Energy and Human Ambitions on a Finite Planet by Tom Murphy

[rufuspollock]

Murphy, Thomas W. 2021. ‘Energy and Human Ambitions on a Finite Planet’. https://doi.org/10.21221/S2978-0-578-86717-5.

TODO: integrate Twitter excerpting: https://twitter.com/rufuspollock/status/1455318676379475978

Notes (in progress)

Book in the spirit of Without the Hot Air but on broader themes of sustainability. Open Access (sort of: it is cc-by-nc so not open)

Pretty good from a first skim.

Abstract

Where is humanity going? How realistic is a future of fusion and space colonies? What constraints are imposed by physics, by resource availability, and by human psychology? Are default expectations grounded in reality? This textbook, written for a general-education audience, aims to address these questions without either the hype or the indifference typical of many books. The message throughout is that humanity faces a broad sweep of foundational problems as we inevitably transition away from fossil fuels and confront planetary limits in a host of unprecedented ways—a shift whose scale and probable rapidity offers little historical guidance. 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. The goal is to shake off unfounded and unexamined expectations, while elucidating the relevant physics and encouraging greater facility in quantitative reasoning. After addressing limits to growth, population dynamics, uncooperative space environments, and the current fossil underpinnings of modern civilization, various sources of alternative energy are considered in detail— assessing how they stack up against each other, and which show the greatest potential. Following this is an exploration of systemic human impediments to effective and timely responses, capped by guidelines for individual adaptations resulting in reduced energy and material demands on the planet’s groaning capacity. Appendices provide refreshers on math and chemistry, as well as supplementary material of potential interest relating to cosmology, electric transportation, and an evolutionary perspective on humanity’s place in nature.

We don't reason well about expontential growth (we tend to think linearly)

Give's the bacteria in jar example (does this go back to "Limits to Growth")?

Now let’s imagine another illustrative scenario in connection with ourjar of bacteria. The time is 11:30 PM: one-half hour before the end. Thejar is one-eighth full. A thoughtful member of the culture projects thefuture and decides that more uninhabited resource-laden jars mustbe discovered in short order if the culture is to continue its trajectory.Imagine for a second the disbelief expressed by probably the vastmajority of other inhabitants: the jar is far from full, and has served for141 generations—a seeming eternity. Nonetheless, this explorer returnsreporting three other equal-sized food-filled jars within easy reach. Ahero’s welcome! How much longer will the culture be able to continuegrowing? What’s your answer?

The population doubles every ten minutes. If the original jar is filledat 12:00, the population doubles to fill the second jar by 12:10. Anotherdoubling fills all four by 12:20. The celebration is short-lived.Now we draw the inevitable parallels. A planet that has served us forcountless generations, and has seemed effectively infinite—imponderablylarge—makes it difficult for us to conceive of hitting limits. Are wehalf-full now? One-fourth? One-eighth? All three options are scary, todifferent degrees. At a 2% rate of growth (in resource use), the doublingtime is 35 years, and we only have about a century, even if at 1/8 fullright now.3

In relation to the bacteria parable, we’ve already done a fair bit ofexploring. We have no more jars. One planet rhymes with jars, but it ishostile to human life, has no food, and is not within easy reach. We haveno meaningful outlet. And even if we ignore the practical hardships,how much time would a second planet buy us anyway for uninterruptedgrowth? Another 35 years?

Hard Energy Limits

The sun deposits energy at Earth’s surface at a rate of about 1,000 W/m2(1,000 Watts per square meter; we’ll reach a better understanding for these units in Chapter 5). Ignoring clouds, the projected area intercepting the sun’s rays is justA�πR2⊕, whereR⊕is the radius of the earth, around 6,400 km. Roughly a quarter of the earth’s surface is land, and adding it all up we get about30×1015W hitting land. If we put solar panels on every square meter of land converting sunlight to electrical energy at 20% efficiency we keep 6×1015W. This is a little over 300 times the current global energy usage rate of 18 TW. What an encouraging number! Lots of margin. How long before our growth would get us there? After one century, we’re 10 times higher, and 100 times higher after two centuries. It would take about 2.5 centuries (250 years) to hit this limit. Then no more energy growth.

The Magic of Technology can fool us it will be like that forever

Decoupling and substituion won't cut it

In summary, decoupling and substitution are touted as mechanismsby which economic growth need not slow down as energy and otherresources become constrained. We can make money using less of theresource (decoupling) or just find alternatives that are not constrained(substitution), the thinking goes. And yes, this is backed up by loadsof examples where such thingshavehappened. It would be foolish toclaim that we have reached the end of the line and can expectnomoregains from decoupling or substitution. But it would be equally foolishto imagine that they can produce dividends eternally so that economicgrowth is a permanent condition.
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[rufuspollock]

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