ArticlePDF Available
Lovejoy and Nobre, Sci. Adv. 2018; 4 : eaat2340 21 February 2018
SCIENCE ADVANCES | EDITORIAL
1 of 1
Copyright © 2018
The Authors, some
rights reserved;
exclusive licensee
American Association
for the Advancement
of Science. No claim to
original U.S.
Government
Works. Distributed
under a Creative
Commons Attribution
NonCommercial
License 4.0 (CC BY-NC).
Amazon Tipping Point
In the 1970s, Brazilian scientist Eneas Salati shattered
the long held dogma that vegetation is simply the
consequence of climate and has no influence on cli-
mate whatsoever (1). Using isotopic ratios of oxygen
in rainwater samples collected from the Atlantic to
the Peruvian border, he was able to demonstrate un-
equivocally that the Amazon generates approximately
half of its own rainfall by recycling moisture 5 to 6 times
as airmasses move from the Atlantic across the basin to
the west.
From the start, the demonstration of the hydrological
cycle of the Amazon raised the question of how much
deforestation would be required to cause the cycle to de-
grade to the point of being unable to support rain forest
ecosystems.
High levels of evaporation and transpiration that forests
produce throughout the year contribute to a wetter at-
mospheric boundary layer than would be the case with
non-forest.This surface-atmosphere coupling is more im-
portant where large-scale factors for rainfall formation
are weaker, such as in central and eastern Amazonia. Near
the Andes, the impact of at least modest deforestation is
less dramatic because the general ascending motion of
airmasses in this area induces high levels of rainfall in
addition to that expected from local evaporation and
transpiration.
Where might the tipping point be for deforestation-
generated degradation of the hydrological cycle? The
very first model to examine this question (2) showed that
at about 40% deforestation, central, southern and eastern
Amazonia would experience diminished rainfall and a
lengthier dry season, predicting a shift to savanna vegeta-
tion to the east.
Moisture from the Amazon is important to rainfall and
human wellbeing because it contributes to winter rainfall
for parts of the La Plata basin, especially southern Paraguay,
southern Brazil, Uruguay and central-eastern Argentina;
in other regions, the moisture passes over the area, but does
not precipitate out. Although the amount contributing
to rainfall in southeastern Brazil is smaller than in other
areas, even small amounts can be a welcome addition to
urban reservoirs.
The importance of Amazon moisture for Brazilian ag-
riculture south of the Amazon is complex but not trivial.
Perhaps most important is the partial contribution of dry
season Amazon evapotranspiration to rainfall in south-
eastern South America. Forests maintain an evapotranspira-
tion rate year-round, whereas evapotranspiration in pastures
is dramatically lower in the dry season. As a consequence,
models suggest a longer dry season after deforestation.
In recent decades, new forcing factors have impinged
on the hydrological cycle: climate change and widespread
use of fire to eliminate felled trees and clear weedy veg-
etation. Many studies show that in the absence of other
contributing factors, 4 degrees Celsius of global warming
would be the tipping point to degraded savannas in most
of the central, southern, and eastern Amazon. Widespread
use of fire leads to drying of surrounding forest and greater
vulnerability to fire in the subsequent year.
We believe that negative synergies between deforesta-
tion, climate change, and widespread use of fire indicate
a tipping point for the Amazon system to flip to non-
forest ecosystems in eastern, southern and central Amazonia
at 20-25% deforestation.
The severity of the droughts of 2005, 2010 and 2015-16
could well represent the first flickers of this ecological
tipping point. These events, together with the severe floods
of 2009, 2012 (and 2014 over SW Amazonia), suggest that
the whole system is oscillating. For the last two decades
the dry season over the southern and eastern Amazon
has been increasing. Large scale factors such as warmer
sea surface temperatures over the tropical North Atlantic
also seem to be associated with the changes on land.
We believe that the sensible course is not only to strictly
curb further deforestation, but also to build back a margin
of safety against the Amazon tipping point, by reducing
the deforested area to less than 20%, for the commonsense
reason that there is no point in discovering the precise
tipping point by tipping it. At the 2015 Paris Conference
of the Parties, Brazil committed to 12 million ha of re-
forestation by 2030. Much or most of this reforestation
should be in southern and eastern Amazonia. The hydro-
logical cycle of the Amazon is fundamental to human well-
being in Brazil and adjacent South America.
– Thomas E. Lovejoy and Carlos Nobre
REFERENCES
1. E. Salati, A. Dall ‘Ollio, E. Matsui, J. R. Gat, Recycling of Water in the Amazon,
Brazil: an isotopic study. Water Resour. Res. 15, 1250–1258 (1979).
2. G. Sampaio,C. A. Nobre, M. H. Costa, P. Satyamurty, B. S. Soares-Filho,
M. Cardoso, Regional climate change over eastern Amazonia caused by pasture
and soybean cropland expansion. Geophys. Res. Lett. 34, L17709 (2007).
10.1126/sciadv.aat2340
Citation: T. E. Lovejoy, C. Nobre, Amazon Tipping Point. Sci. Adv. 4, eaat2340 (2018).
