An over-generalisation, Dianavan. Perhaps you are looking at livestock-grazing thro' North American eyes. The British Isles is anarea of high-density population, yet the import of meat products from the Americas is minimal. Much of the beef industry depends upon cattle-raising on land which is by and large unsuitable for the intensive cultivation which is necessary for food growing. Likewise sheepfarming is predominantly an industry of hill country and moorland. The hill farms are "sustainable" in the environmental sense, although the economics of hill farming is something else---it's a hard life, and doesn't turn out too many millionaires! Many farms in the more fertile areas tend to be managed in a "rotation" system. This applies mostly to dairy producers, who will graze dairy herds on "fallow" land for some seasons, while "rotating" the remainder growing food crops and fodder. It is a very odd farm which isn't self-sufficient in water supply---although this is more and more affected by climate change. The "water-guzzlers" are almost 100% mass-producing industries [and that WOULD include monster hydroponic growers]. That being so, strife over water supply--given the acquisitive nature of much of our "free enterprise"---seems inevitable. Overpopulation has been referred to. Greed as an added ingredient will almost surely lead to strife. Sad; we DO learn, but do enough of us really care?