It's hard to take this comment seriously when you haven't provided any of the relevant facts or sources to back this claim.
https://www.google.com/search?q=(44%2F12)%2F(35MJ%2Fkg+*+0.3...
Global warming potential of CO2 over 100 year timeframe also googleable. These figures are all basic and pretty objective. (You May quibble about me choosing 100year timeframe vs 20 year, but that’s fine… it is still about the same order of magnitude.) More complicated to measure methane’s atmospheric lifetime and infrared absorption proportions, but nothing really controversial.
The EIA website also shows this stuff.
It's down to the person making a claim to provide evidence. If someone points out that there is no evidence provided, that someone doesn't need to provide evidence themselves.
I mean yeah it's snarky, but it's a comment section on the internet.
It should be pretty clear that no sources are needed beyond using your eyes and looking at Robotbeat's comment - unless it's been edited, then it's rather obvious that no sources were provided, which was the claim being made.
Saying "what are your sources" without further elaboration is typically a little rude and combative, but this kind of "no you" comment is flat-out ridiculous.