The Earth is considered by some people to be a living organism called Gaia. The processes that take place tend to give the appearance of a living entity. Water is constantly recycled in the hydrologic cycle: evaporating into the atmosphere, moving to another location by the wind, and then returning to the earth as rain. Organic matter from plants and animals, whether waste or the dead organism itself, is used as food for increasingly smaller plants and animals. Plate tectonics show that the edge of one colliding continental plate will be forced under the other by subduction while the other will be forced up, causing mountains to be formed. These, along with a plethora of other processes, are self-sustaining in nature.
One element that was important to the evolution of life on Earth is heat from the Sun. The thermonuclear chain reaction taking place in the Sun, (i.e. hydrogen atoms fusing to create the heavier element helium), creates extremely large amounts of ultraviolet radiation (UV). This radiation travels through space until it meets a solid object. The UV radiation that strikes the Earth passes through the atmosphere to the surface, where it is changed into heat. Some of this heat is radiated back into space, but the majority is trapped on the planet by gases in the atmosphere. This trapped heat keeps the average temperature of the planet at a temperature 60°F. Were it not for this heat-trapping mechanism, the average temperature on the planet would be approximately -3°F (Bender and Leone 1997).
Occasionally a catastrophic event will take place that interferes with these natural processes. A five mile diameter meteorite striking the Yucatan peninsula in Mexico 65 million years ago is thought to have caused the extinction of most of the dinosaurs. The collision forced ejecta (earth forced from the crater) as far as present-day Colorado. Some of this ejecta, about 1200 times the amount expelled by Mount Saint Helens, was spewed into the atmosphere in the form of dust. This dust caused the UV radiation from the Sun to turn into heat in the upper atmosphere instead of at the surface. Therefore, less heat was trapped and the average temperature of the planet dropped below what the dinosaurs could live in.
Not all catastrophes are extra-terrestrial. Volcanic eruptions such as Mt. St. Helens in 1980 and Mt. Pinatubo in 1991 can force several cubic miles of dust into the atmosphere. Major forest fires contribute tons of soot and dust. These events cause climate changes that may last for years or even decades. One event that is changing the climate even now is the evolution of man. Scientific evidence suggests it may take centuries for nature to recover from the changes caused by our civilization.
The Carbon Cycle
The most important gas that traps heat in the atmosphere is carbon dioxide (CO2). CO2 is a waste product from animals. Animals breathe in air, and some of the oxygen is removed by the lungs. The air is then exhaled, along with the CO2 created by the body. The CO2 remains in the atmosphere until it is absorbed by either the water in the oceans or plants, or is removed by rainout. Plants, whether on land or in the oceans, separate and retain the carbon, and respire the oxygen.
While the CO2 is in the atmosphere it acts like the glass in a greenhouse. The glass of a greenhouse will allow UV radiation to pass through, then traps the heat inside the structure. This is why CO2 and the other heat-trapping gases, such as methane, water vapor, and nitrous oxide, are commonly referred to as "greenhouse gases" (GHG). These gases make a 63°F difference in the average temperature. Most of the temperature difference is due to concentrations of water vapor in the atmosphere, with only about 2°F being contributed by the other GHGs (Details Booklet Part 1).
Not all GHGs occur naturally (EPA Site 2000). Some manmade chemicals are discharged into the atmosphere as a byproduct of manufacturing processes or leaks. Those with the greatest potential for global warming are chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), perflurocarbons (PFCs), and bromine. These gases not only trap heat, but also destroy a natural UV filter called ozone.
The amount of heat trapped in the atmosphere is directly related to the amount of GHGs present. Our two neighbors in the solar system illustrate what can happen if the amount of heat is not within the range that will allow the evolution of life. Mars has very little GHG in its atmosphere. This keeps the average temperature of Mars at -73°F (Compton’s 1998). On the other hand, Venus has an atmosphere that is composed mostly of CO2. This concentration traps enough heat to maintain an average temperature of 890°F. This is why scientists believe life did not evolve on either of our neighboring planets. Venus is far too hot to sustain life, and Mars is too cold.
