Stormy geomorphology: geomorphic contributions in an age of climate extremes

Abstract

The increasing frequency and/or severity of extreme climate events are becoming increasingly apparent over multidecadal timescales at the global scale, albeit with relatively low scientific confidence. At the regional scale, scientific confidence in the future trends of extreme event likelihood is stronger, although the trends are spatially variable. Confidence in these extreme climate risks is muddied by the confounding effects of internal landscape system dynamics and external forcing factors such as changes in land use and river and coastal engineering. Geomorphology is a critical discipline in disentangling climate change impacts from other controlling factors, thereby contributing to debates over societal adaptation to extreme events. We review four main geomorphic contributions to flood and storm science. First, we show how palaeogeomorphological and current process studies can extend the historical flood record while also unraveling the complex interactions between internal geomorphic dynamics, human impacts and changes in climate regimes. A key outcome will be improved quantification of flood probabilities and the hazard dimension of flood risk. Second, we present evidence showing how antecedent geomorphological and climate parameters can alter the risk and magnitude of landscape change caused by extreme events. Third, we show that geomorphic processes can both mediate and increase the geomorphological impacts of extreme events, influencing societal risk. Fourthly, we show the potential of managing flood and storm risk through the geomorphic system, both near-term (next 50 years) and longer-term. We recommend that key methods of managing flooding and erosion will be more effective if risk assessments include palaeodata, if geomorphological science is used to underpin nature-based management approaches, and if land-use management addresses changes in geomorphic process regimes that extreme events can trigger. We argue that adopting geomorphologically-grounded adaptation strategies will enable society to develop more resilient, less vulnerable socio-geomorphological systems fit for an age of climate extremes.

Modeling and Upscaling Plot-Scale Soil Erosion under Mediterranean Climate Variability

“…Extreme precipitation events can lead to considerable soil loss, with implications for downstream flood risk, and shallow landslides [4]. Soil erosion is a great concern all over the world, and a primary problem in many Mediterranean-climate areas of Southern Europe, which are characterized by typical within-year seasonality in precipitation distribution, with heavy rainfalls in fall and spring, and a relatively large year-to-year climate variability [5,6]. This feature affects, in turn, the local hydrological conditions with related instabilities in the vegetation ecosystems when severe perturbations occur [7].…”

Paleohydraulic Reconstruction of Modern Large Floods at Subcritical Speed in a Confined Valley: Proof of Concept

“…This novel application of paleohydrology could be used in other study sites that have experienced similar changes in the stage-discharge relationship in an age of climate extremes [67].…”

Enhancing the Role of Geoconservation in Protected Area Management and Nature Conservation

“…For example, at the coast and along river corridors (e.g. Hopkins et al 2007;Opperman et al 2009;Brazier et al 2012;Jackson et al 2012;Arkema et al 2013;Temmerman et al 2013;Tessler et al 2015), such solutions can help to provide resilience and reduce the vulnerability of protected areas and human communities to natural hazards such as coastal erosion, flooding, landslides, and soil erosion under more extreme climatic events (Dudley et al 2010(Dudley et al , 2015Naylor et al 2017).…”