That's a misunderstanding. The methane stays in the atmosphere a few years until it reacts with oxygen to CO2. So first you have the multiple times worse effect of CH4 and then you're left with CO2, which is still a greenhouse gas. You're left with CO2 either way, even when you burn the methane. That's why it's so bad. And that's why actually when companies or politicians tell you about "clean" gas, it's very misleading. There is significant leakage in production, transport and storage, before the gas even reaches a consumer.
> So first you have the multiple times worse effect of CH4 and then you're left with CO2, which is still a greenhouse gas.
In case anyone else was wondering, the EPA[1] puts a layman figure on that notional multiple:
>> Methane's lifetime in the atmosphere is much shorter than carbon dioxide (CO2), but CH4 is more efficient at trapping radiation than CO2. Pound for pound, the comparative impact of CH4 is 28 times greater than CO2 over a 100-year period.
But note that at the end of that century, the CO2 is still there and will continue to heat the atmosphere indefinitely. We really need to stop adding carbon to the cycle; optimizing the form of that carbon can only ever be a secondary goal.
> optimizing the form of that carbon can only ever be a secondary goal.
If I may be permitted to reiterate: 28x GWP impact factor. Cherry-picking CH4 is hardly premature optimization...it's pure low-hanging fruit!
Consider this paper published in Nature Communications[1] which analyzed CH4 emissions from just low production natural gas well sites in the US. From the abstract:
>> Here, we integrate national site-level O&G production data and previously reported site-level CH4 measurement data (n = 240) and find that low production well sites are a disproportionately large source of US O&G well site CH4 emissions, emitting more than 4 (95% confidence interval: 3—6) teragrams, 50% more than the total CH4 emissions from the Permian Basin, one of the world’s largest O&G producing regions. We estimate low production well sites represent roughly half (37—75%) of all O&G well site CH4 emissions, and a production-normalized CH4 loss rate of more than 10%—a factor of 6—12 times higher than the mean CH4 loss rate of 1.5% for all O&G well sites in the US.
...and further into the paper:
>> At low production well sites, field observations report a common theme revolving around the issue of well site equipment negligence and disrepair as the primary driver of CH4 emissions. Most proximately, recent work by Deighton et al. documents several of these maintenance-related issues, including, for example, (i) leaks at fittings and joints, (ii) leaks and vents from rusted pump jacks, tanks, and other onsite gathering infrastructure, and (iii) evidence of well site neglect or poor maintenance, such as wellheads or casings covered in weeds or fallen trees.
In summary, an estimated 4 teragrams (4 million metric tons) annual CH4 leakage as a direct consequence of operations/maintenance negligence in just the US. Scaled by 28x GWP factor and now we're in the ballpark of 112 million metric tons CO2 equivalence.
Sounds like a big number, but I need a more relatable proxy to square that figure. This source[2] suggests a typical adult human generates 0.9 kg CO2 per day just breathing. Therefore, the value prop of dropping the penal hammer hard on negligent US low production natural gas site operators implies a CO2 sequestration equivalence of offing 341 million warm adult human bodies...effectively the entire US population! Apologies for the morbid anolog, but it's perhaps much easier to internalize impact by this measure.
Only a secondary goal? Sorry, the notion doesn't pass this layman's ballpark sniff test.
The "short-term" effect on warming is quite severe and very relevant. Also, while carbon atoms are conserved, methane is not. You can make a lot of methane from biomass without needing to absorb methane to produce the biomass.
Accelerating the "natural" cycle is bad even if there is no net increase. A massive forest fire technically doesn't cause any net increase in CO2, but releasing that much CO2 at once causes a lot of problems that wouldn't happen if the same amount were released over hundreds of years as those trees died and decayed.
I'm sure some people would argue that burning oil and gas isn't a net increase either, because all of that carbon came from the atmosphere originally. The important question is what emissions will make life worse for humanity, and what can be done to avoid them. Avoidable methane emissions cause real-world problems regardless of their source.
> the question is still whether that carbon came from a fossil source or was part of the cycle to begin with.
I don't think that matters anymore. At some point, we wanted to reduce atmospheric CO2 to a tolerable level and an obvious approach was to not add to natural emissions.
Now we just need to reduce CO2 in the atmosphere. It doesn't do different things based on its source. If we can reduce it by cutting gas production or by cutting some natural source, we should do it.
In your thought experiment the number of extant cows is a variable determined by human behavior as opposed to inherent regulation. There might be historical population numbers from specific regions where carbon was in equilibrium but that's certainly not where we're at today nor is it a goal of ours.
I think we're only able see some carbon sources as "outside the cycle" due to our infinitesimal lifespans.
