A website that quotes Breitbart is a signal that they are not serious about providing accurate scientific information.
Some random person told me that the parts of the spectrum that are absorbed by CH4 are already absorbed by H2O, which is way more prevalent, so the CH4 doesn't matter much.
Is that true/valid/scientific?
In general, this stuff is complicated, and it’s easy for people using “motivated reasoning” to come up with the answer they want. Lots of comments reflecting such misinformation appear on HN — it’s frustrating.
So, listening to random people isn’t such a good idea. Much better to read a report from people who study this stuff, like: https://nca2018.globalchange.gov/, which I recommend to technically interested nonspecialists.
(I eat lunch with one of the co-authors of the technical paper in Nature linked to the OP, the press release is: https://www.jpl.nasa.gov/news/news.php?feature=7535, paper is: https://www.nature.com/articles/s41586-019-1720-3)
Obviously I am not taking in information without skepticism, otherwise I would not have asked the question.
But if I can't read something like that and refute it, then obviously I don't understand the issue very well. The best way to remedy that is to ask (not ignorant silence), so I'm a bit disappointed with the other replies who ridiculed me for asking.
Resources like the overview report I linked are critical.