The CBESS (A hierarchical approach to the examination of the relationship between biodiversity and ecosystem service flows across coastal margins) project has produced a free tool for predicting and mapping carbon stock in salt marshes. The tool is for governmental and non-governmental organisations that have interests in salt marshes and are seeking information about natural carbon stores. There is also a saltmarsh app for the public that includes guides to saltmarsh species, background science and guidance on how to survey for carbon stock. Users can upload their survey results on the accompanying website. If you have any queries about these resources contact Dr Laura Harrison email laura.harrison@york.ac.uk