The last time Western Europe was cut off from the resources of Africa it was called the Dark Ages, they didn’t quite regress to the Stone Ages. LoL.
There’s a much more detailed answers to your question, but I’m on my phone and I am really bad at thumb typing. So I’ll give the short answer:
The way the world economy is structured & the redundancies they have worked into their systems, it would hurt like hell to lose the resources of Africa, but the systems of Global White Domination could sustain for some time but with major adjustments. You have to cut off all sources of nourishment to kill this cancer, not just it’s primary source.