ICES Annual Science Conference 2022

Theme session E

Understanding and anticipating extreme events: their frequency, severity and impacts

Thursday 23 September 13:00 - 14:30
Vavasour Wing I

​​​​​​​​​​​​​​​​​​​​Session format

Our discussions will focus around extreme events, including stock collapses, regime shifts, marine heat waves, cold snaps and storms. We will discuss the impacts these events can have on ecosystems, fisheries and livelihoods, and how these can recover afterwards. We'll also discuss advances in modelling that demonstrate that some of these events may be changing in frequency or severity as a result of climate change, but also that scientist's ability to predict or anticipate such events is starting to improve.  

The session will use a fish bowl format, with all participants able to contribute their ideas and insights.​

Session topics​​​​​​​​​​​​​

​Extreme events, including marine heat waves, cold snaps, and severe storms can have dramatic and long-lasting impacts on marine ecosystems, with major consequences for commercial fisheries and aquaculture. Recent modelling efforts have demonstrated that such events may be increasing in frequency or severity as a result of climate change, but equally that scientist's ability to predict or anticipate such events is starting to improve.

This session focusses on modelling, observational and analytical​ approaches as well as studies of biological consequences and socio-economic implications. The session will also consider economic shocks and disturbances, for example the recent COVID disruption or peaks in oil price.

Four topics will be addressed during the theme session:

  1. Analytical techniques to better characterise extreme events (magnitude, frequency etc) or modelling studies that attempt to forecast or make projections into the future, assuming long-term climate change. This will include typologies of extreme events, analysis of historic time series and 'return periods', future projections of heat waves, cold snaps, low oxygen events, tropical cyclones, tsunamis and severe storms.
  2. Studies that consider the biological or ecological consequences of extreme events, for example mass mortality events, damage to habitats, sudden shifts in distribution, disease outbreaks, strong or weak year classes, influxes of non-native species. How to differentiate the influences of extreme events from pervasive climate change.
  3. Social end economic consequences of extreme events including loss and damage to fishing gears, vessels and aquaculture infrastructure, risk appetite and behavioural responses to extreme events, parametric insurance schemes to build resilience etc.
  4. The impact of economic shock events, for example COVID, peaks in fuel price, import/export restrictions, sudden political change.

While a considerable amount of research interest has been dedicated towards understanding and anticipating long-term directional climate change impacts, there has been much less focus on extreme events or 'shocks' that can have immediate catastrophic consequences for species or marine ecosystems, as well as initiating disruption to maritime industries such as fisheries or aquaculture, that may last for years or even decades.
In particular, there is currently very limited understanding of biological consequences following extreme events in temperate systems (heat waves, cold snaps, and severe storms), where it can be difficult to differentiate between the influence of long-term climate change, the impact of other human pressures, and the result of a single discrete meteorological event. More progress has been made in tropical systems where there are many hundreds of papers focussing on the impact of elevated temperatures (e.g. via bleaching) and/or tropical cyclones on corals and coral reefs.
Scientists are generally getting better at categorizing extreme events, e.g. types of marine heat wave (Hobday et al. 2016) as well as providing estimates of average 'return period', using sophisticated analytical techniques and historic time series. Scientists are also getting better at making future projections, for example in 2020 an Australian team made the world's first marine heatwave predictions, with a lead-in time of five months. Similarly, projections are improving concerning the frequency and severity of storms in the Atlantic. But how do you develop and test longer-term scenarios that encompass extreme events without them coming across as 'science fiction'? How do stakeholders such as fishing fleets or fish farmers balance the risk of injury, disruption or damage against potential rewards? How do economic 'shocks' compare to those of metrological origin, in terms of long-term legacy and consequences? Join this session to discuss these topics and more!
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Nova Mieszkowska (UK)
Sarah Wakelin (UK)
John Pinnegar (UK)
Bryony Townhill (UK)​
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Theme session E

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