A primary conduit for coastal adaptation to climate change on private land is the hardening, or armoring, of the shoreline to mitigate the effects of erosion and sea-level rise (SLR). When such decisions are made at the parcel-level, there is potential for spatial spillovers, including externalities due to deflected wave action and peer effects. We estimate a discrete choice model of landowner armoring choices from 1990 to 2015 in the U.S.
state of Oregon that suggests the impacts of spatial spillovers are highly influential determinants in these private adaptation decisions. Our landscape simulations excluding spatial spillovers may under-predict future armoring by 37e97 percent. From scenario based simulations, we then demonstrate the primacy of policy, as a removal of a current land-use regulation that limits armoring has potential to significantly increase future armoring by 69 percent. Furthermore, inclusion of SLR projections suggests armoring would increase an additional 5.4 percent within four decades.