Highly evolved animals such as humans have a pretty impressive track record when it comes to seeing into the future. The problem does exist that some if not all of us have evolved enough to plan adequately into the long term.
Highly evolved animals such as humans ALSO have a pretty impressive track record when it comes to constructing money- and power-grabbing scams, and detecting such scams when they're being perpetrated upon them.
Unfortunately, the Global Warming Solution Advocates, regardless of the merits of their concerns, used something that has the form of a gigantic scam when promoting their proposals, and promoted proposals that involve massive transfers of wealth, increases in government intervention in private lives and businesses, and reductions in standards of living. This has created substantial skepticism (which moneyed interests that would be harmed by the proposed actions have, of course, gleefully promoted). The failure of the climate to follow their predictions and discoveries of their fudging of the data doesn't help their cause, either.
There are a number of steps between "I think the weather is getting warmer, and people are causing it." to "We must drive the developed world's population down to third world standards RIGHT NOW, to prevent a couple degrees increase in world average temperature, or we're ALL going to DIE!"
Because it looks like a scam, about all they've gotten any substantial traction on is that the temperature is changing a bit (as it has for all of geological time - we ARE coming out of an ice age, after all - and whether the change is actually human-caused is immaterial beyond indicating that we could change it the other way if we tried). But they haven't convinced the population that they have a correct model.
And they haven't even STARTED on the NEXT of several steps: Is global warming, bad, indifferent, or even good? (The geological and historical record seems to indicate that substantially warmer than what we have now - by more than the amount they're concerned about - is actually better for both civilization and life in general.)
With the population unconvinced that there IS a "Grave Threat To Humanity", it's premature to assume that "Our Brains Can't Process" it.
But speaking as if the thing to be proven is already proven IS another technique of scammers. And making such a claim is an obvious prelude to a move by governmental people, who believe "their brains ARE capable of processing it", to go ahead and impose wealth-transferring, power-grabbing, population-impoverishing solutions, "for their own good", whether the populations want to be reduced to serfdom (rather than be killed by what they perceive as the allegedly falling sky) or not.