Thomas E. Lovejoy is
University Professor
in the Department of
Environmental Science
and Policy at George
Mason University. Email:
tlovejoy@unfoundation.org
Carlos Nobre is a Member
of the Brazilian Academy
of Sciences and Senior
Fellow of World Resources
Institute Brazil.
on February 22, 2018http://advances.sciencemag.org/Downloaded from
Amazon Tipping Point
Thomas E. Lovejoy and Carlos Nobre
DOI: 10.1126/sciadv.aat2340
(2), eaat2340.4Sci Adv
ARTICLE TOOLS http://advances.sciencemag.org/content/4/2/eaat2340
REFERENCES http://advances.sciencemag.org/content/4/2/eaat2340#BIBL
This article cites 2 articles, 0 of which you can access for free
PERMISSIONS http://www.sciencemag.org/help/reprints-and-permissions
Terms of ServiceUse of this article is subject to the
registered trademark of AAAS. is aScience Advances Association for the Advancement of Science. No claim to original U.S. Government Works. The title
York Avenue NW, Washington, DC 20005. 2017 © The Authors, some rights reserved; exclusive licensee American
(ISSN 2375-2548) is published by the American Association for the Advancement of Science, 1200 NewScience Advances
on February 22, 2018http://advances.sciencemag.org/Downloaded from
... The interannual variability in AGC fluxes in tropical forests results from a complex interplay between human activities, climatic variability, and plant physiological responses to disturbances [50]. Here, we focus on the Brazilian Amazon as a key hotspot [51,52]. We leverage detailed, long-term deforestation records and maps from the Project for Remote Deforestation Monitoring in the Legal Amazon (PRODES) of the Brazilian National Institute for Space Research (INPE) [53] to further investigate the contributions of gross AGC losses driven by both natural and anthropogenic disturbances. ...
Preprint
Full-text available
As enduring carbon sinks, forest ecosystems are vital to the terrestrial carbon cycle and help moderate global warming. However, the long-term dynamics of aboveground carbon (AGC) in forests and their sink-source transitions remain highly uncertain, owing to changing disturbance regimes and inconsistencies in observations, data processing, and analysis methods. Here, we derive reliable, harmonized AGC stocks and fluxes in global forests from 1988 to 2021 at high spatial resolution by integrating multi-source satellite observations with probabilistic deep learning models. Our approach simultaneously estimates AGC and associated uncertainties, showing high reliability across space and time. We find that, although global forests remained an AGC sink of 6.2 PgC over 30 years, moist tropical forests shifted to a substantial AGC source between 2001 and 2010 and, together with boreal forests, transitioned toward a source in the 2011-2021 period. Temperate, dry tropical and subtropical forests generally exhibited increasing AGC stocks, although Europe and Australia became sources after 2011. Regionally, pronounced sink-to-source transitions occurred in tropical forests over the past three decades. The interannual relationship between global atmospheric CO2 growth rates and tropical AGC flux variability became increasingly negative, reaching Pearson's r = -0.63 (p < 0.05) in the most recent decade. In the Brazilian Amazon, the contribution of deforested regions to AGC losses declined from 60% in 1989-2000 to 13% in 2011-2021, while the share from untouched areas increased from 33% to 76%. Our findings suggest a growing role of tropical forest AGC in modulating variability in the terrestrial carbon cycle, with anthropogenic climate change potentially contributing increasingly to AGC changes, particularly in previously untouched areas.
... A number of large pharmaceutical companies maintain research offices in the Amazon, to bio prospect for new pharmacological and medical materials. A huge proportion of drugs originate from inside the rainforest biome [32]. ...
Research
Full-text available
http://dspace.univ-relizane.dz/home/handle/123456789/685
... This means that achieving NNL would require offset implementation to start earlier, so that regeneration or restoration could advance satisfactorily to actually compensate for the immediate impact. We specifically focus on restoration because in the Amazon the forest loss is already reaching 20% (Gambarini 2020), approaching the 20-25% tipping point, after which the forest could collapse (Amigo 2020;Lovejoy and Nobre 2018). Furthermore, vast areas have also been affected by forest degradation (Qin et al. 2021), hence requiring restoration to recover these areas' ecological functions is crucial. ...
Chapter
To compensate the residual impacts of development projects planned according to the Mitigation Hierarchy, biodiversity offsets have been increasingly used. However, they have widely recognized shortfalls; one of the most common is the time-lag between immediate impact and future delivery of offset benefits. Companies committed to offsetting their impacts either buy private land to restore or protect existing vegetation, contribute to the conservation of public protected areas, or acquire biodiversity credits from so-called “conservation bankings”. Here, we conceptually explore a different avenue for offsetting in the Brazilian Amazonia through conservation banking, considering the social-environmental context of the region. The goal is to approach a realistic measure to be implemented in the world’s largest forest. For this, we accounted for its intrinsic and interconnected characteristics, getting together historical and present features of the region to analyze them qualitatively and in parallel. As results, we came to the suggestion to drop the market-feature of conservation bankings, so that credits would be generated and used by the own developer who offsets. Also, it should be focused on restoration efforts, which should preferably be done by leveraging existing restoration initiatives in the region to be turned into conservation banking for future impacts. Local communities and traditional populations would then be included, opposed to a common credit market, which would likely exclude these people. This approach should enhance offset efficiency and partnerships across the Amazon, and potentialize restoration results and incorporation of social aspect.
