The City of Amsterdam, which is one of the finalists in this year’s Earthshot Prize, first unveiled its circular strategy in 2020, four years after the Dutch government set the same goals nationally. Amsterdam’s vision embraces what the British economist Kate Raworth calls the “doughnut” model of economics, which looks at both environmental and social goals. The outer edge of the doughnut represents the ecological limits of the planet, including biodiversity loss and climate breakdown. The inner ring represents basic human needs, from food to adequate housing, that everyone should be able to access. To live sustainably, society needs to exist inside both limits.

“We don’t just talk about technical solutions, or what’s the best way to [move] materials from here to there,” says Ilektra Kouloumpi from Circle Economy, the organization that helped the city build its short-term road map, including which types of waste it’s focused on reducing over the next few years. “We also talk about, ‘Hey, how can we make a city that is inclusive and just for all, while respecting the planetary boundaries?’ That has become the new vision for the City of Amsterdam.”

It still isn’t clear exactly how that long-term vision will work in practice. But multiple circular initiatives are underway. In one project, researchers are studying how concrete paving stones on streets can be recoated and reused, rather than replaced, when a road needs to be repaved. In another, they’re studying how plants that were once grown in the area—flax and hemp—could be used to make new biodegradable building materials. “We always look at, ‘Okay, how can science help?’” says Joppe van Driel, the program developer for circularity at the Amsterdam Institute for Advanced Metropolitan Solutions (AMS), an organization that connects university researchers with urban challenges, including the studies on pavement and bio-based building materials. “Different kinds of technological innovation are needed to move forward.”

Another AMS Institute study is examining how building products could be made from organic waste, and is bringing potential manufacturers and customers into the R&D process from the beginning. “When a new innovation is being developed, we try to make sure that it is being tested in a real-life environment as soon as possible,” says van Driel. The aim is to get new products to market quickly.