Climate adaptation is also a security issue Interview with climate expert Frank Böttcher

In the following interview, Hamburg climate expert Frank Böttcher explains the phenomenon of the heat dome and other significant changes.

EEHH: In the media coverage of the first heat wave at the end of June, there was often talk of a “heat dome”. What does that mean?

Frank Böttcher: “The most common heat scenario here in northern Germany is as follows: warm air from North Africa flows to us via Spain and France. For two or three days, the temperatures rise due to the influx of increasingly warmer air over northern Germany. We call this warm-air advection. In a heat dome, a high-pressure area trapping the incoming hot-air mass remains stationary over our region, meaning that no new warm air is introduced. Under these meteorological conditions, the trapped air sinks over a wide area within the high-pressure system and is compressed, much like in an air pump. The air becomes drier, the atmospheric pressure rises and, with this, the heat intensifies. These weather conditions are rarer.”

EEHH: Even to a layman, it seems obvious that these meteorological conditions are related to climate change. Have you observed any other unusual weather patterns here in northern Germany?

Frank Böttcher: “Some other things have been noticeable, too. For example, we are seeing south-westerly patterns under high-pressure influence far more frequently. These are precisely the advection weather conditions I just mentioned and mean that warm air is flowing into our region more often. And when this warm air arrives, it is significantly warmer than it was 30 or 50 years ago under similar weather conditions. Especially in spring, this leads to persistent high-pressure systems that bring prolonged dry spells, posing a serious challenge for agriculture, especially in the main growing season. As a result of these recurrent spring droughts, evaporation rates drop, which in turn means less precipitation in summer. Almost every dry hot summer has been preceded by a dry spring. The reverse, however, it is not quite as reliable: not every dry spring is followed by a hot and dry summer.”

EEHH: What measures should policy-makers take now to protect the population?

Frank Böttcher: “According to the RKI, Germany has suffered several thousand heat-related deaths this summer alone. The climate adaptation of buildings must be accelerated. Facades should be lighter in colour and preferably also greened. Air conditioning will become an absolutely necessity in many cases - in offices, schools, hospitals and nursing care homes. In a nursing home, the fundamental right to physical integrity must include access to cool, fresh air for sleeping. Labour law will need to deal even more closely with the issue of heat protection for employees. We also need a different approach to groundwater management, including significantly more retention basins. Water from the heavy rainfall events can be used much more effectively rather than letting it run off through river systems into the world’s oceans.”

EEHH: In your opinion, climate adaptation is also a security issue for every nation. What do you mean by that?

Frank Böttcher: “To give you an example: by the end of the century, 70% of the Netherlands will be below sea level. They will not only need higher dikes to protect against the ocean’s water masses, but also massive pumping stations to pump rivers such as the Rhine and Meuse over the dikes into the higher North Sea, even in extreme flood events. This situation creates vulnerability. A city like Riyadh in Saudi Arabia could not survive for two days without its artificial water supply and is therefore highly vulnerable. In Germany, the development of a decentralised energy infrastructure has long been a cornerstone of national security. A couple of gas-fired power plants can be knocked out quickly; millions of local solar systems and energy storage systems are more resilient.”

Thank you very much for the interesting interview and your insights!