Urban Environmental Geography. GEOSPHERE.

Aggressive, analytical reading. LINK to McCoy

OUTLINE OF McNeill Chapter 2 in the context of Urban Environmental Geography

CHAPTER 2: THE LITHOSPHERE AND PEDOSPHERE: THE CRUST OF THE EARTH

“Human action has altered the earth’s surface biologically, chemically, and physically.” P. 21

I. THE BASICS OF THE EARTH’S CRUST

“Compared with these slow but grand natural movements, the human imprint on the lithosphere seems faint.” P. 22

II. SOIL ALCHEMY

Humans have altered soil chemistry for centuries, since the beginnings of agriculture.

“In the 20^th century, with its pell-mell urbanization and its vast expansion of farming and grazing, the scale of nutrient export became many times greater than ever before.” P. 23

Nutrient depletion… farming

Leads to

Nutrient addition… fertilizer

Leads to

Mining of phosphates for phosphorus; guano;

Production of ammonia for nitrogen

Leads to

Greater demands for energy

AND it’s a system, with interrelated subsystems,

Plowing fields leads to…

Nutrient additions affect hydrosphere (pollution) with effects on biosphere with further impacts on biosphere including to anthrosphere;

Increased energy demands lead to air pollution, specifically CO2

Mining, of various sorts, leads to… (Japan, heavy metals, cadmium… rice… human health)

Chemical industries’ wastes include toxic dumps

Toxic waste leads to exportation of pollutants

And… military operations use lots of products including toxic wastes.

III. EARTH MOVERS

“At the beginning of the 20^th century, human geological impact probably came to less than a tenth of its 1990s proportion, putting it on a par with glaciers.” P. 31

MINING

Mining has been around for centuries… Bronze Age, etc

Then came industrialization.

Industrialization was based on energy from coal Table 2.2. World Coal Output, 1850 – 1995. Approx… if 1800, 1.3 unit; 1850, 10 units; 1900 100, units; 1995, 656 units;

Iron. Sand and Gravel for construction.

Various size and shapes of mines… and consequences. (Utah as an example…)

Consequences to physical environment

Consequences to human condition

THREE PULSES OF SOIL EROSION

“Soil erosion is as old as the continents. Accelerated soil erosion is that which human action provokes, and is as old as agriculture – and on a trivial scale more older still. Nowadays, people induce about 60 to 80 percent of all soil erosion.” P. 35

First pulse: as agriculture moved across terrain. Began around 2000-1000 BC and continues to present, e.g., from river flood plains onto forested or grassland areas of Middle and Far East.

Second pulse: integration of agrarian markets. Began with European conquest of the Americas of 1492 et seq and following migrations, e.g., into Siberia, into … Utah! Replicated their homeland farming practices. Continues in some places today, specifically Africa. Think Dust Bowl, settlers, over utilization of land, animals, wood, plowing, etc. Boom, erosion, bust.

Third pulse: Deforestation of world’s tropics. Began in 1950s and continues to present. Not unrelated to globalization of agrarian markets (above) e.g., coffee, bananas, and beef. Think tropics… weather… soils… torrential rains, erosion. Some places harder hit than others: complex and includes population increase, migration, and customs.

Forcing phenomena include: population, politics, migrations, customs, local and global economics and

Technological changes… heavy machinery

Energy development

Irrigation

Urbanization and roads (paving over, and footprint of cities, and migration)

CONCLUSION

“Soil degradation in one form or another now affects one-third of the world’s land surface. The area now degraded by human action (about 2 billion hectares, or the area of the United States plus Canada) is a quarter again as large as the world’s total cultivated area. An area of about 430 million hectares, seven times the size of Texas, has been ‘irreversibly destroyed' by accelerated erosion.” (according to Lal 1990). P. 48 et seq.

Consequences… time will tell

Options… several … the “loss is a matter of negligence, not necessity.” P. 49