Global Systems Vitousek, Et Al. Issues Vitousek

Global Systems

Vitousek, et al. Issues

Vitousek says the major sources of land transformation are pastureland, agriculture, and urban industrial activity. Agriculture (fisheries, artificial environments, row-crops) are high on the list of land transformation, urban industrial activity medium, and pure pastureland low, depending on human involvement.

Humans alter the oceans in many ways, although some are not easy to quantify. Population centers are concentrated near coastal areas and coastal wetlands are also altered. Fishing alters the ecology of the oceans by focusing on the top predators and throwing the system out of balance. Pollutants and other man-made activities cause algal blooms that are toxic to the ecology of the oceans as well. It is the relationship between the different parts of the food chain that are most effected by human involvement.

Part 3 -- The earth can be viewed as a system concept, with the forests the lungs, the waters the veins, etc. This is balanced in nature, but human intervention causes C02 and other gases to be released into the atmosphere through fossil fuels, industry and other mechanized activities. The water cycle is also affected by humanity, about 70% of the usable run off water being used by agriculture. Human activity has also altered the global Nitrogen cycle by deliberately fixing it to fertilizer and fossil fuel combustion. The consequences are many; climate, flora, fauna, and eco systems all become out of balance; species become extinct, weather patterns change, thus changing human culture.

Part 4 -- Humans have a robust and profound effect upon the biotic systems of earth. Rates of extinction are 100-1000X more than prior to human dominance; species loss then disrupts the ecology of the planet. Humans have also caused a rearrangement of the biotic system by transporting species into parts of the world they are not native (often meaning no predators) and thus destructive to the environment. Humans change the composition of the atmosphere; buildings and freeways increase solar radiation, pollutants, etc. mar the earth's ability to recover quickly (Vitousek, P., et al.).

Foley, et al., 2005

Part 1 -- The irony of human land use is that as the human population increases, more and more demands are made on land use for food, water, and shelter. At the same time, this use of the land (immediate need) has the capacity to degrade and change the long-term ability of the biosphere to continue to provide those needs. Thus, we have a trade-off; resources now, or learn how to protect the planet for continued resource use later.

Part 2 -- Since World War II, specifically since the 1960s, mechanization and technology have changed agricultural production methods. Croplands have become about 40% of the land's surface, and changing practices have allowed production to double and even triple in some areas and with some crops. However, there has been a 700% increase in fertilizer use, and a 70% increase in irrigation, not to mention pesticides and herbicides. The consequences of these changes have been to increase food production, while at the same time eroding soil, ruining certain lands through overgrazing, reduction of soil fertility, and in many case, species and climate change.