Limits to adaptation to climate change: a risk approach

Highlights

• Recent calls for risk-based approaches to climate assessments and discussions of adaptation limits relate to each other in little explored ways.

• A novel risk-based approach to adaptation limits to climate change is described.

• As climate change deepens and accelerates, we expect more adaptation limits of actors to be reached, generating major challenges for climate risk governance.

As attention to adaptation to climate change increases, there is a growing call for adaptation approaches that focus on risk management. There is also greater recognition that the rate and magnitude of climate variability and change may exceed the limits to adaptation of socio-ecological systems. We offer an actor-centered, risk-based definition for adaptation limits in social systems. Specifically, we frame adaptation limits as the point at which an actor's objectives cannot be secured from intolerable risks through adaptive actions. These limits are significant because exceeding a limit will either result in intolerable losses on the affected actor or system, or precipitate a discontinuous (or transformational) change of behavior by actors. Such discontinuities in behavior have implications for the distribution of risks, with potentially significant governance consequences. We further argue that some adaptation limits are dynamic through time. We conclude with recommendations for further research into adaptation limits and challenges to risk governance.

Introduction

As the need for adaptation to climate change impacts becomes increasingly apparent and the evaluation of adaptation choices becomes more detailed and sophisticated, there is growing support for pursuing risk-based approaches to adaptation decision-making [1, 2, 3, 4]. From a risk management perspective, climate change alters the magnitude and distribution of climate-related impacts and generates new risks for people and ecosystems. Much of the current discussion about adaptation and risk is focused on assessing the likelihood and magnitude of impacts and the associated communication challenges (e.g. [5]). But the broader field of risk research has addressed issues such as the social processes by which actors identify and negotiate which risks to manage, what is known and not known about these risks, the strategies available to manage risks, and what are acceptable costs or tradeoffs. How societies debate and decide on adaptation choices and priorities closely resembles the way in which complex risks are managed [6].

In its focus on the objectives of adaptation, the discourse on climate risks foreshadows the issue of limits to adaptation [7, 8, 9••]. Understanding the nature of limits to adaptation requires greater attention because of increasing evidence that greenhouse gas mitigation efforts will not be sufficient to prevent significant global climate change [10••, 11, 12•]. Therefore, climate change will increase stress on natural and human systems, put pressure on adaptation options and increase the likelihood of exceeding limits to the capacity of social actors to adapt. While all human and ecological systems have some capacity to adapt, there are likely to be limits to that capacity in all systems. As a consequence, radical discontinuities of behavior and system-states may be expected, including for instance migration or species extinction. Such discontinuities may represent catastrophic losses for specific communities, as well as the redistribution of risks for the actors and systems affected. They may also have wider systemic effects through complex feedbacks and teleconnections in socio-economic and natural systems. In general, we believe adaptation limits will be associated with significant economic, cultural, or other losses for certain social groups. We argue below that an adaptation limit does not signal the end of the adaptation process. Carefully planned and managed transformational adaptations on the basis of the redefinition of objectives by actors can result in more resilient management and development pathways.

We see significant complementarities between an emerging focus on risk-based decision-making and the developing attention to adaptation limits. These complementarities suggest that connecting these dialogues can be valuable for adaptation research and practice. This paper addresses the objectives of climate adaptation, arguing that the aim of adaptation is to reduce risks to existing valued social objectives, such as standards of flood protection for residential areas. We then argue that the concepts of adaptation limits and transformational adaptation are useful extensions of the established risk management framework. Following this, we articulate a definition of limits to adaptation that takes as a starting point the social actor managing risks to valued objectives through adaptation. We argue that some limits may be dynamic over time and make a distinction between ‘soft’ and ‘hard’ limits. We conclude with some reflections on broader risk governance implications.