Description
Working with data obtained from two ocean sediment cores -- one obtained in 1999 at 66°33.10'N, 17°41.99'W and one obtained in 2006 at 66°33.18'N, 17°42.04'W -- Ran et al. reconstructed summer sea surface temperature (SST) on the North Icelandic shelf for the period AD 940-2006, based on high-resolution and precisely dated diatom records, along with the help of "a modern diatom-environmental dataset from around Iceland [that] was established as a basis for quantitative reconstruction of palaeoceanographic conditions on the North Icelandic shelf." This work revealed, as they describe it, that this location "was not as warm during the last century as during the Medieval Warm Period (MWP)," which they identified as extending from the start of their record in AD 940 to AD 1300. And from the graph of their data shown below, we estimate the peak warmth of the MWP to have been about 0.6°C higher than that of the CWP.

Estimated sea surface temperature vs. time (5 point running mean). Adapted from Ran et al. (2011).