Critical transitions in the Amazon forest system

In the paper

“Patches of white-sand savanna also expanded within the Amazon forest owing to geomorphological dynamics and fires26,27.”

What the sources say

• Disputed

  The Conclusions and Ways Forward section links savannas within the rainforest matrix to evolving fluvial terraces, but says they decreased in size over time as forests replaced them—not that they expanded. The Linkage to past climate section mentions fire-driven expansion only for the Gran Sabana in northern Amazonia, not for the study area's savannas. Page numbers are unavailable in our copy. (LLM, conf=0.86)

  Checked by a reasoning model — may be wrong.

  cites [26] Rossetti, D. F. et al. Unfolding long-term Late Pleistocene-Holocene disturbances of forest communities in the southwestern Amazonian lowlands. Ecosphere 9, e02457 (2018). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [27] Prance, G. T. & Schubart, H. O. R. Notes on the vegetation of Amazonia I. A preliminary note on the origin of the open white sand campinas of the lower Rio Negro. Brittonia 30, 60 (1978). source

In the paper

“By contrast, parts of the western and eastern Amazon forest are becoming wetter, with annual rainfall increasing by up to 20 mm yr−1.”

What the sources say

• Disputed

  The Results sections “Regional scale trends over the MATOPIBA” and “Drought and land cover changes” report declining rainfall in the eastern Amazonia–Cerrado transition region and describe eastern Amazonia’s dry and dry-to-wet seasons as becoming drier. The paper does not report the claimed increase of up to 20 mm yr−1 in annual rainfall in parts of the western and eastern Amazon forest. Page numbers were not available in our copy. (LLM, conf=0.82)

  Checked by a reasoning model — may be wrong.

  cites [31] Marengo, J. A., Jimenez, J. C., Espinoza, J.-C., Cunha, A. P. & Aragão, L. E. O. Increased climate pressure on the agricultural frontier in the Eastern Amazonia–Cerrado transition zone. Sci. Rep. 12, 457 (2022). sourceExperimental — accuracy not yet measured

In the paper

“A potential vegetation model81 found a critical threshold at 20% of accumulated deforestation (Fig. 3a) by simulating Amazon forest responses to different scenarios of accumulated deforestation (with associated fire events) and of greenhouse gas emissions, and by considering a CO2 fertilization effect of 25% of the maximum photosynthetic assimilation rate.”

What the sources say

• Disputed

  The Significance section and ‘Climate Change: Global and Regional Perspectives’ (pages unavailable) identify 40% deforestation—not 20%—as a suggested tipping point for Amazon forests. The paper’s mention of around 20% concerns a modeled increase in local precipitation at low levels of deforestation, not a critical vegetation threshold; the cited 25% CO2-fertilization assumption is also not stated in the passages found. (LLM, conf=0.88)

  Checked by a reasoning model — may be wrong.

  cites [81] Nobre, C. A. et al. Land-use and climate change risks in the Amazon and the need of a novel sustainable development paradigm. Proc. Natl Acad. Sci. USA 113, 10759–10768 (2016). sourceExperimental — accuracy not yet measured

In the paper

“For 65 million years, Amazonian forests remained relatively resilient to climatic variability.”

What the sources say

• Partly supported

  The Fig. 2 caption (p. 3) says floral diversity remained relatively high under cooler Neogene conditions, supporting a limited claim of resilience to climate change. But the paper does not establish that Amazonian forests remained resilient throughout 65 million years; the Andean Uplift section (p. 3) also describes preexisting rainforests being fragmented by wetlands. (LLM, conf=0.85)

  cites [19] Hoorn, C. et al. Amazonia through time: Andean uplift, climate change, landscape evolution, and biodiversity. Science 330, 927–931 (2010). sourceExperimental — accuracy not yet measured

In the paper

“Dry season mean temperature is now more than 2 °C higher than it was 40 years ago in large parts of the central and southeastern Amazon.”

