10316 Days: A comparison of Berlin’s climate during the Wall and since it fell.
When people think of Berlin, they typically think of techno clubs, graffiti, and perhaps David Hasselhoff, but most commonly think of the Berlin Wall. For many around the world, the Berlin Wall is what defines the city in the history books. And rightfully so, as it divided not just a city, but two countries and millions of people for almost three decades. And even today for people living within the city (and especially for those who grew up here), there remains a strong dichotomy between the East and the West. The neighbourhoods in each side of the city look different. They feel different. The people are different. This becomes even more true when you leave the city and move into the further eastern neighbourhoods of the city or into Brandenburg (the German state that surrounds the capital).
Just recently we marked a very particular day in the history of the city —February 6th, 2018 — the day when the length of time since the wall came down exceeded the length of time during which it was up: 10316 days. That’s 28 years, 2 months, and 28 days. That is a long time to divide a city and a people.
Interestingly enough, 10316 days is also pretty close to the time scale at which which climatologists begin to look at the impact of humans on climate change (30+ years… or 10958 days). This is because thirty years is a pretty good estimate of the return period of extreme events, and also covers more than one cycle of most long-term climate oscillations. Scientists studying human impact on climate change use 30 years as the basis for comparing long-term changes
So, with access to high-quality weather observations through my position at MeteoGroup, I thought it would be worthwhile to take a simple look at how different the climate (and not just the political climate) changed between each of these two periods of history. I decided to take weather observations from the iconic Berlin Tempelhof Airfield (the only airport “behind” the wall).
In a previous internal project at MeteoGroup, I also generated charts of the hourly temperature at Berlin Tempelhof dating back to 1929:
While the above image is very captivating (especially seeing how measurements were unavailable during World War II), it doesn’t give us a quantitative look at the differences between the two periods. So… what are the differences?
The results are really quite interesting, and can be summarised as follows:
1. Berlin has gotten warmer
- All temperature metrics averaged over the period (daily average, daily minimum, and daily maximum) have increased
2. Warmer days are getting warmer and occur more frequently
3. Days with freezing temperatures are becoming less frequent
4. The extremes are rising at roughly the same rate
- The average maximum temperature and the average minimum temperature have gone up by roughly the same amount (1.6°C and 1.4°C)
For anyone who is tuned into their climate science, the fact that average temperatures are getting warmer should not be a surprise. In fact, the increase of 0.9°C at Berlin-Tempelhof is pretty consistent with the change in global land-ocean temperature index. This is especially true for much of Europe, which has warmed more than the global average. In fact, high-temperature extremes like hot days, tropical nights, and heat waves have become more frequent, while low-temperature extremes (e.g. cold spells, frost days) have become less frequent (https://www.eea.europa.eu/data-and-maps/indicators/global-and-european-temperature/global-and-european-temperature-assessment-3).
So, while the political climate in Berlin may have cooled a bit since 1989, the temperatures of the city have risen and are projected to keep rising. Well… at least Berlin has plenty of lakes and plenty of beer to cope with the higher temperatures.