CRESCENDO is structured to feed into and benefit from six CMIP6 Model Intercomparison Projects (MIPs).

Advances in modeling the Earth system, along with access to powerful supercomputers, allowed more widespread use of fully coupled models and the capability to undertake transient (i.e., time-evolving) climate simulations, typically spanning the years 1850–2100. This progress is documented in the subsequent IPCC Assessments. As modeling capability has advanced, the need to quantitatively evaluate these models has also grown. To address this, Working Group on Coupled Modeling (WGCM) of the World Climate Research Programme (WCRP) has initiated a series of Coupled Model Intercomparison Projects (CMIP). In preparation for the IPCC Sixth Assessment, the CMIP Phase 6, CMIP6, was launched. A brief summary can be found in the following overview presentation (CMIP6FinalDesign_GMD_160603.pdf).

CMIP6 continuityCRESCENDO will contribute to ScenarioMIP, C4MIP, LUMIP, LS3MIP, AerChemMIP and OCMIP

One of the three major elements of CMIP6 is an ensemble of CMIP-Endorsed Model Intercomparison Projects (MIPs). Contributing to these MIPs through a single project will allow Europe to make a coordinated and significant contribution to CMIP6. CRESCENDO will also be able to draw on the expertise within the MIP communities to further enhance the development and understanding of the project ESMs. Here we outline the six MIPs, highlighting how each relates to CRESCENDO and indicate which CRESCENDO research theme (RT) and Work Package(s) are most linked to a given MIP.

ScenarioMIP: Scenario Model Intercomparison Project

ScenarioMIP brings together scientists from a range of Earth system science disciplines with the aim of; (i) defining and recommending an experimental design for future scenarios to be run by climate models as part of CMIP6, (ii) coordinate the provision of IAM scenario information to climate modelling groups, and (iii) coordinate the production of ESM simulations and facilitate provision of output.

C4MIP: The Coupled Carbon Cycle Climate Model Intercomparison Project

C4MIP is the main international collaboration investigating coupled carbon cycle – climate feedbacks in ESMs (Friedlingstein et al. 2006). As in CMIP5, 3 sets of simulations will be performed in C4MIP using updated CMIP6 ESMs; (i) fully coupled simulations (1%/year CO2 increase as part of the CMIP DECK); (ii) biogeochemically active simulations, where atmospheric CO2 increase has no radiative effect, and conversely (iii) radiatively active simulations, where atmospheric CO2 increase has no direct effect on land or ocean biogeochemistry.

LUMIP: Land Use Model Intercomparison Project

Human land-use has led to large changes in the Earth’s surface, with implications for climate. In the future land-use activities are likely to expand to meet growing societal demands. Improved understanding of the role of land use and land cover changes (LULCC) in the climate system is urgently required (Brovkin et al. 2013). We aim to reduce uncertainties in the response of climate and carbon sources/sinks to past and future LULCC changes. LUMIP simulations proposed for CMIP6 include (i) idealized experiments with gradual global deforestation per year (to complete deforestation) to quantify ESM sensitivity to forest; (ii) historical simulation without LULCC to complement the CMIP DECK simulation with LULCC; (iii) in coordination with ScenarioMIP, two future projections with minimum and maximum deforestation scenarios to quantify the mitigation potential of LULCC.

LS3MIP: Land Surface, Snow and Soil Moisture Model Intercomparison Project

The new Land Surface, Snow and Soil Moisture Model Intercomparison Project (LS3MIP) builds upon several past MIPs investigating biogeophysical feedbacks from land processes on climate. A core element of this project is the follow-up of the Global Land-Atmosphere Coupling Experiment (GLACE), a multi-phase project coordinated by the Global Energy and Water Exchange Project (GEWEX), investigating impacts of land hydrology on climate (including vegetation-mediated effects). The GLACE-Coupled MIP Phase 5 (GLACE-CMIP5) ran using CMIP5 projections (Seneviratne et al. 2013). Experiments consisted of historical and scenario runs modified from the CMIP5 standard by soil moisture and snow cover being prescribed either to a transient climatology or values from a reference period (e.g. late 20th century).

AerChemMIP: Aerosol and Chemistry Model Intercomparison Project

21 CMIP6 MIPsAerChemMIP is a subproject of two initiatives; AeroCom (Aerosol Comparisons between Observations and Models) and CCMI (Chemistry-Climate Model Initiative) and aims to further advance our ability to simulate and diagnose chemistry-aerosol processes. We will investigate the impact of an improved treatment of natural aerosols and, by association, a changed pre-industrial aerosol state (Carslaw et al. 2013) on estimates of anthropogenic aerosol forcing over the historical period.

OCMIP6: Ocean Carbon Cycle Model Intercomparison Project

In coordination with the CORE (Coordinated Ocean-Ice Reference Experiments) group, OCMIP6 will develop an experiment protocol whereby ocean dynamical-biogeochemical models used in coupled ESMs are run in stand-alone mode, driven by observation-based forcing. These simulations will investigate the benefits of improved ocean model resolution and process description, in moving from CMIP5 (typical ocean model resolution of ~1-2°) to CRESCENDO/CMIP6 (typical ocean model resolution of ~0.25°, (eddy-permitting)), on simulated marine biogeochemical cycles, particularly carbon uptake.

The scientific backdrop for CMIP6 is the WCRP Grand Challenges:

  1. Clouds, Circulation and Climate Sensitivity
  2. Changes in Cryosphere
  3. Climate Extremes
  4. Regional Sea-level Rise
  5. Water Availability
  6. Decadal Predictability (pending)
  7. Biogeochemical forcings and feedbacks (pending)

The specific experimental design is focused on three broad scientific questions:

  1. How does the Earth System respond to forcing?
  2. What are the origins and consequences of systematic model biases?
  3. How can we assess future climate changes given climate variability, predictability and uncertainties in scenarios?

For more information visit the Geoscientific Model Development Special Issue: Coupled Model Intercomparison Project Phase 6 (CMIP6) Experimental Design and Organization.