At least for the vegetation, the year 2021 was a good one: after the dry summers of the last three years, there was once again sufficient rainfall in large parts of the country last year. A total of 805 liters per square meter fell, a little more than the average for the reference period from 1961 to 1990, according to the German Weather Service (DWD) recently reported.
The year 2021 was also “too warm”, i.e. around one degree Celsius warmer than the mean of the reference period, but the many extremely hot days that had occurred in previous summers were missing. The meadows and fields stayed green and the bushes could flourish. “The vegetation has recovered well,” says Andreas Marx, head of the German Drought monitors of the Environmental Research Center Leipzig (UFZ).
However, the drought-plagued soil was only soaked up with moisture in the top meter. In the lower strata, large parts of the republic remained too dry. Therefore, the trees that dig their roots deeper could benefit less. “2021 was a good starting point that brought a slight recovery,” says Marx. “But the forest is not over the mountain yet.”
The heavy rainfalls in summer were also of little use. If too much rain falls in a short time, the soil cannot absorb it that quickly. Most of the water simply rushes off the surface and is carried away by streams and rivers. Drought and heavy rain do not have to be mutually exclusive; the former can even promote the latter when the soil is so bone-dry that it hardly absorbs water.
A normal year does not bring the water balance back into balance
In any case, the precipitation in winter is more important so that the soil layers can soak up moisture again, said DWD spokesman Andreas Friedrich. Because then less water can evaporate. And last winter it actually rained a little more than usual.
A “normal year” would not bring the soil water balance straight back into line, Andreas Marx points out. That would take a few normal years in a row with enough rain.
Although, 2021 wasn’t that normal either. It was marked by extremes: February with frosts and snowfalls in the middle of Germany, at the end of March almost early summer temperatures, then the coldest April in 40 years and then the third warmest June since records began, followed by the heavy rainfalls and catastrophic floods in the southwest of the Country. At least for the forests, however, persistent weather conditions such as extreme heat and drought over months have greater consequences.
The impressions from the heavy rain in the summer of last year somewhat hide the fact that the soil, especially in large parts of north-east Germany, was still very dry throughout 2021 and that the forests there suffered particularly. The current winter has so far brought too little rainfall, especially between Hanover and Frankfurt (Oder). “This is our big problem child,” says climate researcher Marx. But even in parts of Bavaria it is currently too dry. “The drought phenomenon has not yet been resolved everywhere in Germany.”
This winter, of all things, the kind of weather that humans like the least would help nature: the temperatures are slightly higher and now and then rain showers. Bad weather.