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L. Tan et al. authored a new peer-reviewed study that found higher temperatures existed between 1,000 and 1,200 years ago in the Asian region of north central China. The study also reconstructed precipitation levels for that area over the 1,800 years.
This study's temperature reconstruction shows higher temperatures in the past that can can clearly be labeled as unprecedented. Late 20th century temperatures were well under the Medieval era temperatures.
"A paper published examines the climate of central China over the past 1800 years using two different types of proxies. The paper finds higher temperatures and precipitation were present during the Medieval Warming Period (960-1100 AD) than at the end of the 20th century. This paper adds to the published work of 986 scientists who have documented that the Medieval Warming Period was as hot or hotter than the present and was a global phenomenon. This study also shows both the rate and magnitude of the rise in temperature from the year ~ 700- 880 AD were much greater than over a comparable period including the 20th century." [L.Tan, Y.Cai, Z.An, L.Yi, H.Zhang, Qin 2011: Climate of The Past]
Additional climate-history and peer-reviewed postings. Other historical temperature charts.