Description: Projected changes in crop yield mean and variability over West Africa in a world 1.5 K warmer than the pre-industrial era Ben Parkes, Dimitri Defrance, Benjamin Sultan, Philippe Ciais, and Xuhui Wang Earth Syst. Dynam., 9, 119-134, https://doi.org/10.5194/esd-9-119-2018, 2018 We present an analysis of three crops in West Africa and their response to short-term climate change in a world where temperatures are 1.5 °C above the preindustrial levels. We show that the number of crop failures for all crops is due to increase in the future climate. We further show the difference in yield change across several West African countries and show that the yields are not expected to increase fast enough to prevent food shortages.

Description: A quantitative approach to evaluating the GWP timescale through implicit discount rates Marcus C. Sarofim and Michael R. Giordano Earth Syst. Dynam. Discuss., https//doi.org/10.5194/esd-2018-6,2018 Manuscript under review for ESD (discussion: open, 1 comment) The 100 year GWP is the most widely used metric for comparing the climate impact of different gases such as methane and carbon dioxide. However, there have been recent arguments for the use of different timescales. This paper uses straightforward estimates of future damages to quantitatively determine the appropriate timescale as a function of how society discounts the future, and finds that the 100 year timescale is consistent with commonly used discount rates.

Description: Tagging moisture sources with Lagrangian and inertial tracers: Application to intense atmospheric river events Vicente Pérez-Muñuzuri, Jorge Eiras-Barca, and Daniel Garaboa-Paz Earth Syst. Dynam. Discuss., https//doi.org/10.5194/esd-2018-8,2018 Manuscript under review for ESD (discussion: open, 1 comment) Two Lagrangian tracers tools are evaluated for studies on atmospheric moisture sources and pathways. Usual Lagrangian methods consider the initial moisture volume to remain constant and the particle follows flow path lines exactly. In a different approach, the initial volume can be considered to depend on time as it is advected by the flow, due to thermodynamic processes. Drag and buoyancy forces must be considered then.

Description: A framework for modelling the complexities of food and water security under globalisation Brian J. Dermody, Murugesu Sivapalan, Elke Stehfest, Detlef P. van Vuuren, Martin J. Wassen, Marc F. P. Bierkens, and Stefan C. Dekker Earth Syst. Dynam., 9, 103-118, https://doi.org/10.5194/esd-9-103-2018, 2018 Ensuring sustainable food and water security is an urgent and complex challenge. As the world becomes increasingly globalised and interdependent, food and water management policies may have unintended consequences across regions, sectors and scales. Current decision-making tools do not capture these complexities and thus miss important dynamics. We present a modelling framework to capture regional and sectoral interdependence and cross-scale feedbacks within the global food system.

Description: How intermittency affects the rate at which rainfall extremes respond to changes in temperature Marc Schleiss Earth Syst. Dynam. Discuss., https//doi.org/10.5194/esd-2018-4,2018 Manuscript under review for ESD (discussion: open, 1 comment) The present study aims at shedding new light on the importance of intermittency and how it modulates the rate at which precipitation extremes (in current climate) depend on temperature. The analysis of 99 stations in the United States reveals that rapid increases or decreases in intermittency cause extremes to respond differently to changes in temperature than expected from Clausius–Clapeyron. A new model is proposed to help better anticipate changes across scales.

Description: Assessing the Impact of a Future Volcanic Eruption on Decadal Predictions Sebastian Illing, Christopher Kadow, Holger Pohlmann, and Claudia Timmreck Earth Syst. Dynam. Discuss., https//doi.org/10.5194/esd-2018-5,2018 Manuscript under review for ESD (discussion: open, 0 comments) The likelihood of a large volcanic eruption in the future provides the largest uncertainty concerning the evolution of the climate system on the time scale of a few years; but also an excellent opportunity to learn about the behavior of the climate system, and our models thereof. So the question emerges how predictable is the response of the climate system to future eruptions? By this we mean, to what extent will the volcanic perturbation affect decadal climate predictions and how does the pre-eruption climate state influence the impact of the volcanic signal on the predictions? To address these questions, we performed decadal forecasts with the MiKlip prediction system in the low-resolution configuration for the initialization years 2012 and 2014, which differ in the Pacific Decadal Oscillation (PDO) phase among other things. Each forecast contains an artificial Pinatubo-like eruption starting in June of the first prediction year. For the construction of the aerosol radiative forcing, we used the global aerosol model ECHAM5-HAM in a version adapted for volcanic eruptions. We investigate the response of different climate variables, including near-surface air temperature, precipitation, frost days, and sea ice area fraction. Our results show that the average global cooling response over four years of about 0.2 K and the precipitation decrease of about 0.025 mm/day, is relatively robust throughout the different experiments and seemingly independent of the initialization state. However, on a regional scale, we find substantial differences between the initializations. The cooling effect in the North Atlantic and Europe lasts longer and the Arctic sea ice increase is stronger than in the simulations initialized in 2014. In contrast, the forecast initialized with a negative PDO shows a prolonged cooling in the North Pacific basin.

