Datsenko et al. (2014) write that the problems of current climate change, the establishment of reasons for it, and the development of scenarios of its further potential evolution are still the "focus of attention of climatologists," and so they proceed to describe their most recent foray into this controversial realm of research.
The six scientists - three Chinese and three Russian - developed a new 1000-year-long history of the temperature of the Northeastern Tibetan Plateau, based on a new method of analyzing very long tree-ring data that they developed and christened eigen analysis, which is described in detail in the studies of Yang et al. (2011a,b). This they did while working with Przewalskii juniper trees growing at a height of approximately 3000 meters in the mountainous region of China, many of which had been alive for over a full millennium.
Datsenko et al. determined "the climate during and immediately after the medieval maximum of solar activity was warmer than the present-day," and all subsequent periods of cooling coincided with "periods of low solar activity." Furthermore, they note S.G. Shiyatov, the most well-known Russian dendrochronologist, corroborates this viewpoint, in that the upper treeline history of the past millennium that he (Shiyatov, 2003) developed "corresponds well," as they describe it, "to the juniper growth reconstruction."
in light of their findings, the Chinese/Russian research team states in their paper's concluding sentence that in regard to what they discovered, "it follows that the statement of the latest report of the Intergovernmental Panel on Climate Change about the unprecedented nature of the current warming is unjustified."
Datsenko, N.M., Ivashchenko, N.N., Qin, C., Liu, J., Sonechkin, D.M. and Yang, B. 2014. A comparison between medieval and current climate warming using the Przewalskii's juniper tree-ring data. Russian Meteorology and Hydrology 39: 17-21.
Shiyatov, S.G. 2003. Rates of change in the upper treeline in the Polar Ural Mountains. PAGES News 11.
Yang, B., Sonechkin, D.M., Datsenko, N.M., Ivashchenko, N.N., Liu, J. and Qin, C. 2012a. Eigen analysis of tree-ring records: Part 2, Posing the eigen problem. Theoretical and Applied Climatology 107: 131-141.
Yang, B., Sonechkin, D.M., Datsenko, N.M., Ivashchenko, N.N., Liu, J. and Qin, C. 2012b. Eigen analysis of tree-ring records: Part 3, Taking heteroscedasticity and sampling effects into consideration. Theoretical and Applied Climatology 107: 519-530.