Difficult message for policymakers from two Leiden reports on circular economy
You should start working now, and the positive results will only be seen long after your term has expired. That is just about the worst thing you can say to politicians and policymakers. Yet that is exactly the message of two recent reports on sustainable resource use from the Centre for Environmental Sciences.
Professor of Sustainable Resource Use Ester van der Voet is the connecting link between the two reports. In one, she and PhD student Janneke van Oorschot, the Netherlands Environmental Assessment Agency (PBL) and Metabolic Consulting put three building scenarios side by side.
Firstly, building as we are used to now. Secondly, building with renewable 'biobased' raw materials such as wood and fibres. Thirdly, circular construction, in which in addition to the use of more renewable raw materials, many components can be reused. For example, an existing building can be given a different purpose.
Looking up to 2100 gives a completely different picture than looking up to 2050
Van der Voet: 'We looked up to 2050, and it was striking that in bio-based and circular construction you can reuse less material than in conventional construction. That is because, in these new scenarios, it is less easy to reuse the material from today's old buildings.' So is conventional construction more sustainable?
No, it is not. 'If you opt for bio-based or circular construction and look ahead to 2100, the reuse rate could actually be higher there. If you start building like this now, materials that can be reused will only be released in at least fifty years, when the buildings are old.'
Start now, you'll see the result much later
The trick here is: looking further ahead gives a more complete picture. And that picture shows: start circular building now, and only after 2050 will it yield considerable sustainability gains. For biobased construction, which can also be interesting, it still needs to be clear whether there will be enough wood available. 'Within the Netherlands, probably not, but it is not a problem if our densely populated country obtains wood elsewhere. But it is important to be self-sufficient on a European scale. Whether that is possible in this scenario, we still need to calculate.'
Stocks in society: the basis for a circular economy
In the other report, Van der Voet, together with PhD student Teun Verhagen, student Lowik Pieters and Statistics Netherlands (CBS), investigated how many raw materials we already have in use in society. In this so-called urban mine, the reserves are enormous. The ideal is that we make do with that and no longer extract any new raw materials from natural supplies (mines).
This third part of a series focused on the gas system, the rail infrastructure and consumer goods. The gas system is particularly interesting as an urban mine. Because of the heat transition, underground gas pipes may become superfluous. In that case, we can recycle them. But how do you do that?
Almost everything has to change
On this subject, the report says: 'These inventories are a starting point for thinking about which activities, actors and even sectors should be set up to shape the circular economy. Information, inventory, collection and processing must be different. Product and material design must be different. New forms of business will be required.'
That one difficult message again
So alas, politicians and policymakers: once again that one difficult message. You have to get to work now, and the positive results will only be seen long after your term has expired.
Why is there so little recycling in the building industry?
Recycling of materials in the building industry could already be done on a much larger scale than is currently the case. That it happens too little is due to two things, says Van der Voet. 'Firstly, it is more expensive than using new materials.' Well, that is because the environmental costs are still not incorporated in new materials. Secondly: 'The construction world is incredibly regulated with safety requirements. To be on the safe side, construction companies and contractors opt for new concrete.'
Governments should actively pursue recycling, Van der Voet believes. 'Municipalities could demand that a new building be built with recycled concrete. But they do not, and so construction companies are rather safe than sorry.' Used concrete is usually tucked away under roads, which on paper is recycling, but in reality is downcycling. Better than nothing, but higher-quality recycling would contribute more to sustainable resource use.
Text: Rianne Lindhout