Whatever past trends were, the rate of progress must slow as we approach physical limits. For example, there must be some minimum size for a reliable resistor. So even if we accept the inevitability of certain past trends, extrapolation is risky.
Once we’ve used most of the oil (or phosphate, for which there’s no substitute), past trends driven by culture, technology, or economics won’t continue. In agriculture, best-farmer yields haven’t increased much since 1980, although averages go up as they buy their neighbors’ land. (My recent book on Darwinian Agriculture discusses some prospects for improvement, but still within limits.) Cheap computer power may substitute for previous forms of education, entertainment, and travel, but not for food. I doubt that enough people will upload their brains to make a difference.
Whatever past trends were, the rate of progress must slow as we approach physical limits.
Past “physical limits” once considered immutable have often been broken. It was not long ago that 9600bps was considered the limit for phone line data rate. Replacing cattle with vat meat grown in factories powered by solar energy and methane digesters can likely alleviate many potential food shortages and environmental issues.
There is no guarantee that there will not be a true limiting factors of progress rate, but it is extremely bold (and misguided) to proclaim that you know in advance what they will be.
I agree that some “limits” have proved illusory. But do you have an example where a limit based on conservation of matter or energy was surpassed?
I assume solar technology will continue to improve, but it would take several orders of magnitude of improvement for food-from-solar cells to be cost-competitive with cattle grazing low-value land. What does an acre of solar cells cost?
I mentioned some far-fetched stuff before, not that we need that much energy yet. There is plenty of energy around, just waiting to be harvested: solar, geothermal, fusion...
But do you have an example where a limit based on conservation of matter or energy was surpassed?
We’re not anywhere near that limit yet. The point is that we’ve approached various things that looked like limits, and they weren’t. When we get near being limited by, say, the amount of matter/energy in the universe, then we’ll find out whether it’s really a limit.
Presumably as phosphate mines get depleted it’ll become profitable to stop pissing away all our phosphorus. Trade in urine was common in medieval Europe; now the yucky bits can be automated and hidden I see no reason it couldn’t start again.
On the other hand, if we reach a point where stockpiling human urine to supply phosphorous for agriculture (as opposed to merely conserving it locally) is economically viable, that implies some pretty scary things about the general availability of food and knock-on effects for general social stability. I’m not sure how much of it we’re (literally) pissing into the sewers and whatnot, but I’d be surprised if agricultural runoff weren’t a much greater percentage of the total.
Yes, we should start with the low-hanging fruit. For example, nutrients in human waste are a small fraction of what’s in animal waste, and the latter should be easier to capture. Even so, much of the manure still gets applied at pollution-causing rates near barns and feedlots, rather than paying the cost of transport to where it is most needed.
But your point about food availability and social stability is more important. Recycling urine seems like a good idea. But a society that needs to recycle urine will be a society where many people are spending most of their income on food and others are going hungry, as was the case for the societies mentioned above.
stockpiling human urine to supply phosphorous for agriculture (as opposed to merely conserving it locally) is economically viable, that implies some pretty scary things about the general availability of food
Not just medieval Europe—plenty of urban environments had such trades, like in China, and night soil trades were (and may still be) pretty much universal. The Ancient Roman urine trade gave us the still-current phrase ‘money doesn’t stink’.
Whatever past trends were, the rate of progress must slow as we approach physical limits. For example, there must be some minimum size for a reliable resistor. So even if we accept the inevitability of certain past trends, extrapolation is risky.
Once we’ve used most of the oil (or phosphate, for which there’s no substitute), past trends driven by culture, technology, or economics won’t continue. In agriculture, best-farmer yields haven’t increased much since 1980, although averages go up as they buy their neighbors’ land. (My recent book on Darwinian Agriculture discusses some prospects for improvement, but still within limits.) Cheap computer power may substitute for previous forms of education, entertainment, and travel, but not for food. I doubt that enough people will upload their brains to make a difference.
Past “physical limits” once considered immutable have often been broken. It was not long ago that 9600bps was considered the limit for phone line data rate. Replacing cattle with vat meat grown in factories powered by solar energy and methane digesters can likely alleviate many potential food shortages and environmental issues.
There is no guarantee that there will not be a true limiting factors of progress rate, but it is extremely bold (and misguided) to proclaim that you know in advance what they will be.
I agree that some “limits” have proved illusory. But do you have an example where a limit based on conservation of matter or energy was surpassed?
I assume solar technology will continue to improve, but it would take several orders of magnitude of improvement for food-from-solar cells to be cost-competitive with cattle grazing low-value land. What does an acre of solar cells cost?
I mentioned some far-fetched stuff before, not that we need that much energy yet. There is plenty of energy around, just waiting to be harvested: solar, geothermal, fusion...
We’re not anywhere near that limit yet. The point is that we’ve approached various things that looked like limits, and they weren’t. When we get near being limited by, say, the amount of matter/energy in the universe, then we’ll find out whether it’s really a limit.
Presumably as phosphate mines get depleted it’ll become profitable to stop pissing away all our phosphorus. Trade in urine was common in medieval Europe; now the yucky bits can be automated and hidden I see no reason it couldn’t start again.
On the other hand, if we reach a point where stockpiling human urine to supply phosphorous for agriculture (as opposed to merely conserving it locally) is economically viable, that implies some pretty scary things about the general availability of food and knock-on effects for general social stability. I’m not sure how much of it we’re (literally) pissing into the sewers and whatnot, but I’d be surprised if agricultural runoff weren’t a much greater percentage of the total.
Yes, we should start with the low-hanging fruit. For example, nutrients in human waste are a small fraction of what’s in animal waste, and the latter should be easier to capture. Even so, much of the manure still gets applied at pollution-causing rates near barns and feedlots, rather than paying the cost of transport to where it is most needed.
But your point about food availability and social stability is more important. Recycling urine seems like a good idea. But a society that needs to recycle urine will be a society where many people are spending most of their income on food and others are going hungry, as was the case for the societies mentioned above.
Well, something like this has already been fake-newsed.
Not just medieval Europe—plenty of urban environments had such trades, like in China, and night soil trades were (and may still be) pretty much universal. The Ancient Roman urine trade gave us the still-current phrase ‘money doesn’t stink’.