What the sources say

• Partly supported

  The Results section, “Compound changes in hydrological and climate variables” (page unavailable), reports warming over four decades in the Eastern Amazonia–Cerrado transition zone, but its July–October trend of 0.38 °C per decade amounts to about 1.5 °C, not more than 2 °C. “Regional scale trends over the MATOPIBA” reports a 1.2 °C change from 1981 to 2020. The copy does not establish the claimed magnitude across large parts of the central and southeastern Amazon. (LLM, conf=0.88)

  cites [31] Marengo, J. A., Jimenez, J. C., Espinoza, J.-C., Cunha, A. P. & Aragão, L. E. O. Increased climate pressure on the agricultural frontier in the Eastern Amazonia–Cerrado transition zone. Sci. Rep. 12, 457 (2022). sourceExperimental — accuracy not yet measured

In the paper

“Within the remaining Amazon forest area, 17% has been degraded by human disturbances38, such as logging, edge effects and understory fires, but if we consider also the impacts from repeated extreme drought events in the past decades, 38% of the Amazon could be degraded39.”

What the sources say

• Supported

  The Extended summary states that adding extreme-drought data to fire, edge effects and timber extraction raises the estimated degraded area to 38% of remaining Amazonian forests. The Spatial extent and severity section specifies that the estimate covers 2001–2018 and accounts for overlaps among the four disturbances. (LLM, conf=0.95)

  cites [39] Lapola, D. M. et al. The drivers and impacts of Amazon forest degradation. Science 379, eabp8622 (2023). source

In the paper

“Only a few small areas in the west of the biome are significantly cooling by around 0.1 °C per decade (Fig. 1a).”

What the sources say

• ?Could not verify

  The Results section on compound changes reports widespread significant warming in the EAC, and the Figure 1 caption says only statistically significant pixels are displayed. Neither passage identifies small cooling areas in the west of the biome or a cooling rate of about 0.1 °C per decade. Searches for western cooling and that rate found no supporting passage in our copy; widespread warming does not rule out local exceptions. (LLM, conf=0.76)

  cites [31] Marengo, J. A., Jimenez, J. C., Espinoza, J.-C., Cunha, A. P. & Aragão, L. E. O. Increased climate pressure on the agricultural frontier in the Eastern Amazonia–Cerrado transition zone. Sci. Rep. 12, 457 (2022). sourceExperimental — accuracy not yet measured

In the paper

“However, during the past 3,000 years, forests have been mostly expanding over savanna in the southern Amazon driven by increasingly wet conditions28.”

What the sources say

• Partly supported

  The Results (section 3.2) and Conclusion report that tree cover expanded across much of the Amazon–Cerrado region, including savannas. The paper links that trend to increasing moisture, but treats precipitation as one possible contributor alongside changes in fire disturbance and other factors. Its measured reference age is about 1,600 years, not 3,000 years, so the stated duration and definitive causal attribution are not fully supported. (LLM, conf=0.88)

  cites [28] Wright, J. L. et al. Sixteen hundred years of increasing tree cover prior to modern deforestation in Southern Amazon and central Brazilian savannas. Glob. Change Biol. 27, 136–150 (2021). sourceExperimental — accuracy not yet measured

In the paper

“These climatic conditions could expose the forest to unprecedented levels of vapour pressure deficit31 and consequently water stress30.”

What the sources say

• Supported

  Citation 30 is attached to the water-stress portion of the sentence. The Discussion says that longer, warmer, drier seasons in eastern Amazonia favor a higher risk of water stress; the Results section on drought and land-cover changes likewise suggests increasing water stress on vegetation. The claim about unprecedented vapour pressure deficit is attached to citation 31, not this source. (LLM, conf=0.92)

  cites [31] Marengo, J. A., Jimenez, J. C., Espinoza, J.-C., Cunha, A. P. & Aragão, L. E. O. Increased climate pressure on the agricultural frontier in the Eastern Amazonia–Cerrado transition zone. Sci. Rep. 12, 457 (2022). source
• ?Could not verify

  No passage from our copy addresses unprecedented vapour pressure deficit or consequent water stress. Searches for those terms and related phrasing returned no relevant passage; the only returned text was project and citation metadata, not a finding from the paper. (LLM, conf=0.68)

  cites [30] Smith, M. N. et al. Empirical evidence for resilience of tropical forest photosynthesis in a warmer world. Nat. Plants 6, 1225–1230 (2020). sourceExperimental — accuracy not yet measured

In the paper

“More recently, during the drier and cooler conditions of the Last Glacial Maximum20 (LGM) (around 21,000 years ago) and of the mid-Holocene epoch21 (around 6,000 years ago), forests persisted even when humans were already present in the landscape22.”

