From IPCC6, due out Monday, some new perspectives and surprising new 'facts' to affect policy:
https://www.theguardian.com/environment/2021/aug/06/reduce-methane-or-face-climate-catastrophe-scientists-warn

1) Methane reductions are probably the only way of staving off temperature rises of 1.5C ... “Cutting methane is the biggest opportunity to slow warming between now and 2040". “We need to see at Cop26 a recognition of this problem, that we need to do something on this”.

2) Cutting methane could balance the impact of phasing out coal ... coal use has a perverse climate effect: the particles of sulphur it produces shield the Earth from some warming by deflecting some sunlight. That means the immediate effect of cutting coal use could be to increase warming, although protecting the Earth in the medium and long term ... cutting methane could offset that.

3) “Today more than 40% of EU gas is methane-heavy gas from Russia, which is worse than coal for the climate”.

4) Governments to consider crafting a new deal, alongside the Paris agreement, that would cover methane and require countries to sharply reduce their gas. “I predict we will have to have a global methane agreement”.

5) Large-scale emissions from permafrost melting are thought to be still some way off, while emissions of methane from agriculture and industry can be tackled today.

So China continuing to burn coal may not be the devil incarnate? Whilst Russia remains the evil twin?

Is there some breakdowns on the sources of Methane?

Posted By: fostertom“Today more than 40% of EU gas is methane-heavy gas from Russia, which is worse than coal for the climate”

That won't be a problem when Russia switches off the supply

Methane-heavy natural gas, eh? That sounds really bad.

Sounds like all that dihydrogen-oxide in the water that you get from [insert bogeymen country here, according to your readers' prejudice]...

I too was initially surprised by the notion of “methane-heavy natural gas”, because natural gas is primarily methane, but after a bit of reflection I think they meant natural gas which comes from sources with more leaks (i.e., poor handling once it's out of the ground).

Posted By: fostertombut 'worse than coal'?

Maybe, if the sources of natural gas are leaking more greenhouse effect in the form of unburned methane than the greenhouse effect of the carbon dioxide from burning coal.

Posted By: fostertomSo it should have read 'methane-leak-heavy gas

+1

The UK has reduced GHG emissions by half since 1990 and a good chunk of that came from reducing methane emissions. Partly that was from forcing industries to clamp down on methane leaks, which seems like an obvious/easy route for other countries to follow.

Partly it was from reducing landfill sites' emissions (ditto)

A good chunk of our methane reduction came from shutting down the coal industry. Underground coal naturally has methane adsorbed in it, which is released when it is mined (>mine explosions). Is not clear if the "methane worse than coal" comparisons include for the coal releasing its methane while it is stockpiled waiting to be burned.


The discussion that I'm surprised not to see here, is that methane is a relatively short-lived GHG. The methane released today will be gone in 10years, which is nothing in geological time, whereas some of the CO2 released today will still be around in 10-100,000years. To me, the worst feature of CC is is that our CO2 emissions will affect hundreds of generations of our descendants.

It's obviously important to focus on methane *as well as* CO2 but the title and content of this thread imply focus *instead of* on CO2. Acute versus chronic problems.

There's a good discussion of methane and other greenhouse gases and their GWP numbers etc on the US EPA site

https://www.epa.gov/ghgemissions/understanding-global-warming-potentials
https://www.epa.gov/gmi/importance-methane
et al

"Because methane is both a powerful greenhouse gas and short-lived compared to carbon dioxide, achieving significant reductions would have a rapid and significant effect on atmospheric warming potential."

"Why aren’t efforts to capture and profitably use methane emissions more widespread?

"Despite multiple benefits, methane recovery is not widespread for several reasons.

"1 Methane is generally a secondary byproduct in the industrial processes from which it is emitted. Coal mines, for example, seek to vent methane from the mine workings because it can cause explosions. Historically, mining companies have not viewed the associated methane as an energy resource in its own right.

"2 Those responsible for the emissions may not be familiar with the technologies available for methane recovery or the potential for profitable recovery projects. This is especially true in developing countries where improved access to information and technical training would be beneficial to generating support for methane recovery projects.

"3 Poorly functioning energy markets and financially insolvent utilities and municipalities within many countries fail to provide the private sector with a climate that will attract their investment in projects to capture and utilize methane."

I think the point is that methane is more important than has been appreciated in many circles and therefore more attention should be focussed on it. I don't think there's any idea we should be reducing efforts on CO2 and other gases though.

As long as methane continues to be emitted, it doesn't matter whether it is relatively short lived.

https://www.realclimate.org/index.php/archives/2021/09/the-definitive-co2-ch4-comparison-post

I can't find the “If adopted around the world…” text in the Guardian article - has the article been edited or did it come from something linked from there?

Still, depending on what's meant to be adopted that seems to me broadly compatible with:

Posted By: Gavin SchmidtThis implies that if you convert the impacts of each set of emissions into temperatures, as was done in the IPCC AR6 report, you get about 0.75ºC from the changes in CO2 and 0.5ºC for CH4 (from the late 19th C, see figure below) or 1ºC and 0.6ºC, respectively, from 1750. Thus despite the smaller concentrations and changes in methane compared to carbon dioxide, the impacts are comparable.

Remember, though, that it would be a one-off reduction. If CH₄ emissions are reduced then, over a decade or so, the temperature drops compared with what it would otherwise have done then continues to climb as a result of CO₂ accumulation.