I make lots of compost for my own use. Composting is at best delaying carbon release. As soon as you stop recycling materials the carbon will be released to the atmosphere. In permaculture circles the goal is to close open loops of waste/resources. If you want to permanently lock carbon in your soil, and improve fertility, make biochar. Throwing charcoal in your compost is the easiest way to make it into biochar. It really works and is a permanent amendment.
If you wanted you could even weigh the raw charcoal to quantify the carbon you have sequestered.
None of the loops are open in the sense that it's all within the earth system as a whole. The issue is extracting carbon from geological deposits. Stuff about farming and methane is temporary and short term.
I don't mean to suggest we shouldn't compost or recycle things. Just that such measures are only indirectly related to carbon emissions.
We either stop extracting hydrocarbons from deep within the crust or else the problem will persist. (I guess technically we could industrially sequester the equivalent but that would almost certainly defeat the cost-benefit of extraction.)