 1000, 1100 and 1430 - when the mean temperature of the region was approximately 0.1°C cooler than the single peak temperature of the Current Warm Period. And we note that the 145-year time interval AD 965-1110 provided the maximum sustained warmth of the Medieval Warm Period (as well of that of the entire reconstruction, including the Current Warm Period), which we thus associate with that specific period of time.