Carbon, biodiversity & ecosystem services:
exploring co-benefits

Updated global carbon map

UNEP-WCMC has recently been working on upgrading the global map of carbon stocks used in its original publication Carbon and biodiversity: a demonstration atlas (Kapos et al. 2008). The greatest need has been to improve upon the rather coarse data on soil carbon included in the original map.

The Harmonized World Soil Database (HWSD) version 1.1 (FAO/IIASA/ISRIC/ISS-CAS/JRC 2009) was used to generate an improved global map of soil organic carbon values to 1m depth at a nominal spatial resolution of 1km (Scharlemann et al. in prep). This new soil carbon map has been combined with the biomass carbon map developed by Ruesch & Gibbs (2008) using IPCC Tier 1 methodology and GLC2000 land cover data to provide a new global map of terrestrial carbon stocks.

Updated global carbon map

The newly updated map provides a better tool for visualizing the distribution of carbon stocks, which are dominated by soil stocks in some parts of the world such as boreal peatlands and tropical swamps. Further improvements could be achieved by incorporating updated biomass carbon estimates derived from 2005 land cover data (currently under review in draft form) and by potentially considering the likely effects of land use change on soil carbon stocks.

Click here to download a poster of the updated global carbon map

A global map of estimated soil carbon stocks to 1m depth was generated based on the soil organic carbon and bulk density values included in the HWSD (FAO/IIASA/ISRIC/ISS-CAS/JRC 2009), adjusting for gravel content and taking account of variations in soil depth. The data in the HWSD were quality checked, incorrect values were adjusted and missing data filled in where possible. Many of these data are based on the FAO 1974 soil mapping units, which are much larger polygons that have been rasterised at 1km resolution. These estimates reflect inherent soil properties at the time of the original survey, but do not take account of land use change.