Carlos A. Nobre

National Institute for Climate Change

Election Year: 2015
Primary Section: 63, Environmental Sciences and Ecology
Membership Type: Foreign Associate


Carlos Nobre is a climate scientist recognized for his work on biosphere-atmosphere interactions and climate impacts of Amazon deforestation. He is known particularly for his studies on the risk of ‘savannization’ of the Amazon forest due to deforestation and climate change, that have delineated the role of biosphere-atmosphere interactions in the humid tropics. He was born in São Paulo, Brazil, in 1951 and grew up in that city. He graduated from the Aeronautics Institute of Technology in 1974, São José dos Campos, Brazil, with a degree in Electronics Engineering and from the Massachusetts Institute of Technology in 1983 with a PhD in meteorology. He was a post-doctoral fellow in meteorology at University of Maryland's Department of Meteorology in 1988. He particularly fascinated about the Amazon region since he was a teenager. Upon finishing undergraduate education, he moved to the Amazon, where he initiated his research carrier in 1975 at the Brazilian Institute for Amazonian Studies, in Manaus, as research assistant. Later, upon returning to Brazil after completion of his doctoral studies, he joined the Brazilian National Institute for Space Research (INPE) in 1983, where he remained until 2012. He has been an architect for the establishment of a number of research institutions in Brazil: the Brazilian Center for Weather Prediction and Climate Studies (CPTEC), where he served as director from 1991 to 2003; the Center for Earth System Science (CCST, 2008-2010) and the National Center for Monitoring and Early Warning of Natural Disasters (CEMADEN; 2015). He has been a pioneer in the creation and implementation of important scientific experiments in the Amazon, such as the largest scientific undertaking in that region, the Large Scale Biosphere-Atmosphere Experiment in the Amazon (LBA), where he acted as Program Scientist from 1996 to 2004. He has been scientific director of the Brazilian Research Network for Climate Change (Rede CLIMA) and has been very active in communicating the science of climate change to society nationally and internationally. He has been the chair of the International Geosphere-Biosphere Programme (IGBP-2006-2011), member of the International Panel on Climate Change (IPCC) and is a member of the UN Secretary-General Scientific Advisory Board (SAB) for Global Sustainability. He is a member of the Brazilian Academy of Sciences, the Academy of Sciences for the Developing Nations and Foreign Associate of US National Academy of Sciences. He worked in science-policy interface as National Secretary for R&D Policies, Brazilian Ministry of Science, Technology and Innovation (2011-2014), and is currently the President of the Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES). He supervised the work of 33 Master’s and PhD students and is author or co-author of over 180 scientific papers, book chapters and books. He has received a number of scientific awards, the “Dr. Luis Frederico Leloir” Prize on Science, Technology and Innovation Cooperation of Argentina, 2011; the Grand-Cross Medal of the National Order of Scientific Merit, Presidency of Brazil, 2010; the Alexander von Humboldt Medal of the European Geophysical Union, 2010, among others.

Research Interests

Carlos Nobre’s research group is interested in biosphere-atmosphere interactions, especially in the Amazon, and has carried out observational and modeling studies on the responses of the climate system to land use change in the Amazon, and, conversely, how climate change may affect tropical ecosystems. They have carried out observational studies as part of international biosphere-atmosphere experiments in the Amazon (e.g., the Amazonian Micrometeorological Experiments (ARME), the Global Tropospheric Experiment-Amazon Boundary Layer Experiment (GTE-ABLA), the Anglo-Brazilian Climate Observations Study (ABRACOS) and the Large Scale Atmosphere-Biosphere Experiment in the Amazon-LBA) to demonstrated that large scale deforestation increases surface temperature, decreases dry season evapotranspiration and may reduce precipitation and lengthen dry season. The predicted lengthening of the dry season is particularly relevant because it determines the vegetation type: short dry season leads to tropical forests; longer than 4 months dry season leads to tropical savannas. To understand the role of the forest for climate, they used a suite of climate system models, including representations of the vegetation and the land vegetation carbon cycle. They simulated large scale deforestation in the models and showed that a probable reduction of dry season rainfall would lead to a tropical savanna-like vegetation in southern and southeastern Amazon, which led to the formulation in 1991 to the hypothesis of Amazon ‘savannization’, a topic that has received considerable attention since then. Later they proposed that the biosphere-atmosphere system in the Amazon has two stable equilibrium states: the current one with tropical forest and a second one with forests and savannas. They have studied the stability properties of these equilibrium states and proposed ‘tipping’ points that should not be transgressed for maintenance of the forest: 3.5°C of global warming or 40% of total deforested area in the Amazon basin. They also examined the role of increasing atmospheric CO2 concentrations on the tropical forest with models since, in principle, the water efficiency of vegetation increases with elevated CO2, and it is a factor to heighten forest’s resilience to climate change. They concluded that ‘CO2-fertilization effect’ could perhaps delay savannization, but not rule it out. They also showed that lightning induced vegetation fire has been a key player in setting the forest-savanna boundary in southern Amazon over vegetation succession time scales (decades to millennia). It the absence of that natural fire ignition mechanism, the forest-savanna boundary would be several hundred km to the south of their actual position. They also show that the observed 3-10 times increase of man-made forest fire frequency may accelerate the trend towards savannization of the Amazon because increases forest vulnerability, whereas fire is part of tropical savanna ecology. They also studied scenarios of future climate change in the Amazon with the indication of enhanced climate extremes, both droughts and floods. They showed that the there is an observed increased in the frequency of extreme droughts and floods in the Amazon since 2005 and the most likely explanation is an early manifestation of climate change.

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