What was done
The authors present an analysis of several data sets related to Holocene climate change in China, one of which is an 1100-year record of annual calcite accumulation derived by Qin et al. (1999) from a stalagmite found in Shihua Cave, Beijing.

What was learned
The thickness sequence of laminae in the Beijing stalagmite, which is a measure of the hydrologic balance of the surrounding area, reveals the existence of a relatively wet Medieval Warm Period running from approximately A.D. 940 to 1200 and a relatively dry Little Ice Age that was most strongly expressed between 1400 and1800.

What it means
One of the driving forces behind the authors' study was, as they phrase it, "the question of whether warming similar to the recent occurred before the Little Ice Age."  Their analysis of the Beijing stalagmite data indicates that most of the A.D. 940 to 1200 period was indeed equivalent to the most outstanding portions of the 20th century with respect to moisture availability, suggesting that temperatures may well have been equivalent also.

Reference
Qin, X., Tan, M., Liu, T., Wang, X., Li, T. and Lu, J.  1999.  Spectral analysis of a 1000-year stalagmite lamina-thickness record from Shihua Cavern, Beijing, China, and its climatic significance.  The Holocene 9: 689-694.