I wonder what happens to the sand at the edge when it can't go anywhere in the long term.

Here in the UK we get regular dust seasons because sand rides the Gulf Stream from Africa and makes cars/other things dirty. I don't know if that sand has an ecological effect and process that goes along with it but I struggle to believe it doesn't do something in some way. Eliminating the ability of that to occur would cause something to happen longterm.

Also I assume the sand at the edge of the desert will just pile up eventually? Like when rubbish piles up at the edge of a curb. Will it just get bigger and bigger? I wonder what happens if the dune gets large enough.

Not saying this stuff shouldn't be done, I'm just curious.