Last update: 2019-06-06 16:16:18
Lead Organizers: Colin Raymond, Radley Horton
Steering Committee: Amir AghaKouchak, Olivia Martius, Thomas Wahl, Jakob Zscheischler, Suzana Camargo, Alex Ruane, Adam Sobel, Michael Oppenheimer, Noah Diffenbaugh, Sonia Seneviratne
This workshop took place at Columbia University (New York, USA) on May 28-31. It was designed to bring together the communities of researchers studying extreme events connected to each other through some physical mechanism. A particular aim was to draw on core disciplines that have used correlated frameworks – for example, multivariate extremes in the hydrological community, or sequential and contingent extremes in the natural-hazards community — and thus to build a more integrated sense of the importance of ‘correlation’ or ‘compounding’ across all climate extremes. Exploring the current thinking and future directions of how to optimally conduct impacts-driven correlated-extremes research was another major theme. The first sessions were structured around a division of events into compound/multivariate, concurrent, and sequential or persistent types, with the latter sessions aiming to integrate these into traditional disciplines of study (e.g. drought or tropical cyclones) as well as into broader societal decision-making.
Approximately 175 people attended the workshop, representing 20 countries. About 2/3 were climate scientists, the remainder being social scientists, company representatives, or government officials. A total of 90 presentations (42 talks and 48 posters) were presented, including 44 by women, 40 by early-career researchers, and 7 by developing-country researchers. The website contains links to the full video recordings of the workshop, and to many of the slides and poster pdfs.
Two keynotes underscored the growing prominence of correlated thinking for hazards that can be understood as resulting from multiple connected drivers, and the simultaneous need to recognize that climate information is most useful to practitioners when generated, packaged, and presented in particular ways. Connection (or correlation, if the linkage is physically based) raises the likelihood that two hazardous events will occur simultaneously or within a short window of time, and these correlation coefficients are themselves variable with climate change (e.g. the intensifying interaction between continental drought and heat). From an impacts perspective, self-consistent ‘storylines’ are often preferable to overlapping sets of probabilities, and specific thresholds often mark the need for qualitative changes in strategy. Additionally, a particular adaptation measure’s usefulness is best measured by the ease with which it can be enhanced in the future, and the complexity and cost with which it is associated, rather than merely its effectiveness in the climate realm over some evaluation period.
The first several sessions covered recent physical-science advances in multivariate (which we termed 'compound') and concurrent extremes, expanding on topics covered in a 2017 WCRP-sponsored workshop. Major themes included the nuanced and sometimes non-monotonic effects across combinations of variables, especially under climate change where conditions will soon be far from 20th-century baselines. Several speakers described the necessity of sophisticated modeling, due to the poor spatial coverage and temporal record of observed variables other than temperature and precipitation, as well as the rarity of certain events. Talks ranged from statistical modeling techniques to fluvial-pluvial flooding to more-exotic combinations of drivers, such as tropical-cyclone winds buffeting the drought-stricken Iberian Peninsula and exacerbating wildfires. The Katia-Irma-Jose sequence of Atlantic tropical cyclones was cited as encapsulating how ‘types’ of correlation are often more a matter of perspective or convenience than a physically meaningful distinction. In the mid-latitudes, recurrent Rossby waves were discussed as contributing strongly to persistent and geographically specific summer heat and extratropical cyclones, though the ultimate origin of these wave patterns remains opaque.
The second day moved into other areas, such as sequences of the same or different types of event, or exceptionally persistent events. Projected increases in persistence were revealed for U.S. temperature/air pollution compound episodes and for mid-latitude consecutive precipitation days. The importance of conducting such assessments with regard to seasonal, subregional, and meteorological conditions, as appropriate for the processes underlying a given correlated extreme, was emphasized.
Splitting into eight breakout groups provided the opportunity for diverse crowdsourced identification of themes, among which were the potential benefits of closer collaboration with engineering organizations and the need for both climate scientists and policy-makers to use metrics that accurately reflect societal impacts and values.
