Max Planck Institute Research Articles

AMSD: The Australian Message Stick Database.

Message sticks are wooden objects once widely used in Indigenous Australia for facilitating important long-distance communications. Within this tradition an individual wishing to send a message would carve a stick and apply conventional symbols to its surface. The stick was entrusted to a messenger who carried the object into the territory of another community together with a memorised oral statement. Between the 1880s and the 1910s, settlers and international scholars took great interest in message sticks and this was reflected in efforts to document, collect and store them in museums worldwide. However, by this period, the practice was already undergoing profound changes, having been abandoned in many parts of the continent and transformed in others. While message sticks were still being used in a traditional way in Western Arnhem Land up until at least the late 1970s, today they feature in public interactions between Indigenous and non-Indigenous organisations, in art production and in oral narrations. Accordingly many questions concerning the history, pragmatics and global significance of message stick communication remain unanswered. To address this we have compiled the Australian Message Stick Database, a new resource hosted at the Max Planck Institute for Evolutionary Anthropology, Leipzig, and The Australian National University, Canberra. It contains images and data for over 1500 individual message sticks sourced from museums, and supplemented with information derived from published and unpublished manuscripts, private collections, and from field recordings involving contemporary Indigenous consultants. For the first time, knowledge about Australian message sticks can be evaluated as a single set allowing scholars and Traditional Owners to explore previously intractable questions about their histories, meanings and purposes.

Effects of idealized land cover and land management changes on the atmospheric water cycle

Abstract. Land cover and land management changes (LCLMCs) play an important role in achieving low-end warming scenarios through land-based mitigation. However, their effects on moisture fluxes and recycling remain uncertain, although they have important implications for the future viability of such strategies. Here, we analyse the impact of idealized LCLMC scenarios on atmospheric moisture transport in three different Earth system model (ESMs): the Community Earth System Model (CESM), the Max Planck Institute Earth System Model (MPI-ESM), and the European Consortium Earth System Model (EC-EARTH). The LCLMC scenarios comprise of a full cropland world, a fully afforested world, and a cropland world with unlimited irrigation expansion. The effects of these LCLMC in the different ESMs are analysed for precipitation, evaporation, and vertically integrated moisture flux convergence to understand the LCLMC-induced changes in the atmospheric moisture cycle. Then, a moisture tracking algorithm is applied to assess the effects of LCLMC on moisture recycling at the local (grid cell level) and the global scale (continental moisture recycling). By applying a moisture tracking algorithm on fully coupled ESM simulations we are able to quantify the complete effects of LCLMC on moisture recycling (including circulation changes), which are generally not considered in moisture recycling studies. Our results indicate that cropland expansion is generally causing a drying and reduced local moisture recycling, while afforestation and irrigation expansion generally cause wetting and increased local moisture recycling. However, the strength of this effect varies across ESMs and shows a large dependency on the dominant driver. Some ESMs show a dominance of large-scale atmospheric circulation changes while other ESMs show a dominance of local to regional changes in the atmospheric water cycle only within the vicinity of the LCLMC. Overall, these results corroborate that LCLMC can induce substantial effects on the atmospheric water cycle and moisture recycling, both through local effects and changes in atmospheric circulation. However, more research is needed to constrain the uncertainty of these effects within ESMs to better inform future land-based mitigation strategies.

New Genomic Techniques and Intellectual Property Law: Challenges and Solutions for the Plant Breeding Sector ‒ Position Statement of the Max Planck Institute for Innovation and Competition

Abstract On 5 July 2023, the European Commission proposed a regulation aiming to ease the requirements for the marketing authorisation of plants obtained through certain new genomic techniques (NGTs) within the European Union (EU). While NGTs are expected to become more attractive to breeders and farmers, the complexity of the intellectual property (IP) landscape surrounding these techniques and resulting products may negatively impact technology diffusion and innovation. Given numerous concerns related to IP protection for NGTs and NGT-derived plants, this Position Statement from the Max Planck Institute for Innovation and Competition presents a set of policy recommendations for facilitating access to and utilisation of IP-protected NGTs and NGT-derived products in the breeding sector.

