South and Central China has a climate dominated by the impact of the East Asian Monsoon. Instrumental records of variation in the strength of the monoon stretch back less than a century. These records hint at a recent change in the strength of the monsoon, and in its linkage to other climate systems such as ENSO. We are working to understand the longer-term history of monsoon variability at seasonal resolution. This will assess the behaviour of the monsoon in different climate states, and its linkage with other climate systems. This work will also indicate whether recent changes in monsoon behaviour relate to human-induced climate change, or to a more general natural variability.

In close collaboration with Dr. HU Chaoyong from the China University of Geosciences in Wuhan, we are using cave deposits such as stalagmites to reconstruct past changes in the monsoon. This work requires a full understanding of the cave environment in which the stalagmites grew. We conduct field work to map the relevant caves, and to collect drip waters and surface scrapes from growing cave carbonates. These will help us to understand how the chemistry of the carbonates relates to changing past climate. This field work also enables us to instrument the cave so that we have a record of annual variation in cave temperature and drip-water chemistry.

The upper photo shows the entrance to Heshang cave, situated in the central Yangtze region. This 250m deep cave is one of our major focuses for this work. The second photos shows four Oxford Geochemists and two of our Wuhan colleagues travelling to Heshang along a tributary of the Yangtze. And the final photo shows Kathleen Johnson sampling drip waters and growing cave carbonates in Heshang.