Two final sessions considered a variety of perspectives on correlated extremes from sectoral experts, and estimates of how these affect systemic risk to global interconnected networks such as food, business supply chains, and ecology. The complex nature of these systems can either exacerbate or buffer shocks from correlated extremes, depending largely on the human-management side of the equation. A few presentations gave hope for increased predictability, such as by highlighting the important role played by ENSO cycles in modulating concurrent crop failures, or by increasing the utility of climate information — such as through learning from water managers that identifying types of years which lie within the current climate space, but for which there are no good historical analogues, is a valuable piece of data for them. Where, when, and on whom the impacts of correlated extremes fall are all telling predictors of their severity, with vulnerability often being compound in a demographic sense as well as a physical one. There was often a two-sides-of-the-same-coin feel to the discussion; for example, in the realization that nonlinearity of impacts is nearly universal, but that it derives in some cases primarily from a physical response (waterlogged soil becoming more susceptible to flooding from subsequent rain), while in other cases from a societal inability to muster enough financial or political resources in the face of repeated extreme events.
An overarching conclusion of the workshop was that risk management requires knowledge of the full spectrum of possibilities, organized into a coherent framework that is digestible by impacts decision-makers through their normal deliberation processes. Correlated extremes are rarely (if ever) incorporated into current policy guidelines for infrastructure, development, etc., indicating that significant effort will be required to translate even our existing scientific understanding. However, a positive realization was that minor but frequent updates to guidelines are not only more politically feasible, but operationally desirable in terms of being able to track changing probabilities of the occurrence of particular correlated extremes as estimations and emissions scenarios are updated.
This summary post was written by Colin Raymond.
Last update: 2019-04-25 14:09:25
Chairperson: Bart van den Hurk
Conveners: Nina Nadine Ridder | Co-conveners: Bart van den Hurk, Philip Ward, Seth Westra, Jakob Zscheischler, Samuel Jonson Sutanto, Claudia Vitolo, Henny A.J. Van Lanen
This is a short summary of the oral session at the EGU 2019 where once again this year a session on understanding and modelling compound climate and weather events and their impacts was being held. The selection of oral presentations showed that the research community is actively exploring the monitoring and modelling of compound events. While most presentations (and posters) focused on the documentation of compound event occurrence or their potential impacts on various sectors, a few studies report progress on forecasting and modelling events that are selected for the compound nature of their driver.
Water interactions leading to high-impact compound events: multiple stakeholder perspectives
Georgia Destouni, Samaneh Seifollahi-Aghmiuni, Zahra Kalantari, Carmen Prieto, and Yuanying Chen
Georgia Destouni discussed ongoing research within the EU COASTAL project, in which coastal zone issues are being examined using “multi-actor labs”. The presentation discussed how multiple stakeholder objectives can be including in modelling water interactions that lead to compound events. Questions addressed include: Which event and impacts are most relevant for stakeholders? What is/needs to be understood about interacting variables and interaction strengths/quantification? They started by creating common mind maps by looking at possible drivers of changes and define key interaction and causal links. These were used as a basis to quantify the interactions and feedbacks in a systems approach using fuzzy cognitive mapping. They found that harbors and agriculture are sectors which can be heavily affected by the strength of these interactions. Eventually, this analysis will be used as a basis for co-developing scenarios and roadmaps towards coastal solutions and mitigation of risks.
Changing compound flood probability at the global scale under anthropogenic climate change
Emanuele Bevacqua, Douglas Maraun, Michalis I. Vousdoukas, Lorenzo Mentaschi, Evangelos Voukouvalas, Giuseppe Zappa, and Mathieu Vrac
Emanuele Bevacqua used model simulations to study compound flooding at the global scale from extreme precipitation and sea-levels. They assessed the dependence of high sea levels and precipitation at the global scale, under both current and future climates. They showed where the change in compound flood return periods in future climate could be attributed due to a change in extreme precipitation, a change in extreme surge, or a change in the dependence between the two. The research shows that the compound flood potential from concurrent storm surge and extreme precipitation in several regions will have substantial changes beyond sea level rise, and should be considered for adaptation planning.
