For starters, they state that the new temperature series "is not only representative of the central-eastern Tibetan Plateau, but also the vast area of central-northern China," and they say that it is "significantly correlated with seven other temperature series of the Northern Hemisphere [and] even has a teleconnection with series for middle-low latitudes in the Southern Hemisphere (Liu, 2010)." And in light of these widespread connections, it is not surprising, as they describe it, that "extreme climatic events on the Plateau, such as the Medieval Warm Period, Little Ice Age and 20th Century Warming appeared synchronously with those in other places worldwide."

Another important finding, in the words of Liu et al. (2011) is that "the largest amplitude and rate of temperature change occurred during the Eastern Jin Event (AD 343-425), and not in the late 20th century." More specifically, they report that "the mean temperature of the late Eastern Jin Event (2.67°C) was the highest in the 2485 years, even exceeding that of the second half of the 20th century (2.57°C)," demonstrating thereby that "the late 20th century was not the warmest period in history."

Power spectrum analysis was used to discover that major periodicities in the Tibetan Plateau temperature series were centered on 1324, 800, 199, 110 and 2-3 years at the 99% confidence level; and the five researchers remark that the 1324-year cycle "approximates the well-known dominant climate change cycle of 1374±502 years in the Holocene (Bond et al., 1997) and the 1470-year cycle in Dansgaard/Oeschger events in the last glacial period," noting that "the inducement mechanism of these cycles may be associated with solar activity (Bond et al., 1997; Xu, 1998; Braun et al., 2005), and perhaps, the inherent solar cycle (Eddy 1977; Ma, 2007)."

And, last of all, they state that "cold intervals corresponded to sunspot minimums."

How interesting it is that Liu et al. (2011) had absolutely no need to make any references to changes in the air's CO2 concentration having anything whatsoever to do with any of these numerous and varied observations.

Sherwood, Keith and Craig Idso

References
Bond, G., Showers, W., Chezebiet, M., Lotti, R., Almasi, P., deMenocal, P., Priore, P., Cullen, H., Hajdas, I. and Bonani, G. 1997. A pervasive millennial scale cycle in North-Atlantic Holocene and glacial climates. Science 278: 1257-1266.

Braun, H., Christl, M., Rahmstorf, S., Ganopolski, A., Mangini, A., Kubatzki, C., Roth, K. and Kromer, B. 2005. Possible solar origin of the 1,470-year glacial climate cycle demonstrated in a coupled model. Nature 438: 208-211.

Eddy, J.A. 1977. Climate and the changing sun. Climatic Change 1: 173-190.

Liu, Y. 2010. Temperature tele-connections reflected in tree rings and ice core from high-latitude regions between Northern and Southern Hemisphere. Journal of Earth Environment 2: 100-104.

Liu, Y., An, Z.S., Linderholm, H.W., Chen, D.L., Song, M.H., Cai, Q.F., Sun, J.S. and Tian, H. 2009. Annual temperatures during the last 2485 years in the mid-eastern Tibetan Plateau inferred from tree rings. Science in China Series D Earth Science 52: 348-359.

Liu, Y., Cai, Q.F., Song, H.M., An, Z.S. and Linderholm, H.W. 2011. Amplitudes, rates, periodicities and causes of temperature variations in the past 2485 years and future trends over the central-eastern Tibetan Plateau. Chinese Science Bulletin 56: 2986-2994.

Ma, L.H. 2007. Thousand-year cycle signals in solar activity. Solar Physics 245: 411-414.

Xu, J.H. 1998. Sun, climate, famine and folk nation transfer. Science in China Series D Earth Sciences 28: 366-384.