What the sources say

• ?Not checked — no full text of the sourcecites [20] Wang, X. et al. Hydroclimate changes across the Amazon lowlands over the past 45,000 years. Nature 541, 204–207 (2017). source
• ?Could not verify

  The Introduction (p. 2) says the paper examines central and western Amazon tree cover under drier mid-Holocene conditions, but the passages available do not establish that forests persisted while humans were present. Searches for human presence, anthropogenic activity, forest persistence, and the Last Glacial Maximum found no passage addressing that conjunction. (LLM, conf=0.70)

  cites [21] Kukla, T. et al. The resilience of Amazon tree cover to past and present drying. Global Planet. Change 202, 103520 (2021). sourceExperimental — accuracy not yet measured
• Partly supported

  Section 3, “Early Human Entanglements in the Neotropics” (page unavailable), reports human occupation in a Brazilian dry-forest region around 22,000 years BP and plant remains from an Atlantic-forest coastal site around 6,000 years BP. These examples support human presence in forested landscapes, but the paper does not establish that forests persisted through both the Last Glacial Maximum and the mid-Holocene under the conditions described. (LLM, conf=0.78)

  cites [22] Clement, C. R. et al. Disentangling domestication from food production systems in the neotropics. Quaternary 4, 4 (2021). sourceExperimental — accuracy not yet measured

In the paper

“The Amazon system has been mostly covered by forest throughout the Cenozoic era19 (for 65 million years).”

What the sources say

• Partly supported

  The Andean Uplift section (p. 3) describes preexisting rainforests that were fragmented by Miocene wetlands, and p. 4 says forested habitats later replaced those wetlands. This supports a long history of Amazonian forest, but the paper does not establish that most of the Amazon system was forest-covered throughout the Cenozoic or for the full 65 million years. (LLM, conf=0.83)

  cites [19] Hoorn, C. et al. Amazonia through time: Andean uplift, climate change, landscape evolution, and biodiversity. Science 330, 927–931 (2010). sourceExperimental — accuracy not yet measured

In the paper

“Indigenous peoples and local communities (IPLCs) would be harmed by forest loss in terms of their livelihoods, lifeways and knowledge systems that inspire societies globally1,7,9.”

What the sources say

• Not checked yetcites [1] Science Panel for the Amazon. Amazon Assessment Report 2021 (2021); www.theamazonwewant.org/amazon-assessment-report-2021/.
• ?Could not verify

  The Results and discussion sections address Indigenous language endangerment, including associations with roads and some forms of land use. They do not say that forest loss harms Indigenous peoples’ and local communities’ livelihoods, lifeways, or knowledge systems (searched for forest loss, deforestation, livelihoods, and knowledge). (LLM, conf=0.77)

  cites [7] Bromham, L. et al. Global predictors of language endangerment and the future of linguistic diversity. Nat. Ecol. Evol. 6, 163–173 (2022). sourceExperimental — accuracy not yet measured
• Partly supported

  The Abstract says loss of plant species and cultural heritage can erode indigenous knowledge, threaten human well-being, and jeopardize livelihoods; Fig. 1 also shows how plants figure in daily life. But the study concerns 57 Neotropical indigenous communities and models plant-species loss, not forest loss and its effects on Indigenous peoples and local communities generally. (LLM, conf=0.83)

  cites [9] Cámara-Leret, R., Fortuna, M. A. & Bascompte, J. Indigenous knowledge networks in the face of global change. Proc. Natl Acad. Sci. USA 116, 9913–9918 (2019). sourceExperimental — accuracy not yet measured

In the paper

“Diversity of other organisms, such as frugivores and pollinators, also increases forest resilience by stabilizing ecological networks15,112.”

What the sources say

• Partly supported

  The ‘Interactions with fauna’ section says frugivores aid recovery through seed dispersal and pollinators support tree reproduction; ‘A network of interactions’ describes a feedback linking both groups to forest cover. The paper does not establish that greater diversity of these organisms increases resilience by stabilizing ecological networks. Page numbers were not available in our copy. (LLM, conf=0.86)

  cites [15] Flores, B. M. & Staal, A. Feedback in tropical forests of the Anthropocene. Global Change Biol. 28, 5041–5061 (2022). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [112] Estes, J. A. et al. Trophic downgrading of planet Earth. Science 333, 301–306 (2011). source

In the paper

“Diverse forests are also more likely to resist severe disturbances owing to ‘response diversity’110—that is, some species may die, while others persist.”

