The statement says that healthy, near-natural mires and floodplains make a disproportionate contribution to climate and biodiversity protection. What do they do?
Franziska Tanneberger: In terms of climate protection, mires are a miracle ecosystem. Via the plants’ photosynthesis, they bring carbon into the ground and store it there for a long time. These thick peat layers, which we also sometimes find in floodplains, are massive carbon stores. Near-natural mires can also be home to a very specific biodiversity.
Klement Tockner: Floodplains also play a big role with their indirect effects, such as retaining water during high waters or return flows in dry periods. At the same time, floodplains are global centres of biodiversity. Together, mires and floodplains only take up some ten percent of the country’s surface area – yet nowhere in central Europe is the variety as high as in these wetlands.
At the moment, rivers and mires are actually fuelling the climate crisis because the systems lack water. What is happening?
Tanneberger: We’ve pulled the plug on mires, so to speak: 94 percent of the mires in Germany have been drained. Water is, however, the key to the carbon storage process. If there is no water, there is no protective layer around the carbon either. This leads to large amounts of CO2 now being released from the surface of mires. These emissions make up seven percent of all greenhouse gas emissions in Germany. And in some regions they make up significantly more; in Mecklenburg-Western Pomerania/Germany approximately 40 percent of all emissions.
Tockner: Streams and rivers have been channelled and divided up so that water can be diverted very quickly and to create space for settlements. Along the whole length of the river Rhein, nine million people now live where there used to be floodplains. This limits natural renaturations because technical solutions and the protection of people are often prioritised.
Now mires and floodplains are not simply being flooded, they are also being used. How can more water still get into the areas despite this?
Tockner: There are many sections that can be renatured. The challenge is that streams and rivers need space – so we’re also dealing with a conflict around the use of space. Therefore the various functions and services of mires need to be emphasised. The population must understand why renaturation is so important.
As a successful example, we can take the Emscher, a tributary of the Rhein in the Ruhr area – 30 years of renaturation, 5.4 million euros invested, that is approximately 50 million per kilometre. Considerable sums of money, but it was worth it: Once an open waste-water canal, the Emscher is now a valuable habitat for animals and people. In short, it can be said that protecting nature means protecting people.
Tanneberger: We need alternatives based on synergies. Agricultural and forestry can also take place on re-wetted mires, where we can create renewable energy via photovoltaics and also produce construction materials.
And diet is also a key. In terms of its land usage, meat consumption takes up disproportionately more than a plant-based diet. It is important to have complaints offices for people to turn to if they feel they are in a worse-off position due to the measures.
A change in society is necessary, according to the statement. What has to happen now?
Tockner: We are following a systematic approach and considering climate and diversity protection as a whole. We are also looking at the water supply, various use options, and legal aspects too. Protecting nature and people requires increasingly hybrid solutions that cleverly link the powers of technical and natural systems. Top priority goes to protecting existing waterways. We cannot set big goals for renaturation and then at the same time not be able to conserve the last natural river sections, such as the Upper Isar.
Tanneberger: Accelerating processes is central to this. Continually postponing is not a good strategy. According to our calculations regarding the mires in Mecklenburg-Western Pomerania, we would need another 180 years for the re-wetting at the current speed. We cannot tolerate such high CO2 emissions for this long. And before we implement technological solutions, some of which are being strongly pushed, for the climate crisis, we should reflect on what our ecosystems can deliver themselves if we let them.
One thing stands out: There is a lot of focus on participation and forms of communication...
Tanneberger: Yes, we cannot achieve this paradigm shift through numbers alone. We also have to talk differently about these things to find another way of dealing with nature and the environment. It is also closely related to how new generations perceive natural landscapes. That we are once again able to imagine what wetlands could look like and that water belongs to our landscape.
Tockner: We need positive role models that require no embellishment. Science can develop excellent solutions, but there is no silver bullet. Even so, Germany, as one of the richest countries in the world, should be a role model and pioneer. It is our responsibility to leave future generations with liveable environments.
The interview was conducted by Christine Werner