Vulnerability and resilience of the Brazilian Amazon forests and human environment to changes in land-use and climate

Deforestation and conversion to agriculture are considered a great concern for the Amazonian environment and human livelihood as well as to the continental and global climate, as a result of changing surface properties, effects on rainfall and emissions of carbon dioxide. Also, evidence is increasing that global climate change has direct and long-term effects on the functioning and sustainability of the current vegetation cover of the Amazon basin, with potentially dangerous feed-forward effects. Paleo-climate evidence suggests that the forests of eastern Amazonia are close to a critical point in which a minor extension of the length of the dry season could turn large expanses of forest into savanna. Such predictions are controversial, however, because possibly buffering feedbacks could result in considerable resilience of the forests and these feedbacks are as yet poorly understood. Only analysis that accounts for the vulnerability of coupled human-environment systems can assess how the system as a whole is sensitive and resilient to the hazards. This recognition has lead to the development of new conceptual frameworks for global environmental change and sustainability science. A central lesson from these is that a focus limited to perturbations and stressors is insufficient for understanding the impacts on and responses of the affected system. In the Amazon basin, this means that the capacity of the ecosystems to absorb climate change and land-use stresses and the risks of irreversible changes need to be evaluated explicitly. There are natural feed-backs in soils, hydrology and the regional climate. When it comes to the vulnerability of society, climate induced and human-induced changes in land cover are likely to feed back on agriculture and land development, which in turn feeds back on climate and regional hydrology. We aim to focus on the role of these feedbacks. The overall hypothesis of the programme is that a network of relatively undisturbed forest areas in the Amazon region can act as a buffer that mitigates regional and continental-scale changes in climate and natural vegetation resulting from climate change, land use change and regional development. The alternative of this hypothesis is that most disturbance, from deforestation or climate change leads to accelerated degradation, through positive feedbacks. The programme will investigate the feef-back mechanisms, to either confirm or reject these hypotheses, following a systems based approach that focuses on the interactions between different components of the human-environment system. The programme will be functioning through three PhD research projects and two postdoc projects, jointly supervised by scientists in the Netherlands and in Brazil. The projects are organised according to discipline and level of organisation: 1) ecosystems; 2) local and regional human livelihood; 3) regional hydrometeorology, 4) integral feed-backs and scenario studies; 5) implications for basin-wide and national development pathways and policy. The overall approach is to study ecosystem and hydrological resilience along wet-dry transects in undisturbed and disturbed forest, both in the very weakly seasonal central Amazon and in the seasonal South-West. What the consequences of drought stress and forest degradation, directly and indirectly, are for land-use change processes will be studied in the same areas, while regional scale climate models will be used to assess whether areas influence each other, enhancing overall resilience of the region to degradation. The linkages between these different feed-back loops and teleconnections will be studied by analysing the effects of scenarios that predict possible future development pathways of the region and its climate. Taking into account national and international policies and influences, and iterating assumptions and results with stakeholder groups at various levels, finally sustainable development pathways and alternatives will be formulated, not for the whole of the Amazon, but relevant for the regions where the field work was concentrated. Apart from many new insights into the functioning and resilience of Amazon ecosystems, the climate system and of the processes in land-use change, the main joint product of this programme will be a series of tools to explore development pathways for the degree of sustainability.