How many years before peak if we had always used oil in a conservative rather than a spendthrift manner? I am guessing that we might have stretched out the oil savings account another decade or two, allowing an even larger population to experience the inevitable.

Much of the thinking about post peak life seems to take the view that the decline will be smooth, a continuation of a symmetric curve, full of adequate substitutes that are somehow magically created out of resources that we do not have. My view is that we will experience a discontinuity, more like a stock market crash, and will return rapidly to a base line (long term trend) from which the oil age allowed population to temporarily diverge, which base is closer to 1 billion rather than the present 6.5+billion.

Thinking about electric cars and mass transit looks like me to be a drop in the bucket when the entire industrial age comes crashing down, and most of what we use for survival is no longer usable. The recent news report of the consequences of an internet attack on electric generating systems resulting in months of shutdown, might be an example of what a discontinuity looks like.

If we hadn't used the oil so carelessly, we might not have such a large population to be at risk.

I don't understand the logic that using oil carelessly resulted in greater population. If you are talking about modern agriculture, I am sure that those who would otherwise starved to death would disagree with the characterization as "careless". Please explain.

To add to my comment about the relative ineffectiveness of being conservative in the big picture, I would like to point out that had we used oil more conservatively in transportation, we would have used the savings somewhere else. Why? Because the oil was there and we are human. If you don't spend your income on gasoline, and spend it instead on something else, that something else took energy to create. To boot, getting around on less energy encourages more getting around, so there goes some more of the conservation.

The hydrocarbon savings account was limited. Using it more conservatively would not have changed that simple fact. The nature of technology is to use resources faster than they would have been used without technology. In effect, most technology is just knowledge applied to resources resulting in increased use of resources in elevating human living standards. Had we not tapped the hydrocarbon savings account we still would be living as we did before we started using coal, complete with that level of population and with similar living conditions.

I think things unfolded, and are unfolding more or less the way nature dictates. It probably was inevitable that the industrial age occurred. It is just as inevitable that we will return to pre-industrial age living conditions as the cause of the industrial age (exploitation of stored hydrocarbons) is depleted. The cycles of nature are far more powerful than the machinations of man. It just so happens that we are at the peak of a very large cycle, about to experience a sharp "return to the mean", complete with overshoot. In all of human history (past and yet to be written), the industrial age will turn out to have been a random blip in an otherwise relatively flat line.

I don't understand the logic that using oil carelessly resulted in greater population.

It created surplus food, rather than just sufficient food.  Without the surpluses, the population would not have grown as quickly and there would have been fewer people alive when production peaked.

If you are talking about modern agriculture, I am sure that those who would otherwise starved to death would disagree with the characterization as "careless". Please explain.

Modern agriculture is a great thing, because it creates urbanization and social arrangements where education is a greater advantage than raw numbers and people have fewer children and invest more in them.  If we could have spread this around the entire world as fast as it came to the OECD countries, the world population might only be 3 billion today and the problem would both be more manageable and not move as quickly.

Had we not tapped the hydrocarbon savings account we still would be living as we did before we started using coal, complete with that level of population and with similar living conditions.

You are assuming that the only way to apply knowledge is to non-renewable resources.  All it takes is one read through "Direct Use of the Sun's Energy" by Farrington Daniels (1965) to show that things could have been very different, and we could have been running much of the world on RE by the present day.  Plant life didn't peak and crash after it invented chlorophyll, and we don't have to either.