Annual Review of Environment and Resources - Volume 42, 2017

Recent changes in arctic vegetation might not be driven by climate change alone. Legacies of human activities have received little attention as a contributing factor. We examine the extent to which traditional human activities (hunting, herding, fire, wood extraction, and agriculture) have had lasting effects on arctic woody plant communities and therefore might continue to affect biome-wide responses to climate change. Evidence suggests that legacies are likely to be evident across meters to hundreds of kilometers and for decades, centuries, and millennia. The evidence, however, is currently sparse, and we highlight the potential to develop systematic assessments through a circumarctic collaboratory consisting of a network of interdisciplinary field sites, standardized protocols, participatory research, and new approaches. We suggest that human activities should be brought into consideration to increase our understanding of arctic vegetation dynamics in general and to assess woody plant responses to climate change in particular.

Through integrative assessment, experts evaluate the state of knowledge on complex problems relevant to societies. In this review, we take stock of recent advances and challenges, rooting our analysis in climate change assessment. In particular, we consider four priorities in assessment: (a) integrating diverse evidence including quantitative and qualitative results and understanding, (b) applying rigorous expert judgment to evidence and its uncertainties, (c) exploring widely ranging futures and their connections to ongoing choices and actions, and (d) incorporating interactions among experts and decision makers in assessment processes. Across these assessment priorities, we survey past experiences, current practices, and possibilities for future experimentation, innovation, and learning. In our current era of climate and broader global change, integrative assessment can bolster decisions about contested and uncertain futures. We consider both opportunities and pitfalls in synthesizing and encompassing evidence and perspectives. Our aim is to advance transparent assessment for a sustainable future.

The article describes the field of sustainability transitions research, which emerged in the past two decades in the context of a growing scientific and public interest in large-scale societal transformation toward sustainability. We describe how different scientific approaches and methodological positions explore diverse types of transitions and provide the basis for multiple theories and models for governance of sustainability transitions. We distinguish three perspectives in studying transitions: socio-technical, socio-institutional, and socio-ecological. Although the field as a whole is very heterogeneous, commonalities can be characterized in notions such as path dependencies, regimes, niches, experiments, and governance. These more generic concepts have been adopted within the analytical perspective of transitions, which has led three different types of approaches to dealing with agency in transitions: analytical, evaluative, and experimental. The field has by now produced a broad theoretical and empirical basis along with a variety of social transformation strategies and instruments, impacting disciplinary scientific fields as well as (policy) practice. In this article, we try to characterize the field by identifying its main perspectives, approaches and shared concepts, and its relevance to real-world sustainability problems and solutions.

Within the past decade, the attribution of extreme weather and climate events has emerged from a theoretical possibility into a subfield of climate science in its own right, providing scientific evidence on the role of anthropogenic climate change in individual extreme weather events, on a regular basis and using a range of approaches. Different approaches and thus different framings of the attribution question lead to very different assessments of the role of human-induced climate change. Although there is no right or wrong approach, the community is currently debating about the appropriate methodologies for addressing various stakeholder needs and scientific limitations. Tackling these limitations with more thorough model evaluation and meaningful bias corrections as well as going beyond the meteorological hazard and attributing the full impacts of extreme weather are the main challenges to face in the coming years.

The growing extraction of natural resources and the waste and emissions resulting from their use are directly or indirectly responsible for humanity approaching or even surpassing critical planetary boundaries. A sound knowledge base of society's metabolism, i.e., the physical exchange processes between society and its natural environment and the production and consumption processes involved, is essential to develop strategies for more sustainable resource use. Economy-wide material flow accounting (MFA) is a framework that provides consistent compilations of the material inputs to national economies, changes in material stocks within the economic system, and material outputs to other economies and the environment. We present the conceptual foundations of MFA and derived indicators and review the current state of knowledge of global patterns and trends of extraction, trade, and use of materials. We discuss the relation of material use and economic development and the decoupling of material use from economic growth in the context of sustainable resource use policies.

Systematic conservation planning (SCP) is a rapidly advancing discipline aimed at providing decision support for choices between alternate conservation actions. SCP is often used to inform choices about areas to protect, in order to optimize outcomes for biodiversity while minimizing societal costs. Despite the widespread application of SCP approaches, there is limited understanding of the types of impacts resulting from related projects, and when and where it is most effective. This is compounded by the absence of a standardized approach to evaluating and reporting on the outcomes of SCP projects. We highlight the challenges of undertaking evaluations of complex planning processes, the current state of knowledge about the outcomes of SCP projects, and emerging opportunities to improve evaluation. There is a need for clarity around theories of change, definitions of SCP and impact, and standardized reporting and information sharing across the discipline.