ClimGen was developed by Tim Osborn (Climatic Research Unit) and Tim Mitchell (Tyndall Centre for Climate Change Research), both in the School of Environmental Science, University of East Anglia, Norwich, UK. ClimGen is being maintained and developed further by Tim Osborn. Other contributions (data processing, advice, testing, etc.) have been made by Craig Wallace, Ian Harris, Tom Melvin, Nigel Arnell, Rachel Warren, Rita Yu, Jeff Price and a number of others.

ClimGen is based on the so-called "pattern-scaling" approach to generating spatial climate change information for a given global-mean temperature change. The pattern-scaling approach relies on the assumption that the pattern of climate change (encompassing the geographical, seasonal and multi-variable structure) simulated by coupled atmosphere-ocean general circulation models (AOGCMs) is relatively constant (for a given AOGCM) under a range of rates and amounts of global warming, provided that the changes are expressed as change per unit Kelvin of global-mean temperature change. These normalised patterns of climate change do, however, show considerable variation between different AOGCMs, and it is this variation that ClimGen is principally designed to explore. Further scientific details are provided in the technical paper given below.

ClimGen also provides a convenient interface for generating these scenarios and for extracting observed climate data in a common format, with options to extract user-defined regions, seasons and specific time periods.

In some respects, ClimGen is similar to other spatial scenario generators that use the pattern-scaling approach, some of which are listed in the technical paper given below. Similar tools have previously been developed at UEA -- notably SCENGEN. Information about SCENGEN version 2.x (Wigley et al., 2000; Hulme et al., 2000) is available here. SCENGEN has since been developed further by Tom Wigley at NCAR, Boulder, Colorado, USA, and information about SCENGEN version 4.x (Wigley, 2003) and is available here. ClimGen does not re-use any of the SCENGEN software code, and only uses the concepts from SCENGEN that are common to all tools of this type.

• The scientific and technical basis for ClimGen is described in the following paper (under review) and references therein:
  
  
  • Osborn TJ, Wallace CJ, Harris IC and Melvin TM (submitted) Pattern scaling using ClimGen: monthly-resolution future climate scenarios including changes in the variability of precipitation. Submitted to Climatic Change.
  
  
• A user manual for ClimGen is available:
  
  
  • Osborn TJ (2009) A user guide for ClimGen: a flexible tool for generating monthly climate data sets and scenarios. Climatic Research Unit, University of East Anglia, Norwich, 17pp.
    • For ClimGen version 1-02 (updated 2009-02-02)
  
  
• Explanations of file names and file formats:
  
  
  • A description of the format and content of ClimGen output files.
    • For ClimGen version 1-22 (updated 2013-07-12)
    • For ClimGen version 1-02
    
    
    
  • How ClimGen output files are named.
    • For ClimGen version 1-22 (updated 2013-07-12)
    • For ClimGen version 1-02
    • The filenames include an identifier of the global temperature changes used to generate the scenario. The temperatures associated with each identifier can be found from the global temperature table.

ClimGen is written in Fortran95 and the source code is available for use in selected projects. Please contact Tim Osborn if you wish to obtain this software.

ClimGen version history

• Version 1-00 written by Tim Mitchell and Tim Osborn in 2004.
  • This version is/was used in:
    • Arnell and Osborn (2006)
    • Tyndall Centre's Community Integrated Assessment System (CIAS) from 2004-2008.
    • Warren et al. (2008)
• Version 1-02 written by Tim Osborn in 2008.
  • This version was used in:
    • NERC QUEST-GSI (Global-Scale Impacts) project, 2007-2011.
    • DECC/Defra AVOID project, 2010-2013.
    • EU ERMITAGE project, 2010-2013.
    • Tyndall Centre's Community Integrated Assessment System (CIAS) from 2009-2012.
• Versions 1-10, 1-11, 1-20 and 1-21 written by Tim Osborn, with contributions from Craig Wallace, in 2012.
  • This version was used in:
    • EU ERMITAGE project, 2010-2013.
    • Tyndall Centre's Community Integrated Assessment System (CIAS) from 2012-2013.
• Version 1-22 written by Tim Osborn, with contributions from Craig Wallace and Tom Melvin, in 2013.
  • This version is/was used in:
    • EU ToPDAd project, 2012-2015.
    • EU HELIX project, 2013-2016.

ClimGen data

ClimGen is being used in the EU ToPDAd project.

• Data created using ClimGen especially for TOPDAD are available from the ClimGen TOPDAD data page.

• Data created using ClimGen especially for QUEST-GSI are available from the ClimGen QUEST-GSI data page.

