Global Land-Use Model (GLM)
The Global Land-Use Model (GLM) is a tool for computing annual, gridded, fractional land-use states and all underlying land-use transitions, including the age, area and biomass of secondary (recovering) lands, and the spatial patterns of wood harvest and shifting cultivation, in a format designed for inclusion in Earth System Models. GLM computes these land-use patterns using an accounting-based method that tracks the fractions of cropland, pasture, urban, primary vegetation, and secondary vegetation in each grid cell as a function of the land surface at the previous time-step. The solution of the model is constrained with inputs and data including historical reconstructions and future projections of: i) land use (crop, pasture, urban), ii) wood harvest, and iii) potential biomass and recovery rate.
Applications
GLM was used to compute an annual historical land-use reconstruction for the years 1500-2000, at 1 degree spatial resolution. More details about this project and the resulting datasets can be found in our 2006 Global Change Biology paper. GLM was also selected as a tool to provide harmonized land-use datasets for the CMIP5 experiments as part of the Fifth IPCC Assessment Report. For this project we computed the land-use states and transitions annually, at half-degree spatial resolution, for the years 1500-2100, using data from Integrated Assessment models for the years 2005-2100. For more information on this Land-use Harmonization (LUH) project, you can visit our LUH website. Our 2011 Climatic Change paper also contains further details.
New GLM developments are underway including further constraining the solution of our model with forest extent and change data from NASA satellites. You can read more about this new project here.
Download GLM Code
The GLM code is freely available for you to download, although at this point we are not able to provide the input datasets that GLM uses owing to them not being our own intellectual property. You can download the latest version of the GLM code here. To stay up-to-date with new releases of the GLM code you can add your name to our mailing list on our LUH site.
Select References
Hurtt,G.C., L. P. Chini, S. Frolking, R. A. Betts, J. Feddema, G. Fischer, J. P. Fisk, K. Hibbard, R. A. Houghton, A. Janetos, C. D. Jones, G. Kindermann, T. Kinoshita, Kees Klein Goldewijk, K. Riahi, E. Shevliakova, S. Smith, E. Stehfest, A. Thomson, P. Thornton, D. P. van Vuuren, Y. P. Wang (2011), Harmonization of land-use scenarios for the period 1500–2100: 600 years of global gridded annual land-use transitions, wood harvest, and resulting secondary lands. Climatic Change 109:117–161, doi:10.1007/s10584-011-0153-2 (Paper).
Hurtt, G.C., S. Frolking, M.G. Fearon, B. Moore III, E. Shevliakova, S. Malyshev, S.W. Pacala, R.A. Houghton (2006), The Underpinnings of Land-use History: Three Centuries of Global Gridded Land-Use Transitions, Wood Harvest Activity, and Resulting Secondary Lands, Global Change Biology 12:1208-1229. (Abstract).
Brovkin, V., L. Boysen, V.K. Arora, J.P. Boisier, P. Cadule, L. Chini, M. Claussen, P. Friedlingstein, V. Gayler, B.J.J.M. van den Hurk, G.C. Hurtt, C.D. Jones, E. Kato, N. de Noblet-Ducoudré, F. Pacifico, J. Pongratz, M. Weiss (2013), Effect of anthropogenic land-use and land cover changes on climate and land carbon storage in CMIP5 projections for the 21st century, Journal of Climate, 26, 6859–6881. (Paper).
Jones, A., W. Collins, J. Edmonds, M. Torn, A. Janetos, K. Calvin, A. Thomson, L.P. Chini, J. Mao, X. Shi, P. Thornton, G.C. Hurtt, M. Wise (2013), Greenhouse gas policy influences climate via direct effects of land-use change, Journal of Climate, 26, 3657–3670. (Paper).
Jones, C. D., J.K. Hughes, N. Bellouin, S.C. Hardiman, G.S. Jones, J. Knight, S. Liddicoat, F.M. O'Connor, R.J. Andres, C. Bell, K.-O. Boo, A. Bozzo, N. Butchart, P. Cadule, K.D. Corbin, M. Doutriaux-Boucher, P. Friedlingstein, J. Gornall, L. Gray, P.R. Halloran, G. Hurtt, W.J. Ingram, J.-F. Lamarque, R.M. Law, M. Meinshausen, S. Osprey, E.J. Palin, L. Parsons Chini, T. Raddatz, M.G. Sanderson, A.A. Sellar, A. Schurer, P. Valdes, N. Wood, S. Woodward, M. Yoshioka, and M. Zerroukat (2011) The HadGEM2-ES Implementation of CMIP5 Centennial Simulations, Geoscientific Model Development, Vol. 4, Issue 1, DOI: 10.5194/gmdd-4-689-2011 (Paper)
Thomson, A. M., K. V. Calvin, L. P. Chini, G. C. Hurtt, J. A. Edmonds, B. Bond-Lamberty, S. Frolking, M. A. Wise, A. C. Janetos (2010), Climate mitigation and the future of tropical landscapes, Proceedings of the National Academy of Sciences of the United States, doi: 10.1073/pnas.0910467107. (Paper)
Shevliakova E., S.W. Pacala, S. Malyshev, G.C. Hurtt, P.C.D. Milly, J.P. Caspersen, L. Sentman, J. Fisk, C. Wirth, C. Crevoisier (2009), Carbon Cycling Under 300 Years of Land-use Changes in the Dynamic Land Model LM3V, Global Biogeochemical Cycles 23(2): 1-16.
Hurtt G.C., S.W. Pacala, P.R. Moorcroft, J. Caspersen, E. Shevliakova, R. Houghton, B. Moore (2002) Projecting the Future of the US Carbon Sink. Proceedings of the National Academy of Sciences of the United States 99(3): 1389-1394.
