> Obviously this would have an impact on the ecosystem

Anticipating the impact is probably a fool's errand, since climate is extremely complex and changes on one part of the world affect others. It's not just about displacing people in the area, you risk altering the patterns that bring rain to places as far as Germany or help grow crops in Brazil. Sahara sand plumes play a role in replenishing phosphates in the Amazon, for example. Even blanketing some parts with solar panels will probably alter global weather patterns significantly.