I don't think they are dismissive points. I think specially the ending makes a whole lot of sense to me. I'd give negative shits about the environment if I struggled for food or housing or basic essentials.
The same way the best way to tackle crime is through better education for the people, getting the existing people out of poverty might be the single best thing we can do to have them realize the impact, reproduce less, and contribute to a solution. I also think this way ends up being pragmatic because it doesn't require "so we change everyone's minds" as step 1.
They're not just dismissive, they're pretty obviously bad faith arguments. "CO2 is plant food" is a classic climate denier talking point that you hear from your crazy uncle on Facebook, who's parroting something they heard from a pundit on Fox News.
Water is also plant food, but that's not a helpful piece of information if you're in a flood. The world is releasing 97 million barrels of gasoline into the atmosphere per day.
