New Study On Heavy Rainfall: “General Long-Term Trend For Whole Germany Consistently Not Evident”

Leibnitz scientists find no significant trends for the whole of Germany in terms of heavy rainfall

We hear the message all the time from the German mainstream media and climate alarmists: Weather extremes are becoming more and more frequent, as the recent flood shows.

But a recent paper titled “Frequency Trend Analysis of Heavy Rainfall Days for Germany” by Deumer et al (2020) tells a very different story.

Hat-tip: Axel Bojanowski.

The two scientists from the renowned Leibnitz research network analyzed data and found no significant trends for the whole of Germany in terms of heavy rainfall.

The abstract:

Climate change is expected to affect the occurrence of heavy rainfall. We analyzed trends of heavy rainfall days for the last decades in Germany. For all available stations with daily data, days exceeding daily thresholds (10, 20, 30 mm) were counted annually. The Mann–Kendall trend test was applied to overlapping periods of 30 years (1951–2019). This period was extended to 1901 for 111 stations. The stations were aggregated by natural regions to assess regional patterns. Impacts of data inconsistencies on the calculated trends were evaluated with the metadata and recent hourly data. Although the trend variability depended on the chosen exceedance threshold, a general long-term trend for the whole of Germany was consistently not evident. After 1951, stable positive trends occurred in the mountainous south and partly in the northern coastal region, while parts of Central Germany experienced negative trends. The frequent location shifts and the recent change in the time interval for daily rainfall could affect individual trends but were statistically insignificant for regional analyses. A case study supported that heavy rains became more erosive during the last 20 years. The results showed the merit of historical data for a better understanding of recent changes in heavy rainfall.”

Regional differences

The paper’s Figure 6 below shows increasing (red) and decreasing (blue) trends of heavy rainfall days with ≥20 mm at rainfall stations, for years (y), summer (s), and winter (w):

Germany as a whole, however, is showing no real overall trend.

DWD foresees no significant changes up to 2050

Also Germany’s DWD national weather services reached similar results based on radar data in their national climate report published in May, 2020.

On page 22, the DWD report writes that they foresee “no significant change in mean annual precipitation total” up to the year 2050.

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