Acid rain, like its name suggests, is rainfall that is highly acidic, much more so than normal precipitation. Acid rain is usually a result of human air pollution such as emissions of sulfur and nitrogen compounds. These compounds react with those in the atmosphere causing acids to be produced and in turn causing precipitation to be acidic in nature. A major public concern due to its ability to damage property, not to mention its negative impact on both aquatic and land animal and plant life, many steps have been taken to reduce acid rain's effect on the environment.
The main cause of acid rain is human consumption. The burning of fossil fuels from numerous sources such as factories, power plants, and automobiles create the gases that lead to acid rain. Power plants that operate with the burning of coal are recognized as being some of the worst sources of acid rain. Although acid rain is usually considered a modern phenomenon, it does occur naturally, though on a lower scale. Emissions from burning volcanoes and from natural biological processes, such as methane emissions from cattle are some of the more common natural causes.
Acid rain is known to cause significant damage to property due to its chemical compound. It eats away at marble and limestone which are often used in the construction of government buildings and monuments as well as gravestones in cemeteries. Metals (iron for instance) are also affected by the alkaline present in acid rain.
The negative impact of acid rain is evident in ecosystems. Acid rain changes the PH levels of rivers and lakes. Animals such as fish are very susceptible to changes in PH and therefore are unable to survive if the change is too drastic. Plankton and invertebrates are put even more at risk. Acid rain in water environments can also affect plant life. On land, acid rain damages forests in high altitudes and also lowers the fertility of soil as important nutrients and minerals are removed from it. These impacts on different aspects of the environment have a trickling down effect that negatively influence entire ecosystems.
Since the recognition of acid rain as an important public concern, many steps have been taken to decrease its occurrence. The National Acidic Precipitation Assessment Program was created in the United States to monitor the effects of acid rain on the environment. Western countries in Europe and North America have taken significant measures to reduce the harmful emissions that are the cause of acid rain. Changes such as stricter emissions regulations for motor vehicles and emissions trading which create economic incentives for factories to decrease their pollution.
Acid Rain does continue to be a global problem. Asia is currently the region in the world that is most affected by it. Lax or nonexistent emissions regulations, especially in China, contribute to this. To address this problem, global treaties such as the Sulphur Emissions Reduction Protocol and the Nitrogen Oxide Protocol have been enacted. Stricter emissions laws both nationally and internationally as well as the introduction of alternative energy sources will no doubt help to prevent acid rain in the future.