It's worth noting that those 'dark times' were periods of perfectly ordinary economic growth compared to the rest of the world and all the millenniums previous.
Comparing those times to the Industrial Revolution that came shortly after is a little unfair - no tradition or souvenir compares well.
Eh, no. The first explosion of efficiency and economic prosperity was in Roman times, when there was peace in much of Europe and cities flourished, complete with sanitation systems, elaborate transportation networks etcetera.
When that crumbled, city states took over, and economic life was once again dictated by the whims of rulers who in reality depended on keeping the ruling classes of the cities in their empire happy; in these cities, tradesmen classes operated in rigid, protectionist and mercantilist guild systems. There was stagnation and in many fields enormous regression until the Enlightenment and the Industrial Revolution (when freedom brought back the drive for progress).
On a small base (like a graph where the initial datapoints are less than 1/27th the ending datapoints), even large percentages can be hard to see. And I'm not sure how you can be agreeing 'exactly', since the Roman empire was as agriculturally based as anything else around (latifunda, panem et circenses, the Egypt grain tribute etc.).
But you are right that the annual growth due to efficiency was relatively small:
> Indeed generations of English schoolchildren have read, probably with bored bemusement, of the exploits of such supposedly heroic innovators as Jethro Tull (author in 1733 of An Essay on Horse-Hoeing Husbandry), “Turnip” Townsend, and Arthur Young. But this agricultural revolution is a myth, created by historians who vastly overestimated the gains in output from English agriculture in these years.4 The productivity growth rate in agriculture was instead modest, at 0.27 percent per year, lower than for the economy as a whole. But even these modest gains represented considerably faster productivity growth than had been typical over the years 1200–1800. Figure 12.4, for example, shows wheat yields per seed sown in England from 1211 to 1453. Medieval agriculture seems to have been totally static over hundreds of years.
(Clark remarks elsewhere that agricultural productivity growth is more like 1 or 2%, and the Chinese had easily double England's agriculture efficiency, but because farming is a war against entropy, with land being damaged and local pests adapting etc., the net productivity growth is small.)
Economic growth came mostly from population growth and exploiting additional natural resources.
You over-estimate Rome. Sanitation systems? Harappa & Mohenjo-dara could boast as much! The Stone Age had elaborate transportation networks for trading rare commodities like tin, and Roman trading networks were not incomparably better than the Phoenician routes; the roads are very nice, but only a constant factor improvement, as programmers like to say. Rome was not the 'first explosion' by any means (if it was, then why didn't the Byzantines just reconquer and improve the West with their superior Roman economics?), nor any kind of paradigm shift like you seem to regard it as; but that's beside the point, since we're discussing what came after the inevitable fall.
> There was stagnation and in many fields enormous regression until the Enlightenment and the Industrial Revolution (when freedom brought back the drive for progress).
Really? Again, your characterizations are unfair and draw on the tired old Whig myths of the Dark Ages and medieval periods. I like the Enlightenment & Industrial Revolution quite well, but I feel no need to exaggerate prior history. The periods of the guilds were no worse than most periods and better than some; from Gregory Clark:
> Figure 12.11 shows the estimated productivity level in book production by decade from the 1470s to the 1860s, calculated as the ratio between the wage of building craftsmen and the price of a book of standard characteristics.9 The rate of productivity growth from the 1460s to the 1560s was 2.3 percent per year, as fast as that for cotton textiles in the Industrial Revolution. In the next hundred years productivity grew more slowly, at only 0.6 percent per year. But this was still faster than the rate seen in most of the economy during the Industrial Revolution. From the 1660s to the 1860s there were apparently few further productivity gains in printing. But all this increase in the efficiency of book production had no appreciable impact on the measured efficiency of the economy before the 1660s, since books were such a tiny share of expenditures for most of the preindustrial era. In the first decade of the sixteenth century the average annual output of books was about twenty thousand volumes, about 0.02 percent of English national income. By the 1550s this had risen to a hundred thousand volumes, but because of the falling prices of books that was still only 0.11 percent of national income.
> Books were not the only goods that saw substantial efficiency advances in the years before 1800 yet had little or no impact on the overall efficiency of the economy because they represented such a small share of aggregate expenditure. Table 12.8 shows the price of nails by fifty-year periods, compared with wages, and the implied efficiency in nail production. A pound of nails in the early thirteenth century cost 3.3 pence, while a day’s wage for a craftsman was 2.4 pence. Thus a pound of nails cost more than a day’s wage. By the years 1850-69 the day wage had increased about seventeenfold, to 40 pence per day. But nail prices were only 3.2 pence per pound, so a craftsman could buy more than 12 pounds of nails with his day’s wage.10
When were the guilds shattered? By the 1700s, I think most would say, yet:
> Figure 10.2 shows, for example, income per capita in England by decade from the 1260s to the 2000s. After six hundred years of stasis, income has increased nearly tenfold since 1800. It continues its inexorable rise. Note, however, that though the conventional date for the onset of the Industrial Revolution in Britain is given as the 1760s there is little sign of rapid growth of income per person until the decade of the 1860s.
> The years around 1300, before the onset of the plague in England in 1349, do show lower wages than in 1800. But wages in the early thirteenth century are close to their level in 1800. It should be stressed that this wage index incorporates the arrival of new goods such as sugar, pepper, raisins, tea, coffee, and tobacco. Even allowing for the gains in real income from the decline in prices of all these new goods in the years 1500–1800, workers in the late Middle Ages were still much richer. They received extra rations of beef and beer as part of their wages, which more than covered any absence of tea or sugar.
While we're on the topic, the rulers were not nearly so economically despotic as your caricature presents them:
> However, the difficulties of collecting the tithe in kind, particularly on animal products, led to tithe owners collecting at a much lower rate. Tithe collections before 1800 averaged only 11 percent of land rents or 4 percent of farm output. So tithe income in preindustrial England was likely less than 4 percent of national income.10 Thus even allowing for the additional taxing power of the church, all taxes collected in preindustrial England before the Glorious Revolution were typically less than 6 percent of income.
And wages could change considerably for the better, even before the Industrial Revolution (a unique occurrence in world history, I will remind you, for whose absence in their time period the medievals you like to condemn are not responsible):
> Referring, for example, to figure 3.1, living standards of English laborers in 1450 were three times as high as in 1300, and nearly double the levels of 1800. This variation in living standards would seem to be explained mostly by variation in mortality rates at given levels of income. Thus the explanation for the very high living standards of Europeans in the years 1350–1600 was undoubtedly the arrival of the Black Death in 1347. Its first onslaught in the years 1347–49 carried away 30–50 percent of the population of Europe. But the plague continued to strike periodically thereafter for the next three hundred years. In England between 1351 and 1485 there were thirty plague outbreaks. As late as 1604, for example, the city of York lost at least a quarter of its population in one year to plague. Paris had twenty-two plague epidemics from 1348 to 1596.6
And that stagnation & regression? Well, the Roman Empire which only loosely controlled part of England must have done one hell of a job, all things considered:
> England in 1200–1800 had an income per person as high as, or higher than, large areas of the modern world. Countries with an aggregate population of more than 700 million people in the year 2000 had incomes below the average of preindustrial England. Another billion people in India had average incomes only 10 percent above those in England before the Industrial Revolution. Some modern countries are dramatically poorer. Hundreds of millions of Africans now live on less than 40 percent of the income of preindustrial England.
Comparing those times to the Industrial Revolution that came shortly after is a little unfair - no tradition or souvenir compares well.