MULTIVALUED WAVES AND THE RICHTMYER–MESHKOV INSTABILITY AS THE CAUSES OF THE FORMATION OF GALAXIES

A few months ago, the Max Planck Institute (Dresden, Germany) organized an International Seminar for outstanding researchers of such a remarkable phenomenon as “extreme waves”. The seminar was led by such famous professors as Nail Akhdiev (Australian National University, Canberra, Australia) [1], Helmut Brand (University of Bayreuth, Germany) [2] and Amin Chabchub (Kyoto University, Japan) [3]. Thе phenomenon of "Extreme waves" is remarkable since widely spread in Nature, and at the same time it is used widely in technology. In particular it is used in modern optical communications (nonlinear optics). The results of the Workshop are widely discussed by experts. They preview promising new directions springing from group efforts. This article is a review of my seminar presentation. At the same time, it includes some results of my book, which is being prepared for publication. The main outlines of this book are outlined by Marat Aksanovich Ilgamov in his article [5]. The book is devoted to multivalued waves existing in various scalar fields. An attempt is made to describe, on this basis, the entire variety of fundamental physical phenomena of the world around us, starting with quantum phenomena and ending with the emergence and initial development of the Universe. It is known that Einstein tried to build a unified (interdisciplinary) field theory that would unite all interactions in nature into a single system. My report to Dresden made an attempt to use this idea, which was developed in the mentioned book and this article. The first three parts of this article examine the stability of Richtmyer–Meshkov and Faraday waves. The last part discusses the theory of the origin of the Universe proposed in [4, 12]. The birth of galaxies in the first moments of the process of spherical expansion of our Universe is associated with the Richtmyer–Meshkov instability.

The history of the Vienna Protocol on dealing with Holocaust era human remains and its resonance with ethical considerations in African American bioarcheology.

The Vienna Protocol on How to Deal with Holocaust Era Human Remains describes what to do when possibly Jewish human remains are found. Based on Jewish medical ethics, it responds to the 2014-2017 discoveries of human remains stemming from biomedical contexts of the Nazi period. Among the finding sites were the Dahlem campus of the Free University of Berlin, the Medical University of Strasbourg, and Max Planck Institute archives. The Vienna Protocol is unique among similar recommendations on Nazi era human remains in its representation of the voices of those who suffered violence and were targeted as victims by Nazi persecution. In addition to discussing the ethics of dealing with physical human remains, these recommendations address the use of images (i.e., visual data) from the bodies of victims of Nazi violence. This paper presents the historical background of the Vienna Protocol and its impact. It also offers a first analysis as to why, at the time of the protocol's formulation, its authors were unaware of its resonance with ethical considerations from African American bioarcheology and a new ethical culture in bioanthropology. Potential reasons for this disconnect may include the historic marginalization of the voices of black scholars in anthropology within the wider scientific community. However, more detailed studies are needed to analyze similarities and differences between the histories and continuities of antisemitism and racism in Europe and the U.S.A., and their ties with scientific theories and practices of disciplines that gain knowledge from human remains.

Impact of groundwater representation on heat events in regional climate simulations over Europe

Abstract. The representation of groundwater is simplified in most regional climate models (RCMs), potentially leading to biases in the simulations. This study introduces a unique dataset from the regional Terrestrial Systems Modelling Platform (TSMP) driven by the Max Planck Institute Earth System Model at Low Resolution (MPI-ESM-LR) boundary conditions in the context of dynamical downscaling of global climate models (GCMs) for climate change studies. TSMP explicitly simulates full 3D soil and groundwater dynamics together with overland flow, including complete water and energy cycles from the bedrock to the top of the atmosphere. By comparing the statistics of heat events, i.e., a series of consecutive days with a near-surface temperature exceeding the 90th percentile of the reference period, from TSMP and those from GCM–RCM simulations with simplified groundwater dynamics from the COordinated Regional Climate Downscaling EXperiment (CORDEX) for the European domain, we aim to improve the understanding of how groundwater representation affects heat events in Europe. The analysis was carried out using RCM outputs for the summer seasons of 1976–2005 relative to the reference period of 1961–1990. While our results show that TSMP simulates heat events consistently with the CORDEX ensemble, there are some systematic differences that we attribute to the more realistic representation of groundwater in TSMP. Compared to the CORDEX ensemble, TSMP simulates fewer hot days (i.e., days with a near-surface temperature exceeding the 90th percentile of the reference period) and lower interannual variability and decadal change in the number of hot days on average over Europe. TSMP systematically simulates fewer heat waves (i.e., heat events lasting 6 d or more) compared to the CORDEX ensemble; moreover, they are shorter and less intense. The Iberian Peninsula is particularly sensitive with respect to groundwater. Therefore, incorporating an explicit 3D groundwater representation in RCMs may be a key in reducing biases in simulated duration, intensity, and frequency of heat waves in Europe. The results highlight the importance of hydrological processes for the long-term regional climate simulations and provide indications of possible potential implications for climate change projections.

