Fossil Fuel Combustion Impacts

Introduction

Coal, oil, and natural gas are the three main fossil fuels—carbon-based fuels stored in Earth’s crust. They release heat when they are burned and this is used directly in many applications, such as heating homes, and to generate electricity in power stations. Fossil fuels account for around 80% of all energy usage in the United States.

Although fossil fuels have many benefits, such as making homes more comfortable, transportation easier, and allowing many nations to build an advanced industrial economy, they also have many adverse impacts on the environment. For example, mining for coal is hazardous and disfigures the landscape, and oil spills from tankers can devastate marine ecology. Sulfur and nitrogen oxide emissions contribute to acid rain, which damages buildings and wildlife. But the major concern is the carbon dioxide emitted from burning fossil fuels. Carbon dioxide levels in the atmosphere are rising and raising the temperature of Earth, which threatens widespread climate change.

Historical Background and Scientific Foundations

Fossil fuels represent a carbon sink, being formed over millions of years beneath Earth’s crust from the carbon-containing remains of long-dead animals and plants. Coal, oil, and natural gas are the main fossil fuels in use today, but oil shales and tar sands are sources that may be used more in the future as supplies of the former start to run out.

People used wood as a source of fuel until the eighteenth century. It was the invention of the steam engine and the advent of steel manufacturing that led to the adoption of coal as a fuel. By the mid-nineteenth century, coal began to take over from wood and the Industrial Revolution was well underway. Around this time, people began to use oil as a fuel also. The first oil well in the United States began operating in Titusville, Pennsylvania, in 1859. The demand for oil increased sharply through the early part of the twentieth century because of the growth in popularity of the automobile. Trains used steam engines, powered by coal, but for the internal combustion engine of a car, gasoline was a more practical option.

The use of coal to generate electricity on a large scale was pioneered by Thomas Edison (1847–1931), the inventor of the lightbulb. He built the first power station in the United States on Pearl Street in Manhattan in 1882. The use of natural gas as a fuel did not come until the second half of the twentieth century. The growth of the population and economic development have led to dramatic increases of our use of fossil fuels since these early days. Fossil fuels make up about 87% of the world’s commercial energy consumption, with oil accounting for about 37% of the total, although the exact proportions will vary in different countries. Estimates of fossil fuel reserves vary, but oil and gas could run out in the twenty-first century, with coal reserves holding out for maybe around 200 years.

Of the three main fossil fuels, coal is the cheapest, gas the most expensive. Because of the costs and difficulties in transporting it, coal is used mainly as a stationary source, to generate electricity in power stations. Oil and gas can be transported in underground pipes. There are several grades of oil that are produced when it is distilled in a refinery. These are used as transportation fuels for airplanes and cars. Oil and gas are also used to provide central heating for homes and commercial premises.

Impacts and Issues

The combustion of fossil fuels emits various gases into the atmosphere and leaves ashes behind. Both may have an adverse impact on the environment. First, emissions of sulfur dioxide and nitrogen oxides, both of which are acidic, mix with moisture in the atmosphere to create so-called acid rain, which damages buildings and trees. Overall, coal is considered to be the most polluting fuel, gas the cleanest when it comes to acid emissions.

oacontans many toxc metas,ncung uranium, arsenic, lead, cadmium, and mercury. These are released as gases when coal is burned or remain in its ashes. Heavy metal pollution is a particular problem in China where hundreds of millions of people burn coal in unvented stoves. High levels of arsenic have accordingly been found in food residues and drinking water. Since the early 1980s, around 3,000 people in the Guizhou province have been identified as suffering from severe arsenic poisoning.

Sulfur is removed from gasoline so vehicle exhaust does not contribute much to sulfur dioxide emissions. It does, however, add nitrogen oxides to the atmosphere, creating not just acid rain, but also ground-level ozone through a chain of chemical reactions catalyzed by sunlight. Ozone damages buildings and plants, and attacks the eyes and lungs, and therefore is a health hazard.

The most serious impact of fossil fuel combustion, however, is the emission of carbon dioxide into the atmosphere. Carbon dioxide is present naturally in the

WORDS TO KNOW

CARBON SINK: A location like a forest where there is net storage of carbon as sequestration exceeds release.

GLOBAL WARMING: Warming of Earth’s atmosphere that results from an increase in the concentration of gases that store heat, such as carbon dioxide (CO₂).

GREENHOUSE EFFECT: The warming of Earth’s atmosphere due to water vapor, carbon dioxide (CO₂, and other gases in the atmosphere that trap heat radiated from Earth’s surface.

RADIATIVE FORCING: A change in the balance between incoming solar radiation and outgoing infrared radiation, resulting in warming or cooling of Earth’s surface.

atmosphere and acts as a greenhouse gas. That is, it tends to increase radiative forcing, which is the balance between the amount of radiation entering the atmosphere and the amount leaving it. Greenhouse gases are invisible, but can absorb infrared radiation, thereby causing an increase in temperature. Satellite studies have confirmed a decrease in the amount of radiation leaving the atmosphere in recent years. Other greenhouse gases present in the atmosphere include water vapor, methane, and nitrogen oxides.

IN CONTEXT: IMPACTS OF FOSSIL FUEL USE

The primary source of the increased atmospheric concentration of carbon dioxide since the pre-industrial period results from fossil fuel use, with land-use change providing another significant but smaller contribution.

SOURCE: Solomon, S., et al. Technical Summary. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. New York: Cambridge University Press. 2007.

Carbon dioxide is a trace gas in the atmosphere, but levels have increased by 35% in the last 200 years. Between 1958 and 2005 alone, levels went up from 316 ppm (parts per million) to 375 ppm. These increases have been linked to global warming, which is the overall increase of 1.25°F (0.7°C) in the planet’s temperature occurring over the last century.

Global warming is associated with a degree of climate change. The year 2004 was the warmest since 1860, when reliable climate records began. Nine of the warmest years recorded have occurred since 1990, and this appears to represent a genuine trend rather than just natural climate variability. Meanwhile, research by the National Aeronautics and Space Administration (NASA) reveals melting glaciers and rising sea levels. Satellite measurements also show a lengthening of plants’ growing seasons and increased production of biomass in many areas.

In the future, populations could be threatened by rising sea levels and there could be profound ecological changes. The international community is trying to take action on global warming, working through the Kyoto Protocol to limit carbon emissions, even as energy use increases globally. Other options include alternative energy sources, like wind power, and cleaner technologies aimed at burying carbon emissions rather than releasing them to the atmosphere.

See Also Carbon Dioxide (CO2) Emissions; Clean Energy; Glacial Retreat; Radiative Forcing; Temperature Records; Weather and Climate

BIBLIOGRAPHY

Books

Cunningham, W.P., and A. Cunningham. Environmental Science: A Global Concern. New York: McGraw-Hill International Edition, 2008.

Kaufmann, R., and C. Cleveland. Environmental Science. New York: McGraw-Hill International Edition, 2008.

Web Sites

BBC Weather Centre. “The Kyoto Protocol.”http://www.bbc.co.uk/climate/policies/kyoto.shtml (accessed March 1, 2008).

National Aeronautics and Space Administration (NASA). “Recent Warming of Arctic May Affect Worldwide Climate.” October 23, 2003. http://www.nasa.gov/centers/goddard/news/topstory/2003/1023esuice.html (accessed March 1, 2008).

Susan Aldridge