A centennial catalogue of hydro-geomorphological compound events and corresponding atmospheric forcing
Alexandre M. Ramos, Susana Pereira, Ricardo M. Trigo, and José L. Zêzere
Alexandre Ramos studied the hydro-geomorphological occurrences of flood (urban, flash flood or river floods) and landslides in Portugal, using a database from 1865 to 2015 compiled from newspaper articles. Their research assessed the atmospheric drivers that caused combined floods and landslides events, in this database. During ~60% of the compound events, SW/W/NW weather types were dominant. In addition, besides the extra-tropical cyclones associated with this events, the atmospheric rivers were associated with more than half of these events enhancing the precipitation event. They also found that the effect of conditional rainfall previous to the even was important in explaining the impact of these events, which created favorable conditions for landslides to occur either from previously wet soils or due to extreme amounts of precipitation. More details on these findings are available here.
Predicting compound dry-hot events over global land areas based on large-scale climate indices
Zengchao Hao, Xinying Wu, Sifang Feng, Vijay Singh, Fanghua Hao, and Xuan Zhang
Zengchao Hao looked into compound dry-hot events which can have very large impacts globally. Such event can be due to natural cycles such as ENSO, large-scale circulation patterns, and relatively greater regional sensitivity to global change. He presented a new method to predict these compound dry-hot events based on ENSO, and demonstrated its first application at the global scale. A predictive model has been developed using a binary variable as predictand based on monthly precipitation and temperature, assessing the probability that both of these exceed various thresholds. The results show several regions where the model shows good predictive skill. More details on these findings are available here.
Joint probability of hot and dry meteorological extremes
Ana Russo, Andreia Ribeiro, and Célia M. Gouveia
The Mediterranean region is a hotspot for extremes, including mega-heatwaves which can lead to large socioeconomic impacts. Andreia Ribeiro presented research looking at the joint probability of hot and dry extremes in the Mediterranean, with the goal of assessing whether hot extremes are preceded by moisture deficits. For moisture, they use SPEI as a proxy, and for hot extremes, the number of hot days per month exceeding the 90th percentile is used. The correlation is assessed between these proxies to identify hotspots. The research shows that in most regions of the Mediterranean (but also in Western Europe), there are significant negative correlations between the number of hot days and SPEI, with the correlations becoming stronger throughout the summer season. The results show potential for early warning. These findings can also be found here.
Vulnerability of hop production due to compound climate events over Europe
Vera Potopová, Martin Možny, Luboš Türkott, Josef Soukup, Javier J Cancela, Paula Paredes, Martin Pavlovič Martin Pavlovič, Deniz Bilge, Francis Heitz, Siniša Srečec, Martin Steinhaus Martin Steinhaus, and Florian Weihrauch
Climate extremes affect most of the core ingredients of beer production (hop, water and barley), and Vera Potopová described research assessing the vulnerability of European hop production to compound climate events, both floods and droughts. The research shows that hop production critically depends on both the duration and coincidence of extreme events. Longer and more severe drought and heatwave occurrences have increased more than shorter, less severe concurrences. Overall, the quality of hops is decreasing whilst demand for hops is increasing. Whilst irrigation can reduce the drought impact, a problem is the decreasing content of alpha acids. Vera states that: “It’s so much easier to be a good manager in a wet year!”
Involvement of Stochastic Weather Generators within the DAMOCLES project
Martin Dubrovsky, Ondrej Lhotka, Petr Stepanek, Jiri Miksovsky, and Jan Meitner
Martin Dubrovsky provided an overview of weather generators, i.e. models to produce synthetic weather data statistically similar to real-world weather data. They presented a promising weather generator, SPAGETTA, that he and colleagues have been developing since 2016. Weather generators are a promising tool for studying compound events (CEs), therefore developing SPAGETTA towards a better representation of some relevant CE characteristics would be relevant. SPAGETTA can already reproduce many relevant features of the observed climate system, such as temporal and spatial structures of hot and dry spells or wet and dry events. An interaction between the SPAGETTA developers and DAMOCLES members would allow for the improvement of the weather generator, which could ultimately be useful for assessing the impact of several CEs.
