This Excel-file contains a simple climate model that can be used to assess climate impacts, in terms of radiative forcing and global mean temperature change, from an emission profile of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). It is an update of the model used for the publication by Persson et al. (2015), and has been revised to reflect the equations and parametrizations used for estimating greenhouse gas metrics in the latest IPCC assessment (Forster & Storelvmo et al. 2021), including the carbon cycle feedback effects of CH4 and N2O emissions. To use the model, enter emission pathways for carbon dioxide (column B), methane (column O), and nitrous oxide (column AF), and the model calculates the resulting impacts in terms of radiative forcing (columns L, AC, and AT, respectively) and temperature change (columns M, AD, and AU, respectively). As is, the model is run with a pulse emission of one ton for each gas in year 1, which means the results can be used to estimate the Global Warming Potential (GWP) and Global Temperature Potential (GTP) for methane and nitrous oxide (columns AW-AZ). Note that the model is a linearized representation of more complex climate models, and as such should be used to assess the climate impacts for small perturbations (i.e., project level emissions scenarios). For larger perturbations (e.g., regional or global emission scenarios) a model that includes the non-linear responses of the climate system (e.g., on greenhouse gas lifetimes and radiative forcings), such as the FAIR model (Smith et al. 2017, 2018) should be used.

{"references": ["Persson, U. M., Johansson, D. J., Cederberg, C., Hedenus, F., & Bryngelsson, D. (2015). Climate metrics and the carbon footprint of livestock products: where's the beef?. Environmental Research Letters, 10(3), 034005.", "Smith, C. J., Forster, P. M., Allen, M., Leach, N., Millar, R. J., Passerello, G. A., & Regayre, L. A. (2018). FAIR v1. 3: a simple emissions-based impulse response and carbon cycle model. Geoscientific Model Development, 11(6), 2273-2297.", "Christopher Smith, Richard Millar, Zebedee Nicholls, Myles Allen, Piers Forster, Nicolas Leach, Giovanni Passerello, & Leighton Regayre. (2018). FAIR - Finite Amplitude Impulse Response Model (multi-forcing version). In Geoscientific Model Development (v1.3.2). Zenodo. https://doi.org/10.5281/zenodo.1247898", "Forster, P., T. Storelvmo, et al. (2021). The Earth's Energy Budget, Climate Feedbacks, and Climate Sensitivity. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I 40 to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press."]}