Indonesia plays a major, yet highly uncertain role in the global carbon cycle. Indonesian Borneo (Kalimantan, 540,000 km2) in particular is experiencing rapid and intensive land use change and large-scale fires, especially during El Nińo Southern Oscillation (ENSO) events. Severe droughts during the 1997/8 ENSO event provoked forest fires that released ~1 Pg of carbon to the atmosphere, equivalent to half the average annual emission from land use change worldwide. The goal of the proposed research is to reduce the considerable uncertainty of the Bornean carbon budget through a combination of remote sensing, iterative field research and validation, and modeling. Our research aims to develop carbon models based on: (1) a regional-scale database that can be used to quantify variations in terrestrial carbon storage as a function of forest cover and land use type, and (2) new regionally-specific approaches based on multiple satellite sensors (e.g. Landsat, MODIS, IKONOS) and field surveys to map the extent of peat forest by phasic zones, as well as oil palm plantations, and areas burned. Within our focal peatland along the west coast of West Kalimantan, we will assess the spatio-temporal patterns of degradation and land cover change and estimate biomass damage from a time-series of satellite imagery. Synergistically drawing on field-derived parameters (from surveys detailing peat depth, condition, vegetation, biomass experimental fires yielding estimates of susceptibility, biomass burned) and satellite derived classifications, we will generate local peat zonation and susceptibility maps for our focal peatland, and use the resultant methodologies to scale up to map Kalimantan’s peatlands. These data sets and products will contribute to the parameterization of R. Houghton’s process-level carbon model (CARLUC), and allow a refinement of Bornean carbon budgets, as well as comparisons to the Amazon. Carbon implications for future land cover scenarios will also be investigated with CARLUC. In addition to providing a refined understanding of the role Indonesian peatlands play in the global carbon budget, we will assess the natural and anthropogenic factors influencing the carbon sources and sinks in forests of this region, and investigate the relative importance of regionally observed factors on the global carbon cycle.