Making the Link Section 6

Kevin and I found that he emits more carbon dioxide in one year by driving than he does by breathing. His car emitted 6.07 X 10^6 g of carbon dioxide in one year, whereas his breath only emits 2.08 X 10^6 g of carbon dioxide in one year. Besides breathing, other activities I do that emit greenhouse gases into the atmosphere would be driving, wasting energy, using air conditioning in excess, and using heat in excess. All of these factors contribute to greenhouse gas emissions.

Making the Link

One reason that the greenhouse gases are rising could be because the sources are able to produce more than the sinks can absorb. Another reason may be that sources are increasing and sinks are decreasing. Deforestation is the loss of a sink for carbon dioxide. Combustion of fossil fuel is the increase of a source. Most of the sources of gases are anthropogenic. Some of these sources are combustion of fossil fuels, forest fires, decomposition of waste in landfills, soil management and coal-mining.

Making the Link

As concentrations of greenhouse gases rise rapidly, it becomes obvious that their emission by the various sources outpace their absorption by sinks.  The sources of carbon dioxide, for instance, greatly outnumber the currently viable sinks.  As humans add more carbon to the sources of the carbon cycle, and deplete the number of trees available to absorb carbon dioxide, the amount that remains in the atmosphere will increase.  And as the population of the world increases, and more countries industrialize, anthropogenic sources will produce increasing amounts of greenhouse gases.  Many of the big sources of greenhouse gases are anthropogenic; most of the excess carbon dioxide is anthropogenic, 60% of methane comes from anthropogenic sources, and a huge amount of the nitrous oxide produced comes from anthropogenic sources.

IR spectra from class today

The reference spectra can be found at this link.

The spectrum of breath is below:

Making the Link

The rise in greenhouse gas concentrations implies that the balance between sources and sinks is unequal. There are not enough sinks for greenhouse gases to balance out the sources, both natural and anthroprogenic. The sinks do not work quickly enough to outnumber the sources and therefore there is an increase in greenhouse gas concentrations. Carbon dioxide has many anthropogenic sources, such as forest fires, cement manufacture, and the combustion of fossil fuels, but so far there are only proposed anthropogenic sinks; there aren’t any anthropogenic sinks for carbon dioxide currently in place. The sources for carbon dioxide, methane, and nitrous oxide are mostly anthropogenic. The list of anthropogenic sources goes on and on from fossil fuel combustion, to forest fires to waste management to fertilizers and soil cultivation, but the list of natural sources is short and has a definite stopping point. Increased industry also means that the list of anthropogenic sources will continue to increase.

Question 5d (UPDATED)

Does CO have an entry for global warming potential in the IPCC reports?  The book said it doesn’t.

Question (?)

How do yo tell the difference in the levels of Carbon Dioxie, Methane, and Nitrous Oxide in the northern and southern hemispheres?

The determining factor for a gas to be a greenhouse gas is if it absorbs IR radiation. To find out which ones are infrared active, the first step is to use the VSEPR theory to see if the bonds are polar through its molecular shape. Then, see if the overall molecule is polar. After that, check each molecular vibration too see if there is a dipole moment and whether it has brought about a net change.

Making the Link

You can tell that a gas is a greenhouse gas because it absorbs IR radiation.  Polar bonds and different polarity cause molecules to absorb IR radiation.  Therefore, greenhouse gases have polar bonds and absorb IR radiation.

Making the Link

A gas is a greenhouse gas if it has an asymmetric stretch. The bond dipoles in molecules with asymmetric stretches absorb infrared radiation