Due to the unique nature of the LTER network, robust, transparent, long–term data sets from agriculture forestry and other vital terrestrial ecosystems are available, that quantify C sequestration and GHG mitigation, resulting from management practice alteration and adaptation to climate, and land–use change. There is great potential for LTER data to be utilized for environmental, economic and social legitimization of forthcoming offset projects suitable for inclusion in the burgeoning C–market. Twenty six scientists participated in the ASM workshop, representing 8 US LTER sites and a further 7 US and International based organizations. The majority indicated a desire to participate in further working group activities, and we expect the remaining workshop attendees to be from this group.