+ Finding Some Facts about Greenhouse Gases

As a railroad buff who's also interested in the environment, I'm curious to learn a little more about the interrelationship of energy, transportation, and global warming. How good or bad is it that I flew to New York for business, or took the train to Montana? Just why is it affordable for a supermarket in Ohio to sell oranges from South Africa and Australia? I thought a good place to start was the basics of greenhouse gases and global warming; it turns out the greenhouse effect is not all bad, and is a misnomer as well.

I'm finding some interesting links as I've started looking into this.

A good start is at http://en.wikipedia.org/wiki/Greenhouse_gas

"Greenhouse gases are components of the atmosphere that contribute to the greenhouse effect. Without the greenhouse effect the Earth would be uninhabitable;[1] in its absence, the mean temperature of the earth would be about -19 °C (-2 °F, 254 K) rather than the present mean temperature of about 15 °C (59 °F, 288 K)[2]. Greenhouse gases include in the order of relative abundance water vapor, carbon dioxide, methane, nitrous oxide, and ozone. The majority of greenhouse gases come mostly from natural sources but are also contributed to by human activity."

“........[warmed by the sun-warmed earth], Greenhouse gases also emit longwave radiation both upward to space and downward to the surface. The downward part of this longwave radiation emitted by the atmosphere is the "greenhouse effect." The term is a misnomer, as this process is not the mechanism that warms greenhouses."

For more on this and a lot of very good information on many energy topics (Your tax dollars at work!) check out the Energy Information Administration (EIA) site at
http://www.eia.doe.gov/oiaf/1605/ggccebro/chapter1.html .


Some samples of the info there:
An EIA graphic, figure 2 to the right, illustrates the global carbon cycle showing the flow of greenhouse gases in Billions of Metric Tons Carbon.





The greenhouse gases generated from human activity are known as "anthropogenic". EIA Figure 3, U.S. Anthropogenic Greenhouse Gas Emissions by Gas, 2001
(Million Metric Tons of [pure]Carbon Equivalent)








EIA has also summarized what produces all this CO2: Figure 4. U.S. Primary Energy Consumption and Carbon Dioxide Emissions, 2001
Looking at the charts, in the US Transportation produces about 1/3 of the total emissions.





If you're interested in more detail on how US CO2 emissions have changed over the years, check out:ftp://ftp.eia.doe.gov/pub/oiaf/1605/cdrom/pdf/ggrpt/057305.pdf or

ftp://ftp.eia.doe.gov/pub/oiaf/1605/cdrom/pdf/ggrpt/057306.pdf


Its interesting to see from this EIA report how our per-capita CO2 emissions have remained fairly constant, but industry and transportation have become significantly more efficient - a trend in the right direction!

There's a lot more understanding to be gleaned from these and other sources, but these excerpts provide a sampling of what's available.