The Mayan collaspe. The Mayans were a highly civilized society. Diamond gives four reasons for the collaspe of Mayan civilization: 1. Mayans damaged their environment by deforestation which caused massive soil erosion. 2. Dramatic and cyclic climate changes contributed to the Mayan collaspe 3. Hostilities among the Mayans limited cooperation in food production, discovery of new technology (crop rotation, alter seed variation, and water management). The Hostiles disrupted a large area because the hostiles lasted for long durations and spanned vast amount of territory. 4. Political and cultural factors limited survival. Competition among kings and nobles lead to the erecting of monuments rather than cooperation in solving problems. The fifth point does not seem to be significant. The fifth point is trade or cessation of trade with external friendly societies. There seems to be ample evidence that trade continued during the warring period.

Rainfall. Rainfall in mesoAmerica was not predictable. Rainfall was characterized as "seasonal tropical fares" and "seasonal desert". The Southern penisulas were agriculturally more dense and thicker soils. The North faced frequent crop failures. In the South penisula, the land surface lied higher from the water table. In the North, for example, in Chichen Itza, water could be hit after digging 75 ft. Reserviors in Tikal held enough water for 10,000 people for 18 monthes. The Mayans in Coba

had built dikes around the lake to raise the water level.

Corn the root of all evil. Mayan agriculture was beans and corn. Corn constituted 70% of the Mayan diet. Mayan farming followed a slash and burn practice of destroying forest clearing by burning the trees and growing crops particularly corn until the soil was depleted. Evidence suggests that Mayan population densities exceeded levels that agriculture food production could support. Some innovation was practiced. For example, the Terracing of the hill slopes provided a structural design that increased soil retention and moisture. Arrays of canals and raised fields provided food. In the canals the Mayans grew fish and turtle for consumption.

Mayan agriculture suffered. Corn yields low protein. The Mayans depended on a narrow range of crop. The humid climate made it difficult to store the corn. Mayan cities remained small between populations of 25,000 to 50,000 people. These cities engaged in length military campaigns over great distances. Mayan temples were construction by stone and wooden tools being erected using human muscle power. Monuments diverted efforts away from food production.

Deforestation. Pines were burned for fuel. Plaster and plaster production along with the lavish use of plaster may have caused the deforestation. Deforestation created a man made drought in the valley bottom because forest plays a major role in the water cycling. People in the valley began too compete for food. Fighting began with the farmers, who were fighting over the best land. In 950 AD, the Mayan population stood at 15,000, a 54% drop in population. Population continued to dwindle until Chichen Itza collasped in 1250 AD and Mayapan collasped in 1450 AD.

Drought and Mayan peak population was a range between 3,000,000 and 14,000,000 people. Massive soil erosion increased during deforestation. Istope 18 become concentrated during drought, as water with lighter istope 16 is evaporated away. Mulluses and shellfish take up oxygen to lay down in their shells. Radiocarbon dating the sedimentary layer and infer from the gypsum and oxygen isotopes measurements reveal the prevailing conditions: Drought in 600 AD, complete collapse in 800 AD, and the worst drought in 7,000 years.

China, the lurching giant has 1.3 billion people, a 1/5 of the world’s population. It is the highest producer of steel, cement, aquacultured food, and television sets; and the highest consumer of coal, fertilizer, and tobacco. China is the largest contributor of sulfur oxides, chlorofluorocarbons, to the atmosphere.

Chinese environmental impacts: 1. Household sizes are decreasing, fewer children per couple, increase in divorce, populating aging and dieing at the same time the number of people living tripled in the same floor area. This trend is creating rapid urbanization. 2. Increase affluence has meant increase demand for beef, lamb, and chicken products. Four fold increase in consumption of milk, eggs, and meat between 1978 and 2001 and increase of waste resulting from 10-20 pounds of plants for one pound of meat. 3. China’s transportation network has grown explosively: 1952-1997, a 108 fold increase in the length of railroads, motor roads, and airline routes; 1980-2001 a 130 fold increase in the number of automobiles and projected increase by a factor of 4 by 2010. China’s economy lurks behind using pollution generating technology. However, I have heard China is very interested in fuel cell technology. Chinese rivers and groundwater sources are declining, due to the industrial and municipal waste water discharges, and agricultural and aquacultural runoffs of fertilizer, pesticides, and manure. 75% of Chinese lakes and almost all the coastal seas are polluted. Blooms of plankton whose toxins are poisonous to fish and other ocean animals have increase 100 percent a year. The Guanting Reservoir in Beijing has become unsuitable for drinking. Only 20% of the domestic water is treated. Many of the cities are experiencing severe shortages of water. 4. China energy efficiency in industrial products is ½ that of the First World: Paper production requires twice as much water; irrigation relies on surface methods responsible for water wastage; ¾ of China’s energy production depends on coal; China’s coal-based production of ammonia, required for fertilizer requires 42 times more water than natural-gas-based ammonia production in the First World. 5. Soil erosion is now effecting 19% of China’s land area. Erosion is especially devastating on the Loess Plateau and increasely on the Yantze River, whose sedimentary discharge is starting to fill the river bottoms inhibiting ship navigation. 6. China problems begin with deforestation trends. China is one of the most forest-poor countries in the world, with only 0.3 acres of forest per person compared to the 1.6 acres world average. Forest cover 16% of Chinese land and the deforestation is a major contributor to soil erosion and floods. The 1998 floods affected 240 million people. China has experienced increasing frequency of droughts, which now affect 30% of its croplands each year. 7. Under way in China are some of the largest development projects: The Three Gorge dam of the Yantze River – the world largest dam, at a cost of $30 billions. (2009 completion date); the South to North Diversion Project (2050) expected to cause water imbalance to the Yantze. 8. Drought is increasing. For 300 AD to 1950, dust storms use to afflict north-western China once every 31 years; from 1950 to 1990, once every 20 months; and since 1990, almost every year. Deforestation has interrupted the rain-producing natural hydrological cycle. Overuse of lakes and wet lands has decreased the water surfaces for evaporation.