M.C. is a real Cutie!

You need to provide something more attractive to him than the carpeting. Here are some suggestions:

Put catnip on your existing scratching posts and move them closer.

Buy a cardboard cat scratcher. Some cats prefer to rip the cardboard over ripping the carpeting. (My mom's cat prefers this, especially with catnip.)

Try wicker. Most of my fosters preferred to sharpen their claws on my wicker laundry hamper. It's so sturdy that it hardly shows any "use." Cheap wicker hampers are a lot easier to replace then carpeting.

Try hanging a sisal rope scratching "post" from a nearby doorknob. These are available at PETsMART or PETCO. Many cats prefer the rope over carpeting. You can also buy scratching posts wrapped with sisal or you can make your own by wrapping something that can be thrown away later.

Then, discourage M.C. from using the carpeting. Do you know about using squirt bottles and the LOUD NO technique?

Good luck.