Addressing ‘deep’ uncertainty over long-term climate in major infrastructure projects: four innovations of the Thames Estuary 2100 Project

Abstract

Climate change brings new challenges for traditional environmental risk management, particularly for major infrastructure projects, where the decisions made today can have long-term implications. A major challenge is that projections of future climate are deeply uncertain. If this uncertainty is not managed appropriately, long-lived infrastructure may need to be replaced or expensively retrofitted before the end of the design lifetime. The Thames Estuary 2100 Project (TE2100) was one of the first major infrastructure projects to explicitly recognise and address the issue of the deep uncertainty in climate projections throughout the planning process. In this paper, we discuss the innovations and techniques that were adopted in this case that enabled it to cope with this uncertainty. We classify the overall approach as 'dynamic robustness', which aims to build flexible strategies that can be changed over time as more is learnt or as conditions change. The project combined four key innovations: (1) the 'decision-centric' process; (2) the combination of numerical models and expert judgement to develop narrative sea level rise scenarios; (3) the adoption of an 'Adaptation Pathways' approach to identify the timing and sequencing of possible 'pathways' of adaptation measures over time under different scenarios; and (4) the development of a monitoring framework that triggers defined decision points. A secondary focus of this paper is an exploration of how climate information was used in TE2100. We suggest that the techniques employed in TE2100 imply different needs from climate science that may cause them to redefine their research priorities related to adaptation; namely a shift in emphasis away from probabilistic modelling, toward greater investment in observations and monitoring; improved understanding of historical climate variability; and improved understanding of physical Earth system processes and their representation in models to enhance 'best guess' models and to better bound future projections using narrative scenarios.

Method selection in adaptation research: the case of the Delta Programme for the Dutch Wadden region

“…This includes a reorientation on the impacts of climate change on existing (water) management objectives. This conforms recent studies that have suggested that adaptation research should start from the adaptation problem in its decision context of socio-economic challenges in order to satisfy information needs of policymakers in the face of long-term planning under uncertainty (Kwadijk et al 2010;Ranger et al 2013;Reeder and Ranger 2011). A reorientation would also be useful in cases where adaptation is to be integrated in existing policies.…”

“…Many different tools and methods exist to do problem-oriented adaptation research and provide decision support (e.g. Hallegatte et al 2012;Ranger et al 2013;Walker et al 2012;Wise et al 2014). Yet which approach is applicable in which situation?…”

Understanding and responding to danger from climate change: the role of key risks in the IPCC AR5

“…For instance, risks to coastal infrastructure and low-lying ecosystems can depend strongly on whether sea level rise is moderate or extreme, and to address this, the Australasia assessment separately evaluated risk levels for different sea-level-rise magnitudes. Iterative adjustment of adaptive responses over time can be a way to address such uncertainty about future sea level rise, recognizing that current choices can constrain or expand future options (e.g., Ranger et al 2013). A priority for future assessment and research is rigorous study of adaptation effectiveness, for current and future actions, across the determinants of risk.…”

Projected Change—North Sea

“…Katsman et al 2011;Ranger et al 2013) is the possibility of an increase beyond the likely range projected by physically based climate models. Such a contribution could originate from additional dynamic ice sheet contributions, linked to the movement of fast ice streams and outlet glaciers.…”