Tagging Manorial Police Regulations in Medieval and Early Modern Flanders: Some Methodological Reflections

In the1990s, the team around Karl Härter and Michael Stolleis at the Max PlanckInstitute for European Legal History (today: the Max Planck Institute for LegalHistory and Legal Theory) developed a four-tier taxonomy to tag policeordinances in the Holy Roman Empire. This taxonomy contained some 1,200keywords, divided into 5 societal sectors, 25 regulatory areas, and c. 200police matters. The goal of this taxonomy was to enable comparative,interterritorial research. In our present research, we took this taxonomy,designed for princely legislation and ordinances promulgated in imperial towns,and applied it to a corpus of 109 medieval and early modern police regulations,containing thousands of legal provisions on all aspects of daily life in manorsin the county of Flanders. While the taxonomy was very helpful for analysingthese provisions, there were also some challenges related to the fact that wewere applying the taxonomy to another region and to another normative sourcetype. Given the continuing process of elaborating the taxonomy and the translation from Germaninto different languages, we argue that some coordination is necessary to avoidthat the meaning of the keywords gets lost in translation. Applying thetaxonomy is not a self-evident process. It is indispensable to have a users’guide and careful decision about translations to guarantee that the taxonomycan become a standard tool for tagging normative sources and enabling thecomparison of norms across territorial and linguistic borders.

Spatiotemporal correlation based self-adaptive pose estimation in complex scenes

In the current digital era, large-scale Artificial Intelligence (AI) models have fundamentally changed the landscape of the AI field. These models excel at extracting complex patterns and information from massive datasets, making them indispensable in a wide range of domains. With the advancement of large-scale AI models, pose estimation has achieved improved performance in managing large data sets and complex computations. However, most existing pose estimation methods suffer from the problem of inaccurate pose graph extraction in complex scenes. Moreover, the existing methods all focus on the message, ignoring the fact that it may not be optimal for the graph structure. This fixed graph structure is difficult to reflect the real dependency relationship between joint points. This study proposes a Character Redetection Model (CRM) to dynamically adjust the foreground extraction strategies to solve these problems. The CRM locates the target position based on the rich spatiotemporal information between the adjacent frames, effectively solving the problem of inaccurate foreground acquisition caused by occlusion and blur in complex scenes. In addition, an Uncertainty Graph Structure (UGS) is designed, which adaptively learns the topological structure of graphs with different Graph Convolutional Network (GCN) layers and skeleton samples in an end-to-end manner and mines the hidden space dependency between data to accurately model the different poses of the characters. The experimental results show that the proposed method achieves a superior performance compared to that of the State-Of-The-Art (SOTA) method, with a percentage of correct keypoints (PCK) value of 94.6% at the Max Planck Institute for Informatics (MPII), along with the mean Average Precision (mAP) values of 83.3% and 82.1% on the PoseTrack2017 and classroom pose datasets, respectively.

Projections and patterns of heat-related mortality impacts from climate change in Southeast Asia

This study aims to investigate the impact of climate change on heat-related mortality in Southeast Asia in the future. The ensemble mean from five General Circulation Models (GCMs) including the Flexible Global Ocean-Atmosphere-Land System Model: Grid-Point Version 3 (FGOALS-g3), Max Planck Institute Earth System Model Version 1.2 (MPI-ESM1-2-LR), EC-Earth3, The Meteorological Research Institute Earth System Model Version 2.0 (MRI-ESM2-0), and Geophysical Fluid Dynamics Laboratory Earth System Model Version 4 (GFDL-ESM4) was used to project severe temperatures and heat indices in Southeast Asia under the Coupled Model Intercomparison Projects Phase 6 (CMIP6). This data was used to correlate with mortality data from the Global Burden of Disease database to quantify heat-related mortality in the region. The ensemble mean results show a reasonable level of accuracy in capturing temperature patterns in the Southeast Asian region with an R2 of 0.96, root mean square error (RMSE) of 0.84 and a standard deviation of residual (SDR) of 0.02. When compared to the baseline (1990–2019), temperature extreme indices are rising across all climatic scenarios, with a substantial increase in the SSP3–7.0 and SSP5–8.5 scenarios, ranging from 10% to 50% over the regions, with the heat index predicted to peak in the middle of the century. The two low-emission scenarios, SSP1-2.6 and SSP2-4.5, on the other hand, anticipate more moderate increases, indicating a potentially less severe impact on the region. As a result, under high-emission scenarios, there is expected to be a significant increase in heat-related mortality across Southeast Asia. The expected impact is estimated to affect between 200 and 300 people per 100,000 people from 2030 to 2079, accordingly. Our results highlight the critical need to address health-related impacts of climate change in this region.

