Weather and Waste

Impact of Pollutants on Weather

Levels of carbon dioxide in the atmosphere have been steadily increasing since the beginning of the Industrial Revolution in the 18th century. Actual measurements of carbon dioxide concentrations in the atmosphere started in 1958, and the amount of gas found has increased every year since. Using these measurements and ice-core data, it has been determined that the concentration of carbon dioxide in the atmosphere was 316 parts per million by volume (ppmv) in 1958. That number rose to 369 ppmv in 1998 and is over 370 ppmv in 2010. Pre-industrial concentrations, in contrast, were approximately 278 ppmv, and ice age levels were about 200 ppmv. Average global temperatures have risen about 9 degrees Fahrenheit since the last ice age. While there are a variety of factors that impacted the end of the ice age and the warming of the atmosphere, carbon dioxide levels played an important part. The data also illustrate that the level of pollution humans created in 200 years is about equal to the natural cycles that occurred over thousands of years.

The large amounts of carbon dioxide released into the atmosphere are generated by a number of human activities. A primary source is the burning of fossil fuels, coal, oil, and natural gas in homes, factories, vehicles, ships, and aircraft. Deforestation is also a contributor, because it removes the vegetation that would convert the carbon dioxide into oxygen. Carbon dioxide absorbs heat radiating from the surface of the Earth, acting like a blanket. The increased air temperature holds more water vapor, creating more blanketing cloud cover, increasing the temperature even more. Gases that have this warming effect when released into the atmosphere are called “greenhouse gases.”

Carbon dioxide is not the only gas contributing to global warming. While it is the greatest contributor, there are a number of greenhouse gases that have similar effects. Another is the colorless, odorless, combustible gas methane. Methane is released from a variety of natural and anthropogenic sources. Natural methane emissions are largely the result of the decomposition of organic materials in oxygen-free environments. As global warming thaws permafrost, increasing amounts of methane will be released. Wetlands, swamps, and peat bogs also provide methane-releasing conditions. Human-made sources include mining operations, emissions from the energy sector, rice production, livestock digestion processes, and municipal solid waste landfills.

...