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It is interesting to consider just how much excess energy it would take to directly upset Earth's thermal balance. In 3001: The Final Odyssey, Arthur C Clarke p
by dTal 5y ago
It is interesting to consider just how much excess energy it would take to directly upset Earth's thermal balance. In 3001: The Final Odyssey, Arthur C Clarke predicted a thermal crisis caused by abundant free energy. Is it plausible?
Total solar insolation is in the region of 1.8x10^17 W, which is some 10,000 times greater than the total energy use of humanity. This is not so far out when you consider our exponential energy use over the past few centuries! If growth does not slow (which it must), we could expect to use that much energy in about 4 more centuries.
But we could expect to hit problems before then. What percentage of disruption to Earth's energy budget leads to visible effect? Our current imbalance due to greenhouse gases amounts to roughly 1 Watt per square meter, or 0.1%. At our current rate of growth we'll reach that in a mere century! So even if we switch entirely over to nuclear power starting today, and continue along our merry way safe in the knowledge that we're producing no greenhouse gases, in 100 years we'll have a similar warming problem from energy alone.
- eloff 5y agoIsaac Arthur on YouTube talks about this quite a bit. Given limitless cheap energy like nuclear fusion, the ultimate limit on human population is not land or water but the waste heat that we generate. We're very far from that being an issue today, but in some dystopian future where we turn earth into Coruscant, that could be a thing. I hope instead we stabilize our population or move to settlements in orbit. I'd like to see the land we currently use for food to be rewilded in a world where we can grow food in orbit and in vertical farms / artificial food factories. It would be nice if future humans mostly lived in cities or space habitats and the earth mostly went back to nature.
- dTal 5y agoI don't know if 100 years is "very far". It's not implausible that someone develops a practical fusion plant this decade, and at that point we're well on our way. We don't even need to turn the planet into Coruscant - by the maths I just spelled out, we're only a factor of 10 away from noticeable warming! A bit more population growth, a few lifestyle upgrades for the global south, and we're there.
- AngryData 5y agoIm skeptical that fusion will be a silver bullet for our problems. While I agree that producing lots of clean energy is the solution we need for many things, im not sure fusion is going to scale very easy when it is becomes practical for power generation. The sun is only producing thermal power per volume equivalent to a pile of manure, so even if we manage to increase that an order of magnitude, we will need an astronomical amount of plants and infrastructure to make it a primary energy source. And with such scales needed, we could have already done the same thing using other sources including fission.
- dTal 5y agoRight, the point was simply to provide a plausible mechanism by which we could continue to increase our energy consumption exponentially, for the sake of argument. The thought experiment of "global warming from pure energy expenditure" doesn't work if the energy source is solar, because that energy offsets insolation. I'm not particularly bullish on fusion power, though we can dream.
- eloff 5y agoYes, that's closer than I thought. We may well need to deploy configurable sunshade at the earth - sun Lagrange point or something similarly drastic to keep the climate in a hospitable band.
- jazzyjackson 5y agoYou might be interested in the book “ethnobotany: people, plants, and culture” to learn why leaving nature alone is not the best option, that biodiversity and rich ecosystems can come from human interference - weeding plants that are taking over, spreading seeds of food and medicine, intentionally building the soil - after a few thousand years you end up with the Amazon rain forest. It doesn’t happen on its own, humans are a part of it. To have this mind of leaving earth alone and even leaving it behind is leaving a lot of good food on the table, I wouldn’t want to live among the factory farms in space.
- dTal 5y agoI don't buy that the Amazon is meaningfully a consequence of human activity. The sheer biodiversity on display is not something I can imagine evolving in just a few thousand years.
- eloff 5y agoThe Amazon is much older than humans in South America. I don't buy this theory either.
- jazzyjackson 5y agoI’m probably being misleading since it’s not my field, but a quick Google suggests that the forest has changed over the past few thousand years - I didn’t mean to suggest that the forest wouldn’t be there without us, but that the ecosystem is richer and more complex because of our interference. Just one source that talks about the changes over the past couple thousand years: "These indigenous systems were highly sophisticated...There are over 80 domesticated or semi-domesticated crops in the Amazon," he said. "In Europe at the time they were working with about six." https://www.reuters.com/article/us-environment-amazon-idUSKBN0FD00N20140708 https://www.reuters.com/article/us-environment-amazon-idUSKB...
- selimthegrim 5y agoMelanesians actually sort of farmed wild plants contemporary to the invention of agriculture elsewhere
- mdale 5y agoTrue .. but if we could just shoot excessive heat off into space no? Like a few city scale central heating / cooling systems that radiated into space.
- dTal 5y agoUnfortunately not. All waste heat is already radiated into space, and there's no way to make it go faster. Heat always flows from hot places to cold places, unless you put energy in - so we can't gather all of our waste heat into one place for disposal, without creating more waste heat. It's the second law of thermodynamics, I'm afraid.