What the sources say

• Supported

  The ‘Seed dispersers in tropical forest systems’ section describes cyclones after which some frugivore species declined drastically while others survived and maintained seed dispersal. The paper identifies those differing responses as response diversity and says their absence could have redirected forest development. Its ‘In a nutshell’ section cautions that species richness alone does not guarantee resilience; the claim’s explanation rests on response diversity rather than richness alone. (LLM, conf=0.86)

  cites [110] Elmqvist, T. et al. Response diversity, ecosystem change, and resilience. Front. Ecol. Environ. 1, 488–494 (2003). source

In the paper

“In the Amazon, an important source of connectivity enhancing forest resilience is atmospheric moisture flow westward (Fig. 2), partly maintained by forest evapotranspiration4,37,67.”

What the sources say

• ?Could not verify

  The available passages contain the paper’s title and bibliographic metadata, but no substantive text establishing westward moisture flow, its contribution to forest resilience, or its maintenance by evapotranspiration. Searches for those terms and for moisture recycling returned only metadata, so this claim cannot be assessed from the available copy. (LLM, conf=0.70)

  cites [4] Staal, A. et al. Forest-rainfall cascades buffer against drought across the Amazon. Nat. Clim. Change 8, 539–543 (2018). sourceExperimental — accuracy not yet measured
• Partly supported

  The Methods (‘Moisture recycling networks’; page not provided) describe links through which evapotranspiration in one Amazon grid cell contributes rainfall to another. The Results (‘Forest shifts’; page not provided) link rainfall to forest resilience. These passages support moisture-mediated connectivity and its relationship to resilience, but they do not establish the claim’s specific westward direction of flow. (LLM, conf=0.83)

  cites [37] Zemp, D. C. et al. Self-amplified Amazon forest loss due to vegetation-atmosphere feedbacks. Nat. Commun. 8, 14681 (2017). sourceExperimental — accuracy not yet measured
• Supported

  The paper’s Abstract describes a westward cascade of precipitation and evapotranspiration across the Amazon. It explains that forest evapotranspiration replenishes moisture in the westward flow, supporting rainfall farther downstream, and that disruption of this coupling can reduce rainfall in undeforested forest. This supports the claim’s description of moisture-flow connectivity and its contribution to forest resilience. (LLM, conf=0.88)

  cites [67] Boers, N., Marwan, N., Barbosa, H. M. J. & Kurths, J. A deforestation-induced tipping point for the South American monsoon system. Sci. Rep. 7, 41489 (2017). source

In the paper

“Nonetheless, a few global climate models3,14,71–74 indicate a broad range for a potential critical threshold in global warming between 2 and 6 °C (Fig. 3a).”

What the sources say

• ?Not checked — no full text of the sourcecites [3] Armstrong McKay, D. et al. Exceeding 1.5 °C global warming could trigger multiple climate tipping points. Science 377, abn7950 (2022). source
• Partly supported

  Table 1 (page unavailable in our copy) lists potential tipping elements with estimated global-warming thresholds spanning roughly 2–6 °C, so the broad range is consistent with the paper. Its table notes say the preliminary numbers come from expert assessments and a literature review, not specifically from a few global climate models, and the thresholds apply to different elements rather than one common threshold. (LLM, conf=0.84)

  cites [14] Lenton, T. M. et al. Tipping elements in the Earth’s climate system. Proc. Natl Acad. Sci. USA 105, 1786–1793 (2008). sourceExperimental — accuracy not yet measured
• Partly supported

  The Discussion reports modelled abrupt regional shifts after temperature thresholds, so the paper supports the general idea that climate models indicate potential thresholds. It does not identify a critical global-warming threshold between 2 and 6 °C: 18 of 37 forced shifts occur below 2 °C, and the paper finds no compelling general relationship between the number of shifts and warming level. Page numbers are unavailable in our copy. (LLM, conf=0.86)

  cites [71] Drijfhout, S. et al. Catalogue of abrupt shifts in Intergovernmental Panel on Climate Change climate models. Proc. Natl Acad. Sci. USA 112, E5777–E5786 (2015). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [72] Salazar, L. F. & Nobre, C. A. Climate change and thresholds of biome shifts in Amazonia: climate change and Amazon biome shift. Geophys. Res. Lett. 37, https://doi.org/10.1029/2010GL043538 (2010). source
• Partly supported

