Without any doubt whatsoever, the most momentus event we face in the future is proliferation of humanity. There are numerous protanagonists to this story as usual and the arguments over what level of population the planet can sustain vary widely, as do the forecasts of what the population will be at the next few census points.
There are two main factors to take into account when considering the potential population.
1, The greater the poplulation, the greater the reliance upon infrastructures to support it.
2, Though all historical census data follows a Newtonian curve, no future projections show a continuation of that curve.
We are clearly underestimating the future population.
Providing adequate food for a growing popluation is a daunting task. Overproduction in some areas, provides for some storage backup but in overall terms of our food intake, the stockpile of overproduced food is very small. The actual production process, whether it is grown or reared is only a small part of the overall structure that is necesarry to get food on plates. The weather of course is a major factor and this has been progressively more unpredicable over the years. Complete crops have been lost through early frosts and hard winters in sub tropical zones for example and floods have also played havoc, particularly in the third world where food production does not always meet demand even in good years. Apart from the weather, the political climate has a big part to play and one of the factors in future wars will be the avoidance of destruction of arable land crops. At the end of the line of infrastructure, we have the delivery chain. This could be quite a complex affair where food is processed through markets and eventually reaches shops but it could be simply growing, storage, distribution in the event of a market collapse. We are only ever 3 missed meals away from anarchy and we would do well to remember this when thinking about potential problems for the future. So much of the overall mechanics of the food production and supply chain rely on stability of markets and adequate goodwill to allow the free distribution of the food. Large scale problems have a remarkable reputation of 'just happening' for no reason at all apart from a rumour, the critical nature of the food supply chain will remain the weakest link in our aility to support the growing poplutaion. I deal with climate change and its potential in other areas as I do with macro modelling so I have not really overplayed this aspect here.
The Newtonian curve is a very curious phenomenon. When applied to population growth, it shows all the increases in populations effectively from the point where censuses were first started properly in the 1700's. Clearly, whilst I was working on figures that showed the population growth to be increasing at a greater rate than that stated by governments (particularly the U.S. and British) I needed to know why they would have an interest in deliberately understating the impact of such a major factor. There are a number of reasons. Whilst the Americans tended to go for the lower figures, there were elements within the US which were discussing numbers in excess of what the Newtonian curve was predicting.
The definitive argument for the growth of future population is shown in the Newtonian curve. The differential equation as formulated by Eular has been incorporated in a very simple Excel spreadsheet by myself that you can copy and paste in to your own copy of Excel. You merely have to copy line 1 into cell A1 and line 2 into A2. Thereafter, you just copy A2 down till A350. There you have it. A complete list of world population over more than 300 years. All I have done is include the population at 1700 and incorporate the Eular differential equation to show the Newtonian curve. It really is a remarkable piece of mathematics to have an algorhythm of only 2 lines which correctly states the poplulation of the world over 3 centuries