I cannot find any part of the article trying to argue that climate change taught people to marry off their children, or that child marriages skyrocketed in Bangladesh because the scientists published papers recording higher average temperatures.
The article does not spell it out, only referring to it as "social norms" and "gender inequality".
As far as I can tell, the article documents such marriages as measures taken when a family is so financially constrained that they have no further means of caring for their children.
Damage from natural disasters, whose intensity increases with climate change as noted in the article, is now more likely to push families to take desperate measures, which in an Islamic country like Bangladesh, means marrying off your daughter.
"After a natural disaster in Bangladesh, child marriages can surge by up to 39 per cent... "
I agree that even if there weren't any climate change, they would still be marrying children off to adult men. I am fully aware of how Islam can warp society's treatment of women and young girls. I know that South Asia (Pakistan, India, Bangladesh) have "social norms" that they really need to leave behind. Unfortunately, that will take a massive cultural change, and until that happens, the above will still happen in response to climate change-enhanced disasters.