Civilizations around the world have risen and declined How much did past societies contribute to their own decline QuickTime and a TIFF Uncompressed decompressor are needed to see this picture Mesopotami a Minoans Greece Rome Indus Angkor Watt Olmec Maya Inca What would be required to sustain a civilization Recognizing that 97 of our food comes from the soil the fundamental condition for sustaining a civilization is sustaining the soil Can soil erosion limit the lifespan of civilizations Politics Social Evolution and Context Every civilization has a unique historical and social setting and the specific social contexts that lead to warfare and institutional evolution crises QuickTime and a TIFF Uncompressed decompressor are needed to see this picture QuickTime and a TIFF Uncompressed decompressor are needed to see this picture Climate Change Volcanos Earthquakes and Floods QuickTime and a TIFF Uncompressed decompressor are needed to see this picture No particular time scale implied by Natural Disasters Climate Change Politics and Social Evolution QuickTime and a TIFF Uncompressed decompressor are needed to see this picture Salinization Overgrazing and Deforestation QuickTime and a TIFF Uncompressed decompressor are needed to see this picture QuickTime and a TIFF Uncompressed decompressor are needed to see this picture Deforestation often blamed for historical soil erosion but trees grow back rapidly QuickTime and a TIFF Uncompressed decompressor are needed to see this picture QuickTime and a TIFF Uncompressed decompressor are needed to see this picture Major civilizations last about 500 to 2000 years Recent archaeological studies have showed that soil erosion played a role in the demise of ancient civilizations of Neolithic Europe Classical Greece Rome the Southern United States and Central America Invention of the plow fundamentally altered the balance between soil production and soil erosion In the permanence of a coat of vegetable mould on the surface of the earth we have a demonstrative proof of the continual destruction of the rocks and cannot but admire the skill with which the powers of the many chemical and mechanical agents employed in this complicated work are so adjusted as to make the supply and the waste of the soil exactly equal to one another Playfair 1802 p 106 7 Z Heimsath et al 1997 ground surface colluvium soil s zb H q s soil production from bedrock h saprolite fractured and coherent bedrock r Weatheringfront X Geomorphology simply z Qs Tectonics t Conventional plowbased agriculture increased soil erosion by more than an order of magnitude Cycles of erosion and soil formation beginning with Bronze Age erosion after introduction of plow based agriculture Van Andel and Runnels 1987 Population of the Southern Argolid Modern Age Classical Age Bronze Age Van Andel and Runnels 1987 Plato 427 347 B C T he rich soft soil has all run away leaving the land nothing but skin and bone But in those days the damage had not taken place the hills had high crests the rocky plain of Phelleus was covered with rich soil and the mountains were covered by thick woods of which there are some traces today Erosion rates in the Roman heartland increased by an order of magnitude starting about the 2nd century B C Judson 1963 1968 You have all traveled through many lands have you seen any country more fully cultivated than Italy Varro 1 2 6 It is also a science which explains what crops are to be sown and what cultivations are to be carried out in each kind of soil in order that the land may always render the highest yields Varro 1 3 Roman ruins in Northern Syria Rome s North African colonies supported extensive olive and cereal plantations in the 1st through 3rd centuries A D Goodchild 1953 All places are now accessible well known open to commerce Delightful farms have now blotted out every trace of the dreadful wastes cultivated fields have overcome woods We overcrowd the world The elements can hardly support us Our wants increase and our demands are keener while Nature cannot bear us Tertullian de Anima 30 George Perkins Marsh Man and Nature 1864 A widely traveled Vermont lawyer Marsh argued that people were reshaping Earth s surface and that civilizations influenced their own fate through deforestation soil erosion and degradation and water pollution T erritory larger than all Europe the abundance of which sustained in bygone centuries a population scarcely inferior to that of the whole Christian world at the present day has been entirely withdrawn from human use or at best is thinly inhabited There are parts of Asia Minor of Northern Africa of Greece and even of Alpine Europe where the operation of causes set in action by man has brought the face of the earth to a desolation almost as complete as that of the moon and though within that brief space of time which we call the historical period they are known to have been covered with luxuriant woods verdant pastures and fertile meadows Marsh 1864 p 9 42 Walter Lowdermilk Timgad Libya Over a large part of the ancient granary of Rome we found the soil washed off to bedrock and the hills seriously gullied as a result of overgrazing Overall average annual soil erosion rates during the Maya period were 5 t ha over more than 2200 years more than an order of magnitude faster than natural soil regeneration Lago Salpeten Guatemala QuickTime and a TIFF Uncompressed decompressor are needed to see this picture QuickTime and a TIFF Uncompressed decompressor are needed to see this picture Maya population vegetation and soil erosion agriculture Deevy et al 1979 In the first few years following a clearing made in the mountains excellent crops are produced because of the humus coat the forest has left But this precious compost as mobile as it is fecund lingers not for long upon the slopes a few sudden showers dissipate it the bare soil quickly comes to light and disappears in its turn France Surell 1870 p 219 Lowdermilk 1953 S o it is at present that Tobacco swallows up all other Things every thing else is neglected B y that time the Stumps are rotten the Ground is worn out and having fresh Land enough they take but little Care to recruit the old Fields with Dung The Present State of Virginia Hartwell Blair and Chilton 1727 p 6 7 QuickTime and a TIFF Uncompressed decompressor are needed to see this picture In a 1796 letter to Alexander Hamilton It must be obvious to every man who QuickTime and a TIFF Uncompressed decompres considers the agriculture of
View Full Document
Unlocking...