... The replacement of natural habitats by human-altered environments has been advancing rapidly, especially in tropical forests. Deforestation for intensive agriculture, industrial logging, and fires comprises some of such activities that lead to habitat loss and fragmentation (Lewis et al. 2015;Spracklen et al. 2015;Lovejoy and Nobre 2018). Such threats hinder connectivity between forest remnants and Among the different approaches to analyzing the effect of land use change on biodiversity, the landscape composition and configuration approach (e.g., amount of forest cover, landscape diversity) can draw fine-scale responses. ...
Book
Este trabalho complementa os Textos para Discussão 3011 e 3013. O objetivo comum a todos esses textos é antecipar a agenda e os eventos do calendário político-institucional do Estado brasileiro em 2024. Este Texto especificamente apresenta o calendário e serve de base empírica para a análise desenvolvida no Texto para Discussão 3013. O calendário expõe eventos mês a mês e, na maioria dos casos, com a especificação exata de acontecimentos com datas previstas com grande antecedência (desde dezembro de 2023). Este levantamento demonstra que as agendas prioritárias do Estado brasileiro são relativamente previsíveis e passíveis de serem prospectadas.
Article
Full-text available
We review the often-invisible powerful processes that drive social and ecological change in Amazonia, and the diverse peoples who inhabit its landscapes. It explores large-scale development ideologies of modernization, and the policy tools that were deployed to carry them out. Outlining general periods of macro policy shifts, we show the evolution of the framework for today’s complex interactions between large-scale agroindustry, mining, and hydrocarbons, and diverse small-scale livelihoods, as well as the clandestine and illicit economies of land grabbing, gold, coca and timber, and their operation in globalized and regional economies. While Pan-Amazonian governments have oscillated between authoritarian and democratic forms of governance since the mid-20th century, more democratic transformations and trade openings have led to interactions among a wide array of new civil society actors and international sources of funding. Integration into numerous globalized markets and finance have had enormous effects on Amazonian politics and economies at all scales. These dynamics have generated new kinds of policies, political framings, institutions, and economies, and restructured old ones, reshaped forms of urbanization, settlements, and land regimes, and stimulated extensive and controversial infrastructure development. On the ground, diverse Amazonian peoples who often suffer the impacts of these processes have continued to adapt to changing circumstances while fighting to advance their own proposals for alternative forms of Amazon conservation and development. KEYWORDS: globalization; urbanization; clandestine economy; deforestation; dams; social movements
Chapter
Territorial management in the Amazon region of Brazil presents essential challenges for the coming years, considering the unresolved problems of the central government instrument, the Economic Ecological Zoning of the EEZ, and the changes that are taking place in this territory. The EEZ is an instrument that has been applied at different scales for more than 30 years. Still, it has yet to overcome the problems related to the diverse and profound pressures on the environment and the poor quality of the social and economic development of the population. Climate modifications, deforestation, environmental degradation, expansion of mining activities, water flow alterations, and human occupation and urbanization processes are some of the changing factors contributing to significant uncertainties in the region. In this sense, the article presents, based on its own experiences, government information, and data and interviews with managers who worked in the elaboration of the EEZ, a reflection on the main obstacles resulting from the implementation of the EEZ and the changes in the development processes in the region (increasing demand for energy, economic production based on natural resources, climate change). Finally, possible ways of overcoming these challenges are presented, considering methodological guidelines, governance, and forms of social participation.
Article
Full-text available
Received 7 May 2007; revised 7 August 2007; accepted 9 August 2007; published 13 September 2007. (1) Field observations and numerical studies revealed that large scale deforestation in Amazonia could alter the regional climate significantly, projecting a warmer and somewhat drier post-deforestation climate. In this study we employed the CPTEC-INPE AGCM to assess the effects of Amazonian deforestation on the regional climate, using simulated land cover maps from a business-as-usual scenario of future deforestation in which the rainforest was gradually replaced by degraded pasture or by soybean cropland. The results for eastern Amazonia, where changes in land cover are expected to be larger, show increase in near-surface air temperature, and decrease in evapotranspiration and precipitation, which occurs mainly during the dry season. The relationship between precipitation and deforestation shows an accelerating decrease of rainfall for increasing deforestation for both classes of land use conversions. Continued expansion of cropland in Amazonia is possible and may have important consequences for the sustainability of the region's remaining natural vegetation. Citation: Sampaio, G., C. Nobre, M. H. Costa, P. Satyamurty, B. S. Soares-Filho, and M. Cardoso (2007), Regional climate change over eastern Amazonia caused by pasture and soybean cropland expansion, Geophys. Res. Lett., 34, L17709,
  • T E Lovejoy
  • C Nobre
Citation: T. E. Lovejoy, C. Nobre, Amazon Tipping Point. Sci. Adv. 4, eaat2340 (2018).