ISMIP6 Antarctica: a multi-model ensemble of the Antarctic ice sheet evolution over the 21st century The Cryosphere DOI 10.5194/tc-14-3033-2020 20 October 2020 The Antarctic ice sheet has been losing mass over at least the past 3 decades in response to changes in atmospheric and oceanic conditions. This study presents an ensemble of model simulations of the Antarctic evolution over the 2015–2100 period based on various ice sheet models, climate forcings and emission scenarios. Results suggest that the West Antarctic ice sheet will continue losing a large amount of ice, while the East Antarctic ice sheet could experience increased snow accumulation. Read more
A protocol for calculating basal melt rates in the ISMIP6 Antarctic ice sheet projections The Cryosphere DOI 10.5194/tc-14-3111-2020 20 October 2020 To predict the future Antarctic contribution to sea level rise, we need to use ice sheet models. The Ice Sheet Model Intercomparison Project for AR6 (ISMIP6) builds an ensemble of ice sheet projections constrained by atmosphere and ocean projections from the 6th Coupled Model Intercomparison Project (CMIP6). In this work, we present and assess a method to derive ice shelf basal melting in ISMIP6 from the CMIP6 ocean outputs, and we give examples of projected melt rates. Read more
The making of the New European Wind Atlas – Part 1: Model sensitivity Geoscientific Model Development DOI 10.5194/gmd-13-5053-2020 16 October 2020 Wind energy resource assessment routinely uses numerical weather prediction model output. We describe the evaluation procedures used for picking the suitable blend of model setup and parameterizations for simulating European wind climatology with the WRF model. We assess the simulated winds against tall mast measurements using a suite of metrics, including the Earth Mover’s Distance, which diagnoses the performance of each ensemble member using the full wind speed and direction distribution. Read more
Review article: Hilbert problems for the climate sciences in the 21st century – 20 years later Nonlinear Processes in Geophysics DOI 10.5194/npg-27-429-2020 15 October 2020 The scientific questions posed by the climate sciences are central to socioeconomic concerns today. This paper revisits several crucial questions, starting with What can we predict beyond 1 week, for how long, and by what methods?, and ending with Can we achieve enlightened climate control of our planet by the end of the century? We review the progress in dealing with the nonlinearity and stochasticity of the Earth system and emphasize major strides in coupled climate–economy modeling. Read more
The future sea-level contribution of the Greenland ice sheet: a multi-model ensemble study of ISMIP6 The Cryosphere DOI 10.5194/tc-14-3071-2020 15 October 2020 In this paper we use a large ensemble of Greenland ice sheet models forced by six different global climate models to project ice sheet changes and sea-level rise contributions over the 21st century. The results for two different greenhouse gas concentration scenarios indicate that the Greenland ice sheet will continue to lose mass until 2100, with contributions to sea-level rise of 90 ± 50 mm and 32 ± 17 mm for the high (RCP8.5) and low (RCP2.6) scenario, respectively. Read more
In situ measurements of soil and plant water isotopes: a review of approaches, practical considerations and a vision for the future Hydrology and Earth System Sciences DOI 10.5194/hess-24-4413-2020 13 October 2020 Water isotopes are a scientific tool that can be used to identify sources of water and answer questions such as From which soil depths do plants take up water?, which are highly relevant under changing climatic conditions. In the past, the measurement of water isotopes required tremendous effort. In the last decade methods have advanced and can now be applied in the field. Herein, we review the current status of direct field measurements of water isotopes and discuss future applications. Read more
Storm tide amplification and habitat changes due to urbanization of a lagoonal estuary Natural Hazards and Earth System Sciences DOI 10.5194/nhess-20-2415-2020 13 October 2020 The geometry of estuaries is often altered through dredging to make room for ships and with extensive landfill over wetlands to enable development. Here, we use historical maps to help create computational models of seawater flow around and into a lagoonal bay of New York City for the 1880s and 2010s. Our results show that these past man-made changes cause higher coastal storm tides and that they result specifically from deeper depths, expanded inlet width, and landfill. Read more
A 6-year lidar survey reveals enhanced rockwall retreat and modified rockfall magnitudes/frequencies in deglaciating cirques Earth Surface Dynamics DOI 10.5194/esurf-8-753-2020 8 October 2020 Rockfall size and frequency in two deglaciating cirques in the Central Alps, Austria, is analysed based on 6-year rockwall monitoring with terrestrial lidar (2011–2017). The erosion rates derived from this dataset are very high due to a frequent occurrence of large rockfalls in freshly deglaciated areas. The results obtained are important for rockfall hazard assessments, as, in rockwalls affected by glacier retreat, historical rockfall patterns are not good predictors of future events. Read more
Current glacier recession causes significant rockfall increase: the immediate paraglacial response of deglaciating cirque walls Earth Surface Dynamics DOI 10.5194/esurf-8-729-2020 8 October 2020 Climate warming is causing significant ice surface lowering even in the uppermost parts of alpine glaciers. Using terrestrial lidar, we quantify rockfall in freshly exposed cirque walls. During 6-year monitoring (2011–2017), an extensive dataset was established and over 600 rockfall events identified. Drastically increased rockfall activity following ice retreat can clearly be observed as 60 % of the rockfall volume detached from less than 10 m above the glacier surface. Read more
A Bayesian framework for emergent constraints: case studies of climate sensitivity with PMIP Climate of the Past DOI 10.5194/cp-16-1715-2020 6 October 2020 Interest in past climates as sources of information for the climate system has grown in recent years. In particular, studies of the warm mid-Pliocene and cold Last Glacial Maximum showed relationships between the tropical surface temperature of the Earth and its sensitivity to an abrupt doubling of atmospheric CO 2 . In this study, we develop a new and promising statistical method and obtain similar results as previously observed, wherein the sensitivity does not seem to exceed extreme values. Read more