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PMIP WG Past2Future - Aims and Scope v1.0, May 2013

Paleoclimate modellers have for many years argued the importance of paleoclimate simulations as a means of increasing understanding of the climate system. However, it is only in the latest iteration of the climate model inter-comparison project (CMIP5) that paleoclimate runs have been officially included. This means that, for the first time, there exists a coherent ensemble of climate models run for past climates, recent historical, control and future scenarios.

This working group seeks to help climate scientists make the best use of this unique situation, so that they may better use past climate information from models and data to learn about future climates.

Two ways of approaching this problem are envisaged (copyright, Gavin Schmidt):

  • In the case where there are high quality data for quantifiable measures such as temperature or precipitation, and a physically plausible and statistically robust relationship (in the ensemble) between past and future changes it may be possible to use statistical methods to combine the models and data to directly produce a constraint on future climate change projections.

  • In cases where the first approach is not tractable, it may be possible to find feature of the climate system (processes, patterns, or more qualitative variables such as vegetation type) that show robust changes in the ensemble that are supported or refuted by the paleoclimate data. In such cases confidence in model projections, particularly of these features, may also be evaluated.

There are presently several discrete but interrelated parallel foci in the working group:

  1. Improving accessibility to models and data. Our initial goal is to make it easier for scientists to explore past-future linkages. Up until now individual climate scientists have typically focussed only on one or two of the three areas of paleoclimate modelling, data synthesis, or future modelling of the climate system. Even those involved in paleoclimate studies typically have detailed knowledge of particular paleoclimate intervals. We hope to encourage scientists to evaluate of the different paleoclimate intervals both individually and jointly. Firstly it is important to understand what the different paleoclimate intervals teach us about different aspects of future climate. Secondly, we need to explore to what extent the different intervals agree in what they teach us about future climate. In the case where they disagree, can we identify why? In the case where they agree, can we put the intervals together to make strong statements about future climate? 

In order to make information on all the available resources more readily available we are developing a wiki with sections on data (Valérie Masson-Delmotte), models (Dan Lunt) and methods (Julia Hargreaves). 

  2. Sharing development of progress for using paleoclimate to learn about the future.
The first few meetings of Past2Future have piggy-backed on major conferences such as the AGU, EGU and PAGES Open Science Meeting. We also had a session at the EGU in 2013, which we hope to continue in 2014. Should we have anything else - internet forum, twitter hashtag etc…?! 

  3. Additional dedicated experiments will be identified as required, but it is expected that the emphasis will be on existing PMIP, as well as CMIP5 experiments, when available from the same models. Suggestions so far:
    1. Dedicated experiments to estimate equilibrium climate sensitivity including consistent approach between model groups.
    2. Transient simulations including forcing from meltwater: Eemian, Deglaciation and Holocene.
    3. Investigating monsoons in existing climate models: integrated approach, covering several PMIP time periods; relevance for future changes in the monsoon.
  4. Development of relevant “key scientific questions”.
 Suggestions so far:
    1. How do past warm climates compare and how do they relate to a future warm greenhouse climate?
    2. What can we learn from PMIP experiments about equilibrium climate sensitivity? Are additional dedicated experiments required? What are the reasons for different results reached by different methods?

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Past to Future guest account, 2013/05/17 15:55

Julie, this is a great lay out of ideas/goals/products. One thing that I think would be beneficial would be to include a component on modeled and reconstructed ice-sheet volume/GIA-sea level during these paleo periods and how that can be used to constrain future sea-level change. Anders

Hugues, 2013/05/23 06:47

Thanks for the synthesis. In addition to the key research questions, I think it would be nice to identify some key conclusions (or key needs ?) derived from proxy records that are robust enough to be used as benchmark of models, which then can be related to the skill of the projections (as mentioned in the first 'ways of approaching this problem'). If it was for instance possible to have a reliable estimate of summer sea ice extent for the early or mid-Holocene in the Arctic, that would certainly be a strong test for models that could contribute to a selection of the best models used for future changes. Hugues

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pmip3/wg/p2f/aims_and_scope_v1.0.txt · Last modified: 2013/05/17 02:49 by jules