ClimGen was originally developed by Tim Osborn (Climatic Research Unit, CRU) and Tim Mitchell (then at the 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 CRU/UEA -- notably SCENGEN. Information about SCENGEN version 2.x (Wigley et al., 2000; Hulme et al., 2000) is available here (archived copy). SCENGEN was subsequently developed further by Tom Wigley at NCAR, Boulder, Colorado, USA, and information about SCENGEN version 4.x (Wigley, 2003) was available here (archived copy). 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 and references therein:
  
  
  • Osborn TJ, Wallace CJ, Harris IC and Melvin TM (2016) Pattern scaling using ClimGen: monthly-resolution future climate scenarios including changes in the variability of precipitation. Climatic Change 134, 353-369 https://doi.org/10.1007/s10584-015-1509-9
  
  
• 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 1-51 (updated 2018-11-15)
    • 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.
  
  
• Explanation of the global temperature change database available in ClimGen:
  • global temperature table

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  ClimGen software: availability and versions

  ClimGen availability

  ClimGen is written in Fortran95 and the source code is available for use in selected projects. See source code for more details if you wish to obtain this software.

  ClimGen version history

  • Version 1-00 written by Tim Mitchell and Tim Osborn in 2004. This version was used in:
    • Tyndall Centre's Community Integrated Assessment System (CIAS) from 2004-2008.
    • Arnell and Osborn (2006); Warren et al. (2008)
    
    
  • Version 1-02 written by Tim Osborn in 2008. It included CMIP3 and QUMP GCM patterns. This version was used in:
    • NERC QUEST-GSI (Global-Scale Impacts) project, 2007-2011.
    • Todd et al. (2011); Gottschallk et al. (2012); Osborn et al. (2016); Arnell et al. (2016a,b)
    • DECC/Defra AVOID project, 2010-2013.
    • Arnell et al. (2013)
    • DECC/Defra/NERC AVOID2 project, 2014-2016.
    • Arnell et al. (2016c, 2018)
    • EU ERMITAGE project, 2010-2013.
    • Tyndall Centre's Community Integrated Assessment System (CIAS) from 2009-2012.
    • Warren et al. (2012)
    
    
  • Versions 1-10, 1-11, 1-20 and 1-21 written by Tim Osborn, with contributions from Craig Wallace, in 2012. It included GENIE patterns and extra options for change fields and netCDF output. This version was used in:
    • EU ERMITAGE project, 2010-2013.
    • Warren et al. (2018)
    • Tyndall Centre's Community Integrated Assessment System (CIAS) from 2012-2016.
    • Warren et al. (2013)
    
    
  • Version 1-50 was written by Tim Osborn, with contributions from Craig Wallace and Tom Melvin, in 2013. It included CMIP5 GCM patterns. This version was used in:
    • EU ToPDAd project, 2012-2015.
    • Osborn et al. (2016)
    • EU HELIX project, 2013-2017.
    • Osborn et al. (2016, 2018)
    
    
  • Version 1-51 was written by Tim Osborn and Craig Wallace in 2017. It included additional CMIP5 GCM patterns, additional RCP projections and updated observations (CRU TS3.24 to 2015). This version was used in:
    • BEIS-funded projects on the implications of global warming of 1.5C and 2C (2017-18) and impacts of intermediate levels of warming (2018-2023)
      • Colon-Gonzalez et al. (2018); Warren et al. (2018)
      • Tyndall Centre's Community Integrated Assessment System (CIAS) from 2017-present

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  ClimGen data

  A wide range of datasets have been generated using ClimGen for many projects (see papers listed later). Some have been shared via this website, so they are listed here to provide an archive in case those studies need to be reproduced.

  ClimGen was used in the EU ToPDAd project.

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

  ClimGen was used in the NERC QUEST-GSI (Global-Scale Impacts) project.

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

  ClimGen was used in the EU ERMITAGE project.

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

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  Papers that used ClimGen results

  These papers were based partly or fully on scenarios generated using the ClimGen pattern-scaling methods and software.

  
  2022
  
  • He Y, Manful D, Warren R, Forstenhäusler N, Osborn TJ, Price J, Jenkins R, Wallace C, Yamazaki D (2022) Quantification of impacts between 1.5°C and 4°C of global warming on flooding risks in six countries. Climatic Change 170, 15 (https://doi.org/10.1007/s10584-021-03289-5).
  • Price J, Warren R, Forstenhäusler N, Wallace C, Jenkins R, Osborn TJ, van Vuuren DP (2022) Quantification of meteorological drought risks between 1.5°C and 4°C of global warming in six countries. Climatic Change 174, 12 (https://doi.org/10.1007/s10584-022-03359-2).
  • Warren R, Andrews, O, Brown S, Colón-González FJ, Forstenhäusler N, Gernaat DEHJ, Goodwin P, Harris I, He Y, Hope C, Manful D, Osborn TJ, Price J, Van Vuuren, DP, Wright RM (2022) Quantifying risks avoided by limiting global warming to 1.5 or 2°C above pre-industrial levels. Climatic Change 172, 39 (https://doi.org/10.1007/s10584-021-03277-9).
  • Wells CD, Jackson LS, Maycock AC, Forster PM (2022) Understanding pattern scaling errors across a range of emissions pathways. EGUsphere [preprint] (doi:https://doi.org/10.5194/egusphere-2022-914).
    2021
    