  The ‘Response of Amazon forest’ passage (p. 6) says that continued dieback after emissions cuts implies a climate threshold beyond which dieback is committed. The copy does not give a 2–6 °C threshold range, and its discussion of multiple vegetation models does not establish that a few global climate models produced that range. (LLM, conf=0.84)

  cites [73] Jones, C., Lowe, J., Liddicoat, S. & Betts, R. Committed terrestrial ecosystem changes due to climate change. Nat. Geosci. 2, 484–487 (2009). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [74] Schellnhuber, H. J., Rahmstorf, S. & Winkelmann, R. Why the right climate target was agreed in Paris. Nat. Clim. Change 6, 649–653 (2016). source

In the paper

“By contrast, most seasonal forest trees have various strategies to cope with water deficit owing to evolutionary and adaptive responses to historical drought events32,63.”

What the sources say

• Partly supported

  The Hydraulic traits distribution section reports differences in drought-related hydraulic traits among Amazonian forests. The Implications and conclusions section suggests that drought-resistant xylem may be an evolutionary adaptation and that periodic El Niño events may have selected for drought-adapted taxa in central eastern forests. It does not establish that most seasonal forest trees have multiple coping strategies because of historical droughts. (LLM, conf=0.86)

  cites [32] Tavares, J. V. et al. Basin-wide variation in tree hydraulic safety margins predicts the carbon balance of Amazon forests. Nature 617, 111–117 (2023). sourceExperimental — accuracy not yet measured
• Partly supported

  The Discussion (p. 11) suggests that vulnerable hydraulic architecture is common in trees without a history of drought or fire, which is consistent with a possible response to past drought. But it does not establish that most seasonal-forest trees have various water-deficit strategies or that those strategies evolved in response to historical drought; its discussion of bark as a drought-tolerance trait is explicitly cautious (p. 10). (LLM, conf=0.72)

  cites [63] Staver, A. C. et al. Thinner bark increases sensitivity of wetter Amazonian tropical forests to fire. Ecol. Lett. 23, 99–106 (2020). sourceExperimental — accuracy not yet measured

In the paper

“As result, a ‘CO2 fertilization effect’ could increase forest resilience to climatic variability53,54.”

What the sources say

• Partly supported

  The Discussion (page unavailable) says tropical forests outside the Amazon are more likely to experience decreasing moisture stress as CO2 rises, which is consistent with a possible increase in resilience. But it does not establish greater resilience to climatic variability generally; it finds the opposite regional response in the Amazon. (LLM, conf=0.82)

  cites [53] Kooperman, G. J. et al. Forest response to rising CO2 drives zonally asymmetric rainfall change over tropical land. Nat. Clim. Change 8, 434–440 (2018). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [54] Lapola, D. M., Oyama, M. D. & Nobre, C. A. Exploring the range of climate biome projections for tropical South America: the role of CO2 fertilization and seasonality: future biome distribution in South America. Global Biogeochem. Cycles 23, https://doi.org/10.1029/2008GB003357 (2009). source

In the paper

“Amazonian regions with the highest linguistic diversity (a proxy for ecological knowledge diversity123) are found in peripheral parts of the system, particularly in the north-west (Extended Data Fig. 7b).”

What the sources say

• Partly supported

  The citation is attached to the parenthetical claim that linguistic diversity is a proxy for ecological knowledge diversity, not to the geographic pattern attributed to Extended Data Fig. 7b. The paper’s Abstract reports that medicinal-plant knowledge is often unique to a single language, supporting the proxy for that kind of knowledge, but it does not establish the relationship for ecological knowledge more broadly. (LLM, conf=0.84)

  cites [123] Cámara-Leret, R. & Bascompte, J. Language extinction triggers the loss of unique medicinal knowledge. Proc. Natl Acad. Sci. USA 118, e2103683118 (2021). sourceExperimental — accuracy not yet measured

In the paper

“Experimental evidence suggests that CO2 fertilization also depends on soil nutrient availability, particularly nitrogen and phosphorus57,58.”