This summary blog was written by Philip Ward, Anaïs Couasnon and Emanuele Bevacqua.
Last update: 2019-03-18 00:02:55
The Workshop on Correlated Extremes will take place on Columbia University’s Morningside campus (Manhattan, NYC) on May 29-31, 2019, preceded by an evening panel on May 28. It will be comprised of a blend of invited talks and abstract submissions (both talks and posters), and will also have a significant amount of time devoted to discussions. A total attendance of around 125 is anticipated.
For more information and a complete workshop schedule please visit
Note that registration is required and is open through April 30.
Last update: 2019-03-17 23:45:08
A part of its Excellence 100 recruitment, Loughborough is recruiting for a Lectureship in Energy Adaptions and Climate Change Resilience. This is an open ended academic position. The application deadline is 11 March 2019. Details can be found at this website under the Geography tab. Please do not be put off by the 'Social Science' umbrella, we do world-class physical environmental science within this, and hazard and risk will mesh nicely with the 'Resillience' aspect of the call. Of course, resilience might need to be to compound events.
On behalf of John Hillier.
Last update: 2019-03-17 23:46:49
The announcement for a position for a Doctorate Researcher under the Project IMPECAF ref: PTDC / CTA-CLI / 28902/2017 was published and is available at http://www.fc.ul.pt/pt/concursos, n. 2725.
IMPECAF's main objective is to deepen the existing knowledge on individual and compound dry and hot weather extremes (heat waves, droughts and flash-droughts) affecting the agricultural and forestry ecosystems on the Iberian Peninsula.
The objectives of the work program are:
1) the selection of adequate hydro-meteorological indexes for the identification of extreme events in the Iberian Peninsula (IP);
2) the characterization of extreme events regarding to their duration, intensity and severity;
3) the development of agricultural and forest risk models based on earth observation data and high spatial resolution data (e.g. satellite data)
4) the analysis of the influence of short-medium-term meteorological forecasts on losses of agricultural yield and fire risk;
5) analysis of the influence of climate change on agriculture and forests
The work will be hosted by IDL-University of Lisbon, Campo Grande, Lisbon, Portugal.
Please note that this is also available on the Eracareers portal with the following link: http://www.eracareers.pt/opportunities/index.aspx?task=global&jobId=109657.
Last update: 2019-02-18 13:22:10
Might the severe risk posed by hurricanes become worse if they increasingly link with deadly heatwaves? As global temperatures rise, individual climate-driven hazards might become more intense or frequent. But, perhaps our concern should focus on entirely new or unrecognized risks caused by combinations of two or more hazards [e.g. Hillier et al, 2015], which may prove to be the most catastrophic. After all, it is events beyond human experience which are most likely to result in game changing consequences for society [Zscheischler et al., 2018]. “Black-swan” events are surprises that could not have been be anticipated (e.g. the terrorist attacks of September 11th 2001), but with suitable physical understanding of the climate system it should be possible to identifying likely devastating natural hazard combinations before they first impact. This predictability renders such potential surprises “grey swan” events. Clearly, the stakes are high in detecting such emergent threats and there is strong incentive to develop plans for minimizing their impact.
This PhD project will contribute in this regard by addressing the rising grey swan hazard of deadly (humid) heat events following tropical cyclones (TCs). The supervisors’ initial work shows that this compound hazard has so far missed densely populated regions, but that good fortune looks unlikely to hold as dangerously hot weather and powerful TCs are expected to become more frequent as the climate continues to warm [Matthews, 2018; Matthews et al., 2017; Kang and Elsner, 2015]. The possible impacts from such a hurricane-heatwave “multiplier” hazard actually unfolding cannot be overstated, given the growing dependency on air conditioning, and the mega blackouts that have followed recent major TCs [Houser and Marsters, 2018; Barreca et al., 2013] (Fig. 1).
The most sophisticated multi-hazard probabilistic risk modelling (i.e. catastrophe modelling) is in insurance [Kappes et al., 2012], with the World Bank now leading efforts to drive these expertise into the Disaster Risk Finance (DRF) community [Mitchell-Wallace et al., 2017]. This PhD will feed into that effort, contributing to pursuit of the United Nations Sustainable Development Goals, and equipping the student with a highly-employable skill set, knowledge and experience.