Perfil bibliométrico da Revista Ius Commune

The aim of this research was to investigate the profile and characteristics of the scientific output published in the Max Planck Institute's journal Ius Commune between 1967 and 2001. Bibliometric techniques were used, with a predominantly quantitative approach. The research universe consisted of all the articles published in all the editions of this journal. The bibliometric indicators measured were a total of 28 editions, 285 articles, 163 authors, 26 female authors, 22 nationalities and nine languages. The author who published the most in the journal was Johannes-Michael Scholz, with 19 articles. The nationality with the highest number of authors in the journal is German. The results show an overview of the topics covered and the authors, nationalities and languages that have contributed to the journal Ius Commune. A discussion of the results of this research concludes the importance of the journal Ius Commune for the diffusion, dissemination and socialization of scientific production on legal topics and for the formation of a legal conceptual framework for European unification.

Cell scientist to watch – Jörg Renkawitz

ABSTRACT Jörg Renkawitz is an endowed Peter Hans Hofschneider Professor in Molecular Medicine at Ludwig Maximilians-University Munich, Germany. Following his bachelor and Master's degrees in biochemistry, during which he was first introduced to the field of cell motility, he completed his doctoral work with Prof. Dr Stefan Jentsch at the Max Planck Institute of Biochemistry in Martinsried, Germany, studying the mechanisms of DNA repair. Still intrigued by the mechanics of migrating cells, he moved to the Institute of Science and Technology in Vienna, Austria for his postdoc with Prof. Dr Michael Sixt, which cemented his passion for understanding how motile cells navigate their environments. In 2018, he started his own lab at Ludwig Maximilians-University Munich, and now applies his molecular expertise to unravel the mechanobiology of the immune system by combining omics approaches with engineered microenvironments and high-throughput imaging. We spoke with Jörg over Zoom to learn about his career path, rigorous approaches to experimental design and mentorship philosophy.

Sir Michael John Berridge. 22 October 1938—13 February 2020

Sir Michael Berridge was a giant in the fields of physiology and biochemistry who, by his discovery in 1983 of inositol 1,4,5-trisphosphate (IP 3 ) as the ubiquitous intracellular messenger releasing Ca 2+ from intracellular stores, revolutionized our concepts of signal transduction mechanisms. Mike, as he was universally known, discovered one of the most important regulatory mechanisms in animal cells, involved in the control of virtually all bodily functions, including secretion, contraction and memory. Mike, working at the Department of Zoology at the University of Cambridge, personally identified IP 3 as one of the two initial products of hormone- or neurotransmitter-elicited inositol phospholipid breakdown and then, in collaboration with the research group led by Irene Schulz at the Max Planck Institute for Biophysics in Frankfurt, demonstrated directly the Ca 2+ -releasing effect of IP 3 in pancreatic acinar cells. Subsequently, in collaborations with research groups in Switzerland and the USA, Mike confirmed the Ca 2 +  -releasing action of IP 3 in insulin-secreting cells, hepatocytes and photoreceptors. The IP 3 –Ca 2 +  -releasing pathway became accepted amazingly quickly as one of the key elements of cellular signal transduction mechanisms and is now featured in virtually all textbooks of physiology and biochemistry. Mike was also a great synthesizer, who created an entirely new field, namely calcium signalling. Through his numerous, highly cited review articles, and his insightful keynote lectures at the most important biomedical congresses, he dominated this large and increasingly important research field for more than 30 years following his momentous 1983 discovery.

Impact of climate change on persistent cold-air pools in an alpine valley during the 21st century

