Investigation was made on whether the recent historical changes in frequency and amplitude of rainfall extremes can be considered statistically significant under the hypothesis of no trend or temporal clustering of rainfall extremes. The analysis was based on a 107-year time series of 10-min Peaks-Over-Threshold rainfall data obtained from the Uccle station in Belgium. Rainfall intensities were aggregated at levels ranging from 10 min to the monthly scale, and defined for different seasons and block lengths between 5 and 15 years using sliding windows. Perturbations in rainfall extremes were derived, which represent the empirical quantile changes. Significant deviations in rainfall quantiles were found, which persisted for periods of 10 to 15 years. In the winter and summer seasons, high extremes were clustered in the 1910s-1920s, the 1960s and recently in the 1990s. This temporal clustering highlights the difficulty of attributing ``change'' in climate series to anthropogenically induced global warming. Research in a variety of climate phenomena is essential for the attribution of changes in the climate.