For more information and contact details visit the CENTA website.
On behalf of Dr. Tom Matthews and Dr. John Hillier, Loughborough University
Last update: 2019-01-12 10:52:44
We are excited to invite submissions to the session "Understanding and modelling compound climate and weather events and their impacts (NH1.3/AS4.49)" at the EGU General Meeting in April 2019. This session, organised by DAMOCLES, aims to bring together climate scientists, impact modellers, statisticians, and stakeholders to discuss Compound Events, share their findings and connect to the Compound Event community.
Abstracts will be accepted until the 10th of January 2019 and should be submitted through the official EGU abstract submission system. More information on how to submit an abstract can be found here.
The session will focus on the following topics:
- Synthesis and Analysis: What are common features for different classes of Compound Events? Which climate variables need to be assessed jointly in order to address related impacts? How much is currently known about the dependence between these variables?
- Stakeholders and science-user interface: Which events are most relevant for stakeholders? What are novel approaches to ensure continuous stakeholder engagement?
- Impacts: What are the currently available sources of impact data? How can they be used to link observed impacts to climate and weather events?
- Statistical approaches, model development and evaluation: What are possible novel statistical models that could be applied in the assessment of Compound Events?
- Realistic model simulations of events: What are the physical mechanisms behind different types of Compound Events? What type of interactions result in the joint impact of the hazards that are involved in the event? How do these interactions influence risk assessment analyses?
We are looking forward to your submission and attendance at the session!
Official start of the COST Action on 'Understanding and modeling compound climate and weather events (DAMOCLES)'Published: 2018-09-15 05:43:24
Last update: 2018-09-16 14:05:22
- several opportunities for early career investigator (ECI) from Inclusiveness Target Countries to win conference grants for next year’s EGU General Assembly in Vienna
- a number of Short Term Scientific Mission grants,
- travel grants for ECIs to participate at a workshop in Oslo early next year, and
- the organisation and travel support for the first public meeting of the Action in Prague (CZ) on the 17th and 18th of December 2018.
- Bart van den Hurk (KNMI) - Action vice-chair,
- Christopher White (University of Strathclyde) - Short Term Scientific Missions Manager, and
- Wim Thiery (Vrije Universiteit Brussel) - Science Communications Manager.
Last update: 2019-02-18 13:22:31
Last update: 2018-12-21 16:02:54
Last update: 2018-12-21 15:52:38
Last update: 2018-12-21 15:53:20
Last update: 2018-12-21 15:55:18
- Synthesis and analysis framework
- Stakeholder involvement and science-user interface
- A meta-database of impact data
- New statistical approaches for model development and evaluation
- Realistic model simulations for specific event types
- identify key process and variable combinations underpinning compound events
- describe the available statistical methods for modelling dependence in time, space, and between multiple variables
- identify data requirements needed to document, understand, and simulate compound events
- propose an analysis framework to improve the assessment of compound events
Session on compound events at the 8th GEWEX open science conference: 'Extremes and water on the edge'Published: 2018-04-16 05:25:43
Last update: 2018-05-22 07:36:53
Last update: 2018-05-22 07:37:27
On Tuesday 10th April 2018 we will host the session “Addressing the challenge of compound events, multi-risk modelling and cross-risk assessment methods: Extremes, inter-dependencies, non-stationarities, impacts and vulnerability” at the EGU General Assembly in Vienna.
There will be 6 oral presentations between 15:30-17:00 in room L6. There will also be 18 posters in Hall X1 (poster boards X1.135 to X1.153). Posters will be there all day, with authors in attendance between 17:30-19:00.
The session will be convened by representatives from the Institute for Environmental Studies (IVM) of the Vrije Universiteit Amsterdam, ETH Zürich’s Institute for Atmospheric and Climate Sciences, University of Southampton, University of Adelaide, and Karlsruhe Institute of Technology, among others.
We look forward to seeing you at the session!
Last update: 2018-05-22 07:37:45