Scaling down all the amounts of time, here’s how that situation sounds to me: US output doubles in 15 years (basically the fastest it ever has), then doubles again in 7 years. The end of the 7 year doubling is the first time that your hypothetical observer would say “OK yeah maybe we are transitioning to a new faster growth mode,” and stuff started getting clearly crazy during the 7 year doubling. That scenario wouldn’t be surprising to me. If that scenario sounds typical to you then it’s not clear there’s anything we really disagree about.
Moreover, it seems to contradict your claim that 0.14% growth was already high by historical standards.
0.14%/year growth sustained over 500 years is a doubling. If you did that between 5000BC and 1000AD then that would be 4000x growth. I think we have a lot of uncertainty about how much growth actually occurred but we’re pretty sure it’s not 4000x (e.g. going from 1 million people to 4 billion people). Standard kind of made-up estimates are more like 50x (e.g. those cited in Roodman’s report), half that fast.
There is lots of variance in growth rates, and it would temporarily be above that level given that populations would grow way faster than that when they have enough resources. That makes it harder to tell what’s going on but I think you should still be surprised to see such high growth rates sustained for many centuries.
(assuming you discount 1350 as I do as an artefact of recovering from various disasters
This doesn’t seem to work, especially if you look at the UK. Just consider a long enough period of time (like 1000AD to 1500AD) to include both the disasters and the recovery. At that point, disasters should if anything decrease growth rates. Yet this period saw historically atypically fast growth.
OK, thanks. I’m not sure how you calculated that but I’ll take your word for it. My hypothetical observer is seeming pretty silly then—I guess I had been thinking that the growth prior to 1700 was fast but not much faster than it had been at various times in the past, and in fact much slower than it had been in 1350 (I had discounted that, but if we don’t, then that supports my point) so a hypothetical observer would be licensed to discount the growth prior to 1700 as maybe just catch-up + noise. But then by the time the data for 1700 comes in, it’s clear a fundamental change has happened. I guess the modern-day parallel would be if a pandemic or economic crisis depresses growth for a bit, and then there’s a sustained period of growth afterwards in which the economy doubles in 7 years, and there’s all sorts of new technology involved but it’s still respectable for economists to say it’s just catch-up growth + noise, at least until year 5 or so of the 7-year doubling. Is this fair?
There definitely wasn’t 0.14% growth over 5000 years. But according to my data there was 12% in 700, 0.23% in 900, 11% in 1000 and 1100, 47% in 1350, and 21% in 1400. So 14% fits right in; 14% over a 500-year period is indeed more impressive, but not that impressive when there are multiple 100-year periods with higher growth than that worldwide (and thus presumably longer periods with higher growth, in cherry-picked locations around the world)
Anyhow, the important thing is how much we disagree, and maybe it’s not much. I certainly think the scenario you sketch is plausible, but I think “faster” scenarios, and scenarios with more of a disconnect between GWP and PONR, are also plausible. Thanks to you I am updating towards thinking the historical case of IR is less support for that second bit than I thought.
Scaling down all the amounts of time, here’s how that situation sounds to me: US output doubles in 15 years (basically the fastest it ever has), then doubles again in 7 years. The end of the 7 year doubling is the first time that your hypothetical observer would say “OK yeah maybe we are transitioning to a new faster growth mode,” and stuff started getting clearly crazy during the 7 year doubling. That scenario wouldn’t be surprising to me. If that scenario sounds typical to you then it’s not clear there’s anything we really disagree about.
0.14%/year growth sustained over 500 years is a doubling. If you did that between 5000BC and 1000AD then that would be 4000x growth. I think we have a lot of uncertainty about how much growth actually occurred but we’re pretty sure it’s not 4000x (e.g. going from 1 million people to 4 billion people). Standard kind of made-up estimates are more like 50x (e.g. those cited in Roodman’s report), half that fast.
There is lots of variance in growth rates, and it would temporarily be above that level given that populations would grow way faster than that when they have enough resources. That makes it harder to tell what’s going on but I think you should still be surprised to see such high growth rates sustained for many centuries.
This doesn’t seem to work, especially if you look at the UK. Just consider a long enough period of time (like 1000AD to 1500AD) to include both the disasters and the recovery. At that point, disasters should if anything decrease growth rates. Yet this period saw historically atypically fast growth.
OK, thanks. I’m not sure how you calculated that but I’ll take your word for it. My hypothetical observer is seeming pretty silly then—I guess I had been thinking that the growth prior to 1700 was fast but not much faster than it had been at various times in the past, and in fact much slower than it had been in 1350 (I had discounted that, but if we don’t, then that supports my point) so a hypothetical observer would be licensed to discount the growth prior to 1700 as maybe just catch-up + noise. But then by the time the data for 1700 comes in, it’s clear a fundamental change has happened. I guess the modern-day parallel would be if a pandemic or economic crisis depresses growth for a bit, and then there’s a sustained period of growth afterwards in which the economy doubles in 7 years, and there’s all sorts of new technology involved but it’s still respectable for economists to say it’s just catch-up growth + noise, at least until year 5 or so of the 7-year doubling. Is this fair?
There definitely wasn’t 0.14% growth over 5000 years. But according to my data there was 12% in 700, 0.23% in 900, 11% in 1000 and 1100, 47% in 1350, and 21% in 1400. So 14% fits right in; 14% over a 500-year period is indeed more impressive, but not that impressive when there are multiple 100-year periods with higher growth than that worldwide (and thus presumably longer periods with higher growth, in cherry-picked locations around the world)
Anyhow, the important thing is how much we disagree, and maybe it’s not much. I certainly think the scenario you sketch is plausible, but I think “faster” scenarios, and scenarios with more of a disconnect between GWP and PONR, are also plausible. Thanks to you I am updating towards thinking the historical case of IR is less support for that second bit than I thought.