The Crash Course - Chris Martenson [17]
For example, if we take our population chart above, and instead of setting the left axis at 10 billion we set it at one billion (Figure 5.3), we see that the line disappears entirely off the chart somewhere around 1850. We can’t see the part after that because it is now way above the top of the chart frame, but in this version of the chart we note that the turn-the-corner event appears to happen around 1900. Instead of having this conversation about turning the corner with population growth right now, it appears as though we really should have had it back in 1900.
Figure 5.2 World Population
The solid line is historical; the dotted line represents the UN projection.
Source: U.S. Census Bureau Historical Estimates2 & U.N. 2004 Projections.3
Figure 5.3 World Population
Same world population chart as Figure 5.2, but with left axis set at one billion.
Source: U.S. Census Bureau Historical Estimates.
Similarly, if we scale our left axis to, say, one trillion (Figure 5.4), the corner disappears entirely and the entire line becomes flat. We can’t see its curve anymore. But it is still there; it has just been suppressed by our management of the left axis. No more population problem! Right?
Figure 5.4 World Population
Same world population chart as Figure 5.2, but expressed in trillions.
Source: U.S. Census Bureau Historical Estimates.
So the turn-the-corner moment is really just a product of how we draw our chart. Does it mean that the turn-the-corner stage is a worthless artifact and that we can forget all about it? No, far from it. It is very real and vitally important. Let me explain why.
Where the turn-the-corner stage becomes enormously meaningful and important is when you can reasonably set a boundary—that is, fix the left axis to a defined limit—because you know how much of something you have. When you do this, the shape of the chart tells you important things about how much time you have left and what the future will hold. For example, if we were studying yeast growth, we might start with a flask that holds one liter of grape juice, a quantity that we already know can only support so many yeast cells. With this defined limit, we can accurately calculate when an introduced population of yeast will crest and then crash.
Similarly, if we happen to know the carrying capacity of the earth for human beings, then we can “fix the left axis” and make some important observations about what the future might bring and how much time remains to stabilize things. Without fossil fuels to assist with agricultural production, the total carrying capacity of the earth for humans is thought to be somewhat less than the current 6.8 billion and possibly as low as one billion.4
Even if these carrying-capacity calculations prove to be pessimistic and we could set the left axis for sustainable human population at 10 billion (although I’ve not read any scientific analyses that would support such a number), we would still discover that population has turned the corner and that we’re no longer on the flat portion of the curve but the steep portion. This means that you and I happen to live in a very different world with entirely different challenges and opportunities than the people who came before us. We live at a time when most people alive will hopefully witness the transition of human population from exponentially expanding to “not growing.” I say hopefully, because the alternative is to overshoot and collapse, just like our friends, the yeast in the flask.
Speeding Up
A critical concept that I want you to take away from this discussion about exponential growth is that of “speeding up.”
It doesn’t matter how you