Abstract. When anticyclonic conditions persist over mountainous regions in winter, cold-air pools (i.e. thermal inversions) develop in valleys and persist from a few days to a few weeks. During these persistent cold-air pool (PCAP) episodes the atmosphere inside the valley is stable and vertical mixing is prevented, promoting the accumulation of pollutants close to the valley bottom and worsening air quality. The purpose of this paper is to address the impact of climate change on PCAPs until the end of this century for the alpine Grenoble valleys. The long-term projections produced with the general circulation model MPI (from the Max Planck Institute) downscaled over the Alps with the regional climate model MAR (Modèle Atmosphérique Régional) are used to perform a statistical study of PCAPs over the period 1981–2100. The trends of the main characteristics of PCAPs, namely their intensity, duration, and frequency, are investigated for two future scenarios, SSP2–4.5 and SSP5–8.5. We find that the intensity of PCAPs displays a statistically significant decreasing trend for the SSP5–8.5 scenario only. This decay is explained by the fact that air temperature over the century increases more at 2 m above the valley bottom than in the free air at mid-altitudes in the valley; this might be due to the increase of specific humidity near the ground. The vertical structure of two PCAPs, one in the past and one around 2050, is next investigated in detail. For this purpose, the WRF (Weather Research and Forecasting) model, forced by MAR for the worst-case scenario (SSP5–8.5), is used at a high resolution (111 m). The PCAP episodes are carefully selected from the MAR data so that a meaningful comparison can be performed. The future episode is warmer at all altitudes than the past episode (by at least 4 ∘C) and displays a similar inversion height, which are very likely generic features of future PCAPs. The selected episodes also have similar along-valley wind but different stability, with the future episode being more stable than the past episode. Overall, this study shows that the atmosphere in the Grenoble valleys during PCAP episodes tends to be slightly less stable in the future under the SSP5–8.5 scenario, and statistically unchanged under the SSP2–4.5 scenario, but that very stable PCAPs can still form.

Cell scientist to watch – Jakub Sedzinski

ABSTRACT Jakub Sedzinski is an Associate Professor at the University of Copenhagen and the Novo Nordisk Foundation Center for Stem Cell Medicine (reNEW), Denmark. After his undergraduate and Master's degrees in biotechnology at the University of Wroclaw, Poland, he completed his PhD in Prof. Ewa Paluch's lab at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden, Germany, where he studied biophysical aspects of fundamental cell behaviours. Next, he moved to the University of Texas at Austin in the USA for a postdoctoral fellowship with Prof. John Wallingford. There, he became interested in how cell-level mechanics influence the complex development and maintenance of tissues like the mucociliary epithelium. In 2017, he started his own lab in Copenhagen where he continues to integrate biophysics with cell biology and developmental models in order to elucidate the relationships between cell and tissue mechanics and cell fate acquisition in epithelial tissue dynamics. We spoke with Jakub over Zoom about his career and how his cross-disciplinary approach to research is driven by his fundamental passion for learning new things.

The significant influence of the Atlantic multidecadal variability to the abrupt warming in Northeast Asia in the 1990s

Northeast Asia experienced unprecedented abrupt warming in the 1990s since the last century. Based on a robust time series and rank frequency evaluation, the Max Planck Institute for Meteorology Grand Ensembles of CMIP5 (MPI-GE5), CMIP6 (MPI-GE6), EC-Earth3 and IPSL-CM6A-LR were identified as the models that best simulate the external forcing and internal variability in observations and represent observations most adequately. The negative-to-positive phase transition of the Atlantic multidecadal variability (AMV), combined with the external forcing, can explain 88% [60%−111%] of the 1990s warming. With prescribed anthropogenic emissions in the near future, a phase shift in the AMV to +2 (-2) standard deviation will amplify (weaken) the warming over Northeast Asia by 37% [29%−49%] (19% [15%−25%]). This highlights the importance of natural climate variability in Northeast Asia’s government decision-making and risk management, and emphasizes that only climate models with an adequate representation of forced warming can quantify these contributions correctly.

Nonlinearity and Asymmetry of the ENSO Stratospheric Pathway to North Atlantic and Europe, Revisited

AbstractNonlinearities and asymmetries of El Niño Southern Oscillation (ENSO) stratospheric pathway to the North Atlantic and Europe are examined in large ensembles conducted with fully coupled climate models during wintertime. The analysis is centered on historical experiments of the Max Planck Institute Grand Ensemble (MPI‐GE, 95 members) and expanded to six other ensembles of more limited size. In MPI‐GE, significant responses are obtained for each ENSO phase and three different intensities (weak, moderate and strong). Overall, linear relationships are found for either El Niño or La Niña key diagnostics that characterize the pathway. These relationships are generally weaker for the cold La Niña than for the warm El Niño so that asymmetries between them develop as the events intensify. Specifically for strong events, the extra‐tropical North Pacific and stratospheric responses are asymmetric, with larger responses for El Niño. In addition, the stratospheric asymmetry in strong events seems to contribute to the asymmetry in strong events in the North Atlantic—Europe response in the troposphere in late winter. The extra‐tropical North Pacific response shows general agreement between MPI‐GE and the other large ensembles. However, this agreement is not as large when other parts of the pathway are compared. Relatively high inter‐model response spread confirms the typical model uncertainty found when examining atmospheric circulation responses which include the stratosphere in state‐of‐the‐art climate models.

