Diverting future agricultural production onto underutilized, low-carbon land with insignificant ecological services is deemed a better option than converting forests or other high-carbon lands for production, especially in the face of the growing demand for food and materials. This may effectively avoid carbon stock loss from forest conversion, in comparison to the expected business-as-usual scenario (Austin et al. 2015). Also, proper management of these lands may help to avoid further land degradation and replenish lost carbon stock. Activating underutilized low-carbon land is thus deemed a key strategy in establishing a sustainable bio-economy.

Various names, e.g., “abandoned”, “degraded”, and “marginal” land, have been proposed to quantify land available for future expansion. For example, the terms “lahan kritis” (“critical land”) and “lahan suboptimal” (“suboptimal land”) are used by the forestry and agricultural departments in Indonesia, respectively, to describe land that has experienced degradation. However, their definitions or criteria may be different, and some are not entirely clear, e.g., abandoned land is not necessarily degraded, and vice versa (Smit et al. 2013). A study by Gibbs and Salmon (2015) shows that global estimates of “degraded” land based on different databases and methodologies can vary widely from 1 billion ha to over 6 billion ha. Furthermore, the conditions of land may change significantly from time to time, complicating the monitoring efforts. At the moment, high-resolution monitoring on a landscape scale is still too costly to be implemented.

In the past, ambiguous definitions had created unrealistic expectations and unintended consequences in policymaking. In some cases, the classification of degraded land was used as an excuse for forest clearing under the guise of reforestation programmes, although the “degraded” land may still be rich in carbon stock and biodiversity (Obidzinski and Dermawan 2010). On this basis, it is crucial to understand how future expansion may take place on these lands, considering the multiple factors and perspectives of various stakeholders. This chapter explores this strategy in the aspects of agroecology, economy, society, and institutions.

AGROECOLOGICAL PERSPECTIVES

To be more explicit, land resources with the following criteria, or socalled underutilized low-carbon (ULC) land, may potentially be used where: (i) the lands are in non-ecologically sensitive areas; (ii) the level of carbon stock is low so that land utilization is unlikely to incur additional carbon stock loss; and (iii) the current economic productivity of the land is insignificant or low.