Time machines are no longer science fiction, but a serious matter. At least when it comes to the future of the climate. The journey from Munich to the end of the century is worthwhile, even if it is worrying: the less climate protection, the warmer. The hotter, the more unpleasant it is to live in Munich. This is not just predicted by climate activists in high-visibility vests, this is what a Bavarian authority, the State Office for the Environment, says.
It’s a bit hidden, the time machine. It can be found on the website of the State Office (lfu.bayern.de), an authority assigned to the Ministry of the Environment. If you click on “climate tool” in the climate information system, you can fast forward and rewind time and climate. The climate calculator is freely accessible and not difficult to use. You enter how far into the future you want to travel and, above all, into which one: warm or hot, with or without climate protection? The machine spits out how people will live in Munich and the surrounding area in thirty, fifty or eighty years.
There will be more hot days with temperatures rising above 30 degrees. Munich residents will sleep worse because the number of tropical nights increases if the temperature does not drop below 20 degrees. And in winter there will be less frost and therefore less snow. All of this is inevitable. What matters is the extent of these changes. This is where the different scenarios come into play, and then there is a very crucial footnote for Munich.
Christopher Zier works as a meteorologist and geographer in the LfU Climate Center and first emphasizes that the time machine does not spit out any forecast, nothing that could be compared to a weather forecast. Rather, they are projections based on various assumptions about global climate protection. Or, to put it another way, depending on the proportion of greenhouse gases in the atmosphere.
Two scenarios provide the most meaningful data, says Zier: without climate protection, based on a global business as usual, in climate expert circles they speak of Representative Concentration Pathway (RCP) 8.5. And secondly, in contrast, the “with climate protection” scenario, in which the Paris goals are met and global warming does not exceed two degrees, called RCP 2.6.
Because most climate protection measures will only take effect from the middle of the century, the end of the century will show what climate protection will bring to the people living in Munich, says Zier. What sounds far away is already very close; it is the world in which the children and grandchildren of most of today’s adults will live.
Extremes in particular cause problems for people
It’s not so much the average temperatures but the extremes that cause problems for people. If climate protection does not work, the number of hot days per year in Munich is likely to increase by a good 24 from just under four in the 30-year period from 1971 to 2000; On the Paris route there is a moderate increase of almost four days. The tropical nights are particularly exhausting: at the end of the last century, statistically speaking, it only happened once every 18 years that the temperatures at night were 20 or more degrees. In 80 years, if climate policy continues as is, it will statistically be a good seven days per year.
According to the projection, the winters will also be significantly warmer: at the end of the last century there were around 105 frost days per year in which the temperature fell below zero degrees at least once a day, but in the unfavorable scenario there will be around 63 fewer. If climate protection works, it is only 18 days less.
How the precipitation will develop is now much more difficult to project than the temperature, says Zier, because so many factors come into play. But we can already see that precipitation is increasing in Northern Europe and decreasing in Southern Europe. Bavaria is in between, which makes the simulation so difficult. But one thing is certain, and this has already been observed over the last few decades: summers are becoming drier and the days on which it pours and there is a risk of flooding are becoming more frequent.
More heavy rain, more flooding: That’s what Munich is threatened with in the future.
(Photo: Wolfgang Maria Weber/Imago)
If you want to know something about Munich’s future, you should use the climate calculator to select either the southern Bavarian hills, a wide band from west to east north of the foothills of the Alps, as the region; or the Munich-Ebersberg region, which is the city and district of Munich plus the Ebersberg district. The reason for this unusual combination, says Zier, is that more precise specifications are not yet possible due to computer capacity. The results for the two regions hardly differ, says Zier, and then points out something that can be seen as a warning: it will be significantly warmer in the city center than the time machine calculates.
The calculated projections for Munich-Ebersberg are average values from the metropolis and the rural surroundings. The specific city climate, which is significantly warmer due to dense development and lots of asphalt, is weakened in the computer by the temperatures from the cooler surrounding areas. In reality, the heat island of Munich is getting even hotter, especially in the inner area and especially at night.
This emerges from studies by the German Weather Service (DWD), which compares the temperatures of the city center and the airport for the years 1993 to 2018: Twelve hot days per year in the city, 6.6 at the airport. On such hot days, the city center doesn’t cool down much at night because facades and asphalt store the day’s heat and release it after sunset. According to the DWD, the difference between inside and outside is up to nine degrees. In the future, the heat island of Munich is likely to shine even more strongly at night.
Munich in the snow, a sight that is becoming increasingly rare. Winters have become significantly milder over the past 30 years.
(Photo: Robert Haas)
As disturbing as the look into Munich’s future is, the look into the past is equally revealing: a mirror image of the projection, back to a cool time. The state office evaluated the seven decades from 1951 to 2019 for the southern Bavarian hills: According to this, the annual mean temperature rose by two degrees during the period and the number of hot days rose by nine per year.
The winters have become warmer: there are 25 fewer frost days. Annual precipitation has remained largely the same, but with major differences between the seasons: summers have become drier, with 13 percent less rain falling. And the heavy rain in spring is up to 29 percent more intense. This development, says climate expert Zier, will continue if humanity does not radically curb emissions.
The people of Munich will not stop climate change alone. Munich depends on all states and people taking part in climate protection. Just like every other city and region, Munich also needs to take part. This means that the people of Munich will not be immediately rewarded with slightly less hot summers if they behave in an exemplary manner when it comes to climate protection. Everyone has to take part, says Zier, just everyone.
But that alone is not enough, says the climate expert: “We will have to adapt to climate change.” For example, the city protects green spaces and maintains fresh air corridors to allow the cooling wind from the mountains into the city. Breaks up sealed areas and allows trees and meadows to grow. None of these are new recipes; what needs to be done has been known for a long time.
Life in Munich will become more unpleasant on many days, that is the logical consequence of warming. The people of Munich and their politicians are sitting today at the temperature controller for tomorrow. You can help, turn it down in time.