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Thanks for putting it into context! Generally I wonder about sustainability of rare earths (and other elements with limited supply like helium). We build a lot

Thanks for putting it into context! Generally I wonder about sustainability of rare earths (and other elements with limited supply like helium). We build a lot of products that don't last very long - some of it gets recycled, a lot of it doesn't. Wonder what humans 200 or 2000 years later will think of our consumption

kragen 7y ago
Helium is a special case: when it leaks into the atmosphere, it eventually escapes into space. So the humans really do consume helium, just as the humans consume fossil fuels. By contrast, all the lithium, phosphorus, carbon, aluminum, iron, hafnium, zirconium, and erbium ever mined on Earth is still on Earth, except for the extremely small amounts sent to Venus, Mars, the Moon, and interstellar space on spacecraft, or transmuted to other elements in nuclear reactors. It is not consumed, just moved around a bit. Where is it? Well, it varies by element. While some of the phosphorus makes up human bones, most of it is dissolved in the ocean as phosphate, enormously less concentrated than the original deposits of apatite and other minerals it was mined from. At some point the humans might run out of easily accessible apatite deposits, since phosphorus only makes up 0.1% of the Earth's crust. If we consider only the top 2 km of the continental crust (29% of the surface) to be "easily accessible", that's only 3.0 × 10⁸ km³ of rock, or about 7.1 × 10¹⁷ tonnes, of which about 7.1 × 10¹⁴ is phosphorus. Since phosphorus is currently being mined at 153 million tonnes per year, the humans are currently on track to deplete most of it in only 4.6 billion years, considerably earlier than the Earth is on track to be destroyed by the sun. As for the carbon, it's mined for its chemical potential energy, which is lost when it is burned; but the carbon remains on Earth. 870 billion tonnes of it is in the atmosphere, of which about a third is due to the humans setting rocks on fire; a comparable amount has been added to terrestrial biomass and carbon in the oceans. The part in the atmosphere is relatively easy to recover; existing processes have comparable cost to the cost of digging up rocks. This is not being done at scale because it is "unprofitable". More than half of the aluminum that has been mined on Earth is still in use. The other half is mostly in landfills, where it is less concentrated than the bauxite ores that are commercially mined, but less oxidized. Most of the iron that has been mined is in landfills, but not only ores but also slag heaps near foundries are a more concentrated form of iron. Rarer metals like gold, hafnium, zirconium, and erbium are mostly in landfills. They mostly do not readily form soluble ions to leach into the ocean or groundwater, and they mostly only find their way into the air when incinerated. Their concentrations in landfills are dramatically higher than the concentrations in the ores they are mined from, and this is becoming a "profitable" way for the humans to spend their lives before being killed by the hazards of the landfills. Presumably automation will speed up this process.
- dharma1 7y ago
  This is really insightful. A lot of human “progress” and activity includes us exporting growing amounts of high entropy waste, for a mostly unaccounted for, deferred cost. In most natural systems there is no waste - everything gets recycled. We create a mess digging for elements around the planet, consuming the “value” of the things we make from those elements (and large amounts of energy) in a way which lasts a very short time, and disposing of the waste which then mostly get spread around the planet in even greater mess. I find it difficult to see how automation will easily solve our waste problem - it seems many orders of magnitude easier to try to solve it before human waste gets to a giant garbled heap or gets spread around the atmosphere/oceans/groundwater/(soon low earth orbit) where it’s difficult to retrieve, and seems to cause huge problems to the natural world (and ultimately is) by being in places it shouldn’t be. Why are humans so good/bad at creating a mess? Are we equipped with skills/incentives to solve this conundrum, or will we continue to drown in our mess?
  - kragen 7y ago
    The Earth doesn't recycle solar energy; it wastes ≈100% of it by radiating it away into space. Over 99% of it never even gets photosynthesized, just being absorbed as heat and then reradiated as infrared. Far less than 1% was ever accumulated in fossil fuels, and of course accumulating it as heat at the surface would be fatal. Nor does it recycle, for example, crustal iron; once the iron finds its way into a subduction zone and melts into the mantle, it gradually finds its way to the core, never to return. Even the fast CO₂ cycle is noticeably leaky, as a substantial amount of CO₂ is taken up by marine organisms that sink to the bottom and stay there, eventually being compacted into limestone and remaining limestone for hundreds of millions of years (the slow CO₂ cycle), until probably being liberated again by volcanism. So, I think that for most definitions of "waste", it is false that in most natural systems there is no waste. It's true that recovering materials from the atmosphere and oceans is more difficult than mining them. But most of the materials we're discussing don't end up in the atmosphere and oceans; they end up in landfills. And recovering them from landfills is, generally, much easier than mining them from natural deposits. Landfills are much more concentrated and heterogeneous deposits of "valuable" elements than the ores from which they are mined; for example, a single accidentally discarded catalytic converter may contain 5 grams of platinum-group metals, which are reduced and relatively easy to recover; commonly mined natural ores of platinum-group metals (the Merensky, chromitite, and contact types of deposits) typically contain 5 grams per tonne of ore, mostly oxidized and thus requiring not only froth flotation but also smelting. And catalytic converter platinum-group elements are far from the only "valuable" elements in landfills. The trouble is that when the humans go digging around in landfills with their bare hands, it reduces their life expectancy a lot, because of poisons, injuries, and poor safety practices around refining. This is not a new problem for mining — the Spanish silver mines were a death sentence for the enslaved indigenous Americans sentenced to work in them — but the particular measures needed to solve the problem are different for landfills than for other mining. Automation will largely solve them. I suspect that the same ritual-pollution taboos that cause the humans to deprecate garbage collectors, cannibals, and undertakers are a major factor in the slow development of landfill mining. A Kessler syndrome in LEO will be only a short-term problem, as the lifetime of objects there is limited to decades, not even a single million years!, by atmospheric drag, and the quantity of mass there is limited by launch "costs". MEO Kessler syndrome would be a more serious problem. Doing things creates messes. Lowering entropy locally — one definition of life — raises entropy globally. Doing more things will create more messes. Doing things intelligently can create safely contained messes.

