Quantitative temperature reconstruction based on growth rate of annually-layered stalagmite: a case study from central China

We used the annual growth rate of a stalagmite (XL21) collected from Xianglong Cave, central China, to quantitatively reconstruct regional terrestrial temperature changes over the last 95 years (1912-2006 AD). Based on a significant positive correlation between the growth rate and the observed temperature, a transfer function was designed, and the temperature from the previous September to May (P9-5) was reconstructed, with an explained variance of 43.5%. Our results show an increasing trend in temperature during the last century, and especially over the last 30 years. The temperature variability from central China recorded here bears a striking similarity to that in the Northern Hemisphere, and also to global trends. However, the cooling between the 1980s and the early 1990s seen in the stalagmite record, which interrupted the warming trend that began in the 1960s, is not observed in the mean conditions found in China, the Northern Hemisphere, neither globally. This methodology for reconstructing historical temperature from stalagmite growth rates overcomes the limitation of the short meteorological observation period and supports the potential of stalagmite lamina climatology.