ClimGen is being used in the EU ERMITAGE project.

• Data created using ClimGen especially for ERMITAGE are available from the ClimGen ERMITAGE data page.

Papers that used ClimGen results

• Arnell NW, Brown S, Gosling SN, Gottschalk P, Hinkel J, Huntingford C, Lloyd-Hughes B, Lowe JA, Nicholls RJ, Osborn TJ, Osborne TM, Rose GA, Smith P, Wheeler TR and Zelazowski P (submitted) A global-scale, multi-sectoral regional climate change risk assessment. Submitted to Climatic Change.
• Osborn TJ, Wallace CJ, Harris IC and Melvin TM (submitted) Pattern scaling using ClimGen: monthly-resolution future climate scenarios including changes in the variability of precipitation. Submitted to Climatic Change.
• Arnell NW, Brown S, Gosling SN, Hinkel J, Huntingford C, Lloyd-Hughes B, Lowe JA, Osborn T, Nicholls RJ and Zelazowski P (2014) Global-scale climate impact functions: the relationship between climate forcing and impact. Climatic Change online (doi:10.1007/s10584-013-1034-7).
• Arnell NW, Lowe JA, Brown S, Gosling SN, Gottschalk P, Hinkel J, Lloyd-Hughes B, Nicholls RJ, Osborn TJ, Osborne TM, Rose GA, Smith P and Warren R (2013) A global assessment of the effects of climate policy on the impacts of climate change. Nature Climate Change 3, 512-519 (doi:10.1038/NCLIMATE1793).
• Warren R, Lowe JA, Arnell NW, Hope C, Berry P, Brown S, Gambhir A, Gosling SN, Nicholls RJ, O'Hanley J, Osborn TJ, Osborne T, Price J, Rose G and Vanderwal J (2013) The AVOID programme's new simulations of the global benefits of stringent climate change mitigation. Climatic Change 120, 55-70 (doi:10.1007/s10584-013-0814-4).
• Warren R, VanDerWal J, Price J, Welbergen JA, Atkinson I, Ramirez-Villegas J, Osborn TJ, Jarvis A, Shoo LP, Williams SE and Lowe J (2013) Quantifying the benefit of early climate change mitigation in avoiding biodiversity loss. Nature Climate Change 3, 678-682 (doi:10.1038/nclimate1887).
• Gottschalk P, Smith JU, Wattenbach M, Bellarby J, Stehfest E, Arnell N, Osborn TJ, Jones C and Smith P (2012) How will organic carbon stocks in mineral soils evolve under future climate? Global projections using RothC for a range of climate change scenarios. Biogeosciences 9, 3151-3171 (doi:10.5194/bg-9-3151-2012).
• Warren R, Yu RMS, Osborn TJ and de la Nava Santos S (2012) Future European drought regimes under mitigated and unmitigated climate change: application of the Community Integrated Assessment System (CIAS). Climate Research 51, 105-123 (doi:10.3354/cr01042).
• Todd MC, Taylor RG, Osborn TJ, Kingston DG, Arnell NW and Gosling SN (2011) Uncertainty in climate change impacts on basin-scale freshwater resources - preface to the special issue: the QUEST-GSI methodology and synthesis of results. Hydrology and Earth System Sciences 15, 1035-1046 (doi:10.5194/hess-15-1035-2011).
• Warren R, de la Nava Santos S, Arnell NW, Bane M, Barker T, Barton C, Ford R, Fuessel H-M, Hankin RKS, Klein R, Linstead C, Kohler J, Mitchell TD, Osborn TJ, Pan H, Raper SCB, Riley G, Schellnhuber HJ, Winne S and Anderson D (2008) Development and illustrative outputs of the Community Integrated Assessment System (CIAS), a multi-institutional modular integrated assessment approach for modelling climate change. Environmental Modelling and Software 23, 592-610 (doi:10.1016/j.envsoft.2007.09.002).
• Arnell NW and Osborn TJ (2006) Interfacing climate and impacts models in integrated assessment modelling. Tyndall Centre Technical Report 52, Tyndall Centre, UEA, Norwich, UK, 72pp.
• Goodess CM, Hanson C, Hulme M and Osborn TJ (2003) Representing climate and extreme weather events in Integrated Assessment Models: a review of existing methods and options for development. Integrated Assessment 4, 145-171. Available here.
• Goodess CM, Osborn TJ and Hulme M (2003) The identification and evaluation of suitable scenario development methods for the estimation of future probabilities of extreme weather events. Tyndall Centre Technical Report 4, Tyndall Centre, UEA, Norwich, UK, 69pp.