LBA-Eco Project Summary v2
Why the Amazon?
The Amazon is the largest expanse of tropical forest on Earth, covering just 5% of the Earth’s land surface (excluding Antarctica) while responsible for 10% of the net primary productivity of the terrestrial biosphere. Once an undisturbed and inaccessible region, the Amazon has been experiencing rapid land cover change as a consequence of economic development.
The LBA Project
In 1998, the Brazilian science community, joined by an international team of scientists, established the Large-scale Biosphere-Atmosphere Experiment in Amazonia (LBA) to study how Amazonia currently functions as a regional entity within the larger Earth system, and how changes in land use and climate will affect the biological, physical, and chemical functioning of the region’s ecosystem. The project, led by the Brazilian Ministry of Science, consisted of 100 coordinated research groups involving about 600 scientists from South and North America, Europe, and Japan. NASA’s Terrestrial Ecology and Land Use-Land Cover Change Programs sponsored a group of LBA projects which formed the LBA-ECO (formerly LBA-Ecology) Program. Across the Amazon, the program supported scientists studying climate, atmospheric chemistry, carbon and nutrient cycling, land surface hydrology and water chemistry, land use and land cover, and the interaction of humans with the landscape.
The LBA-ECO Science Question
The focal science question was:
- How do tropical forest conversion, re-growth, and selective logging influence carbon storage, nutrient dynamics, trace gas fluxes, and the prospect for sustainable land use in Amazonia?
LBA-ECO Science Approach
The LBA-ECO Science Team pursued an integrated approach involving synthesis of past results and data, modeling, remote sensing, Geographic Information System (GIS)- based analyses as well as new field observations and process studies, training and education and synthesis and integration of new results. NASA funded 63 teams working in four thematic areas: Carbon Dynamics, Land Use/Land Cover Change, Nutrient Dynamics and Trace Gases. In addition, 11 teams were funded as LBA-HYDROMET, an unofficial module of LBA that lasted from 1999-2003. Research from these investigations focused on seasonal-to-interannual hydrometeorological prediction and the effects of land cover change in the Amazon region on hydrology and climate.
LBA-ECO Phases and Objectives
LBA-ECO included three phases: Phases I and II (Phase I: July 1998 through December 2002, Phase II January 2003 through December 2005) emphasized the collection of data from field campaigns, experiments and remote sensing instruments. Phase III, which began in January 2006 and ended in December 2008, shifted emphasis to the synthesis and integration of data collected in the previous two phases and current scientific understanding to address the research questions at a regional to global scale.
Due to the difference in emphasis between Phases I and II and Phase III there was a corresponding shift in science objectives used to address the focal science question.
The main objectives in Phases I and II included:
- To quantify, understand and model the physical, chemical and biological processes controlling the energy, water, carbon, trace gas and nutrient cycles found within Amazonia and to determine how these link to the global atmosphere.
- To quantify, understand and model how energy, water, carbon, trace gas and nutrient cycles respond to deforestation, agricultural practices and other land use changes, and how these responses are influenced by climate. As well to predict the impacts of these responses both within and beyond Amazonia under future scenarios of changes in land use and climate.
- To determine the exchanges of key greenhouse gases and species regulating the oxidizing potential between Amazonia and the atmosphere, and to understand the processes regulating these exchanges.
- To provide quantitative and qualitative information to support sustainable development and ecosystem protection policies in Amazonia, in the context of both its regional and global functionality.
Objectives in Phase III included:
- Amazonian carbon dynamics. In particular, quantification of sources and sinks in the Amazon and reduction of errors and uncertainties.
- Sustainability in Amazonia. Integration of research on nutrient dynamics, types of land use, land management practices, and the effects of climate change and variability in order to address the prospects for the sustainability of land use and ecosystem goods and services.
- Whole system functioning. Quantifying interactions among Amazonia's ecological, biogeochemical, hydrological, atmospheric, and climatic components.
- Hydrometeorology. Clarification of the linkages between the land surface hydrology of Amazonia and mesoscale circulation patterns and how remotely sensed data can contribute to our understanding.
- Future trajectories of change in the Amazon. Modeling studies that make projections of future Amazonian state and functions over a range of plausible scenarios of change and include an explanation of underlying assumptions as well as documentation of uncertainties.
Have land-use and climate change in the Amazon basin caused changes in the cycles of carbon, nitrogen and water that exceed the natural variation characteristic of the Amazon Basin?
Deforestation has likely moved the Basin-wide carbon budget from a small sink in the late-twentieth-century to net C source currently. This directional change is consistent with recent results of inverse modelling based on the TransCom3 network of CO2 measurements.
The hydrological cycle of the Amazon Basin is subject to great variation across both space and time. Annual precipitation is strongly influenced by the ENSO as well as a 28 year cycle in precipitation volume and the Atlantic Multi-Decadal Oscillation. Across the basin annual rainfall distribution varies as well, from the ever wet forests in the northeast to more humid/seasonally dry forests as you move southeast with the cerrado ecosystems in the southern Amazon experiencing the strongest dry periods of up to 5 months. To varying degrees these ecosystems are adapted to seasonal and moderate drought, but as shown by recent natural severe droughts (2005 and 2010) and experimental drought natural resilience can be exceeded resulting in increased mortality and reduced productivity.
It is unclear whether recent severe droughts and other extreme events are patterns expected to persist or anomalies. The responses seen suggest that predicted changes rainfall and temperature could overwhelm the resilience of the current Amazon forests.
While precipitaton is highly variable, so far no significant decrease basin-wide has been measured. However in two of the large river basins —the Tocantins and Araguaia basins—in the southeastern Amazon where deforestation rates have historically been high, significant increases in wet season discharge and sediment load have been recorded. This suggests the loss of forest cover and associated evapo-transpiration have altered the local hydrologic cycle.
“Narrowing uncertainties about the effects of deforestation on regional precipitation, temperature and fire risk will require combining realistic spatial patterns of deforestation and degradation with improved mesoscale circulation models of climate. The emerging evidence of a system in biophysical transition highlights the need for improved understanding of the trade-offs between land cover, carbon stocks, water resources, habitat conservation, human health and economic development in future scenarios of climate and land-use change.“ (Davidson et al. 2012)
- Developed new remote sensing methodologies to detect and quantify selective logging in the Amazon and quantify its effect on carbon budgets.
- Developed a Brazilian early warning system for deforestation (DETER) based on NASA MODIS technology.
- Developed a model (operational in Brazil at CPTEC) using satellite fire detections to predict the transport of smoke.
- Over 200 published datasets
- Over 650 published articles and chapters
Overall, the entire LBA Project produced 1154 research publications, including 8 Special Issues, and trained 932 students, including 241 Ph.Ds.