The article mentions natural gas is mostly methane (CH4).
Here is the combustion reaction for burning methane:
CH4 + 2 O2 → CO2 + 2 H2O
Note right side of equation.
The "climate scientists" cited in the referenced article have confusion on this issue, as they contrast the effects of methane releases to those of CO2.
It's interesting to contemplate what has to occur for someone to adopt the title "scientist" and leading authority in a subject while remaining confused about freshman highschool chemistry.
Burning natural gas may release some incidental uncombusted methane, but the major gaseous combustion product is clearly CO2. An unlearned person reading these articles would not know that from the way methane emissions are presented as the relevant issue.
It's also interesting to see that methane has now been rehabilitated in some minds into a friendly and relatively clean emission after years of hysteria regarding the impending doom that is coming from cow flatulence; statements such as "A significant portion of [global greenhouse gas] emissions come from methane, which, in terms of its contribution to global warming, is 23 times more powerful than carbon dioxide." (http://www.newscientist.com/blogs/shortsharpscience/2013/03/..., http://science.howstuffworks.com/zoology/mammals/methane-cow...)
You have clearly misunderstood. I try to simplify: Methane is 4 H per 1 C, oil is approx. 2 H per 1 C. Burning the H-part produces just water, which is harmless. The bottom line is that burning methane gives only half the CO2 emissions, compared to burning oil, per energy produced.
So in theory, burning methane to produce energy, would give only half the greenhouse gas emissions, compared to burning oil.
But, methane is 25 to 72 times more potent a greenhouse gas than CO2 [1], so even relatively small leakages during the production + transport + use of methane might be enough to spoil the advantage.
If methane has 25x larger global warming potential than CO2, then – even though methane is 2x more energy efficient – a mere 4% leakage would be enough the bring methane back to the level of CO2.
(I have no idea what are the typical leakage amounts in methane production, transport and use.)
Well, true, but the amount of water vapor in the atmosphere is determined by the balance of (i) water vapor condensing back to liquid water (e.g. rain), and (ii) water evaporating to atmosphere from oceans, lakes, soils and ecosystems. This balance is mostly determined by the temperature.
So you can't really add much water to the atmosphere by only emitting water vapor by e.g. burning gas, or even boiling huge amounts of water, because the excess water vapor will just condense back to liquid water.
Also if we imagine some huge industrial process that dries the air, removes water vapor from the air, this wouldn't really decrease the amount of water vapor in the atmosphere, because the drier air would just suck up the water back when it next comes into contact with a water body, damp soil or vegetation.
> Also if we imagine some huge industrial process that dries the air, removes water vapor from the air, this wouldn't really decrease the amount of water vapor in the atmosphere, because the drier air would just suck up the water back when it next comes into contact with a water body, damp soil or vegetation.
That's true on the macroest of macro scales, but in local climates, water vapor doesn't maintain a steady state. Otherwise every climate would be relatively green. In any case, if it's really so much better to capture methane and burn it for fuel than let it escape, then we should be forcing natural gas companies to figure out how to capture melting methane clathrates instead of taking them out of ground wells where they're relatively stable.
You should read the article. The issue is that CH4 is a vastly more powerful greenhouse gas than CO2, because of how strongly it absorbs IR [0]. Even small methane leaks are significant. This is counterbalanced by methane
* Being less carbon-rich [than coal] -- looking at the right side of your equation, about half the energy comes from fusing hydrogen (H-O) as opposed to carbon (C=O) [1]
* Allowing more efficient combustion (Muller says 60% vs. 44%)
You cannot come to any conclusion here without doing the math!
I'm not sure what you're getting at. The scientists explicitly mention the fact that burning methane produces CO2:
> If a methane molecule is burned, it produces one CO2 molecule.
> Methane produces about 2 times as much energy as does coal for the same CO2.
Perhaps the title on HN is a bad one, but the scientists are specifically arguing against the assertion that natural gas is even worse for the environment than coal because a large amount of it leaks into the atmosphere before it ever even has the chance to burn.
Consumption by plants is mostly carbon neutral, since they release it again later. It looks like individual CO2 molecules survive in the atmosphere only about 5 years. But still if you put a pulse of CO2 into the atmosphere, the half life is 30 years and (since it isn't a simple exponential decay) even 100 years from now still 36% of it will be in the atmosphere. In contrast, it looks like methane is gone in 12 years.
Here is the combustion reaction for burning methane:
CH4 + 2 O2 → CO2 + 2 H2O
Note right side of equation.
The "climate scientists" cited in the referenced article have confusion on this issue, as they contrast the effects of methane releases to those of CO2.
It's interesting to contemplate what has to occur for someone to adopt the title "scientist" and leading authority in a subject while remaining confused about freshman highschool chemistry.
Burning natural gas may release some incidental uncombusted methane, but the major gaseous combustion product is clearly CO2. An unlearned person reading these articles would not know that from the way methane emissions are presented as the relevant issue.
It's also interesting to see that methane has now been rehabilitated in some minds into a friendly and relatively clean emission after years of hysteria regarding the impending doom that is coming from cow flatulence; statements such as "A significant portion of [global greenhouse gas] emissions come from methane, which, in terms of its contribution to global warming, is 23 times more powerful than carbon dioxide." (http://www.newscientist.com/blogs/shortsharpscience/2013/03/..., http://science.howstuffworks.com/zoology/mammals/methane-cow...)