Southwest Renewable Energy Fair
duBois Center, NAU
August 9, 2002
Man was the first creature to use fossil fuel…or was he?
E. Allan Blair, Ph.D.
Fossil energy or fossil fuel is solar energy stored as chemical energy in the form of coal, petroleum, and natural gas. It is plant material that has accumulated in sediments and thereby removed from the biosphere. If the plant material had stayed at the surface of the earth (in the biosphere), it would have been decomposed to carbon dioxide and water by bacterial action.
Ecology books present the concept that life consumes energy and that all energy for life comes from the sun. Plants collect solar energy by photosynthesis and everything else gets its energy by eating the plants or other creatures that eat plants, or directly from the sun. An exception to this rule has been recently discovered in a group of creatures living on geothermal and geochemical energy on the ocean floor. Since it was so unusual, it attracted a great deal of attention.
Since about 1600, man has not obeyed the rule that energy for life comes from the sun. Before Elizabethan times, man had no other energy source except the sun. It furnished not only our food, but our warmth and shelter–our warmth from burning wood or animal fat, and our shelter (including clothing) from wood, other vegetable materials, or animal skins. The world could only support the number of humans that the sun’s energy could support.
Then, in the Elizabethan age, man learned to use coal, a fossil fuel. The use of fossil fuel meant that man’s population could increase beyond the number that solar energy could support. If the use of fossil fuels stopped, a large portion of the people on Earth would freeze or starve. There are still places where the only source of energy for human life is the sun. We call them underdeveloped nations.
Man was the first creature that learned to use fossil fuels—-Or was he?
The latest knowledge of geochemistry says that when the Earth was formed about 4.6 billion years ago, it had an atmosphere consisting mostly of nitrogen, methane, and carbon dioxide. The heat from the sun evaporated water and caused rain as it does now. Some of that rain came as thunderstorms, and as shown by the work of Urey and Miller in 1953, the lightning caused the gases of the atmosphere to react to form organic compounds. These compounds, which included all of the chemical building blocks of life, were washed into the oceans where they collected like salt does today. Also, since there was no oxygen in the atmosphere, there was no ozonosphere to absorb the ultraviolet radiation from the sun, so the surface of the earth was exposed to a tremendous amount of UV radiation. Talk about sunburn! Ultraviolet radiation is used today to promote chemical reactions, and in those ancient days, it must have caused further reactions of the compounds formed by lightning. In addition, the volcanic hydrothermal vents on the ocean floor caused more, and probably different reactions.
Those organic compounds in the ocean were formed, either directly or indirectly, by solar energy. Solar energy caused the thunderstorms and lightning and solar energy in the form of UV radiation caused the lightning formed compounds to combine into more complex chemical compounds. This “primordial soup” was solar energy stored as chemical energy, just like the other fossil fuels. Some reactions may have taken place in the ocean floor geothermal vents, where the pressures and therefore temperatures are much higher than can be achieved on the surface of the earth.
Over the approximately 600 million years before the beginning of life (that is as long as the time that the earth has been occupied by multicelled organisms), these organic compounds accumulated in the ocean, and must have reached a fairly high concentration. During that time, the environment of the earth was constantly changing. Organic compounds (compounds containing carbon) were accumulating in the oceans, and the composition of the atmosphere was changing as the original gases were used up.
Then about 4 billion years ago, some of these organic compounds joined together to form chemical compounds with some of the characteristics of life. They could use the energy of some of the other compounds in the primordial soup of the ocean to reproduce themselves, breaking down part of the material to carbon dioxide, water, and nitrogen compounds. These “living” compounds eventually organized themselves into something like protozoa and eventually, they used up all the organic compounds in the oceans, converting them into “bio-mass”, nitrogen compounds, and carbon dioxide.
During that time, the environment of earth was still changing constantly, as the chemicals in the primordial soup were used up by the “proto life” and converted to “living” compounds while the carbon dioxide and nitrogen in the atmosphere were replenished. This was the first example of the consumption of fossil solar energy. The compounds in the primordial soup that had accumulated for 600 million years were consumed by the new proto life, and the environment was changed by their action.
