Two and a Half Millennia of Fram Strait Sea-Surface Temperatures
Bonnet, S., de Vernal, A., Hillaire-Marcel, C., Radi, T. and Husum, K. 2010. Variability of sea-surface temperature and sea-ice cover in the Fram Strait over the last two millennia. Marine Micropaleontology 74: 59-74.
Bonnet et al. report that the sea surface temperature (SST) histories they developed via the two techniques they employed were "nearly identical and show oscillations between -1°C and 5.5°C in winter and between 2.4°C and 10.0°C in summer," and their graphical results indicate that between 2500 and 250 years before present (BP), the mean SSTs of summers were warmer than those of the present about 80% of the time, while the mean SSTs of winters exceeded those of current winters approximately 75% of the time, with the long-term (2250-year) means of both seasonal periods averaging about 2°C more than current means.
The highest temperatures of all were recorded in the vicinity of 1320 cal. years BP, during a warm interval that persisted from about AD 500 to 720 during the very earliest stages of the Medieval Warm Period (MWP), when the peak summer and winter temperatures of the MWP both exceeded the peak summer and winter temperatures of the first several years of the 21st century by about 3°C.
These several observations, as well as the many similar findings we have described in the Medieval Warm Period section of our Topical Archive, clearly indicate there is nothing unusual, unnatural or unprecedented about the world's current level of warmth, which further suggests there is no compelling reason to attribute the Little Ice Age-to-Current Warm Period transition to the concomitant historical increase in the air's CO2 content.