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Re:In few years renewable power may become a better economic... by pdonis on Tuesday October 09, 2018 @09:44PM (#18181364)
> natural gas is a fossil fuel and if you take methane into account it might even be worse than coal

Huh? Natural gas only produces about half the CO2 per unit of energy that coal does.

Re:In few years renewable power may become a better economic... by CydeWeys on Tuesday October 09, 2018 @09:49PM (#18181387)
The point is that natural gas (also known as methane) can leak out into the environment during production and distribution, and methane is a very potent greenhouse gas, 30X as bad per mass.

So if burning methane only produces half the CO2 per unit of energy, but just 2% of it leaks into the atmosphere at any point in the production/distribution pipeline, then it's actually worse.

Re:In few years renewable power may become a better economic... by quotemstr on Tuesday October 09, 2018 @10:46PM (#18181574)
Methane has a relatively short half-life in the atmosphere, only 8.6 years, which means that over the long term it's not that potent a GHG versus long-lived CO2 (about 100 years, but it's complicated). The radiative forcing alone doesn't tell the whole story.
Re:In few years renewable power may become a better economic... by DennisP on Wednesday October 10, 2018 @07:56AM (#18183973)
Yes but it's not only direct forcing over the long term that matters. Push the planet hard enough in the short term, and we'll kick off positive feedbacks that take things several degrees further with no more help from us. The exact threshold is unknown but it's thought to be about two degrees C over preindustrial.
Re:In few years renewable power may become a better economic... by pdonis on Wednesday October 10, 2018 @12:57PM (#18186718)
> Push the planet hard enough in the short term, and we'll kick off positive feedbacks

Which have never actually been observed. The whole "positive feedbacks" thing is based on computer models which have been falsified by the actual data.

Re:In few years renewable power may become a better economic... by DennisP on Wednesday October 10, 2018 @03:26PM (#18188066)
No, it's based on extensive geological evidence. See Hansen's book for details.

Besides that, it's based on the fact that we're already seeing things like polar ice melt and emissions from permafrost.

Re:In few years renewable power may become a better economic... by pdonis on Wednesday October 10, 2018 @05:43PM (#18189175)
> No, it's based on extensive geological evidence.

We don't have accurate enough geological evidence to support the kinds of "positive feedback" claims that are being made. Hansen's book lays out a partisan case.

> we're already seeing things like polar ice melt and emissions from permafrost.

What were these things doing a thousand years ago? Five thousand years ago? Ten thousand years ago? We don't know. And that means we don't have the data to put what we're currently seeing in proper perspective. And nobody is claiming that we do: as I said, the claims of possible disaster based on positive feedback are based on models, not data. And the models have been falsified by the data.

Re:In few years renewable power may become a better economic... by DennisP on Wednesday October 10, 2018 @06:42PM (#18189598)
I take it you've read his book then? Could you point out specifically what's wrong with his evidence?

It seemed pretty convincing to me, since there were multiple independent lines of evidence that all pointed to the same conclusion.

Re:In few years renewable power may become a better economic... by pdonis on Wednesday October 10, 2018 @07:51PM (#18189959)
> I take it you've read his book then?

No, I've read scientific papers on the topic, his and others. I don't trust what is said in books on science for lay people; I've caught too many scientists misrepresenting the science when they write for lay people, because they know they can get away with it (and not just in climate science--I've caught physicists doing it about general relativity and basic QM, which are a lot more solidly nailed down by evidence and controlled experiments than climate science is).

Re:In few years renewable power may become a better economic... by DennisP on Thursday October 11, 2018 @03:55PM (#18196541)
Ok. Tell me something he gets wrong, and why it's wrong.
Re:In few years renewable power may become a better economic... by quotemstr on Wednesday October 10, 2018 @10:36AM (#18185230)
Feedbacks depend on which model you use. Still, it's not particularly relevant to the question of slow methane leakage from a natural gas distribution system, which is what we're talking about.
Re:In few years renewable power may become a better economic... by DennisP on Wednesday October 10, 2018 @11:48AM (#18186006)
Sure it's relevant. If we use twice as much methane this year, we'll probably have twice as much leakage, and that means twice as much climate impact from this year's methane over the next few decades.
Re:In few years renewable power may become a better economic... by quotemstr on Wednesday October 10, 2018 @01:10PM (#18186874)
The feedbacks depend on total temperature not atmospheric gas composition, so methane raising temperatures by X degrees isn't any worse than CO2 causing the same temperature rise, and methane will exit the atmosphere faster. That is, feedback is proportional to the time integral of warming, not the forcing!
Re:In few years renewable power may become a better economic... by DennisP on Wednesday October 10, 2018 @01:35PM (#18187141)
Yeah fine but total warming over the next 25 years could well be sufficient to get us over the critical threshold, and methane does have a greater impact than CO2 over a period of 25 years.
Re:In few years renewable power may become a better economic... by foota on Tuesday October 09, 2018 @09:47PM (#18181376)
I don't know about the claims re: methane and natural gas, but methane causes warming significantly worse per kg than CO2 does.