Search

It is commonly recognized that large uncertainties exist in modelled biofuel-induced indirect land-use change, but until now, spatially explicit quantification of such uncertainties by means of error propagation modelling has never been performed. In this study, we demonstrate a general methodology to stochastically calculate direct and indirect land-use change ( dLUC and iLUC) caused by an increasing demand for biofuels, with an integrated economic - land-use change model. We use the global Computable General Equilibrium model MAGNET, connected to the spatially explicit land-use change model PLUC. We quantify important uncertainties in the modelling chain. Next, dLUC and iLUC projections for Brazil up to 2030 at different spatial scales and the uncertainty herein are assessed. Our results show that cell-based (5 × 5 km2) probabilities of dLUC range from 0 to 0.77, and of iLUC from 0 to 0.43, indicating that it is difficult to project exactly where dLUC and iLUC will occur, with more difficulties for iLUC than for dLUC. At country level, dLUC area can be projected with high certainty, having a coefficient of variation (cv) of only 0.02, while iLUC area is still uncertain, having a cv of 0.72. The latter means that, considering the 95% confidence interval, the iLUC area in Brazil might be 2.4 times as high or as low as the projected mean. Because this confidence interval is so wide that it is likely to straddle any legislation threshold, our opinion is that threshold evaluation for iLUC indicators should not be implemented in legislation. For future studies, we emphasize the need for provision of quantitative uncertainty estimates together with the calculated LUC indicators, to allow users to evaluate the reliability of these indicators and the effects of their uncertainty on the impacts of land-use change, such as greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

The Cerrado, the tropical savanna covering 22% of Brazil's territory, or approximately 1.783 million km2, has suffered significant human impacts during the past three decades. This paper re-examines estimates of Cerrado vegetation change dynamics using high-resolution satellite remote sensing data from an area of interest extracted from eastern Mato Grosso State. This region has undergone a high degree of typical agricultural development since the early 1970s. Results indicate significant loss of original vegetation as well as high levels of regeneration, suggesting Cerrado vegetation may be more resilient to human impacts than catastrophic estimations suggest. The paper concludes with a critical review of Cerrado land-cover change studies and the implications of evidence for vegetation regeneration, land-cover dynamism and land-use intensification, paying particular attention to spatial scale and research methods. The discussion concludes that Cerrado land-cover change studied at a higher resolution and larger scales (smaller area) is required to represent more effectively the complexity of land conversion for better assessment of human impacts and environmental policy. [ABSTRACT FROM AUTHOR]