Energy and Human Ambitions on a Finite Planet

"Salvaging a decent future requires keen awareness, quantitative assessment, deliberate preventive action, and—above all—recognition that prevailing assumptions about human identity and destiny have been cruelly misshapen by the profoundly unsustainable trajectory of the last 150 years."

Brilliantly said. I believe a lot of resistance to the idea that our way of life is unsustainable stem from grief that the future that we were "promised" by the last century of media and marketing isn't coming. The first step towards adapting to the imminent collapse of the high-consumption lifestyle due to energy and resource limitations is to process this grief.

Here's a fun little exercise: Open up a spreadsheet.

Label the first column C for capital. This starts at 1.

Label the second column T for total resources extracted. This starts at 0.

Label the third column r for resources extracted this step.

Label the fourth column E for extraction efficiency.

Label the 5th column m for maintenance. Make it proportional to capital.

Now, for each step:

E is some positive function of T with a negative slope. It doesn't have to have a finite area under the curve (you don't have to assume total resources to be finite, in other words). You just have to assume that the next unit of resources to be extracted requires a bit more effort than the last one. Use E = .1*exp(-.01*T) or something like that.

r = C*E

m = C*k where k is any positive number between 1 and 0- .01 is a good constant to use.

C += r*q - m where q is again some constant, say .2

T += r

Now observe the behavior of the system. Plot the value of C over time. For the above constants you'll want to include about 3000 steps.

(Edit: forgot the maintenance term)

The rule of 70 isn't "hand waving bad math".. perhaps you just don't understand its derivation?

The issue is he then uses the approximations to do with math without calling them approximations. 1.10^7 is reasonably close to 2, but 1.1^21 is 7.4 which is a fair distance from 8.

He goes so far as asks someone to do the approximation across several hundred years of compounding. And sure it get’s a big number but one no even close to accurate.

The entire book falls apart because of two facts, both of which are in the book itself!

"Hands down, solar is the only renewable resource capable of matching our current societal energy demand. Not only can it reach 18 TW, it can exceed the mark by orders of magnitude." (Section 13.9)

"We would likely not be discussing a finite planet or limits to growth or climate change if only one million humans inhabited the planet, even living at United States standards. We would perceive no meaningful limit to natural resources and ecosystem services." (Section 3.5) An energy source that is thousands of times more abundant than fossil fuels is basically equivalent to having one one thousandth the population.

While I must acknowledge the truth that converting things to run on electricity will be a large engineering and logistical challenge, and that battery production must be scaled up (as well as converting some loads to run where the sun is shining), both of these challenges pale in comparison to the money part of that first quote: "exceed the mark by orders of magnitude." In other words, even if we could only store electricity at an efficiency of 1%, we'd be fine. (In actuality, we ALREADY store electricity at efficiencies over 80 times that.)

Ecosystem services, availability of raw materials, and many other challenges exist as well. However, all of them are meaningless in the face of "we would perceive no meaningful limit to natural resources." Having an energy source that is thousands to millions of times more abundant than the ones we use today lets us substitute energy for basically all of our needs. (Need clean water? Energy + dirty water = clean water. Need more steel? Dirt + energy = steel. Need to remove CO2 from the atmosphere? You can do it, at only the cost of several times the energy you got putting the CO2 into the atmosphere, which is only a few % of the future energy budget from solar. Think of it this way. In the past, we relied on cutting down forests for heat. Putting the forests back would have seemed like an insurmountable task, because our fuel came from the forests. But now that we run on fossil fuels, which are approximately 100x more abundant than forests, putting the forests back is a matter of politics and land usage discussions, not one of practicality.)

In other words, we are the only ones we have to blame if the future is not MUCH wealthier than the past, both per person and also for our total economy.