I have heard it said that we should consider switching from farming cows to kangaroos, because kangaroos do not fart methane.

However, while they might work as a meat animal, I don't see kangaroos substituting for a dairy cow any time soon.

I also understand many species of antelope do not fart methane...

Pitting cars against meat implies that people would be making choices between the two, while in reality they are not willing to give up either.

So it's a moo point.

or a MOT point :P

Methane degrades to CO2.
One red meat meal = 12 or more vegetarian meals and all the water
Methane is 84X as powerful as CO2 in it's first 20 years in the atmosphere, apparently a lot more during it's first 10 years.
Life time of methane is ill understood. It is degraded by hydroxyls and it's life time depends on how much hydroxyl is available.
Hydroxyls aren't infinite, methane can stay in the atmosphere for a long time.
The warming potential of methane is 30'ish times that of CO2 after 100 years. I wonder why scientists make the effort to calculate that.?
Maybe your assumption is false @Kam-Yung Soh

@A. Randomjack Possible. The article does suggested that cars have a bigger effect in the long term. Here's another extract from the article:

If we convert global “burping cow” methane emissions in 2015 (70 MtCH4/yr) to CO2 emissions that would have the same climate impact over the following 20 years (70 MtCH4/yr * CH4 GWP20: 84 = 5,880 MtCO2e20/yr), then burping cows will have a larger impact on climate in the near-term than all the cars worldwide in 2015 (4.6 tCO2/yr/vehicle * 947,080,000 passenger vehicles = 4,360 MtCO2/yr). However, if we instead look at the climate impact of burping cows over the following 100 years (70 MtCH4/yr * CH4 GWP100: 28 = 1,960 MtCO2e100/yr), then the climate impacts of cars worldwide is larger. This is why scientists have suggested always using two time horizons when comparing climate impacts of multiple greenhouse gases – to prevent confusion and clarify climate impacts over all timescales.

@Kam-Yung Soh Somehow I hadn't seen the link in your post, sorry...
It also depends what you include in the "carbon footprint", like deforestation for cows and all the extra NO2/CO2 emitted to grow feed: 1 red meat meal = 12 vegetarian meals. One could also include transport, packaging, storing etc.
For cars, 50% of their total emission come from manufacturing, but we could also add all the plastic in them.
I read today that 10 million tons of plastic a second are produced every second on this planet, that was a shocker.
As for methane's warming potential (can't find the link) I read in National Geographic a few months ago, may be 50% higher than though because of it's many interactions with other of our pollutants.
But yes, cow's methane emissions were quite exaggerated in some documentaries/articles in the last few years, I wonder who would make such a fake claim...

I read today that 10 million tons of plastic a second are produced every second on this planet, that was a shocker.

And a, to me, unconscionable amount of that plastic is cheap crap designed and expected to break after a few uses and be thrown away and replaced. (Or simply thrown away, period.) More is fungible simply because metal parts were replaced with plastic ones without considering whether any changes to the design of the part were indicated.

@Phil StracchinoThis is where I read that