diff --git a/README_ELUC.md b/README_ELUC.md index 9001f2f..f9403ba 100644 --- a/README_ELUC.md +++ b/README_ELUC.md @@ -12,7 +12,8 @@ made to reduce CO2 emissions? ### ELUC BLUE simulations with committed emissions could be used to estimate the long-term CO2 impact. -Committed emissions: all the emissions that are caused by a land-use change event are attributed to the year of the event +"Committed emissions" means all the emissions that are caused by a land-use change event are attributed to the year +of the event. BLUE (bookkeeping of land use emissions) is a bookkeeping model that attributes carbon fluxes to land use activities. See [(BLUE: Bookkeeping of land use emissions)](https://doi.org/10.1002/2014GB004997) for more details. @@ -22,25 +23,128 @@ The team in charge of the BLUE model performed such simulations with BLUE and ge ### LUC -The Land Use Change (LUC) data provided by the LUH2 project [(LUH2: Land Use Harmonization 2)](https://luh.umd.edu/) +The Land Use Change (LUC) data is provided by the LUH2 project [(LUH2: Land Use Harmonization 2)](https://luh.umd.edu/) +The land-use harmonization strategy estimates the fractional land-use patterns, underlying land-use transitions, +and key agricultural management information, annually for the time period 850-2100 at 0.25 x 0.25 resolution. -## Modeling +The LUH2 model and datasets prepared for CMIP6 are described in +[Hurtt et al. 2020.](https://gmd.copernicus.org/articles/13/5425/2020/gmd-13-5425-2020-discussion.html) + +Land-use Harmonization (LUH) data for [GCB 2022](https://doi.org/10.5194/essd-14-4811-2022) is provided in +3 separate files, which can be downloaded from the following links +(for the states, transitions, and management data layers respectively): + +http://luh.umd.edu/LUH2/LUH2_GCB_2022/states.nc +http://luh.umd.edu/LUH2/LUH2_GCB_2022/transitions.nc +http://luh.umd.edu/LUH2/LUH2_GCB_2022/management.nc + +These files are based on the new HYDE3.3, as well as the 2021 FAO wood harvest data, for all years 850-2022. + +The data files are for the years 850-2022, which keeps the file format consistent with the LUH2 data produced for CMIP6, +hence the start year of 850. The LUH2-GCB2022 data will be different from the LUH2 v2h data used for CMIP6 for all +years, due to the use of the new HYDE3.3 crop/grazing land dataset. + +See https://luh.umd.edu/ for more details. + +### Land Use Types + +Primary: Vegetation that is untouched by humans +- **primf**: Primary forest +- **primn**: Primary nonforest vegetation + +- Secondary: Vegetation that has been touched by humans +- **secdf**: Secondary forest +- **secdn**: Secondary nonforest vegetation + +Urban +- **Urban**: Urban areas + +Crop +- **c3ann**: Annual C3 crops (e.g. wheat) +- **c4ann**: Annual C4 crops (e.g. maize) +- **c3per**: Perennial C3 crops (e.g. banana) +- **c4per**: Perennial C4 crops (e.g. sugarcane) +- **c3nfx**: Nitrogen fixing C3 crops (e.g. soybean) + +Pasture +- **pastr**: Managed pasture land +- **range**: Natural grassland / savannah / desert / etc. + + +## Modeling decisions + +A decision can be represented by 3 constituents: **context**, **actions** and **outcomes** + +> In a particular **context**, what was the **outcomes** of the decision maker **actions**? + +In other words, in a particular situation, what were the results of the decisions of the decision maker? ### Context -The context is the current usage of the land +The context describes the current situation the decision maker is in. +For the land use change use case this is a particular grid cell, +a point in time when the decision had to be made, and the current usage of the land: + +- Latitude +- Longitude +- Area +- Year +- Land usage, as a percentage, summing up to 100% + - primf + - primn + - sedf + - secdn + - urban + - c3ann + - c4ann + - c3per + - c4per + - c3fnx + - pastr + - range + - nonland + +Latitude and longitude represent the cell on the grid. +Area represents the surface of the cell. Cells close to the equator have a bigger area than cells close to the poles. +Year is useful to capture historical decisions: the same cell has been through a lot of land use changes +over the years. +Land usage represents the percentage of the land used by each land type. Note there is a 'nonland' type that represents +the percentage of the cell that is not land (e.g typically sea, lake, etc.). The land usage types sum up to 100%. ### Actions +Actions represent the decisions decision makers can make. How can they change the land? +We considered 2 limitations: +1. Decision makers can't affect primary land: + 1. It's better to preserve primary vegetation. Destroying it is not an option. + 2. It's not possible to re-plant primary vegetation. Once destroyed, it's destroyed forever and + can't be planted back (it would become secondary vegeation) +2. Decision makers can't affect urban areas. We consider the needs for larger / smaller urban areas are dictated by + other imperatives, other decision makers. + 1. It doesn't seem reasonable to recommend to destroy a city + 2. It doesn't seem reasonable to recommend to expand a city + ### Outcomes -1. Emissions from Land Use Change (ELUC): CO2 emissions, in metric ton of carbon per hectare (tC/ha), +- Emissions from Land Use Change (ELUC): CO2 emissions, in metric ton of carbon per hectare (tC/ha), resulting from the land use change -2. Percentage of land that was changed +- Percentage of land that was changed + +There is a trade-off between these 2 objectives: it easy to reduce emissions by changing +most of the land, but that would come at a huge cost. This "cost" can be approximately derived from +the percentage of land that was change. In other words decision makers have to: +- minimize ELUC +- while minimizing land change at the same time + +## Modeling + +### Predictions + +### Prescriptions ## References ELUC data provided by the BLUE model [(BLUE: Bookkeeping of land use emissions)](https://doi.org/10.1002/2014GB004997) Land use change data provided by the LUH2 project [(LUH2: Land Use Harmonization 2)](https://luh.umd.edu/) -Setup is described in Appendix C2.1 of the GCB 2022 report [(Global Carbon Budget 2022 report)](https://essd.copernicus.org/articles/14/4811/2022/#section10/) +Setup is described in Appendix C2.1 of the GCB 2022 report [(Global Carbon Budget 2022 report)](https://doi.org/10.5194/essd-14-4811-2022) The Global Carbon Budget report assesses the global CO2 budget for the Intergovernmental Panel on Climate Change [(IPCC)](https://www.ipcc.ch/)