The worst solution to this problem is declawing. The common belief is that declawing is just like trimming fingernails, but it could be more wrong than that. The cat's nails are a vital part for his survival, behavior, and balance. Amputating them might lead to behavioral problems, worse than the scratching problem you are facing now.
You should create for your cat an alternative clawing post. It should be similar as possible to the old one. My tip is to simply get an old couch you don't care about, place it next to your original couch and try to attract your cat to it by playing on it and rewarding him each and every time he plays on it.
Gradually you can take the new clawing post to a remote spot in the house, but only after the cat got used to clawing only on his post.