Extreme events and risk assessment

extremes-ID-10024304Hurricanes, storms, droughts and floods are among the most spectacular and dramatic features of the climate system. Those extreme events occur on a wide range of timescales, ranging from a few hours for some severe storms to years or decades for persistent droughts. They strongly impact the natural systems and the human societies and even the short duration events can lead a long term imprint in the environment.

The extreme events are in most cases relatively rare, and consequently the instrumental period has a too short duration to provide an adequate sampling and characterization. A robust risk assessment of their probability is thus only possible by extending the data series using natural archives that record the occurrence and impact of past extreme events at natural scales.

This integrated activity is focused on the documentation of the occurrence and the understanding of the mechanisms at the origin of past climatic and ecological extreme events. A quantitative approach is expected in order to obtain robust probability estimates based on long term series that can be compared directly to their equivalent derived from instrumental data. These efforts are directly relevant to risk assessment.


Natural archives provide many records of past extreme events over a wide range of climate and environmental conditions, in particular for floods, droughts and storms. The goals of this integrated activity are to reinforce the coordination between existing research lines, to stimulate new analysis and to facilitate the transfer of relevant information to potential users.

Those objectives can be articulated around the following questions:

- For which type of event and which periods could we provide robust statistics of extremes based on paleodata?

- What is the impact of extreme events on ecosystems and what is their resilience to such events?

- What is the impact of changes in the mean state on the probability of occurrence and the intensity of extreme events?

- Are the current models able to reproduce the observed properties of extreme events as well as the links between large-scale drivers and the regional to local scale triggers or amplification mechanisms?

- How should we present research results so that they can be easily used by scientists working on the instrumental period and specialists of risk assessment?



1. Lunchtime session during the OSM, Zaragoza, Spain, 10 May 2017

The goal of this open meeting is to discuss the current research on extreme events in the PAGES community, to identify the activities such as workshops or review papers that would allow a better integration of existing studies and contribute to new developments and to propose actions that would reinforce the visibility and the impact of the scientific results, including for stakeholders.

If you are interested in attending or would like to give a brief overview of some activities related to extreme events during the session, please contact Blas Valero-Garcés and Hugues Goosse (details below).

Read more: http://pastglobalchanges.org/calendar/upcoming/127-pages/1668-extremes-ia-meeting-spain-17

2. Future Earth initiative: Extreme Events and Environments from climate to Society (E3S).

PAGES will join colleagues from the Future Earth research projects and WCRP in this Future Earth initiative addressing extreme events amd their impacts on societies.

Project website: www.e3s-future-earth.eu

The Cross community workshop on Extreme Events and Environments from Climate to Society (E3S) was held in Berlin, Germany, from 14-16 February 2016. Read a Future Earth blog article about the event here.



Blas Valero-Garcés
Hugues Goosse



Image credit: Courtesy of Evgeni Dinev at FreeDigitalPhotos.net