I dunno so much about the rest of the state, but New Orleans has been sinking since it was founded.
Large parts of the state are uncompacted sediment. It does compress and settle as a result. There are a bunch of things you can do though:
- Stop extracting and burning fossil fuels to slow sea level rise
- Stop the oil and gas industry from cutting channels through marshes, which causes them to erode quickly
- Divert sediment from the Mississippi to wetland restoration, raising land levels
- Help people move when that’s the best remaining option