Proper landfill design & operation ensures the landfill is aerated, which keeps decomposition primarily aerobic which produces little methane. A poorly designed or operated landfill with little aeration will switch to aerobic metabolism, which is what produces large quantities of methane.
If everyone went zero waste then nothing would be added to the landfill, and its methane production would taper out to nothing as a result.
From the top charts for image search "landfill gas chart", suggests methane(CH4) vents heavily for 3-5 years, then a long taper.
Consumers do have some power, but they are not the only ones and we should demand an effort from all parts of society there.
On the other hand, I doubt it is plastic waste that produce methane, an organic byproduct. Maybe food wastes are at fault. In which case your enemy is not overpackaging and may actually be your (temporary) ally
The rising CO2 levels in the atmosphere come from burning hydrocarbons which originate from below the earth's surface, where they were not part of the carbon cycle for millions of years. Burning faster than natural sequestration below the surface is reaponsible for the overall rise.
All else being equal, methane has a stronger greenhouse effect, but breaks down, unlike CO2 which is only sequestered by plants.
More worrisome is that, done at a scale that would matter to the atmosphere, it would have to be buried in containers that are impermeable to water forever, lest all of our underground aquifers become contaminated by bacteria and heavy metals that are naturally occurring in plants.
As I said elsewhere in this post, you can cut emission but population growth offsets all the benefits. You cannot address climate change without drastic long term reduction in human activity/population.
Of course you can. You must change activities to be carbon neutral, but you can maintain the same level of comfort you have today. More than "can maintain", you "must".
If you rely on sacrifice from the whole planetary population in order to tackle climate change, we are doomed. It will never happen, as it goes against the competitive nature of humans.
The correct path is forward: innovate, so that carbon neutral forms of energy and materials are better than carbon-emitting versions. Energy is an almost solved problem, using this vector. Let's attack materials now.
As excesses become realized, increasingly, a fundamental relationship between these figures can become measurable.
That exact relationship, the proven algorithm, may not realistically be very well agreed upon in detail, but as these factors rise rapidly above baseline levels that function should more accurately be discerned above the background as time goes on.
Maybe before this happens, sustainability would be better achieved by actions resulting in trends which reduce these two figures low enough in combination where no relationship could then be considered realistic.
So carbon neutrality might not be enough without taking too much from population.
Completely disagree. Reducing waste, recycling waste, and re-using waste are some of the ways to address climate change. Saying modifying human activity/population is the only way to solve a problem is as extreme as saying climate change isn't real.
> No business is out there emitting methane for shits and giggles.
No one says this, you're reducing the broader point to a poor cliff-note. The point is that the incentives for businesses to better address their waste are not there. If all one gets for managing waste responsibly is a higher bill every month and a good feeling in their stomach, why would a proper capitalist businessperson do that in the short term?
My point was that the "capitalist" is not running that production line in isolation, it is the end consumer demand that drives that pipeline. So yes consumer demand is the ultimate source of all this.
Carbon tax is but a first step but it is necessary as it will force the actors to take action. As you correctly pointed out they have no "incentive" to do so right now.