It’s enough to make us miss Climate targets even if fossil fuels were eliminated today. We have to tackle both

Yeah, if every single trend occurring today continues linearly into the future and we don't account for the fact that all of the methane emissions have to be offset by carbon sinks from plant growth, we'll have a problem.

Fortunately none of that will happen. Your study is literally assuming that we will stop using all carbon within 20 years, but yet continue to use it for nitrogen fixation.

If you go look at their graphs, you notice a trend. The lines comparing fossil fuels and food emissions don't diverge until the absurd linear assumptions they make go nuts 50 years into the future.

At the end of the day, if you remove the fossil fuel usage, the cycle must self-balance, else eventually you run out of some resource.

Further for the bit about feed addatives, those don’t do as much as you’d think

That is one option, you can reduce methane emissions through things like medication.

You can gather the cows into one big airtight building, collect the methane emissions, and burn it before it gets into the atmosphere instead of just venting it raw into the atmosphere.

And you can do the same thing for manure.

Right now we aren't doing anything because these really aren't the problems we need to solve right now. The vast vast majority of emissions today are coming from:

Transportation.

Manufacturing.

Electricity use.

Agriculture is ten percent. Land carbon sinks in the United States? They offset 12 percent.