Somewhere between Martyn's post #11 and Vibrac's post #19 lies a possible solution. Technology can be wonderful and most of us would not be here without it. Certainly not communicating via this medium. However, any economic model which requires a continuously increasing numbers of producers and consumers cannot have a long term future. If every couple had three children, all of whom survived, then one does not have to be a mathematician to realise that every generation results in 50% more people. One could take the Chinese model and restrict couples to only one or two children which many find unacceptable but there is another way which I never see discussed. If people breed when they are twenty years old then we have a generation of 20, 40, 60 and 80 year olds. That is four and a bit generations at any one time. However, if people bred at 35 then we have 35, 70 and some remnants, that is two and a half generations. Within one or two generations then we have cut the population by about 25%. No restrictions on number of children or other draconian rules. The exact age of between 20 and 35 could be discussed but the principle is clear enough. If one looks at the overcrowded cities, the pollution, the mess left behind when people go to their local park and the amount of plastic waste that ends up in the sea and eventually gets into our food chain it is clear that something needs to be done but whether human beings are capable of the improvement needed is doubtful. Here endeth the rant.