Reliable and trustworthy evaluation methods
GRAS provides relevant sustainability information about biodiversity, carbon stock, land use change and social issues. Each data source is carefully selected and the collected data is thoroughly processed and evaluated, according to the needs of our users. The GRAS Index unites sustainability indicators into one comprehensive score to support the risk assessment of agricultural products and their sustainable origin.
Methodology
The basic idea of the GRAS Index is to unite sustainability indicators into one comprehensive index, that supports the risk assessment of agricultural products and their sustainable origin. The GRAS Index is capable to gather and merge the relevant data from the fields Biodiversity, Land Use Change, Carbon Stock and Social Indices and displaying the overall score as a simple and easy-to-use value that can be applied to a region or a whole country.
GRAS uses the EU Renewable Energy Directive (EU-RED) as an orientation for selecting suitable indicators for the various factors that are included in the calculation of the GRAS Index. For example, the EU-RED is used for defining areas with high priority for nature conservation or for choosing appropriate social sustainability indicators. The revised and latest version of the EU Renewable Energy Directive is of 2023 and can be found here.
The three factors for Biodiversity, Land Use Change, Carbon Stock are based on the share of overlapping areas of the categories with the assessment area. The fourth factor covering Social topics is a comprehensive value derived from a number of most relevant national indices. Then, all four factors are translated into one comprehensive value using predefined weighting factors. In the paragraphs below you will find more detailed descriptions of the different factors that are relevant for the calculation of the GRAS Index and how they are calculated and weighted to form the GRAS Index. On the right side you will find an example for each of the four factors for an assessment area in India.
Biodiversity Factor
The biodiversity information displayed in the GRAS Tool+ represents protected and biodiverse areas and is compiled from global, interregional (European Union), national and subnational databases. GRAS researched and aggregated the best available data sources for each country. The integration of complementary data sources ensures that a complete picture of biodiversity is painted. All biodiversity databases used in the GRAS Tool+ are selected according to specific criteria regarding content, data source, data quality, data format and availability of data. The integrated biodiversity data is a comprehensive collection and shows protected areas, i.e. areas designated by national or international law for environmental protection purposes, as well as areas that have been identified as biodiverse and/or vulnerable by NGOs, Institutes or Organizations. Furthermore, the database contains areas with a certain land cover e.g. primary forest.
To facilitate interpretation of the biodiversity data, the GRAS approach is to classify the various biodiversity areas into so called “No-Go Areas” and “Risk Areas”. The GRAS Biodiversity Factor is solely calculated from the “No-Go Areas”.
“No-Go Areas” refer to protected areas where essentially no agricultural production is allowed due to national or international environmental law regulations. The compilation of no-go areas in addition contains the Intact Forest Landscapes and Ramsar Sites.
“Risk Areas” refer to areas where production regulations are in place, but agricultural management might be allowed under limiting requirements. Thus, production of sustainable raw material could be possible. However, if not further specified protection regulations of those risk areas must be checked with local authorities.
After the classification of the “No-Go Areas” and “Risk Areas” the GRAS Biodiversity Factor is calculated as shown in the figure below. Therefore, the “No-Go Area” is divided by the total area of interest.
Example: Biodiversity
Carbon Factor
The carbon map used for the measurement of the Carbon Factor was developed by Ruesch and Gibbs and is a global map of biomass carbon stored in above and below ground living vegetation. It was created using the International Panel on Climate Change (IPCC) Good Practice Guidance for reporting national greenhouse gas inventories. The authors followed the IPCC GPG Tier-1 method for estimating vegetation carbon stocks using the globally consistent default values provided for above ground biomass (IPCC 2006).
For the calculation of the Carbon Factor only areas in the highest carbon category are used (i.e.: >65 t/ha total biomass carbon). The figure below depicts the calculation of the Carbon Factor: The areas in the highest carbon stock category are divided by the total area of interest.
Example: Carbon
Land Use Change Factor
The Land Use Change (LUC) map depicts areas of gross tree cover loss including potential deforestation after a specific cut-off year. It is derived from the annual tree loss dataset, which is part of the Global Forest Change dataset (Hansen et al., 2013). The Global Forest Change dataset summarizes the global forest extent as well as annual changes in the forest extent since the year 2000 applying a time-series analysis of Landsat satellite imagery. GRAS filters the annual tree loss dataset to determine changes in the Land Use. Depending on the context, you can choose different LUC cut-off years.
Relevant cut-off years are:
- 2006 for the 4C Certification
- 2008 for the ISCC and RED system auditors
- 2021 for the EUDR
The figure below depicts the calculation of the GRAS LUC Factor. After identifying the LUC area for the specific cut-off date, it is divided by the total area and then multiplied by ten.
Example: Land Use Change
Social Factor
GRAS implemented the following indices for the calculation of the GRAS Social Factor: The effects of the increasing production of biomass for biofuels on hunger (represented in GRAS by the Global Hunger Index), working conditions (represented in GRAS by the Global Slavery Index), human development (represented in GRAS by the Human Development Index) and governance (represented in GRAS by the World Governance Indicators) as an indicator for political stability and efficiency (e.g. corruption, land use rights, etc.). In the calculation of the final GRAS Social Factor for each country, these four indices (Global Slavery Index (GSI), Global Hunger Index (GHI), Human Development Index (HDI) and the World Governance Indicators (WGI)) are each weighted with 20%. The remaining 20% is made up of three EPI Indices (EPI Sustainable Nitrogen Management (4%), EPI Sustainable Pesticide Use (4%), EPI Wastewater Treatment (4%)) and two UNICEF Indices (UNICEF access to drinking water (4%), UNICEF Access to sanitation (4%)), which represent the social consequences of environmental problems associated with the increasing agricultural production (e.g. water problems, use of pesticides/fertilizers and sanitation).
All social indices from varying sources on national level are comprised in an overall social factor that is valid for the whole country. Therefore, the GRAS Social Factor is calculated at country level. In the above example for an assessment area in India, the country-specific GRAS Social Factor is “0.48”.
Example: Social
The GRAS Index
After calculating each of the four relevant factors (Biodiversity Factor, Carbon Factor, Land Use Change Factor and Social Factor) the GRAS Index can be derived.
How each of the factors is weighted in the GRAS Index is displayed in the figure on the right. The Biodiversity Factor is weighted with 35%, the Carbon Factor with 15%, the Land Use Change Factor with 35% and the Social Factor with 15%.
The weighting factors are set based on:
- Relative importance given to biodiversity, carbon stock, land use change and social factors inside the EU RED for the production of biomass
- Availability of comprehensive and reliable data
In our approaches, we respect regional and customer-specific requirements. Therefore, the GRAS Index weighting factors can be adjusted to the needs of your specific strategy, reporting criteria and specialties of the assessment region. At the same time, the methodology stays sound and transparent.
Don’t hesitate to contact us to discuss possible options for your specific sustainability strategy.
GRAS Index: Weighting
Exemplary calculation of the GRAS Index for an assessment area in India