Description: The concurrence of atmospheric rivers and explosive cyclogenesis in the North Atlantic and North Pacific basins Jorge Eiras-Barca, Alexandre M. Ramos, Joaquim G. Pinto, Ricardo M. Trigo, Margarida L. R. Liberato, and Gonzalo Miguez-Macho Earth Syst. Dynam., 9, 91-102, https://doi.org/10.5194/esd-9-91-2018, 2018 This paper analyses the potential role of atmospheric rivers in the explosive cyclone deepening. Using ERA-Interim reanalysis data for 1979–2011, we analyse the concurrence of atmospheric rivers and explosive cyclogenesis over the North Atlantic and North Pacific basins for the extended winter months (ONDJFM).

Description: Process-level improvements in CMIP5 models and their impact on tropical variability, the Southern Ocean, and monsoons Axel Lauer, Colin Jones, Veronika Eyring, Martin Evaldsson, Stefan Hagemann, Jarmo Mäkelä, Gill Martin, Romain Roehrig, and Shiyu Wang Earth Syst. Dynam., 9, 33-67, https://doi.org/10.5194/esd-9-33-2018, 2018 The performance of updated versions of the four earth system models (ESMs) CNRM, EC-Earth, HadGEM, and MPI-ESM is assessed in comparison to their predecessor versions used in Phase 5 of the Coupled Model Intercomparison Project. The Earth System Model Evaluation Tool (ESMValTool) is applied to evaluate selected climate phenomena in the models against observations. This is the first systematic application of the ESMValTool to assess and document the progress made during an extensive model development and improvement project. This study focuses on the South Asian monsoon (SAM) and the West African monsoon (WAM), the coupled equatorial climate, and Southern Ocean clouds and radiation, which are known to exhibit systematic biases in present-day ESMs. The analysis shows that the tropical precipitation in three out of four models is clearly improved. Two of three updated coupled models show an improved representation of tropical sea surface temperatures with one coupled model not exhibiting a double Intertropical Convergence Zone (ITCZ). Simulated cloud amounts and cloud–radiation interactions are improved over the Southern Ocean. Improvements are also seen in the simulation of the SAM and WAM, although systematic biases remain in regional details and the timing of monsoon rainfall. Analysis of simulations with EC-Earth at different horizontal resolutions from T159 up to T1279 shows that the synoptic-scale variability in precipitation over the SAM and WAM regions improves with higher model resolution. The results suggest that the reasonably good agreement of modeled and observed mean WAM and SAM rainfall in lower-resolution models may be a result of unrealistic intensity distributions.

Description: Contribution of atmospheric circulation to recent off-shore sea-level variations in the Baltic Sea and the North Sea Sitar Karabil, Eduardo Zorita, and Birgit Hünicke Earth Syst. Dynam., 9, 69-90, https://doi.org/10.5194/esd-9-69-2018, 2018 We analysed the contribution of atmospheric factors to interannual off-shore sea-level variability in the Baltic Sea region. We identified a different atmospheric circulation pattern that is more closely linked to sea-level variability than the NAO. The inverse barometer effect contributes to that link in the winter and summer seasons. Freshwater flux is connected to the link in summer and net heat flux in winter.The new atmospheric-pattern-related wind forcing plays an important role in summer.

Description: How Robust is Your System Resilience? Mehran Homayounfar, Rachata Muneepeerakul, and John M. Anderies Earth Syst. Dynam. Discuss., https//doi.org/10.5194/esd-2017-124,2018 Manuscript under review for ESD (discussion: open, 1 comment) For many complex social-ecological systems, robustness and resilience are difficult to quantify and the connections and trade-offs between them difficult to study. In this study, we present an analytical framework to address the linkage between robustness and resilience more systematically. The results reveal the tradeoffs between robustness and resilience. They also show how the nature of such tradeoffs varies with the choices of certain policies internal stresses and external disturbances.