PMIP 3 Overview

Brief history

The Paleoclimate Modelling Intercomparison Project (PMIP) emerged from two parallel endeavours. During the 1980s, the Cooperative Holocene Mapping Project showed the utility of combining model simulations and syntheses of paleoenvironmental data to analyse the mechanisms of climate change. At the same time, the climate-modelling community was becoming increasingly aware that responses to changes in forcing were model dependent. The need to investigate this phenomenon led to the establishment of the Atmospheric Modelling Intercomparison Project (AMIP) - the first of a plethora of model intercomparison projects of which PMIP (and CMIP1) are part.

The specific aim of PMIP was, and continues to be, to provide a mechanism for coordinating paleoclimate modelling and model-evaluation activities to understand the mechanisms of climate change and the role of climate feedbacks. To facilitate model evaluation, PMIP has actively fostered paleodata synthesis and the development of benchmark datasets for model evaluation. During its initial phase (PMIP1), the project focused on atmosphere-only general circulation models; comparisons of coupled ocean-atmosphere and ocean-atmosphere-vegetation models were the focus of PMIP2.

In PMIP3, project members are running the CMIP5 paleoclimate simulations and will lead the evaluation of these simulations. However, PMIP3 will also run experiments for non-CMIP5 time periods and will be coordinating the analysis and exploitation of transient simulations across intervals of rapid climate change in the past. PMIP also provides an umbrella for model intercomparison projects focusing on specific times in the past, such as the Pliocene Modelling Intercomparison Project (PlioMIP), or on particular aspects of the paleoclimate system, such as the Paleo Carbon Modelling Intercomparison Project (PCMIP).

PMIP membership is open to all paleoclimatologists, and we actively encourage the use of archived simulations and data products for model diagnosis or to investigate the causes and impacts of past climate changes.

Quoted from Braconnot et al, "Evaluation of climate models using palaeoclimatic data", Nature Climate Change 2, 417-424 (2012), doi:10.1038/nclimate1456

What is PMIP now?

PMIP organizes:

• Coordinated paleo-experiments, multi-model analyses
  
  PMIP organizes coordinated model experiments for key past periods. From being restricted to the Last Glacial Maximum (LGM, ~21000 years ago) and the Mid-Holocene (MH, ~6000 years ago) in the first phases of the project, the list has now grown to include many other periods when climate was at equilibrium as well as simulations of past climate changes (more details below). These experiments are designed to study the impact of changes in boundary conditions (e.g. ice-sheets for the LGM) and external forcings (e.g. insolation for the MH) as well as the impact of feedbacks or new processes progressively added in climate models. The availability of results from many models allows an assessment of range of model responses and of the robustness of the mechanisms leading to the simulated climate changes.
  
  
• Benchmarking of model results based on paleo-data
  
  Models that perform equally well for present-day may produce very different responses to likely changes in forcing in the future. This makes it vital to evaluate and benchmark models, by comparing simulations of past climates against paleo-observations. PMIP organizes paleo-benchmarking of models, by defining experimental protocols, assembling evaluation data sets and undertaking quantitative assessment of simulations.
  
  
• A forum for discussing paleoclimatic models and data
  
  PMIP has involved hundreds of scientists in simulating paleoclimates and promoted synergies within the paleo-data community. This has resulted in improvements in the paleoclimate simulations and in the paleoclimate reconstructions. Discussions take place during PMIP workshops and conferences and within working groups. The list of working groups evolves following the interests of the PMIP community.

PMIP3 coordinated experiments (as of August 2013):

• 6ka and 21ka (aka CMIP5 midHolocene and lgm)
  
  
• Last millennium (aka CMIP5 past1000)
  
  
• Early Holocene and 8.2ky BP event
  
  
• Last Interglacial (key time slices and transient experiments 130-125-115 ky)
  
  
• Mid-Pliocene

PMIP3 key references

• Braconnot et al, Evaluation of climate models using palaeoclimatic data, Nature Climate Change 2, 417-424 (2012), doi:10.1038/nclimate1456
  
  
• Braconnot et al, The Paleoclimate Modeling Intercomparison Project contribution to CMIP5, CLIVAR Exchanges No. 56, Vol. 16, No.2, May 2011, pp 15-19

Note: CMIP5 key references are available on the CMIP5 web site.

Other references

Other references are available in the Publications' section.