  • Hasan E, Tarhule A, Kirstetter P-E (2021) Twentieth and Twenty-First Century Water Storage Changes in the Nile River Basin from GRACE/GRACE-FO and Modeling. Remote Sensing, 13, 953 (https://doi.org/10.3390/rs13050953).
  • Turchin P, Currie T, Collins C, Levine J, Oyebamiji O, Edwards NR, Holden PB, Hoyer D, Feeney K, François P & Whitehouse H (2021) An integrative approach to estimating productivity in past societies using Seshat: Global History Databank. The Holocene, 31, 1055–1065 (https://doi.org/10.1177/0959683621994644).
  • Wang D, Jenkins K, Forstenhäusler N. et al. (2021) Economic impacts of climate-induced crop yield changes: evidence from agri-food industries in six countries. Climatic Change 166, 30 (doi:https://doi.org/10.1007/s10584-021-03062-8).
    2020
    
  • King MR (2020) One approach for downscaling climate change data towards regional implications in climate change scenarios: the case for Newfoundland and Labrador, Canada. SN Appl. Sci., 2, 2039 (doi:https://doi.org/10.1007/s42452-020-03776-x).
    2019
    
  • Arnell NW, Lowe JA, Bernie D, Nicholls RJ, Brown S, Challinor AJ, Osborn TJ (2019) The global and regional impacts of climate change under representative concentration pathway forcings and shared socioeconomic pathway socioeconomic scenarios. Environmental Research Letters, 14, 084046 (https://doi.org/10.1088/1748-9326/ab35a6).
  • Arnell NW, Lowe JA, Challinor AJ, Osborn TJ (2019) Global and regional impacts of climate change at different levels of global temperature increase. Climatic Change 155, 377–391 (https://doi.org/10.1007/s10584-019-02464-z).
  • Warren RF, Edwards NR, Babonneau F, Bacon PM, Dietrich JP, Ford RW, Garthwaite P, Gerten D, Goswami, S, Haurie A, Hiscock K, Holden PB, Hyde MR, Joshi SR, Kanudia A, Labriet M, Leimbach M, Oyebamiji OK, Osborn TJ, Pizzileo B, Popp A, Price J, Riley G, Schaphoff S, Slavin P, Vielle M, and Wallace C (2019) Producing Policy-relevant Science by Enhancing Robustness and Model Integration for the Assessment of Global Environmental Change. Environmental Modelling and Software, online (doi:10.1016/j.envsoft.2018.05.010).
    2018
    
  • Arnell NW, Lowe JA, Lloyd-Hughes B and Osborn TJ (2018) The impacts avoided with a 1.5°C climate target: a global and regional assessment. Climatic Change 147, 61-76 (doi:10.1007/s10584-017-2115-9).
  • Colon-Gonzalez FJ, Harris I, Osborn TJ, Bernado CSS, Peres CA, Hunter PR and Lake IR (2018) Limiting global-mean temperature increase to 1.5-2°C could reduce the incidence and spatial spread of dengue fever in Latin America. Proceedings of the National Academy of Sciences online (doi:10.1073/pnas.1718945115).
  • Osborn TJ, Wallace CJ, Lowe JA and Bernie D (2018) Performance of pattern-scaled climate projections under high-end warming, part I: surface air temperature over land. Journal of Climate 31, 5667-5680 (doi:10.1175/JCLI-D-17-0780.1).
  • Warren R, Andrews, O, Brown S, Forstenhaeusler N, Gernaat DEHJ, Goodwin P, Harris I, He Y, Hope C, Colón-González FJ, Nicholls R, Osborn TJ, Price J, Van Vuuren, DP, Wright RM (2018) Risks associated with global warming of 1.5°C or 2°C. Tyndall Centre Briefing Note (available from Tyndall Centre, UEA, Norwich).
    2016
    
  • Arnell NW, Brown S, Gosling SN, Hinkel J, Huntingford C, Lloyd-Hughes B, Lowe JA, Osborn T, Nicholls RJ and Zelazowski P (2016) Global-scale climate impact functions: the relationship between climate forcing and impact. Climatic Change 134, 475-487 (doi:10.1007/s10584-013-1034-7).
  • 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 (2016) The impacts of climate change across the globe: a multi-sectoral assessment. Climatic Change 134, 457-474 (doi:10.1007/s10584-014-1281-2).
  • Arnell NW, Lowe JA, Warren RF, Bernie D, Brown S, Gambhir A, Hawkes E, Kebede AS, Lloyd-Hughes B, Napp T, Osborn TJ and Price JT (2016) The impacts of climate change avoided by future reductions in emissions as defined in the Intended Nationally-Determined Contributions. AVOID Report B2c to the DECC AVOID2 programme, 52pp (available here: http://www.avoid.uk.net/2016/02/the-impacts-of-climate-change-avoided-under-the-indcs/).
  • Osborn TJ, Wallace CJ, Harris IC and Melvin TM (2016) Pattern scaling using ClimGen: monthly-resolution future climate scenarios including changes in the variability of precipitation. Climatic Change 134, 353-369 https://doi.org/10.1007/s10584-015-1509-9
    2015
    
  • Conway D, Archer van Garderen E, Deryng D, Dorling S, Krueger T, Landman W, Lankford B, Lebek K, Osborn TJ, Ringler C, Thurlow J, Zhu T and Dalin C (2015) Climate and southern Africa's water-energy-food nexus. Nature Climate Change 5, 837-846 (doi:10.1038/nclimate2735).
    2013
    
  • 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).
    2012
    
  • 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).
    2011
    
  • 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).
    2008
    
  • 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).
    2006
    
  • 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.
    2003
    
  • 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.