The Amazon in Transition


President and Senior Scientist Dr. Eric A. Davidson

Three WHRC scientists – Michael Coe, Foster Brown, and myself, along with 12 of our American and Brazilian colleagues, are co-authors of a review paper published in Nature this week, entitled “The Amazon Basin in Transition.” This is a culmination of the Large-scale Biosphere-Atmosphere Experiment in Amazônia (LBA), which is a multinational, interdisciplinary research program led by the Brazilian Ministry of Science and Technology. Its goals are to understand how Amazônia functions as a regional entity in the Earth system and how ongoing changes in land use and climate are affecting Amazônia. In addition, LBA seeks to contribute a scientific basis for addressing the sustainability of development in the region.

Some of the major conclusions of this review are:

  • Changes in energy and water balances have been demonstrated in the southern and eastern flanks of the basin, leading to longer dry seasons, increased river flow (and flooding) in wet seasons, and increased soil erosion and sedimentation in the rivers.
  • While deforestation rates have declined significantly during the last decade, the incidence of fire has not declined, meaning that there is still risk of forest degradation from escaped fires used to burn weeds in pastures or to make charcoal.
  • We do not yet have the data to know whether the Amazon Basin is a net sink or source of carbon, but we can say that the direction of change is toward less of a sink and more of a source due to on-going deforestation.
  • The Amazon Basin is so large that it makes much of its own weather, through recirculation of water from rain, through the soils and trees, and back to the atmosphere to make more rain. However, deforestation and fire are changing the patterns of rainfall locally and regionally, and we are only just beginning to understand how climate change, agricultural expansion, and fire are interacting to affect the regional climate.

Perhaps the greatest legacy of the LBA program – even more important than its many published papers like this new one in Nature – will be the new generation of young scientists who were trained in disciplines such as hydrology, meteorology, aquatic and terrestrial ecology, remote sensing, biogeochemistry, and socioeconomics. No single tool could answer the LBA questions, so collaboration and integration across disciplines was required and encouraged. In total, more than 2300 researchers, students, technicians, and interns have participated in LBA, including over 1400 Brazilians, and resulting in more than 200 doctoral dissertations and nearly 300 masters theses. This new generation of Earth system scientists who cut their teeth on LBA research are now integrating into the academic, government, and NGO research and policy communities in Brazil and elsewhere. We close our article by emphasizing how important this human resource of scientists will be for the future of the Amazon:

“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. Brazil is poised to become one of the few countries to achieve the transition to a major economic power without destroying most of its forests. However, continued improvements in scientific and technological capacity and human resources will be required in the Amazon region to guide and manage both biophysical and socioeconomic transitions.”

Read the Press Release for “The Amazon Basin in Transition” here.

Read the Nature article.