The AmazonFACE project addresses the overarching question of how climate change will affect the Amazon forest, the biodiversity it harbors, and the ecosystem services it provides to humanity.

© João M. Rosa | AmazonFACE

© João M. Rosa | AmazonFACE

The central feature of the AmazonFACE project is a field experiment of unprecedented scope that exposes mature tropical trees to projected future CO2 concentrations on-site in an old-growth Amazon forest stand located near Manaus, Brazil using Free-Air CO2 Enrichment (FACE) technology. The project aims to increase knowledge on the functioning of the world's largest tropical forest in light of climate change and to use this knowledge for steering regional policies on climate change mitigation and adaptation.

The project was featured at a session during COP26 in Glasgow. Click on the video link below to learn more about the project and listen to the COP26 panel discussion.


Rapid changes in the Earth's climate caused by the burning of fossil fuels and deforestation pose a severe threat to forests of the Amazon basin. Warmer temperatures and drier conditions are predicted to cause widespread forest dieback, with associated threats to regional economies, social welfare, and natural capital through changes in agricultural output and hydropower supply. Nonetheless, the implications will be global as Amazon forests provide substantial services to all humankind by regulating the climate through the cycling of carbon, water, and energy; and harboring a large part of the world's biodiversity.

The impact of climate change on tropical ecosystems, however, is highly uncertain. Reducing this uncertainty is critical for global assessments of ecosystem vulnerability to climate change and for steering development policies for the Amazon region under future climate change scenarios. To this end, the AmazonFACE project aims to resolve a key source of uncertainty: the potential impact of continuously rising atmospheric CO2 concentrations on Amazon forest resistance and resilience to drought. So far, the magnitude and duration of this supposed CO2 fertilization effect, which has been proposed to stimulate forest growth in tropical forests remains largely undetermined, despite its potential importance for the global carbon cycle, in buffering tropical forests against the deleterious effects of climate change.

A Free-Air CO2 Enrichment (FACE) experiment is the most direct and robust scientific approach for reducing this uncertainty. No such experiment has ever been attempted in a tropical forest, despite the long- standing recognition in science and policy communities of the need for such an experiment. The AmazonFACE experiment will provide us with new insights for model development, which should enable us to make more reliable projections of tropical ecosystem functioning under future scenarios.

Collaboration partners and associate committee members 

Related publications

Pereira, I. S, H. E. M. Nascimento, M. B. Vicari, M. Disney, E. DeLucia... & F. Hofhansl. 2019. Performance of laser-based electronic devices for structural analysis of Amazonian terra-firme forests. Remote Sensing 11: 510.

Hofhansl, et al. (2016). Amazon forest ecosystem "responses to elevated atmospheric CO2 and alterations in nutrient availability: filling the gaps with model-experiment integration. Front. Earth Sci. DOI: 10.3389/feart.2016.00019

Schaap, K.J., Fuchslueger, L., Hoosbeek, M.R., Hofhansl, F., Martins, N.P., Valverde-Barrantes, O.J., Hartley, I.P., Lugli, L.F., et al. (2021). Litter inputs and phosphatase activity affect the temporal variability of organic phosphorus in a tropical forest soil in the Central Amazon. Plant and Soil DOI: 10.1007/s11104-021-05146-x. []

Martins, N.P., Fuchslueger, L., Fleischer, K., Andersen, K.M., Assis, R.L., Baccaro, F. B., Camargo, P.B., Cordeiro, A.L., et al. (2021). Fine roots stimulate nutrient release during early stages of leaf litter decomposition in a Central Amazon rainforest. (In Press)

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Last edited: 09 November 2021


Florian Hofhansl

Research Scholar Biodiversity, Ecology, and Conservation Research Group - Biodiversity and Natural Resources Program


2020 - 2030


International Institute for Applied Systems Analysis (IIASA)
Schlossplatz 1, A-2361 Laxenburg, Austria
Phone: (+43 2236) 807 0 Fax:(+43 2236) 71 313