Good question, I believe it depends on the landfill?

Bacteria probably need the right conditions to efficiently break down materials, cellulose is quite tough.

Some landfills capture the released methane and burn it (to avoid atmospheric pollution), which seems like a decent solution (even more with power generation). Some of the material will remain undecomposed (or take a really long time) so it is a net carbon sink. I think this depends on properly sealing landfills and arranging extraction infrastructure.

Seems like a good resource:

https://www.epa.gov/lmop/basic-information-about-landfill-ga...

Another idea would be to curb methane generation or decomposition somehow. Apparently aerobic decomposition reduces or prevents the release of methane:

https://www.agric.wa.gov.au/climate-change/composting-avoid-...

Burning trash directly is also an alternative I guess, though one I'm not very comfortable with due to trace elements contained in everyday items -- surely some mercury and heavy metals will sneak into residues? (and then into the atmosphere and our lungs)

Another reason compact fluorescent bulbs were a mistake.

There's more mercury released into the environment from incandescent bulbs than CFLs -- or there was, when incandescents were still common and so were coal-fired power plants, and the Obama-era regulation of mercury emissions from power plants hadn't come into force.

Now, of course, we have LEDs in place of CFLs, and coal burning power generation is on the way out, so it's all moot.

Is that comparison true on a socket for socket basis? Low adoption of CFL shouldn't excuse any poor pollution characteristics.

The idea was to get an efficiency law passed and now we have a huge move to LED bulbs as a result. So, no, it wasn't a mistake, the CFLs were a stepping stone.