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Workshop on Confronting Earth System Model Trends with Observations: The Good, the Bad, and the Ugly

Boulder, Colorado and Virtual

Comparing historical trends in Earth system models with observations to identify and understand where models are performing well and poorly to focus the community on where more work is needed to ensure credible projections moving forward. What are we getting right? What are we getting wrong and why?  What have we not yet paid enough attention to and where might surprises lie?


For over 40 years, and through several rounds of IPCC reports, the climate science community has made projections of climate change under specific emissions scenarios.  While assessments of the fidelity of Earth System Model simulations over the historical period have been performed for basic variables such as near surface air temperature, internal variability and a relatively small signal in a short observational record has made a comprehensive assessment challenging. Our observational record is increasing in length, the climate change signal is increasing in size, and with increased computing capacity, large ensembles of Earth System Model simulations are becoming more standard. While challenges still exist, we are now in a unique position to confront Earth System Models with the emerging signals of climate change over a much greater range of variables and Earth system components than has been previously done. It is time for the research community to perform a broader stock-take of the modeled representation of historical trends than has been done previously and answer the following questions: Are the trends in observations and Earth System Models consistent? If inconsistencies exist, can we relate this to deficiencies in the representation of forced trends or of internal variability and understand the origins of the problem? Confronting Earth System Model trends with observations across different variables is key to focusing the community on where inconsistencies occur, where surprises might lie, and where more work needs to be done. 

The workshop will bring together a diverse, interdisciplinary group of researchers from different Earth science communities with an interest in comparing observed and modeled trends to achieve the following two principal goals:

  1. Take stock of the ability of models to capture recent trends and to answer the following questions: What are we getting right? What are we getting wrong? What have we not yet paid enough attention to and where might surprises lie?
  2. Identify research challenges and new directions moving forward, including both scientific and methodological questions.


Scientists across all fields within Earth science with an interest in the assessment of trends as represented by Earth System Models are welcome to attend. We anticipate 100 in-person participants and at least another 50 virtually. Registration for in-person participation is on a first-come, first-served basis until capacity is reached. Abstracts are not a requirement for participation. Limited travel support is available for early career scientists (within 10 years of last degree) and scientists from underrepresented races/ethnicities. A short application form will be provided during registration.


The 3-day meeting will be hybrid, with participants convening in person at the NCAR Mesa Lab in Boulder and online. The format will include plenary sessions with invited overview talks and contributed presentations, interactive poster sessions, in-depth plenary and breakout discussions, and a networking event.


In addition to sharing of knowledge and ideas among the participants, the workshop will result in a report that summarizes a current assessment of the comparison of observed trends with Earth System Models and the major challenges that need to be addressed in this realm. Other outcomes could include a review or perspective on this topic and the formulation of a prospectus for a possible future community driven US CLIVAR working group to address the outstanding issues that emerge from the workshop.

Scientific Organizing Committee

Tiffany Shaw (Co-chair, The University of Chicago)
Isla Simpson (Co-chair, National Center for Atmospheric Research)
Paulo Ceppi (Imperial College London)
Amy Clement (University of Miami)
Erich Fischer (ETH Zurich) 
Kevin Grise (University of Virginia)
Angie Pendergrass (Cornell University)
James Screen (University of Exeter)
Robb Jnglin Wills (ETH Zurich)
Tim Woollings (University of Oxford) 

Program Organizing Committee

Alyssa Johnson, US CLIVAR
Mike Patterson, US CLIVAR
Keri Dawn, CPAESS  

Workshop Sponsors

Agency sponsors for the Confronting climate workshop

In-person registration (closed)

In-person registration deadline: closed; capacity met

Virtual registration

Virtual registration deadline: extended to March 8
Virtual general registration cost: $150 
Virtual student/early career/underrepresented participants cost: $75

*Early Career is within 10 years since last degree. Underrepresented Racial and/or Ethnic groups in the US include American Indian or Alaska Native, Black or African American, Hispanic or Latino, Middle Eastern or North African, and Native Hawaiian or Pacific Islander.

Abstract submission (closed)

Abstract submission period: September 21 - November 16, 2023