Background
The authors write that "long-term temporal analysis of trends and cycles is crucial in understanding the natural variability within the climate system." Hence, they provide a stellar example of such a "crucial analysis" with respect to extremes of rainfall in Belgium over the past hundred-plus years.

What was done
Ntegeka and Willems conducted "an empirical statistical analysis of trends in rainfall extremes ... based on the long-term high-frequency homogeneous rainfall series at the climatological station of the Royal Meteorological Institute of Belgium at Uccle." Amazingly, this series was recorded by "the same measuring instrument at the same location since 1898 and processed with identical quality since that time," and it was done at a measuring frequency of ten minutes, which has yielded more than 107 years of continuous data.

What was learned
The Belgian researchers report that "significant deviations in rainfall quantiles were found, which persisted for periods of 10 to 15 years," such that "in the winter and summer seasons, high extremes were clustered in the 1910s-1920s, the 1960s and recently in the 1990s."

What it means
"This temporal clustering," in the words of Ntegeka and Willems, "highlights the difficulty of attributing 'change' in climate series to anthropogenically induced global warming," and they say that "no strong conclusions can be drawn on the evidence of the climate change effect in the historical rainfall series."

We find this negative or null result to be extremely interesting, especially in light of the fact that climate alarmists -- who argue that global warming should produce both more floods and more droughts -- typically contend that the warming of the earth over the past century or more has been unprecedented over the past one to two millennia. Perhaps their worries are not all that well founded.