Read here. Map source here. More research from China confirms Medieval temperatures were significantly warmer than current ones. The study also provides direct evidence that the Medieval Warming was a global phenomenon, not just a European regional climate condition, as the IPCC speculates.
"...the authors extracted cores of peat from a location close to Hani Village, Liuhe County, Jilin Province, China; and they used them to develop, as they describe it, "a peat cellulose δ18O temperature proxy record proximately existing for 14,000 years.""....."Their efforts revealed, first of all, that the MWP had indeed held sway on the Chinese mainland over the period AD 700-1400, peaking at about AD 900......they say MWP temperatures were as much as "0.9-1.0°C higher than modern temperatures "....."with respect to the last 14,000 years, Hong et al. write that "sudden cooling events, such as the Older Dryas, Inter-Allerod, Younger Dryas, and nine ice-rafted debris events of the North Atlantic are almost entirely reiterated in the temperature signals of Hani peat cellulose δ18O."....."indicating that the recurring warming and cooling did indeed occur "outside the European region" and that it truly was "a common phenomenon.""
Additional climate history postings.