Position Statement of the Max Planck Institute for Innovation and Competition of 6 February 2024 on the Commission's Proposal for a Regulation on Standard Essential Patents

Position Statement of the Max Planck Institute for Innovation and Competition of 6 February 2024 on the Commission's Proposal for a Regulation on Standard Essential Patents

Analytical improvements and assessment of long‐term performance of the oxidation–denitrifier method

The analysis of the nitrogen (N) isotopic composition of organic matter bound to fossil biomineral structures (BB‐δ15N) using the oxidation–denitrifier (O–D) method provides a novel tool to study past changes in N cycling processes.MethodsWe report a set of methodological improvements to the O–D method, including (a) a method for sealing the reaction vials in which the oxidation of organic N to NO3− takes place, (b) a recipe for bypassing the pH adjustment step before the bacterial conversion of NO3− to N2O, and (c) a method for storing recrystallized dipotassium peroxodisulfate (K2S2O8) under Ar atmosphere.ResultsThe new sealing method eliminates the occasional contamination and vial breakage that occurred previously while increasing sample throughput. The protocol for bypassing pH adjustment does not affect BB‐δ15N, and it significantly reduces the processing time. Storage of K2S2O8 reagent under Ar atmosphere produces stable oxidation blanks over more than 3.5 years. We report analytical blanks, accuracy, and precision for this methodology from eight users over the course of ~3.5 years of analyses at the Max Planck Institute for Chemistry. Our method produces analytical blanks characterized by low N content (0.30 ± 0.13 nmol N, 1σ, n = 195) and stable δ15N (−2.20 ± 3.13‰, n = 195). The analysis of reference amino acid standards USGS 40 and USGS 65 indicates an overall accuracy of −0.23 ± 0.35‰ (1σ, n = 891). The analysis of in‐house fossil standards gives similar analytical precision (1σ) across a range of BB‐δ15N values and biominerals: zooxanthellate coral standard PO‐1 (6.08 ± 0.21‰, n = 267), azooxanthellate coral standard LO‐1 (10.20 ± 0.28‰, n = 258), foraminifera standard MF‐1 (5.92 ± 0.28‰, n = 243), and tooth enamel AG‐Lox (4.06 ± 0.49‰, n = 78).ConclusionsThe methodological improvements significantly increase sample throughput without compromising analytical precision or accuracy down to 1 nmol of N.

Extreme heat and drought typical of an end-of-century climate could occur over Europe soon and repeatedly

Extreme heat and drought typical of an end-of-century climate could soon occur over Europe, and repeatedly. Despite the European climate being potentially prone to multi-year successive extremes due to the influence of the North Atlantic variability, it remains unclear how the likelihood of successive extremes changes under warming, how early they could reach end-of-century levels, and how this is affected by internal climate variability. Using the Max Planck Institute Grand Ensemble, we find that even under moderate warming, end-of-century heat and drought levels virtually impossible 20 years ago reach 1-in-10 likelihoods as early as the 2030s. By 2050–2074, two successive years of single or compound end-of-century extremes, unprecedented to date, exceed 1-in-10 likelihoods; while Europe-wide 5-year megadroughts become plausible. Whole decades of end-of-century heat stress could start by 2040, by 2020 for drought, and with a warm North Atlantic, end-of-century decades starting as early as 2030 become twice as likely.

Optimizing Seasonal‐To‐Decadal Analog Forecasts With a Learned Spatially‐Weighted Mask

AbstractSeasonal‐to‐decadal climate prediction is crucial for decision‐making in a number of industries, but forecasts on these timescales have limited skill. Here, we develop a data‐driven method for selecting optimal analogs for seasonal‐to‐decadal analog forecasting. Using an interpretable neural network, we learn a spatially‐weighted mask that quantifies how important each grid point is for determining whether two climate states will evolve similarly. We show that analogs selected using this weighted mask provide more skillful forecasts than analogs that are selected using traditional spatially‐uniform methods. This method is tested on two prediction problems using the Max Planck Institute for Meteorology Grand Ensemble: multi‐year prediction of North Atlantic sea surface temperatures, and seasonal prediction of El Niño Southern Oscillation. This work demonstrates a methodical approach to selecting analogs that may be useful for improving seasonal‐to‐decadal forecasts and understanding their sources of skill.