Development of regulations limiting greenhouse gas emissions is creating demands and new markets for land-based carbon sinks. Expectations of development of clean technologies and new sources of clean energy are affecting the supply side, creating opportunities for remuneration for sustainable development of natural resources. This paper [1] presents a model developed to gain a realistic understanding of the heterogeneous roles of capoeira (fallow agricultural land) in land use dynamics and CO 2 balance in the Brazilian Amazon. The model estimates the areas and CO 2 balance of different types of capoeira in association with different farming activities and also monitors carbon intensity over time in the context of technological trajectories (distinct farming systems). Modeling with agricultural census data compared six different, competing technological trajectories of capoeira for changes in major land use variables and impacts on CO 2 balance from 1990 to 2011. Results revealed that: a) technological trajectories contribute differently to net emissions of CO 2 , with livestock for meat enterprises being the highest net emitters and peasant agroforestry and plantation enterprises the lower emitters; b) carbon intensity tends to diminish over time because of increased weight of trajectories with lower carbon intensity, in combination with reduced carbon intensity of trajectories with higher carbon intensity; and c) for most trajectories, reuse of “old land” becomes increasingly more important for explaining the essence of agricultural dynamics, including CO 2 balance, than is deforestation for opening up new agricultural land. These results draw attention to the role of capoeiras in modernization and intensification of the agricultural sector through renovation of deforested land. The model allows evaluation of deforestation and CO 2 emissions as functions of the evolution of markets for agricultural products and of deforestation dynamics decoupled from those market fluctuations. The model points to the land market as a possible hypothetical determinant of deforestation; and has possible applications to development policies targeting the Brazilian Amazon.