Earlier quoted context omitted.
Cows and other animal agriculture contributes as much or more [1], to climate change than all cars and trucks. So eating less meat is one good way. > Livestock is responsible for 65% of all human-related emissions of nitrous oxide – a greenhouse gas with 296 times the global warming potential of carbon dioxide, and which stays in the atmosphere for 150 years. -“Livestock’s Long Shadow: Environmental Issues and Option…
Nitrous oxide and Methane both break down in the atmosphere. If we where starting from zero then sure they would both have a large impact but they are both in sufficient quantities that lot's of them are breaking down making the future contribution have a negotiable net effect.
From https://en.wikipedia.org/wiki/Greenhouse_gas:
"For example, the direct radiative effect of a mass of methane is about 72 times stronger than the same mass of carbon dioxide over a 20-year time frame[20] but it is present in much smaller concentrations so that its total direct radiative effect is smaller, in part due to its shorter atmospheric lifetime. On the other hand, in addition to its direct radiative impact, methane has a large, indirect radiative effect because it contributes to ozone formation. Shindell et al. (2005)[21] argue that the contribution to climate change from methane is at least double previous estimates as a result of this effect.[22]"
"Methane has an atmospheric lifetime of 12 ± 3 years. The 2007 IPCC report lists the GWP as 72 over a time scale of 20 years, 25 over 100 years and 7.6 over 500 years.[20] A 2014 analysis, however, states that although methane's initial impact is about 100 times greater than that of CO2, because of the shorter atmospheric lifetime, after six or seven decades, the impact of the two gases is about equal, and from then on methane's relative role continues to decline.[37] The decrease in GWP at longer times is because methane is degraded to water and CO2 through chemical reactions in the atmosphere."
Immediately following this last paragraph they show a table which says that carbon dioxide has a GWP (Global Warming Potential) of 1 over all time periods, while that of methane is 72 over 20 years, 25 over 100 years, and 7.6 over 500 years.
> If we where starting from zero then sure they would both have a large impact but they are both in sufficient quantities that lot's of them are breaking down making the future contribution have a negotiable net effect.
Maybe it's too early in the morning for me, but I don't understand the point you're trying to make here, and I am apparently not the only one. Care to clarify?