Research Theme 3: Analysing and constraining future projections

In addition to process-level evaluation, CRESCENDO will develop a community benchmarking system for evaluating coupled ESMs. Such a system, named ESMValTool, will benchmark key large-scale aspects of full ESM-simulated variability and trends, comparing to observations, earlier versions of the same ESM or different ESMs, as well as allowing assessment of key measures of Earth system change across a range of projection protocols. ESMValTool v1.0 has been developed in the EU project EMBRACE (; Eyring et al. 2016), where a range of climate performance metrics and diagnostics are developed. In CRESCENDO we will extend this work to include additional biogeochemical and aerosol/trace gas metrics. The aforementioned process-level diagnostics will also be included in the ESMValTool source code repository, making them available to the wider research community. An important goal of ESMValTool is that it becomes a community system, open both to users and developers, encouraging open exchange of evaluation methods in order to avoid duplication of effort.

These two evaluation approaches, bottom-up (process-level) and top-down (full ESM benchmarking), aim to ensure ESMs deliver the correct answer for the correct reasons, while making sure overall realism in full ESM climate states is achieved. Both approaches are necessary to increase confidence in ESMs while retaining scientific rigour.

  • ESMValTool website:
  • Eyring, V., Righi, M., Lauer, A., Evaldsson, M., Wenzel, S., Jones, C., et al. (2016). ESMValTool (v1.0) – a community diagnostic and performance metrics tool for routine evaluation of Earth system models in CMIP, Geosci. Model Dev., 9, 1747-1802.

RT3 members

CRESCENDO's RT3 members

  • Veronika Eyring
    RT3 leader, ESMValTool PI
    Institute for Atmospheric Physics (DLR), Germany.
    Veronika Eyring
    RT3 leader, ESMValTool PI

    Veronika is involved in the World Climate Research Programme (WCRP) through her roles as Chair of the Coupled Model Intercomparison Project (CMIP) Panel and member of the scientific steering committees for the Chemistry-Climate Model Initiative (CCMI), the Working Group on Coupled Modeling (WGCM), the WCRP Data Advisory Council's (WDAC) Observations for Model Evaluation Task Team, and the Working Group on Numerical Experimentation (WGNE)/WGCM Climate Model Metrics Panel.

  • Reto Knutti
    RT3 leader
    Institute for Atmospheric and Climate Science (ETH), Switzerland
    Reto Knutti
    RT3 leader

    Reto’s research and teaching include many topics related to climate change and computer models: long term projections, scenarios, climate targets, climate and carbon cycle feedbacks, uncertainties, model evaluation, model weighting, natural climate variability, detection and attribution, climate sensitivity, ocean heat uptake, extreme events, regional projections, climate services, and more.

  • Alexander Löw †
    WP7 leader, ESMValTool developer
    Ludwig Maximilian University (LMU), Germany
    Alexander Löw †
    WP7 leader, ESMValTool developer

    Alex’s research interests involve: global energy and water flows, climate modelling and model evaluation, remote sensing (focusing microwave remote sensing), synergy of models and data (data assimilation).

    deceased, 2 July 2017


    Peter Cox
    WP8 leader

    Peter’s current research interests are: climate-carbon cycle feedbacks, dynamic global vegetation modelling, impact of atmospheric pollutants on ecosystem services, carbon cycle data assimilation, geoengineering, climate tipping points, and maximum entropy production and the Earth system.

  • Bill Collins
    WP9 leader
    University of Reading (UREAD), UK
    Bill Collins
    WP9 leader

    Bill’s research interests include: biogeochemical feedbacks in the Earth System, climate impacts of short-lived climate pollutants, impacts of climate change on air quality, and impacts of ozone and nitrogen deposition on ecosystems.