Science – Researchers: “40 degrees in Germany has become the norm” – Wikipedia

Karlsruhe (dpa) – With no further subject matter, climate researchers are just as confident about the future direction as with temperature and heat.

When it comes to precipitation, there is a lot to be said for more extremes. But models are uncertain on this point, especially for Central Europe, says Jacob Zschichler of the Helmholtz Center for Environmental Research in Leipzig. “When it’s hot, it’s clear that things will continue as they have in recent years.” In all models it gets warmer, even in some very hot cases.

“40 degrees in Germany has become the norm,” explains Peter Hoffmann of the Potsdam Institute for Climate Impact Research. “Today’s extreme years with 20 hot days will become average summer by the end of the century if we don’t take massive countermeasures in the coming years.”

range of climatic scenarios

Climate models’ projections for the future always have a range. As a rule, two extreme scenarios are distinguished: if everything continues as before with regard to climate protection (the so-called emissions scenario RCP8.5) and if global projects are constantly implemented (RCP2.6).

For this purpose, a network of experts from the Federal Ministry of Transport has calculated specific figures with experts from the German Weather Service (DWD), among others: according to this, the 30-year average temperature in the summer months in Germany in can be The period from 2071 to 2100 is three to five degrees higher than in the corresponding period of 1971 by the year 2000. As a result, daily highs above 45 degrees will be reached at least as often as is currently the case for the 40 degree mark. .

According to this data, the number of hot days of 30 degrees and more is likely to range from 9.4 to 23.0 per year on average across Germany. For comparison: From 1971 to 2000, there were only 4.6 days on average nationwide. The number of summer days with maximum temperatures of 25 degrees or more can rise from 39.5 to 63.8 (comparison period: 29.0). On tropical nights when the thermometer does not fall below 20 degrees, 0.8 to 7.8 degrees per year is possible. In the comparative period from 1971 to 2000, the value was 0.1. The national average values ​​also mean that regions can deviate significantly from this.

The current climate trajectory looks bad

According to Andreas Becker, Head of Climate Monitoring at the Department for Social Development, current measurements clearly indicate that Germany and the world are still moving on a worst-case scenario (RCP8.5). This does not include climate protection projects. However, it is important to consider other scenarios. “Even if we are just starting to protect the climate today, we can still exert an impact,” he explains. “Every tenth of a degree counts.”

Baker also emphasizes the intergenerational conflict in climate protection: Depending on climate protection efforts, many decision makers today are expected to warm by the end of life expectancy around 2050 in the range of 1.1 to 1.4 degrees (compared to 1971 to 2000) ). “That’s a difference of 0.3 degrees. It also makes a big difference.” By the end of the century, depending on climate protection measures, the temperature could rise by 1.1 to 3.8 degrees.

This means that the difference between successful and unsuccessful climate protection for children and grandchildren is 2.7 degrees. Baker explains that the latter has “tragic consequences, some of which were not yet foreseen.” “The costs of our adaptation to climate change of this magnitude will far exceed the costs of current, ambitious climate protections, and even run against the limits of feasibility.”

Autumn in particular is likely to be much warmer

With all average values, there can of course be more pronounced regional fluctuations, Zscheischler explains. The expected development of the seasons also varies. Climate-risk analysis for Germany by the Federal Environment Agency assumes that the temperature rise in autumn is much greater than in spring.

Climate researcher Andreas Fink of the Karlsruhe Institute of Technology is working with colleagues as part of the ClimXtreme Network on approaches to better preparedness for extreme events and on the question of how to better view extreme heat waves. “Ultimately, it will not be changes in monthly rates or the average number of hot days, but extreme heat waves in intensity, duration and extent that will cause the most ‘damage’.”

Hoffmann of the Potsdam Institute for Climate Impact Research hypothesizes that there will also be heat waves and phases of slight cooling in the future. However, changes in air flow can stabilize extreme weather conditions for a longer period of time. The expert explains that the jet stream is slowing down and with it the rotation of the westerly winds. This could cause air masses to flow from one direction to central Europe for a longer time. The first days of summer after that could be the onset of a prolonged heat wave – or hopefully rain could be the cause of flooding.

“Heat waves can get really dangerous,” Hoffman warns. “40 degrees over several days as in the Mediterranean is too much for our usual conditions.” In nature, you can already see the consequences of mild winters, warm springs, and hot, dry summers. The researcher warns that long periods of heat also pose a danger to human health. This has consequences for productivity: “Heat waves don’t always have to fall on vacation.”

© dpa-infocom, dpa: 220809-99-324598 / 2