Brilliant.
I watched the follow up to see how they explained it afterwards:
Absolutely unbelievable. Almost turned it off halfway but kept going in a sort of horrified fascination.
In case you don’t want to torment yourself: they claim that concrete does grow, because it expands. This is what he meant by “growing”. Just like you can say the economy grows, but that doesn’t mean it’s planted in the ground. Trees are not sustainable, because they take a long time to grow.
The worst thing is that people actually watch this and take it seriously.