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The Effects of Human Activities on Ecosystems & the Biosphere

The earth's biosphere is composed of many different types of biological environments called ecosystems. The biological communities of the various ecosystems interact with the environment to create a living space for specific life forms. The interdependent ecosystems integrate into larger units, or biomes. Biomes combine to form the biosphere, a life-supporting zone that stretches from the upper atmosphere to deep within the earth's crust. Effects on the biosphere from human activities have dramatically increased since the Industrial Revolution.

Biosphere
- The earth's biosphere is a closed system of dependent ecosystems in a delicate balance. It doesn't take much to upset the equilibrium of the symbiotic relationships between interlocking ecosystems. Mass extinctions have occurred with regularity across eons of geological time. Most were from natural causes. The Industrial Revolution spurred the beginning of significant anthropogenic effects on the planet's biosphere. In the early 21st century, human activity seems to be causing an accelerated extinction of species, including corals, rhinoceros, orangutans and the double-humped Bactrian camel.
Overpopulation
- Reproduction is a major human activity affecting individual ecosystems and the overall biosphere. The sheer number of human beings may be exceeding its sustainable population level. The rapid expansion of the human race is a key factor in upsetting the equilibrium within and between ecosystems. Human demand for resources leaves less for other organisms and results in lowered biodiversity. Mining, clear-cut logging and water over-consumption can destroy natural habitats and cause extinctions.
Land and Water Pollution
- Changing the chemical composition of the biosphere influences the type and numbers of organisms that live there. Human agricultural activity increases the amount of nitrogen, phosphorus and other nutrients in the soil. Fertilizer runoff from farm fields raises the nutrient level of rivers, lakes and the oceans, causing algae blooms and damage to fish and other wildlife. Industrial dumping of toxic byproducts upsets the chemical balance of soil and water-based ecosystems.
Air Pollution
- Starting in the late 19th century the smokestack industries of the world contributed to ecological imbalances affecting the entire biosphere. Levels of carbon dioxide from the burning of fossil fuels may be a factor in increased global temperatures. Most electricity is generated by coal-burning power plants that release sulfur compounds into the atmosphere, causing acid rain. Methane is another anthropogenic greenhouse gas. Chlorofluorocarbons released into the atmosphere by humans may have damaged the protective ozone layer of the stratosphere.

Nature