"Peak Cement" may have taken place in 2015, stopping the exponentially growing curve that would have led us to turn the Earth into a bowling ball, similar to the fictional planet Trantor, Galactic capital in Isaac Asimov's series "Foundation" (image source).
When giving an example of an exponentially growing production curve, I used to cite cement production. Look at the data up to 2013: a beautiful growing curve with a doubling time of -- very roughly -- 10 years. Then, if we assume that the current concrete covered area in the world is about 2% (an average of the data by Schneider et al., 2009 and the Global Rural-Urban Mapping Project, 2004) then we would get to Trantor -- bowling ball planet -- in some 50 years.
Of course that wasn't possible, but it was still a surprise to discover how abrupt the change has been: here are the most recent data (the value for 2018 is still an estimate from cemnet.com)
Impressive, right? Steve Rocco, smart as usual, had already noticed this trend in 2017, but now it is clearer. It looks like a peak, it has the shape of a peak, it gives the impression of a peak. Most likely it is a peak -- actually, it could be the start of an irreversible decline in the global cement production.
Now, what caused the decline? If you look at the disaggregated data, it is clear that the slowdown was mainly created by China, but not just by China. Several countries in the world are going down in terms of cement production -- in Italy, the decline started in 2010.
My impression -- that I share with the one proposed by Rocco -- is that this is not a blip in the curve, nor a special case among the various mineral commodities produced nowadays. It is a symptom of a general problem: it may be the clearest manifestation of the concept of "peak civilization" that the 1972 "Limits to Growth" study had placed for some moment during the 1st or 2nd decades of the 21st century.
Peak Cement is not alone another major peak was detected by Antonio Turiel for diesel fuel in 2015.
And, of course, we know that another major commodity went through a global peak in 2014: coal. (data from bp.com)
So, are we really facing "peak civilization"? It is hard to say. On a time scale of a few years, many things could change and, in any case, you don't expect peaking to take place at the same time for all mineral commodities, everywhere. A strong indication that the whole world system is peaking would come from the behavior of the global GDP. Rocco had proposed that also the GDP had peaked in 2015, but the data available at present are insufficient to prove that.
In any case, it has been said that we would see the great peak "in the rear mirror"and this may well be what we are seeing. Whatever is happening it will be clearer in the future but, if it is really "the peak", expect the Seneca cliff to open up in front of us in the coming years. And maybe it won't be such a bad thing(*): did we really want to turn the Earth into a bowling ball?
(*) Antonio Turiel lists in a post of his (in Spanish) all the advantages ensuing from a societal collapse: reducing emissions, less pollution, a saner society and more)