How does:
> reducing methane emissions won't change a thing, compared to CO2 emissions.
Follow from:
> once methane emissions reach a steady level
If we removed literally all methane from the atmosphere, this would be equivalent to reducing carbon dioxide concentration to 380 ppm. This would bring us back to climate of 2005. By any reasonable measure, climate in 2023 is not significantly different than the climate in 2005 (eg. you’d hardly be able to observe any difference without making a lot of very careful measurements, you wouldn’t “feel” any difference on your own skin).
And that’s if we remove literally all methane. Most of the methane in atmosphere is a result of natural processes, not caused by human activity. Thus, if we stop all methane emissions caused by human activity, we can maybe at best slow down climate change by 10 years. In terms of practical effects as felt by human beings, this is accurately described as “won’t change a thing”. Actually, to be more specific, slowing climate change by 10 years won’t make any difference, but stopping all methane emitting activities would be tremendously negative to human flourishing.
Global Warming Potential of Methane over a 20 year Time period is a bit more than 80 times that of CO2. https://www.epa.gov/ghgemissions/understanding-global-warmin...
So, redrawing your path by your method, if we remove ALL of the Atmospheric Methane today, we would be reducing GHG concentrations by about 160ppm CO2 equivalent, which takes the overall CO2 concentrations to less than that of pre-industrial levels(280ppm), 260ppm.
This negates your conclusion that we would hardly observe ANY difference.
If we remove literally all of the Methane today, we would have solved Global warming from the perspective of concentration of Green House gases and will just have to wait and watch for the Global Temperatures to catch up (meaning they will go down).
Where in the linked document it says that? Because I do not think it’s true.
'Devastating' melt of Greenland, Antarctic ice sheets found https://news.ycombinator.com/item?id=35657570
This was here just yesterday. You may not feel it "on your own skin", but Earth does. And what exactly will happen when we'll lose all ice, we simply do not know. We just know it won't be pretty.
> stopping all methane emitting activities would be tremendously negative to human flourishing
How? I smell bullsh*t.
Actually no, I don't think you would because raising/using cattle would not be allowed if we stopped all methane emitting activities. Also your farts can contain methane, so you'd have to hold them in ... forever. If you've ever had to do that during a long meeting, you should know it is negative to human fluorishing.
Giving up hamburgers and farting is not the only thing we'd have to do. I get the feeling you didn't think very hard about GP's comment before arrogantly and ignorantly dismissing them as bullshit. If you honestly think a world where only the wealthy had heated homes and many other products that everybody now takes for granted won't negatively effect human fluorishing, I'd be (truly) interested in hearing why, such as what would either replace those things or why we would no longer need them.
The OP has an excellent point which you didn't address them: most methane in the atmosphere is from natural causes. When the amount due to humans is removed, the effect on heating is not very significant in comparison of our CO2 emissions.
Stated another way, the OP is warning against premature optimization focusing our energy on issues that are an order of magnitude away from the main process.
If this were a conversation about a C loop, we wouldn't be emotional about it and we'd could argue better (for example, methane production also releases green house gases)
https://nsidc.org/arcticseaicenews/charctic-interactive-sea-...
Arctic sea ice extent is currently tracking the 2010-2020 average. Nothing much is happening in terms of Arctic sea ice extent at the moment and that's been true for a while. There has been a steady decline since 1979, which is the earliest year Charctic shows. But data exists for much longer. This is unfortunately standard for climatology, they truncate many data sets starting at this time and then declare records based on that truncated data set. That's not because nobody cared about the poles before the 80s, people definitely did.
Here are some examples. In the 1990 IPCC report, we can see satellite data for the Arctic going back to ~1972 and it shows a huge rise in sea ice extent during that decade ([1], p224, figure 7.20). This data is no longer shown on modern graphs.
This 1985 report [2] is by the US Department of Energy "Office of Basic Sciences Carbon Dioxide Research Division", it covers many topics around the construction of global climate models. Figure 5.2 on page 181 shows data on sea ice extents going back to the 1920s, citing Vinnikov et al. It shows a massive fall in sea ice from the 1920s to about 1955, when it turns around and starts climbing again. This data is corroborated by news reports. In the 1920s there were reports about melting ice caps. These were the dustbowl years and the 20s-30s were very hot. But in the middle of the century that turned around and by the mid 1960s the climate had been cooling for decades. The NYT reported [3] that:
The United States and the Soviet Union are mounting large‐scale investigations to determine why the Arctic climate is becoming more frigid, why parts of the Arctic sea ice have recently become ominously thicker and whether the extent of that ice cover contributes to the onset of ice ages.
Sea ice continued to thicken and by 1975 newspapers were reporting a consensus of experts that the future had a lot more ice in it, claims made credible by the growing Arctic ice conditions [4]:
In the last decade, the Arctic ice and snow cap has expanded 12%, and for the first time this century ships making for Iceland ports have been impeded by drifting sea ice [...] Many climatologists see this as evidence that a significant shift in climate is taking place [....] No scientists are predicting a full-scale Ice Age soon, but some predict that in a few decades there might be little ice ages
So the Arctic and Antarctic have changed quite a bit in the 20th century. They grow, they shrink, and scientists know this but no longer are willing to show these old datasets because the picture they paint is not a very interesting one. It certainly would not convince anyone that climatology is the key to saving the planet from doom.
[1] https://archive.ipcc.ch/ipccreports/far/wg_I/ipcc_far_wg_I_c...
[2] https://www.osti.gov/servlets/purl/5885458
[3] https://www.nytimes.com/1970/07/18/archives/us-and-soviet-pr...
[4] https://chicagotribune.newspapers.com/search/?query=%20new%2...
Also some of the "natural" causes are suspect now, since they include things like permafrost thaw, which itself is caused by warming...
https://cleantechnica.com/2021/02/06/a-differential-equation...
This is because the methane is being converted to CO2 at a relatively quick clip.
The timescale for CO2 is larger-- centuries.
Actually, it's more than that. The 20x global warming potential of CH4 is based on a 100-year average, which is the yardstick unit of measurement in the scientific literature. But as you say, methane degrades in 20 years so its average-20x contribution happens within those 20 years:
> The IPCC reports that the global warming potential (GWP) for methane is about 84 in terms of its impact over a 20-year timeframe [..] and 105 times the effect when accounting for aerosol interactions
-- from https://en.wikipedia.org/wiki/Atmospheric_methane?useskin=ti...
Indeed, this means most of the warming you get from emitting a molecule of CH4 is after it has decayed to the more stable CO2. Of course, sharp increases in methane are of concern for dynamic effects, from things like permafrost thaw.
