Climate variability across scales: from the butterfly’s wings to the age of the Earth

An online seminar series from November 2020 to March 2021





Since the formation of planet Earth 4.54 billion years ago the interplay between its solid, liquid and gaseous compartments has led to variable conditions as a backdrop to the evolution of life. Today, weather observations from ground and space allow to reconstruct and project surface climate with unprecedented precision, and to attribute local to global-scale meteorological changes to human-made greenhouse gases. Yet, there are outstanding research challenges in climate, and one of them is the spectrum of climate. In 1976 John Murray Mitchell jr., an American climatologist, published a paper entitled “An Overview of Climatic Variability and Its Causal Mechanisms” (J. Murray Mitchell Jr., Quat. Research, 1977, DOI:10.1016/0033-5894(76)90021-1). In this seminal paper he sketched a variance spectrum for the climate system spanning from timescales of hours (10-4 years) to the Age of the Earth (109 years), identified relevant processes and postulated their interactions. Today we have evidence from palaeoclimate data that allow to reconstruct the spectrum and see that the interactions between timescales are stronger than Mitchell envisaged. Theoretical understanding and modeling capacity of this spectrum is, however, still lacking.

This series of eight lectures is organized in the framework of the Past Global Changes Programme working group on Climate Variability Across Scales. 44 years after Mitchell’s paper it brings together experts on timescales from minutes to millions of years, to review the state of knowledge on Earth surface climate variability across timescales.

Dates and Speakers:

  1. Juerg Schmidli – IAU Frankfurt, Germany “Variability at sub-daily time scales – from seconds to hours”. Tuesday 10.11.2020 16:00-17:00. Abstract and speaker announcement here. Recorded video here.    
  2. Christian Grams – IMK-TRO/KIT, Germany “Synoptic to sub-seasonal surface climate variability in the Atlantic-European region: the role of weather regimes.”.  Thursday 26.11.2020 16:00-17:00. Abstract and speaker announcement here. Recorded video here.
  3. Tine Nilsen – UIT, Norway “Decadal variability and the scaling paradigm”. Thursday 3.12.2020 16:00-17:00
  4. Michel Crucifix – UC Louvain, Belgium “The challenge of centennial climate variability”. Friday 18.12.2020 11:00-12:00. Recorded video here.
  5. Julie Schindlbeck-Belo – GEOMAR Kiel, Germany – “The links between volcanism and climate”. Wednesday 20.1.2021 11:00-12:00
  6. Heather Andres – MUN, Canada “Dansgaard-Oeschger cycles: the hybrid beast of millennial climate variability”. Thursday 21.1.2021 16:00-17:00. Abstract and speaker announcement here. Recorded video here.
  7. Oliver Friedrich  GEOW HD, Germany – "Glacial/Interglacial climate variability (105-107 years)". Wednesday 27.1.2021 11:00-12:00. Abstract and speaker announcement here.
  8. Valerio Lucarini Reading, UK – Heatwaves and Cold Spells and Assessing Their Response to Climate Change” Wednesday 10.02.2021 11:00-12:00. Abstract and speaker announcement here.
  9. Mario Trieloff - GEOW HD, Germany - "Climate variability on time scales of 10 8 years: stabilisation through the carbonate silicate cycle". Friday 05.03.2021 11:00-12:00. Abstract and speaker announcement here.
  10. Shaun Lovejoy  McGill University, Canada – "Linking Climate Variability Across Scales". Thursday 18.3.2021 15:00-16:00. Abstract and speaker announcement here.


All times stated are CET (Berlin).

Some recordings will be made available afterwards on the PAGES YouTube channel


Registration: The link to the online meeting (Zoom) will be given to registered participants. For registration and technical questions, please send an email to with the mail header “CVAS lecture series”. The link will be sent to the first 75 registrations on the previous day of each talk around 6pm. 
Contact: Kira Rehfeld (



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