Climate-induced managed retreat in the U.S.: A review of current research

Human responses to climate change are continuing to evolve. At one time, mitigation (reduction) of human emissions of greenhouse gases appeared to offer the best response to prevent the worst impacts of a changing climate. It soon became clear, however, that the world would not be able to reduce emissions quickly enough or to a level sufficient to prevent, in the words of the United Nations Framework Convention on Climate Change, “dangerous anthropogenic interference with the climate system”. Climate change is already altering the frequency and severity of extreme weather events worldwide, and these trends are expected to increase in the foreseeable future. Accordingly, it is well recognized that adapting in place to the changing climate is necessary. Yet, that may not be enough. An additional step in responding to climate risks is emerging, one that requires fundamentally and permanently changing the human interactions with nature in parts of the world. This strategy is often referred to as “managed retreat,” but that term has become controversial, and other terms are needed that express inclusion of the positive societal benefits that can emerge from proactive action. This paper provides a review of the emerging themes within the literature of managed retreat as a climate risk management approach, uses examples from the transportation and infrastructure sector, collects and identifies important nomenclature and definitions, key decision-making considerations, and research gaps that warrant immediate attention. The results of this review are intended to be useful to academic climate change adaptation researchers and infrastructure practitioners alike.