kragen 7y ago

Helium is a special case: when it leaks into the atmosphere, it eventually escapes into space. So the humans really do consume helium, just as the humans consume fossil fuels. By contrast, all the lithium, phosphorus, carbon, aluminum, iron, hafnium, zirconium, and erbium ever mined on Earth is still on Earth, except for the extremely small amounts sent to Venus, Mars, the Moon, and interstellar space on spacecraft, or transmuted to other elements in nuclear reactors. It is not consumed, just moved around a bit. Where is it? Well, it varies by element. While some of the phosphorus makes up human bones, most of it is dissolved in the ocean as phosphate, enormously less concentrated than the original deposits of apatite and other minerals it was mined from. At some point the humans might run out of easily accessible apatite deposits, since phosphorus only makes up 0.1% of the Earth's crust. If we consider only the top 2 km of the continental crust (29% of the surface) to be "easily accessible", that's only 3.0 × 10⁸ km³ of rock, or about 7.1 × 10¹⁷ tonnes, of which about 7.1 × 10¹⁴ is phosphorus. Since phosphorus is currently being mined at 153 million tonnes per year, the humans are currently on track to deplete most of it in only 4.6 billion years, considerably earlier than the Earth is on track to be destroyed by the sun. As for the carbon, it's mined for its chemical potential energy, which is lost when it is burned; but the carbon remains on Earth. 870 billion tonnes of it is in the atmosphere, of which about a third is due to the humans setting rocks on fire; a comparable amount has been added to terrestrial biomass and carbon in the oceans. The part in the atmosphere is relatively easy to recover; existing processes have comparable cost to the cost of digging up rocks. This is not being done at scale because it is "unprofitable". More than half of the aluminum that has been mined on Earth is still in use. The other half is mostly in landfills, where it is less concentrated than the bauxite ores that are commercially mined, but less oxidized. Most of the iron that has been mined is in landfills, but not only ores but also slag heaps near foundries are a more concentrated form of iron. Rarer metals like gold, hafnium, zirconium, and erbium are mostly in landfills. They mostly do not readily form soluble ions to leach into the ocean or groundwater, and they mostly only find their way into the air when incinerated. Their concentrations in landfills are dramatically higher than the concentrations in the ores they are mined from, and this is becoming a "profitable" way for the humans to spend their lives before being killed by the hazards of the landfills. Presumably automation will speed up this process.

