Kaku isn’t ‘dumb’ by any means.
Then he’s an ideologue with an agenda. The average minimum temperature in Niagara Falls is 16F. Sochi is about 34F for the same minimum in January. And yet Kaku uses this as evidence of grave bodily harm to Gaia due to the miniscule amount of CO2 contributed by humans to the atmosphere.
No, he's stupid.
from dictionary .com
stu·pid
[stoo-pid, styoo‐] adjective, stu·pid·er, stu·pid·est.
1. lacking ordinary quickness and keenness of mind; dull.
2. characterized by or proceeding from mental dullness; foolish; senseless: a stupid question.
3. tediously dull, especially due to lack of meaning or sense; inane; pointless: a stupid party.
4. annoying or irritating; troublesome: Turn off that stupid radio.
5. in a state of stupor; stupefied: stupid from fatigue.
He may not be dumb but he is an extremely evil human being.
He is consciously pushing the LIE of man-made global warming because he is a leftist control freak.
He is a liar pushing his claims not based upon scientific principles, but simple because he is a rabid leftist.
Hence, his actions make him an extremely evil human being. The reason he and others are evil is because the solutions they propose will cause the deaths of millions of innocent human beings.
Obviously not dumb, since he is verbally spewing ignorance.
OTOH, he seems willfully deaf & blind.