Annual global vegetation carbon stocks to identify global spatiotemporal trends

These annual global maps are computed based on the original methodology by Gibbs and Ruesch (2008) [1] and using IPCC 2006 [2] default factors to estimate the value of above-ground and below-ground vegetation carbon stock. The maps are provided at 300 m spatial resolution, the model to estimate these stock considers:

• the land cover class of the area observed, according to the European Space Agency - Climate Change Initiative (ESA-CCI) dataset,
• the ecological area, from the Food and Agriculture Organization of the United Nations (FAO)'s Ecofloristic region and
• the geographical zones to capture regional/ continental specific characteristics.

For forests, the carbon content additionally depends on how intact the forest is, with so-called primary forest storing a higher quantity of carbon. Moreover, areas burned by fire are modeled to have a significantly lower to no vegetation carbon stock.

Results include both above-ground and below-ground vegetation carbon but do not consider any contribution of the coarse woody debris or soil organic carbon stocks. The results represent the worldwide terrestrial carbon stocks in vegetation that are modeled based on yearly spatially explicit information on the above-noted inputs, particularly dynamic land cover, primary forest, and burned area data.

Datasets used in the analysis

1. ESA-CCI land cover data [3] provide a complete time series of land cover from 2001 to 2020. Land cover classes are used to assign IPCC 2006 values of carbon stock. Some classes, such as water bodies and glaciers, provide no vegetation carbon storage, while others, like bare areas and lichen and moss, contribute negligibly to carbon stock.
2. Ecofloristic region [4] and geographical zones [5]. The zones are assumed to be static and are used to select default IPCC 2006 values and to produce results at different spatial scales.
3. Spatially explicit layers on intact/primary forests [6]. The layers provide information on the presence of intact forests, which are used as a proxy for primary forests. The information is available for the years 2000, 2013, 2016, and 2020. Whenever data for a year is not available, the model uses the latest observation for that variable in the time series ( e.g. the information in 2000 has been used to estimate values from 2001 to 2012 included). The location of intact and non-intact forests allows for a proxy of the degree of forest degradation and other anthropogenic effects that affect vegetation carbon stocks in non-intact areas.
4. Occurrence of fires [7] (annually available from 2001 to 2020). The information is required to incorporate the effect of wildfires on vegetation carbon storage.

Interpretation of results

The results represent the worldwide terrestrial vegetation carbon stocks based on inputs described in the previous section. These inputs ensure consistent global results by using time series global data sets and an approach aligned with the 2006 IPCC guidelines. Data may not align with country-level estimates produced using different data, methods, or spatiotemporal scales, and do not provide a full view of carbon fluxes from lands or other, non-CO2, greenhouse gas emissions. It is important to emphasize that changes in these results are mainly driven by land cover changes, and potentially by land cover re-classification, which do not always match with the real, but rather the observed ecological information. Forests’ results can also be affected significantly by the occurrence of fire.

The average global contribution of each aggregated land cover class from 2001-2020 (expressed in %) to vegetation carbon stock:

• Forest 70,50% ..................................................................................... (ESA-CCI LC 50 - 90)
• Shrub and Herbaceous vegetation 14,18%.......................................... (ESA-CCI LC 100 - 130)
• Agricultural vegetation 9,29%............................................................... (ESA-CCI LC 10 - 40)
• Wetland 5,31% .................................................................................... (ESA-CCI LC 160 - 180)
• Bare area 0,40% ................................................................................. (ESA-CCI LC 140, 200 - 202)
• Sparse vegetation 0,33% .................................................................... (ESA-CCI LC 150 - 153)
• Artificial Surface, Waterbody, and Permanent snow and ice 0,00%..... (ESA-CCI LC 190, 210 and 220)

Funding and acknowledgment

This work was produced by the ARIES team at BC3 and funded by the World Bank under the GPS and PROGREEN programs.

ARIES (ARtificial Intelligence for Environment and Sustainability) - https://aries.integratedmodelling.org/technology

BC3 (Basque Center for Climate Change) - https://www.bc3research.org/index.php

GPS (Global Program for Sustainability) - https://www.worldbank.org/en/programs/global-program-on-sustainability

PROGREEN (Global Partnership for Sustainable and Resilient Landscapes) - https://www.progreen.info/about_page

References and citations

1. Gibbs and Ruesch (2008) - New IPCC Tier-1 Global Biomass Carbon Map for the Year 2000 (dataset): https://www.osti.gov/biblio/1463800
2. IPCC 2006 - https://www.ipcc.ch/report/2006-ipcc-guidelines-for-national-greenhouse-gas-inventories/
3. ESA-Climate Change Initiative (CCI) dataset: https://doi.org/10.24381/cds.006f2c9a
4. (FAO)'s Ecofloristic region: https://databasin.org/datasets/dc4f6efd1fa84ea99df61ae9c5b3b763/
5. Geographic (continental) areas: https://cdiac.ess-dive.lbl.gov/ftp/global_carbon/continental_regions.zip
6. Intact Forest Landscapes data: https://intactforests.org/data.ifl.html.
7. MODIS burned land maps: https://modis-fire.umd.edu/ba.html, product MCD64A1