Who makes greenhouse gases?

Anonymous asked this question on 5/13/2000:

1.what are the characteristics of each gas that make up the atmosphere?
2. where do green house gases come from?
3.What produce them? long do they stay at the atmosphere once they are released? much each gas is produced each year?
6.which countries produce the most green house gases?
7.How are these green house gases released into the atmosphere?

JesseGordon gave this response on 5/14/2000:

Wow, that's a lot of questions. I'll answer each one briefly and give web addresses or keywords where you can look up more.

1. The main gases in the atmosphere (and their approximate percentages) are Nitrogen (79%), Oxygen (20%), Argon (under 1%) and carbon dioxide (CO2, under 1%). Everything is pretty much "trace quantities," but they're important traces. Look up "atmospheric chemistry" for more on this -- it varies significantly at higher altitudes.

2. "Greenhouse gases" (GHGs) means any gas that contributes to warming the atmosphere by retaining heat from sunlight. CO2 is the most important only because there's the most of it. Methane, ozone, and numerous other gases are actually "stronger" greenhouse gases, because they retain more heat, but have less overall effect because there's less of them. For details see (chapter 2 of a paper I wrote on GHGs)

3. Those gases are all produced naturally as well as by industrial sources. CO2 comes from bio-degrading logs, as well as from burning oil. Methane is also known as "swamp gas" and comes from normal biological processes in swamps, as well as from commercial cow operations. Ozone is produced by lightning (it's that lightning smell), as well as from industrial processes. For discussions of global warming, we only care about the man-made processes, of course.

4. The length of time is not as important as the net effect on global warming. That's called the "greenhouse warming potential" (GWPs), and accounts for both the expected lifetime of the gas as well as its effectiveness in trapping heat. If you actually want to know "how long" they last, you'll have to look it up under atmospheric chemistry. In the same chapter 2 cited above, you can get numbers for GWPs in detail.

5 & 6. Usually that's measured by country, in terms of "equivalent tons of CO2". That means that all the GHGs are converted into their effect as if CO2 were the only gas involved. You can see the details in Table 2 of that paper at , and look at the bibliography references for that table if you want actual figures. In summary:
United States 4.2 billion tons of CO2
Former USSR 4.2 billion tons
China (PRC) 2.8 billion tons
Western Europe 1.6 billion tons
Japan 0.9 billion tons
India 0.8 billion tons
All others 7.3 billion tons

7. The real question here is, "What processes can we change that affect release of greenhouse gases". Your question asks how the GHGs are released, but most are released from natural processes that we have no control over (like from the oceans, forests, and swamps). The ones that matter are the human sources that we DO have control over. The single most important human source is burning fossil fuels, for heating, transportation, and industrial processes. Any burning of gas, oil, or other fuels releases CO2 -- the political discussion is on how to reduce the greenhouse effect of what we have to do economically.

Hope that gets you started.

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