How well is Germany getting through the winter this year? Is the gas enough? The German weather service is now expecting a comparatively mild winter and speaks of a good forecast quality. But how good are such seasonal climate forecasts really?
Models predict a mean temperature of 2 degrees
the Model calculations by the German weather service DWD show: This winter could get warmer than 2 degrees in Germany on average. For comparison: An average temperature of only 1.4 degrees has been measured in the past 30 years. But even if it stays milder on average in the coming winter, it can get colder on individual days or weeks, according to Dr. Andreas Paxian from the German Weather Service.
In fact, climate change is not only causing rising temperatures, but also a higher climate variability, i.e. stronger short-term climate fluctuations. The climate is becoming more unpredictable. At the same time, the models that simulate the earth’s climate system on the computer are also becoming more precise. So how reliable are the climate forecasts?
Green light for the winter forecast
The German Weather Service has been publishing since October 2021 seasonal climate forecasts – with traffic light system. The maps show temperature and precipitation trends for the whole of Germany, but also regionally and for individual cities. The traffic lights shown indicate the forecast quality: red means bad, yellow means medium and a green traffic light stands for a relatively good forecast quality.
But even a relatively good quality of climate forecast is currently not as good as that of weather forecasts, according to Paxian. And so the forecasts are mainly about probabilities: 50 percent of the winter will be warmer than in the past 30 years, the probability of a cold winter is only 18 percent. For an average winter, the probability is given as 32 percent.
Computing power limits the possibilities of climate modelling
Inaccuracies lie, among other things, in atmospheric processes that take place in the smallest of spaces. They fall through the grid of the climate model, which, for reasons of computing capacity, can only calculate the climate development at discrete intervals on the earth’s surface and in the atmosphere. With new supercomputers, however, the grid is getting finer and finer and the forecast is getting better.
“Frugality is the order of the day, even when the temperatures are milder.”
Even if the climate statements are currently based on probabilities, they already have a social benefit: A warm winter is currently the most likely scenario throughout Germany. This could help in the energy crisis this year. The Federal Network Agency also looks at the DWD’s seasonal climate forecasts. In a milder winter, it would be easier to sustain the necessary 20 percent savings in gas consumption, says Klaus Müller, President of the Federal Network Agency.
Saving energy consumption is still required. Because some days can get cold despite the milder average temperature. Then the energy stores empty, warns Müller.