In medusae, mesoglea comprises the bulk of the animal and forms a resilient skeleton. In polyps, the water-filled coelenteron acts as a hydrostatic skeleton, which, in concert with the mesoglea, maintains the form of these animals. Muscles in cnidarians are extensions of the bases of ectodermal and endodermal cells.
I believe reducing our co2 emmisions would reduce wave erosion because the sea level would lower, meaning waves wouldnt getas far or high as they do now.