Fossil Fuels: Environmental Impacts of Carbon Emissions
Environmental Impacts of Fossil Fuel Use
Carbon Dioxide and the Greenhouse Effect
One of the most significant impacts of fossil fuel use on the Earth’s environment is the increased concentration of carbon dioxide (CO2) in the atmosphere. The amount of atmospheric CO2 had been stable for centuries, but since 1750, it has increased by 30%. This change is significant because it can cause a temperature increase on Earth through the greenhouse effect. Atmospheric carbon dioxide prevents longwave radiation from escaping into outer space, leading to more heat retention and a rise in global temperatures.
Significant global warming of the atmosphere would have serious environmental effects. It would accelerate the melting of polar ice caps, raise sea levels, cause regional and global climate change, disturb natural vegetation, and affect crops. These changes, in turn, would have an enormous impact on human civilization. In the twentieth century, the average global temperature increased by 0.6 degrees Celsius, and scientists predict that Earth’s average temperature will rise between 1.4 and 5.8 degrees Celsius between 1990 and 2100.
Acidification
Acidification is also associated with the use of fossil fuels, due to the emission of sulfur dioxide and nitrogen oxides from power plants and motor vehicle exhaust. These products interact with sunlight, humidity, and oxidants to produce sulfuric and nitric acid, which are transported by atmospheric circulation and fall to the ground, washed by rain and snow as acid rain, or as dry deposition of particulate matter and gases. Acid rain is a significant global problem. It erodes metal, corrodes buildings and stone monuments, and injures and kills vegetation.
Destruction of the Ozone Layer
In the 1970s and 1980s, scientists began to discover that human activity was having a negative impact on the ozone layer, a region of the atmosphere that protects the planet from harmful ultraviolet rays. Without this gaseous layer, located about 40 km above sea level, life would be impossible on our planet.
Studies showed that ozone was being affected by the increasing use of chlorofluorocarbons (CFCs, fluorine compounds), which are used in air conditioning, cooling, cleaning solvents, packaging materials, and aerosols. Chlorine, a chemical in CFCs, attacks ozone, which is composed of three oxygen atoms, by snatching one of them to form chlorine monoxide. This then reacts with oxygen atoms to form oxygen molecules, releasing chlorine molecules that decompose ozone molecules.
Investigations revealed, in 1985, the existence of a large hole centered over Antarctica, where 50% or more of the ozone disappeared seasonally. In 2001, the hole covered an area of 26 million square kilometers, a size similar to that detected in the last three years.
Chlorinated Hydrocarbons
The extensive use of synthetic pesticides derived from chlorinated hydrocarbons in pest control has had disastrous side effects on the environment. These organochlorine pesticides are very persistent and resistant to biological degradation. Slightly soluble in water, they stick to plant tissue and accumulate in the soil substrate from the bottom of streams and ponds, and in the atmosphere.
Once volatilized, pesticides are distributed throughout the world, contaminating large remote wilderness areas in agricultural regions, and even in the Arctic and Antarctic areas.