The above graph shows energy consumption in the UK through the industrial revolution, along with Italy in the 1860s, when they were still an agrarian society. It's from an essay by Tony Wrigley, a retired Cambridge economic historian. He writes:
The most fundamental defining feature of the industrial revolution was that it made possible exponential economic growth – growth at a speed that implied the doubling of output every half-century or less. This in turn radically transformed living standards. Each generation came to have a confident expectation that they would be substantially better off than their parents or grandparents. Yet, remarkably, the best informed and most perspicacious of contemporaries were not merely unconscious of the implications of the changes which were taking place about them but firmly dismissed the possibility of such a transformation. The classical economists Adam Smith, Thomas Malthus, and David Ricardo advanced an excellent reason for dismissing the possibility of prolonged growth.and
They thought in terms of three basic factors of production, i.e. land, labour, and capital. The latter two were capable of indefinite expansion in principle but the first was not. The area of land which could be used for production was limited, yet its output was basic – not just to the supply of food but of almost all the raw materials which entered into material production. This was self-evidently true of animal and vegetable raw materials – wool, cotton, leather, timber, etc. But it was also true of all mineral production since the smelting of ores required much heat and this was obtained from wood and charcoal. Expanding material production meant obtaining a greater volume of produce from the land but that in turn meant either taking into cultivation land of inferior quality, or using existing land more intensively, or both. This necessarily meant at some point that returns both to capital and labour would fall. In short, the very process of growth ensured that it could not be continued indefinitely. This was a basic characteristic of all “organic” economies, those which were universal before the industrial revolution.
Access to energy that did not spring from the annual product of plant photosynthesis was a sine qua non for breaking free from the constraints afflicting all organic economies. By an intriguing paradox, this came about by gaining access to the products of photosynthesis stockpiled over a geological time span. It was the steadily increasing use of coal as an energy source which provided the escape route.This is exactly my view, and it's very nice to see it documented in more detail by somebody with "economic" in their job title. The one thing that came as a surprise to me was the relatively large use of coal in England as early as the seventeenth century - over two centuries before the Italians, say, started using fossil fuels in any quantity. This raises the question of what it was about renaissance England that led it to be the first to run up against the constraints of wood supply, causing the switch to coal (which in turn positioned it to be where the industrial revolution would happen). The most obvious guess would be Tudor shipbuilding - starting on the project that later became England's naval dominance.
It was simple to substitute coal for wood as a solution to the problem of increasing the supply of heat energy, at least where the heat generated by burning coal and the object to be heated were separated by a barrier that allowed the transfer of heat but prevented chemical exchange.
Coal could, for example, readily be substituted for wood to heat salt pans or dye vats. It could also readily be used as a source of domestic heat in an open fire though it was some time before trial and error gave rise to a chimney which could both improve combustion and evacuate smoke. The early expansion of coal production was largely for domestic use, dominated by the supply of coal from coal pits near the Tyne to London. The east coast coal trade expanded so greatly from Tudor times onwards that by the end of the seventeenth century roughly half the tonnage of the merchant navy was devoted to this trade. But it took many decades of trial and error to enable coal or coke to be substituted for charcoal in smelting iron because the transfer of chemical impurities prevented a good quality result.
Until the early eighteenth century, coal, although used increasingly by the English, offered a solution only to the problem of supplying heat energy. Mechanical energy remained a matter of muscle power and was therefore limited by the photosynthesis constraint. Hence the central importance of the slow development of an effective steam engine that made it possible to convert heat energy into mechanical energy. Once this was possible the problem of limited energy supply was solved for the whole spectrum of material production and transport.
At any rate, Wrigley has a book out, and I ordered it to see what other questions he might answer.