Petroleum, or crude oil, is a naturally occurring oily liquid found in large quantities below the surface of the earth. It is used as fuel and as raw material in the chemical and plastic industries.
Modern industrial societies use it primarily to achieve a degree of mobility that was unimaginable a hundred years ago. In fact, modern civilization depends on petroleum and its products: the way of life in the suburban communities surrounding great cities are the result of an ample and inexpensive supply of petroleum. Additionally, developing countries exploit petroleum deposits to supply food for their growing populations. All of this is based on the assumption of petroleum availability.
In recent years, worldwide availability of petroleum has steadily declined and its relative cost has increased. Pollution caused by the burning of fossil fuels has created additional complications, causing industrialized nations to consider alternative, non-polluting, renewable fuels. Petroleum will probably cease to be a common commercial material by the mid 21st century.
World production of petroleum was 85 million barrels per day in 2009. The United States, Russia, and Saudi Arabia are the world's largest producers, accounting for about one third of the world's petroleum production. The US is by far the biggest consumer, using 20.6 million barrels per day, more than one fourth of the world's total and double the amount it produces. This forces America to import 13 million barrels of petroleum each day. No other country consumes even half as much.
Petroleum is formed under the earth's surface by decomposed marine life, enmeshed with fine sands that settle to the bottom of sea basins. Such deposits, which are rich in organic material, grow thicker under pressure and from the heat of the Earth's core. The mud and sand harden into shale, and the remains of the dead organisms are transformed into crude oil and natural gas. This process takes millions of years.
Crude oil has been used by humans for thousands of years. In areas where oil bubbled up to the surface, it was used for caulking boats, waterproofing cloth, and fueling torches. During the Renaissance, oil was distilled for lubricants and medicinal products, but the wholesale exploitation of petroleum began in the 19th century. The Industrial Revolution brought a search for new fuels. Various scientists developed processes to make commercial use of petroleum. The Canadian physician Abraham Gessner patented an affordable, oil-based lamp fuel called kerosene in 1852. In 1855, an American chemist named Benjamin Silliman published a paper on the wide range of useful products that could be derived from the distillation of petroleum.
In this way, the quest for greater supplies of crude oil began. The concept of drilling for oil soon followed. With the invention of the automobile and the energy needs brought on by World War I, the petroleum industry became one of the hallmarks of industrial society.
Ocean pollution disturbs marine ecosystems, and is primarily noticed when an oil well at sea is damaged or when an oil carrying ship leaks into the sea as the result of an accident. The 1989 Exxon Valdez and the 2010 Deepwater Horizon disasters are two examples. Despite this perception, most ocean oil pollution is caused by municipal and industrial runoff, cleaning of ships' tanks, and other routine events. Tar, plastic, and sewage wash up on beaches, making swimming hazardous. Plastic, which does not break down in the ocean, is a hazard to sea life. International treaties prohibit disposal of such wastes that can cause these environmental threats, but these treaties are very difficult to enforce.
Scientists agree that burning fossil fuels is a major factor in causing global climate change. The US has attempted to pass laws limiting carbon emissions, such as the "Cap and Trade" bill. So far, these efforts have stalled.
For an insightful look into the history of oil production, check out Oil, by Upton Sinclair.