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• Impact and uncertainty framework for the identification of compound hydro-hazards. • UK example application using EDgE RCP8.5 projections. • NE Scotland and SW UK identified as spatio-temporally compound hotspot regions. • Hydrological models identified as the largest source of variability. • Raises questions regarding spatial variability of hydroclimatological modelling uncertainty. There exists an increasing need to understand the impact of climate change on the hydrological extremes of flood and drought, collectively referred to as 'hydro-hazards'. At present, current methodology are limited in their scope, particularly with respect to inadequate representation of the uncertainty in the hydroclimatological modelling chain. This paper proposes spatially consistent comprehensive impact and uncertainty methodological framework for the identification of compound hydro-hazard hotspots – hotspots of change where concurrent increase in mean annual flood and drought events is projected. We apply a quasi-ergodic analysis of variance (QE-ANOVA) framework, to detail both the magnitude and the sources of uncertainty in the modelling chain for the mean projected mean change signal whilst accounting for non-stationarity. The framework is designed for application across a wide geographical range and is thus readily transferable. We illustrate the ability of the framework through application to 239 UK catchments based on hydroclimatological projections from the EDgE project (5 CMI5-GCMs and 3 HMs, forced under RCP8.5). The results indicate that half of the projected hotspots are temporally concurrent or temporally successive within the year, exacerbating potential impacts on society. The north-east of Scotland and south-west of the UK were identified as spatio-temporally compound hotspot regions and are of particular concern. This intensification of the hydrologic dynamic (timing and seasonality of hydro-hazards) over a limited time frame represents a major challenge for future water management. Hydrological models were identified as the largest source of variability, in some instances exceeding 80% of the total variance. Critically, clear spatial variability in the sources of modelling uncertainty was also observed; highlighting the need to apply a spatially consistent methodology, such as that presented. This application raises important questions regarding the spatial variability of hydroclimatological modelling uncertainty. In terms of water management planning, such findings allow for more focussed studies with a view to improving the projections which inform the adaptation process. [ABSTRACT FROM AUTHOR]

We begin our April issue with a paper describing the developments and effects of storm ‘Katie’, which brought significant effects to the United Kingdom on Easter Monday, 2015. In ‘Storm Katie – Rapid cyclogenesis and damaging winds of Easter Monday 2016’ on p. 103, Steven Ramsdale and Jason Kelly describe the meteorological developments that developed this low‐pressure system, the uncertainties associated with its development, the warnings issued and the damage caused, in part limited by its presence on a Bank Holiday. On p. 109, Colin Clark describes a flood 112 years ago in ‘The storm and flood of 13 May 1906 at Mells, Somerset, UK’ Dr Clark discusses the significance of the flood and its possible return period using synoptic charts of the time and descriptions published in local newspapers immediately following the event, emphasising our need to know more about floods in history. One of the least explored parts of the Middle East is the Empty Quarter. In the 1940s and 50s, the English explorer and writer Wilfred Thesiger crossed this area of extreme aridity. His discoveries and travels are described by Michael de Villiers in ‘Thesiger's weather in the Arabian Peninsula’ on p. 120. On p. 123, we present Iain Cameron and Adam Watson's annual review of the survival of snow on Scottish mountains. The overall warmth of last year is reflected in this year's title: ‘No Scottish snow patches survive until winter 2017/2018’. Weather and climate have a significant effect on human life and this journal often describes significant weather events, especially those that have affected Britain. But the local variability of weather may arguably present a more significant effect – not least, in the Developing World. Many factors affect school attendance, but weather and climate, including drought, rainstorms and dust pose important challenges, sometimes because of the secondary effects. Joseph Adejuwon discusses these effects in the Sahel zone in ‘Climate variability and the dichotomy in male–female school attendance: a case study of Zamfara State in semi‐arid Nigeria’ on p. 125. [ABSTRACT FROM AUTHOR]

With evidence suggesting that climate change is resulting in changes within the hydrologic cycle, the ability to robustly model hydroclimatic response is critical. This paper assesses how extreme runoff—1:2- and 1:30-year return period (RP) events—may change at a regional level across the UK by the 2080s (2069–2098). Capturing uncertainty in the hydroclimatic modelling chain, flow projections were extracted from the EDgE (End-to-end Demonstrator for improved decision-making in the water sector in Europe) multi-model ensemble: five Coupled Model Intercomparison Project (CMIP5) General Circulation Models and four hydrological models forced under emissions scenarios Representative Concentration Pathway (RCP) 2.6 and RCP 8.5 (5 × 4 × 2 chains). Uncertainty in extreme value parameterisation was captured through consideration of two methods: generalised extreme value (GEV) and generalised logistic (GL). The method was applied across 192 catchments and aggregated to eight regions. The results suggest that, by the 2080s, many regions could experience large increases in extreme runoff, with a maximum mean change signal of +34% exhibited in East Scotland (1:2-year RP). Combined with increasing urbanisation, these estimates paint a concerning picture for the future UK flood landscape. Model chain uncertainty was found to increase by the 2080s, though extreme value (EV) parameter uncertainty becomes dominant at the 1:30-year RP (exceeding 60% in some regions), highlighting the importance of capturing both the associated EV parameter and ensemble uncertainty. [ABSTRACT FROM AUTHOR]