What the sources say

• Supported

  The main-text discussion of Fig. 1 identifies soil C:N ratio, an indicator of nitrogen availability, and soil phosphorus availability as predictors of the biomass response to elevated CO₂. It reports that their relationships with the response differ by mycorrhizal type, supporting the claim that CO₂ fertilization depends on these soil nutrients. (LLM, conf=0.94)

  cites [57] Terrer, C. et al. Nitrogen and phosphorus constrain the CO2 fertilization of global plant biomass. Nat. Clim. Change 9, 684–689 (2019). source
• Supported

  The paper’s main text reports that earlier elevated-CO2 experiments found reduced productivity stimulation when nitrogen was limiting. It also reports that its own experiment found no significant productivity increase under elevated CO2 on a phosphorus-limited site, and concludes that phosphorus availability may constrain the response. No page numbers are provided in our copy. (LLM, conf=0.93)

  cites [58] Ellsworth, D. S. et al. Elevated CO2 does not increase eucalypt forest productivity on a low-phosphorus soil. Nat. Clim. Change 7, 279–282 (2017). source

In the paper

“Forests across the Amazon are already responding with increasing tree mortality rates that are not simulated by these models46, possibly because of compounding disturbance regimes (Fig. 1).”

What the sources say

• Partly supported

  The Results (p. 4) report a long-term increase in tree mortality across the studied tropical South American forests. The discussion (p. 5) says demographic feedbacks are not explicitly included in dynamic global vegetation models, but it does not establish that CMIP6 models fail to simulate the observed mortality increase. (LLM, conf=0.88)

  cites [46] Brienen, R. J. W. et al. Long-term decline of the Amazon carbon sink. Nature 519, 344–348 (2015). sourceExperimental — accuracy not yet measured

In the paper

“Currently, 86% of the Amazon biome may be in a stable forest state (Extended Data Fig. 1b), but some of these stable forests are showing signs of fragility33.”

What the sources say

• Supported

  The Discussion reports a marked loss of resilience across vast areas of Amazon rainforest where the broadleaf forest fraction has not strongly decreased. This supports the claim that some forests still in a forest state show signs of fragility; the cited paper need not establish the separately cited 86% figure. (LLM, conf=0.93)

  cites [33] Boulton, C. A., Lenton, T. M. & Boers, N. Pronounced loss of Amazon rainforest resilience since the early 2000s. Nat. Clim. Change 12, 271–278 (2022). source

In the paper

“Globally, Indigenous peoples and local communities (IPLCs) have a key role in maintaining ecosystems resilient to global change113.”

What the sources say

• Partly supported

  In “Consequences of Indigenous influence on land management” (page unavailable), the paper says Indigenous Peoples and local communities contribute to biodiversity conservation, and that Indigenous Peoples sustain ecosystem diversity worldwide. It describes Indigenous management institutions as resilient, but does not establish that the ecosystems they maintain are resilient to global change. (LLM, conf=0.86)

  cites [113] Garnett, S. T. et al. A spatial overview of the global importance of Indigenous lands for conservation. Nat. Sustain. 1, 369–374 (2018). sourceExperimental — accuracy not yet measured

In the paper

“Road networks (Fig. 1d) facilitate illegal activities, promoting more deforestation, logging and fire spread throughout the core of the Amazon forest38,39.”

What the sources say

• ?Not checked — no full text of the sourcecites [38] Bullock, E. L., Woodcock, C. E., Souza, C. Jr & Olofsson, P. Satellite-based estimates reveal widespread forest degradation in the Amazon. Global Change Biol. 26, 2956–2969 (2020). source
• Partly supported

  The 'Projecting Amazon forest degradation' section says that roads promote degradation and deforestation. The copy does not establish the more specific chain that road networks facilitate illegal activities and thereby promote logging and fire spread throughout the forest core. (LLM, conf=0.84)

  cites [39] Lapola, D. M. et al. The drivers and impacts of Amazon forest degradation. Science 379, eabp8622 (2023). sourceExperimental — accuracy not yet measured

In the paper

“Tree functional diversity increases forest adaptability to climate chance by offering various possibilities of functioning99.”

