The gentlemen agreed however on most topics and shared similar visions. ‘We don’t disagree a whole lot about how to build a more sustainable society’, Buisman comments. Both professors do place different accents how to achieve this however. ‘Closing cycles and retrieving nutrients is essential to guarantee enough food for the future; energy is not something to worry about, we will have plenty’, claims Lettinga. ‘But we should avoid really big cities and try to regain the balance between waste production and waste processing, for example by reducing the amount of sewage.
Buisman confirms the importance of reducing waste production and the significance to recover nutrients, but emphasizes the need to work more with nature. ‘Real sustainability, are things we can do forever with 10 billion, equally rich people. We can only achieve this by staying close to nature’, he says. ‘But to become rich as a country, people should cooperate and contribute to society and not just to their own kind. This is the only way to achieve high productivity. People in poor countries in general don’t cooperate, in rich countries they do.’ Besides cooperation, Buisman claims we have to produce our food in a more natural way: work biologically, avoid intensive farming and focus on natural ways to stay healthy and fight diseases. Lettinga couldn’t agree more: ‘Like Cees, I am convinced that a sustainable society should be based on nature, just like our technologies should be based on nature’, he states. ‘With natural principles, we can regain the balance between consumption, waste production, processing and recycling!’
According to Lettinga, there should be way more emphasis on applying existing environmental technologies: ‘With the current level of science and technology a sustainable society can be build’, he stresses. ‘All tools to make it happen are there, but the challenge is to implement these technologies. So, we should definitely focus more on implementation.’ Lettinga expresses great appreciation for the successful way Buisman puts new technologies into the market by closely cooperating with companies and by stimulating Ph.D. students to start their own business based on their innovations. This way, a sustainable society becomes within reach, step by step.