pg_xlog_archive folder size is very big
A WAL archive can be used for disaster recovery, PITR (point in time recovery), or as part of a replication set up.  If you don't know why you set it up in the first place, then maybe you don't need it.  The consequences of turning it off is that you can't use that type of disaster recovery, can't do PITR for after the time it was turned off, and can't use that kind of replication anymore.

Also, note that WAL often compresses extremely well, often 25 fold or more, with something like "xz" or "lzip". So if you mostly concerned with storage, you can implement compression.