The flood of Africans (both northern and sub-Saharan) into Europe is a recent thing. It's happening because Merkel swung the door open to everyone. If the continent decided tomorrow that no more are allowed in, then it would be done. It's not hard to keep out inflatable boats. Give me a break. 

The real reason behind all of this is leftist ideology. They think it's the West's moral obligation to let in the entire third world.