Greening the Rooftops?

Green roofs have long been in vogue in Scandinavia but there now is a plan to upscale the approach for much larger buildings in the city of Utrecht in the Netherlands (https://www.theguardian.com/world/2020/mar/27/utrecht-rooftops-greened-plants-mosses-vertical-forest). I have long had a sneaky regard for Utrecht having lived there for a few months in the early 1970s. Many of the things they are attempting on living and transportation seem to be innovative and brave.