dharma1 7y ago
This is really insightful. A lot of human “progress” and activity includes us exporting growing amounts of high entropy waste, for a mostly unaccounted for, deferred cost. In most natural systems there is no waste - everything gets recycled. We create a mess digging for elements around the planet, consuming the “value” of the things we make from those elements (and large amounts of energy) in a way which lasts a very short time, and disposing of the waste which then mostly get spread around the planet in even greater mess. I find it difficult to see how automation will easily solve our waste problem - it seems many orders of magnitude easier to try to solve it before human waste gets to a giant garbled heap or gets spread around the atmosphere/oceans/groundwater/(soon low earth orbit) where it’s difficult to retrieve, and seems to cause huge problems to the natural world (and ultimately is) by being in places it shouldn’t be. Why are humans so good/bad at creating a mess? Are we equipped with skills/incentives to solve this conundrum, or will we continue to drown in our mess?
- kragen 7y ago
  The Earth doesn't recycle solar energy; it wastes ≈100% of it by radiating it away into space. Over 99% of it never even gets photosynthesized, just being absorbed as heat and then reradiated as infrared. Far less than 1% was ever accumulated in fossil fuels, and of course accumulating it as heat at the surface would be fatal. Nor does it recycle, for example, crustal iron; once the iron finds its way into a subduction zone and melts into the mantle, it gradually finds its way to the core, never to return. Even the fast CO₂ cycle is noticeably leaky, as a substantial amount of CO₂ is taken up by marine organisms that sink to the bottom and stay there, eventually being compacted into limestone and remaining limestone for hundreds of millions of years (the slow CO₂ cycle), until probably being liberated again by volcanism. So, I think that for most definitions of "waste", it is false that in most natural systems there is no waste. It's true that recovering materials from the atmosphere and oceans is more difficult than mining them. But most of the materials we're discussing don't end up in the atmosphere and oceans; they end up in landfills. And recovering them from landfills is, generally, much easier than mining them from natural deposits. Landfills are much more concentrated and heterogeneous deposits of "valuable" elements than the ores from which they are mined; for example, a single accidentally discarded catalytic converter may contain 5 grams of platinum-group metals, which are reduced and relatively easy to recover; commonly mined natural ores of platinum-group metals (the Merensky, chromitite, and contact types of deposits) typically contain 5 grams per tonne of ore, mostly oxidized and thus requiring not only froth flotation but also smelting. And catalytic converter platinum-group elements are far from the only "valuable" elements in landfills. The trouble is that when the humans go digging around in landfills with their bare hands, it reduces their life expectancy a lot, because of poisons, injuries, and poor safety practices around refining. This is not a new problem for mining — the Spanish silver mines were a death sentence for the enslaved indigenous Americans sentenced to work in them — but the particular measures needed to solve the problem are different for landfills than for other mining. Automation will largely solve them. I suspect that the same ritual-pollution taboos that cause the humans to deprecate garbage collectors, cannibals, and undertakers are a major factor in the slow development of landfill mining. A Kessler syndrome in LEO will be only a short-term problem, as the lifetime of objects there is limited to decades, not even a single million years!, by atmospheric drag, and the quantity of mass there is limited by launch "costs". MEO Kessler syndrome would be a more serious problem. Doing things creates messes. Lowering entropy locally — one definition of life — raises entropy globally. Doing more things will create more messes. Doing things intelligently can create safely contained messes.