Jiang, T., Zhang, Q., Blender, R. and Fraedrich, K. 2005. Yangtze Delta floods and droughts of the last millennium: Abrupt changes and long term memory. Theoretical and Applied Climatology 82: 131-141.
What was done
The Yangtze Delta, located in Eastern China (30 to 33°N, 119 to 122°E), is a nearly-level plain with an elevation that averages only 2 to 7 meters above sea level across 75% of its area. As such, this low-lying terrain is vulnerable to flooding and maritime tidal hazards, which have been well recorded. Consequently, Jiang et al. analyzed pertinent historical documents to produce a time series of flood and drought occurrence in the Delta since AD 1000, from which we can evaluate one of the oft-repeated claims of climate alarmists, i.e., that global warming results in increased frequencies and greater magnitudes of both floods and droughts.
What was learned
Alternating wet and dry episodes occurred throughout the 1000-year period; and the data demonstrate that droughts and floods usually occurred in the spring and autumn seasons of the same year, with the most rapid and strongest of these fluctuations occurring during the Little Ice Age (1500-1850).
What it means
With respect to the climate-alarmist claim that global warming leads to more frequent and more intense floods and droughts, data from the Yangtze Delta suggest otherwise. In fact, they suggest just the opposite, with higher frequencies and greater magnitudes of these hydrological extremes occurring during the Little Ice Age than during both the preceding Medieval Warm Period and the following Modern Warm Period.