The carbon cycle is very important to the continuation of life on Earth. If left alone the planet will maintain the correct amount of GHGs in the atmosphere, keeping the temperature at the proper level. Any change to the chemical makeup of the atmosphere could cause catastrophic events for mankind. The problem is that science does not show how wide the allowable temperature range is.
A History of Energy
The Industrial Revolution began in the middle of the 17th century. Machines were invented that could replace tedious human labor. Manufacturing processes were constantly reassessed and revised. What was necessary to enable these advances to take place was power. Energy sources, like industry itself, had to evolve over the centuries; and with each new source of energy came problems.
Brute strength was the first energy source utilized by man. Human muscles would swing a hammer to form a sword or lift a stone to build a temple. The domestication of animals eased some of the burden by using animals to power simple machines. This freed men to think about, and refine, the processes used to manufacture goods.
The advent of the Industrial Revolution brought about problems with using animals as an energy source. Animals had to be housed within the cities around which manufacturing was centered, but few cities had large amounts of land than could be used for grazing. This is why there was a reversion to human power, which crated labor for a larger population, which created sanitation problems, and so on. What was needed was a cleaner source of energy.
People then looked to nature for an answer to their energy needs. The energy needed to power manufacturing facilities came largely from rivers. Waterwheels were built that used the dynamic force of the running water to turn shafts running throughout the plants. Individual pieces of machinery were connected to the shafts using large flat belts.
While water power would appear to be a perfect energy source, it too presented problems. Factories could only be built along rivers or large streams. This meant that large expanses of land could not be used for manufacturing. Another problem occurred during periods of drought. As surface water becomes more scarce the water in a river exerts less force. If the drought is severe enough the river could dry up completely. In order to expand manufacturing facilities, a more universal energy source was required. People found this source in electricity.
20th Century Energy
Electricity was harnessed during the 19th century. Electricity generating plants could be built almost anywhere and the electricity transported in small wires to where it was needed. The energy required to turn the generators came from several sources. Coal, oil, natural gas, or wood could be burned to create the heat to boil water to turn steam turbines. Some generating stations used water by damming a river and allowing the water to fall through turbines attached to the generators.
The electrification of the world then began. Homes were wired for electricity. Cities replaced gas lighting with electric street lights. Factories were built in the middle of farmland. The electrification is so complete that few areas in developed countries are without electricity.
One dilemma that developed was how to transport goods from where they were manufactured to where they were needed. Horses are limited in how much they can pull and how far they can travel in a day. The solution to this problem was the internal combustion engine. Cars and trucks were developed to transport people and goods. These vehicles were equipped with an engine that burned vegetable oil much like a modern diesel engine. The discovery of oil-refining processes to produce gasoline and diesel fuel gave people an energy source that was cheaper than vegetable oil.
Unforeseen until the 1980s was a problem lurking in this energy utopia. The burning of these fossil fuels (i.e. coal, crude oil, and natural gas) emit CO2, water vapor, and sulfur. These emissions have greatly increased GHGs in the atmosphere above pre-Industrial Revolution levels. In the last two centuries the level of CO2 has increased by 30% (What is climate change? 1999), and this is expected to increase by another 30-150% if no controls are implemented (EPA Website 2000).
Another GHG that is increasing at an alarming rate is methane. Methane is a natural gas that is emitted by animals through flatulence, as well as from rotting organic matter. Some of the major contributors of methane are landfills, cattle, and rice paddies (What is climate change? 1999). The number of each of these sources is growing due to the increased population on the planet. Methane levels have doubled since the mid 17th century (EPA Website 2000) and can be expected to continue to increase.
Second part of The Industrial Revolution: An Environmental Catastrophe?
Written May 30, 2000
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