Has anybody done any kind of study to determine what size of population the agricultural land around the city of Mecca could have supported based on the technology of those times? How could the administrative center of such a massive and growing empire have supported the armies neccesary to conquer all those new lands?
Arabs were not and many still are not farmers, they were pastoralists specialising in goats, which have very significant ecological effects.
The great Roman cities of the Middle East and North Africa some of the most iconic archaeological sites on earth. There are literally hundreds of them, in various states of preservation. In most cases the pillars of temples and public buildings still stand, like the “bleached bones” (as Kenneth Clark described them) of classical civilization. The Roman cities of Europe tend to be in a much poorer state of preservation because they were not abandoned. In Europe settlements such as London, Paris, Trier, Regensburg, Cordoba, etc, were occupied continuously from ancient times, and the fine cut stones of the temples and palaces were reused and remodelled on numerous occasions throughout the Middle Ages. And because people still lived in the localities many meters of debris came to cover the Roman settlements. It was not so in the Middle East and North Africa; here the great classical settlements were (with a handful of exceptions) abandoned and never reoccupied.
The abandoned cities usually now stand in semi-arid territories, landscapes that have not been cultivated for many centuries, though it is evident that they were extensively cultivated in Roman and Byzantine times. Historians are in no doubt that the majority of the abandoned cities were deserted because of the collapse of agriculture in the surrounding countryside. These settlements, with their large populations, needed productive farming communities in order to survive. The desertification of the territories in which they stood would have been a death sentence for them. But what caused the agricultural collapse?
..
For decades the core of the debate raged around two opposing positions: One school of thought looked to climate change; another looked to human action. By the late 1940s however the evidence had moved decisively in favor of the latter, and the definitive work was published in 1951 by Rhoads Murphey, Professor Emeritus of History at Harvard. In an article entitled “The Decline of North Africa since the Roman Occupation: Climatic or Human?” he provides a detailed outline of the problem. I shall quote him at some length, as what he says is most instructive:
“The Romans were an agricultural people who expanded into their Mediterranean empire from a relatively humid base in Italy. It was natural that they should extend this approach to the natural environment into the African provinces. The Arabs were on the contrary a nomadic people, nurtured in the true desert of Arabia, and totally unused to an agricultural economy. Their technique was unequal to understanding or managing the highly-developed irrigation works of North Africa bequeathed to them by the Romans, and they had no need for dependence on the agriculture which these works had supported. Their different use of the land does not need to be explained by a change in climate. No military conquest is conducive to the maintenance of civil order nor the administration and technical organization which an intricate irrigation economy requires, especially when the conquerors are nomads. The Arab conquest destroyed the Roman irrigation works, or allowed them to deteriorate, and established in their stead a nomadic pastoral economy over most of North Africa.” (Rhoads Murphey, “The Decline of North Africa since the Roman Occupation: Climatic or Human?”, ANNALS, Association of American Geographers, Vol. XLI, no. 2, (June 1951))....
He continues: “Nevertheless, it is possible that the changed land use which the Arabs brought with them did in time affect the natural environment in a critical way. By the end of the eighth century AD there were approximately one million Arabs in North Africa. Each Arab family kept a large flock of sheep and goats, variously estimated at between fifteen and fifty per family. Goats are notoriously close croppers, and their unrestricted grazing in the Mediterranean area has had a virtually irreparable effect. In North Africa too, the added presence of several million goats undoubtedly destroyed large areas of grass, scrub, and trees, increasing the run-off, decreasing precious supplies of groundwater and lowering the water table perhaps critically, adding to the erosion of water courses, and disrupting the optimum distribution of surface water …” (Ibid.) Furthermore, “Contemporary Arab disrespect for trees (notorious in both Arabia and North Africa) except as lumber or firewood, and lack of understanding of the long-term value to themselves of tree-cover may suggest a further deteriorating effect of Arab land use on the productivity of North Africa. Indeed, one student of the problem, while agreeing that the North African climate has not changed significantly in the last 2000 years, states that the primary cause of the economic decline during that period has been deforestation, for which he lays the blame at the door of the Arabs.” (Ibid., pp. 124-5)
Of course, the above is "pastoralist" but still, Allah does seem to have been asleep in the ecology 101 class!
http://www.newenglishreview.org/custpage.cfm/frm/104822/sec_id/104822
Topic: Islam: the untold story