• Timing of ecosystem restoration can influence its resilience to climate change. • This study quantifies the opportunity cost of delaying restoration-based GHG mitigation. • Delaying mitigation substantially decreases the economic benefits of peatland restoration. • Climate change beliefs explain variation in benefits of increased peatland resilience. • Results provide economic arguments for early investments in nature-based solutions. Ecosystem restoration and, in particular, peatland restoration, are considered a promising greenhouse gas (GHG) mitigation strategy to move towards net zero emissions. To remain within acceptable limits for projected warming scenarios, inaction with respect to GHG mitigation in the short term implies a need for even larger removals of GHGs in the longer term, which can be conceptualized as a 'mitigation debt'. This paper explores the economic implications of delaying GHG mitigation through ecosystem restoration using data of a large survey (N = 1377) that included a choice experiment to elicit the public's willingness to pay (WTP) for peatland restoration in Scotland, UK. The valuation specifically considers the interaction between the timing of restoration action and long-term ecosystem resilience. We find that respondents have a substantial WTP for peatland restoration. Importantly, we find considerable benefits for early restoration action (up to £191 million annually in our case study), which is linked to an increased resilience of peatlands under future climate change. This demonstrates that delaying restoration and thus accumulating a mitigation debt has an important opportunity cost that substantially decreases the related economic benefits. Attitudes towards climate change and climate change beliefs are found to explain variation in the public's WTP. Our research strengthens the economic argument for not delaying climate change mitigation through ecosystem restoration, demonstrating that the mitigation debt also translates into a welfare loss. To fully realise the potential benefits associated with immediate mitigation using peatland restoration, however, more needs to be understood about the mechanisms that facilitate large-scale implementation in practice. [ABSTRACT FROM AUTHOR]

Meeting global targets that maintain temperatures at 1.5 °C above pre-industrial levels while adapting to the growing impacts of climate change requires significant and rapid societal change. Within this context, there has been growing interest in building community resilience to shocks and stressors and as a forward-looking process. Yet while there has been extensive attention to conceptual aspects, there has been much less on how this can be achieved in practice. This research worked with three communities in Scotland (UK) regularly exposed to flooding and other integrated challenges to learn from action about community resilience building. A carefully developed four-tiered transdisciplinary approach was applied that included: relationship-building; enhancing capacities to work with interconnections; enabling processes; and supportive action-oriented research. The findings of the analysis of the system dynamics that were occurring during the resilience-building process highlight that it is a complex and messy social process. Yet, it also shows that if quality and sufficient quantity of support and time to help surface and deliberate on underlying assumptions about communities and change is provided, it can be possible to stimulate emergence of beneficial reinforcing social dynamics that begin to support collaborative and systemic action. To further advance know how about resilience building, much greater focus will be needed on the 'how' of resilience. This, in turn, will require new framings of, and approaches for, community resilience and new framings of research, knowledge and knowing. [ABSTRACT FROM AUTHOR]

Anthropogenic climate change calls for rapid and enormous cuts in emissions of CO2 and other greenhouse gases to mitigate future impacts. Even with these, however, many changes will continue to occur over the next 20-30 years adding to those already observed. Adaptation is crucial and urgent, but identifying strategies is complex and requires dialogue and cooperation among stakeholders, especially for infrastructure that exhibits interdependent risks in that failure in one type may impact others. A serious game was codeveloped with infrastructure operators to communicate climate projections and climate hazards to them; identify potential interdependencies, cascading impacts, cumulative effects, and vulnerability hot spots; and engage them to improve cooperation and enable a shared understanding of cross-cutting climate risks and interdependencies. In the game, players provide present-day infrastructure services in the Inverclyde district, Scotland, as they experience a plausible decade of 2050s weather characterized by a sequence of hazard events. This sequence was extracted from climate model projections to ensure scientific plausibility. The infrastructure operators were responsible for drinking water and gas supplies, road and rail transport, wastewater treatment, and civil infrastructure. When playing the game the participating U.K. infrastructure providers felt that although there were challenges, they could cope with 2050s climate change. None of the projected hazard events were anticipated to cause catastrophic impact cascades on infrastructure. The game was positively received, and the study suggests it is a useful tool to both communicate climate hazards and explore potential interdependent risks by bringing together stakeholders' individual expertise in an engaging way. [ABSTRACT FROM AUTHOR]