The oceans must have looked like fermenting beer, full of micro-organisms living on dissolved organic material. The land was totally barren, because there was no food there (it had all been washed into the ocean,) and UV sterilized everything. The atmosphere again consisted of methane, carbon dioxide and nitrogen, and did not contain any oxygen at all. There was probably no life in fresh water either, because there was little food there.
When the living (or semi living) creatures had used up all the chemical compounds in the primordial soup that had been created by solar energy, about 2.8 billion years ago, they had to find something else to live on. Talk about an energy crisis! It involved all life on earth, not just the small fraction of Homo Sapiens that live in “developed nations.” By that time, the living chemicals had probably organized themselves into cells and may have developed cell walls, like bacteria and algae have. They had converted all available organic compounds into biomass and the gases carbon dioxide and nitrogen. Probably, some of these “creatures” had mastered the art of eating the proto-living compounds in the sea, and became the first “primary consumers.”
In order to survive, life had to find a new energy source!
It did, in the form of photosynthesis. In photosynthesis, plants absorb sunlight, and use its energy to convert carbon dioxide and water to carbohydrates (starch and cellulose) and oxygen. Imagine the environmental impact statement for that new chemical process! It changed the composition of the entire atmosphere from oxygen free to oxygen rich, removed most of the carbon dioxide from the atmosphere, and made it possible for life to invade the land. It changed the entire atmosphere and surface of the Earth. Even the US Army Corps of Engineers never did anything so outrageous!
When a high enough concentration of oxygen had been developed in the atmosphere, the ozonosphere was formed, protecting the surface of the earth from UV radiation, and life could eventually move onto the land without dying of sunburn. There was no food there, but photosynthesis made that unnecessary. All plants needed was sunlight, carbon dioxide, some minerals, and water. With oxygen available, the Earth could develop modern style ecology, where plant-type life would use solar energy to convert carbon dioxide, nitrogen compounds, and water into oxygen and living matter, and animal-type life (primary consumers) would convert oxygen and living matter into carbon dioxide, water, and nitrogen compounds.
Eventually, most of the carbon dioxide was used up, and the environment reached the first steady state in history. Even that was not an entirely steady state, because plants produced more organic matter than animals could consume. This was removed from the biosphere (the part of the Earth where life exists), by being buried under sediments, and ended up as coal, natural gas, or petroleum–fossil energy.
By now, the concentration of carbon dioxide in the atmosphere has leveled out at a fraction of one percent. Carbon dioxide, nitrogen compounds, potassium, and phosphorus are the limiting factors in the growth of plants. Since there is a shortage of these materials, plants can not use all of the available solar energy for photosynthesis. This has allowed incredible inefficiency in the use of solar energy by plants. Why be efficient if you have more of one resource than you can use?
Western man has learned to find and use fossil energy with greater efficiency than any other creature. All known supplies will be exhausted in a few hundred years, and the first use of it was only four hundred years ago. It took our single celled ancestors about 1.2 billion years to do the same thing. Homo Sapiens is really a wonderfully capable creature!
What will our new energy source be? We don’t have many choices. Many potential sources have been used in the past and abandoned in favor of fossil energy. Those include wind, tides, low head water power, direct sun, etc. New sources include ocean currents, ocean water temperature differentials, geothermal, and nuclear energy. All of these alternative sources are hampered by politics and/or by short-term economics.
The one thing of which we can be sure is that Mother Earth cannot support us in the manner to which we are accustomed if we don’t find a satisfactory alternative to fossil energy in the next few hundred years.
In modern times, man has shown remarkable ingenuity in finding solutions to problems like this. This one will probably be solved by something that we haven’t even thought about. Whatever it is, I doubt that the environmental impact of our new energy source will be any greater than the one that was developed 2.8 billion years ago by our single celled ancestors.
Historical Energy Crises
Date Crisis Solution
1600 Exhaustion of trees in British Isles Use Coal
1820s Exhaustion of trees in Eastern USA by iron industry Ship coal from frontier, build canals
1830s-1940 Stopping canal shipments by drought or freezing Build railroads
1974-1978 Gasoline Crisis Raise gasoline price