I do so agree with the content of Roger's letter but I also think that there is a parallel driver and that is the next stages of evolution of technology and the effect on jobs.  Yes population is growing exponentially and there is only a finite resource.  This has been recognised by the work in Product Service Systems, Service Science, and the transition of manufacturing through the growth of servitization.  The Green Issue is very concerning and valid but it is not the only elephant in the room.  I refer to the evolution of manufactured product through automation, AI, and eventually autonomy within the work place.  I have attended various think tanks and other meeting with politicians, academics and researchers in this field and there is growing concern as to what sociiety will do as this technological shift takes place.  It is anticipated that there will be significant job losses in the service sector and blue collar manufacturing with only those who have the techician and above skill sets being employable.  That means that over 50% of the population could be unemployable.  In addition there is talk of job share with those that are employable with only a 2-3 day working  week being available by madate.  This then brings other issues as what to do with the unemployed and how do we fund them.  I see a massive social upheaval caused by the convergence of the point that Roger raises and the ongoing technical evolution and I feel that whilst most are sleep walking into this crisis, those that see it coming  have no idea what to do about it.