What was done
The authors say that "according to Walsh and Ryan (2000), future global climate trends may result in an increased incidence of cyclones."  Consequently, and realizing that "understanding the behavior and frequency of severe storms in the past is crucial for the prediction of future events," they devised a way to decipher the history of severe storms in the region of the southern South China Sea.  Specifically, working at Youngshu Reef (9°32'-9°42'N, 112°52 -113°04'E), they used both standard radiocarbon dating and TIMS U-series dating to determine the times of occurrence of storms that were strong enough to actually "relocate" large Porites coral blocks that are widespread on the reef flats there.

What was learned
Yu et al. determined that "during the past 1000 years, at least six exceptionally strong storms occurred," which they dated to approximately 1064 ± 30, 1218 ± 5, 1336 ± 9, 1443 ± 9, 1682 ± 7 and 1872 ± 15 AD, yielding an average recurrence frequency of 160 years.

What it means
Although climate alarmists typically claim that (1) storms will become more frequent and severe in response to global warming and (2) the warming of the 20th century was the most significant of the past millennium, none of the six severe storms identified by Yu et al. occurred during the past millennium's last century.  Consequently, for this particular part of the world, i.e., the southern South China Sea, their predictions are not born out by real-world data.

Reference
Walsh, K.J.E. and Ryan, B.F.  2000.  Tropical cyclone intensity increase near Australia as a result of climate change.  Journal of Climate 13: 3029-3036.