Periodic Reporting for period 2 - CENAE (compound Climate Extremes in North America and Europe: from dynamics to predictability)
Reporting period: 2022-09-01 to 2024-02-29
Extreme climate events in a changing climate are one of the most challenging problems facing society. Indeed, the World Climate Research Programme and the European Commission have both stressed the need to further our knowledge of current and future climate extremes. The EU-funded CENÆ project works to shed light on how different climate extremes (cold spells, heavy rains and strong winds) interact and co-occur, leading to larger socioeconomic impacts than the sum of their individual components. The project also focuses on the predictability aspect of these extremes. The multivariate nature and inherent rarity of co-occurring extremes poses a formidable challenge to current analysis techniques, requiring a combination of different disciplines to attain the project's goals.
The project began by computing co-occurrence statistics of climate extremes in North America and Europe, both using conventional statistical techniques and approaches issued from dynamical systems theory, and identifying the physical processes leading to the co-occurring extremes. The latter has included the study of recurrent large-scale atmospheric patterns in North America and Europe. The project team has also focussed on the predictability aspects of climate extremes, by building statistical and data-driven models for investigating the predictability of the extremes being studied, and investigating how to extract useful information on high-impact weather or climate events from ensemble forecasts. Finally, we have recently considered impacts of the extremes being studied, with a specific focus on windstorms in Europe. Project members have presented their results as scientific publications, at scientific meetings, at events open to the general public, in schools and in the media.
Several knowledge gaps hinder our understanding of co-occurring climate extremes in Europe and North America. First of all, we lack a detailed understanding of the drivers and characteristics of the co-occurring cold spell, heavy rain and strong wind extremes studied in CENÆ. The literature investigating present-day European wet and windy extremes has mostly addressed the two separately. The co-occurrence of extremes on both sides of the North Atlantic has received even less attention. Second, some analysis approaches which have been developed in applied mathematics to study extremes in complex systems have yet to the applied to the study of co-occurring climate extremes. We are also yet to leverage machine learning for studying the predictability of co-occurring extremes. Finally, little is known about how climate change may affect the occurrence and predictability of co-occurring extremes.
CENÆ seeks to address these four knowledge gaps. The results thus far have focussed on the first three points, and we are starting to touch the fourth point. By the end of the project we expect to have made progress on all four of these knowledge gaps, leading to a step-change in our understanding of the drivers and predictability of co-occurring climate extremes, including how climate change may affect these two aspects.
CENÆ seeks to address these four knowledge gaps. The results thus far have focussed on the first three points, and we are starting to touch the fourth point. By the end of the project we expect to have made progress on all four of these knowledge gaps, leading to a step-change in our understanding of the drivers and predictability of co-occurring climate extremes, including how climate change may affect these two aspects.