No Net Loss was enunciated as a policy in response to fill of wetlands by development. The official policy of the federal government is that there shall be “no net loss” of wetlands as a result of development or other activities. The No Net Loss policy means that lost wetlands functions must be restored through the mitigation process of creating new wetlands or preserving existing wetlands and enhancing their functionality. This policy was first put forward by the first President Bush and has remained the official policy since then.
There has been little if any discussion of the No Net Loss policy being used to ensure the survival of as-of-yet unexisting wetlands, but there is no reason the policy could not be widened to include adaptation for rising sea levels. It is more a question of political will than a policy impediment. If anything, the current policy of No Net Loss should encourage the Corps and other agencies to take a more proactive stance with respect to replacing wetlands lost to sea level rise.