Josef Kowatsch and Stefan Kämpfe at the European Institute for Climate and Energy (EIKE) analyze the winter data from Germany’s DWD Weather Service an conclude that winters have been cooling.
The two authors present a lengthy analysis of German winter trends and what factors impact them the most. Today I will focus on the first part of their article, i.e. winter trends in Central Europe – mainly Germany. What follows is an abbreviated summary version.
Because of Western Europe’s proximity to the Atlantic, mild winters are nothing unusual and have occurred many times in the past. Two mild winters in a row occurred from 1909/10 to 1912/13, 1918/19 to 1920/21, 1934/35 to 1936/37, 1947/48 to 1949/50, 1987/88 to 1989/90. The article by Kowatsch and Kämpfe looks at if German winters are really getting warmer and less snowy, as is frequently claimed. They are not.
Now trend in snow coverage
An important indication for the character of a winter in Germany is the number of days with a snow cover on the ground that is at least 1 cm. That can be traced back thanks to the records of the Potsdam station, which goes back to 1893/94. There snow can fall already in October and well into April, and so it makes sense to look at the seasonal snow coverage days, where by the season goes from October 1 to April 30:
Figure 1: The number of snow coverage days – which fluctuates wildly – has been unchanged over the long-term. There’s no indication of reduced snow coverage days for Potsdam. The low snow year 2014/15 in the German lowlands is not included in this chart; yet it will show significantly more snow coverage days than the extremely low snow winter of 1974/75. (Source: PIK).
When one considers only the meteorological winter (DJF), no trend is detectable for snow coverage. However there are periodic fluctuations (Figure 2):
Figure 2: In the 1910s to the 1930s 1910er as well as at the end of the 20th century, there were generally fewer snow coverage days, instead the winters were wetter, milder. (Data source: PIK).
Over a large regional scale (entire northern hemisphere) reliable data on snow cover are available since 1967. During this almost 50-year period snow coverage fluctuated strongly, yet there is no declining trend:
Figure 3: Since 1967 there has been no reduction in wintertime snow cover days over the northern hemisphere (Source: NOAA).
German winter temperatures – cooling!
Next we will look back at German winters over the past 28 and 18 years, and do so without considering the urban heat island effect despite the ongoing landscape alteration by man: Every day some 108 hectares are being built upon in Germany and thus creating growing heat islands around temperature measurement stations.
Germany’s winter of 2015 is currently pegged by the German DWD Weather Service as being 1.8°C above normal. Thus it’s the second warmer than normal winter in a row. However, the German DWD neglects to tell the public one thing: Over the long-term winter temperatures have dropped. It’s getting colder. See Figure 4. Data come from the German DWD Weather Service in Offenbach.
Figure 4: Winter temperatures have been falling in Germany for almost 30 years. The two recent mild winters have not changed that trend.
Result: Despite the alleged “global warming”, which is supposed to make itself evident especially in the winters, German winters are ignoring the forecasts made by the so-called climate scientists. It’s going to take an impressive series of mild winters just to flatten the trend.
This is proving to be terribly inconvenient for climate scientists who banked on warming. In the meantime cooling phases are being ignored, or data are even being falsified.
Perhaps Obama should speak to the media again about over-hyping; “if it chills, send shills”.
Statement by Dr. Wei-Hock Soon
The AGW fanatic’s witchhunt continues.