Dear Eric,
Surprise! I am at my desk and your email asking me about an eventual independent “peer review” on the current state of science and accomplishment under the heading of Circular Economy arrived moments ago and is staring at me. In fact I was at a conference on just this topic in another country, which was OK, except that I could have given virtually all the talks myself.
I didn’t learn very much, which was disappointing. Waste of time, except it got me thinking more about one aspect of the circularity problem. In brief, most of the elements in the periodic table are now “in play”, and most of them are really “hitch-hikers” obtained from the ores of major industrial metals (copper, zinc, aluminum etc.).