What the sources say

• Partly supported

  The indexed Abstract says functional diversity can enhance ecosystem resilience by providing greater response diversity, and that plant trait diversity may enable Amazon forests to adjust to new climate conditions. This supports the proposed mechanism, but the citing sentence states the effect as certain for forests generally, whereas the paper's own finding is qualified and concerns Amazon forests. (LLM, conf=0.82)

  cites [99] Sakschewski, B. et al. Resilience of Amazon forests emerges from plant trait diversity. Nat. Clim. Change 6, 1032–1036 (2016). sourceExperimental — accuracy not yet measured

In the paper

“In addition, CO2 may reduce water stress by increasing tree water-use efficiency29.”

What the sources say

• Supported

  The paper’s Abstract (page not available in our copy) reports increased tree water-use efficiency with rising atmospheric CO2 and says reduced transpiration was very likely. That mechanism supports the citing sentence’s hedged claim that CO2 may reduce water stress. (LLM, conf=0.85)

  cites [29] van der Sleen, P. et al. No growth stimulation of tropical trees by 150 years of CO2 fertilization but water-use efficiency increased. Nat. Geosci. 8, 24–28 (2015). source

In the paper

“These emerging positive feedback loops could accelerate a systemic transition of the Amazon forest15.”

What the sources say

• Partly supported

  The Introduction and “A network of interactions” section say positive feedback can amplify change and sometimes propel tropical forests into contrasting states. The South America case study discusses Amazon deforestation disrupting rainfall, but its illustrated consequences concern wildfire risk in the Pantanal; it does not specifically say these loops could accelerate a systemic transition of the Amazon forest. Page numbers were not available in our copy. (LLM, conf=0.82)

  cites [15] Flores, B. M. & Staal, A. Feedback in tropical forests of the Anthropocene. Global Change Biol. 28, 5041–5061 (2022). sourceExperimental — accuracy not yet measured

In the paper

“The ecosystem often becomes dominated by fire-tolerant tree and palm species, together with alien invasive grasses and opportunistic herbaceous plants96,97, such as vines and ferns.”

What the sources say

• ?Not checked — no full text of the sourcecites [96] Veldman, J. W. & Putz, F. E. Grass-dominated vegetation, not species-diverse natural savanna, replaces degraded tropical forests on the southern edge of the Amazon Basin. Biol. Conserv. 144, 1419–1429 (2011). source
• Partly supported

  The fire-induced grass-invasion section reports that exotic pasture grasses can establish after fires, and the persistence section says fire-degraded forests may become dominated by vines, resprouts and pioneer trees. The paper does not establish the claimed combined dominance by fire-tolerant trees, palms, invasive grasses and opportunistic plants, and the cited passages do not mention ferns. Its persistence section also notes that grass dominance may be transient. (LLM, conf=0.86)

  cites [97] Silvério, D. V. et al. Testing the Amazon savannization hypothesis: fire effects on invasion of a neotropical forest by native cerrado and exotic pasture grasses. Phil. Trans. R. Soc. B 368, 20120427 (2013). sourceExperimental — accuracy not yet measured

In the paper

“These alternative trajectories may be irreversible or transient depending on the strength of the novel interactions15.”

What the sources say

• Partly supported

  The Conclusions (page not available) say that the balance of strong and weak feedbacks will determine how global changes affect tropical forests. The ‘A network of interactions’ section (page not available) says positive feedbacks can propel forests to a contrasting state, but our copy does not say whether the resulting trajectories are irreversible or transient. (LLM, conf=0.83)

  cites [15] Flores, B. M. & Staal, A. Feedback in tropical forests of the Anthropocene. Global Change Biol. 28, 5041–5061 (2022). sourceExperimental — accuracy not yet measured

In the paper

“Estimates from the southern Amazon indicate that 5−6% of the landscape has already shifted into degraded open-canopy ecosystems due to deforestation and fires45,96.”

What the sources say

• Partly supported

  The Results report forest-cover loss in the Território Indígena do Xingu, with fire the most important predictor, and the Abstract describes degradation as reduced canopy cover. But the paper estimates approximately 7% for this specific territory, not 5–6% of the southern Amazon landscape. (LLM, conf=0.88)

  cites [45] Silvério, D. V. et al. Intensification of fire regimes and forest loss in the Território Indígena do Xingu. Environ. Res. Lett. 17, 045012 (2022). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [96] Veldman, J. W. & Putz, F. E. Grass-dominated vegetation, not species-diverse natural savanna, replaces degraded tropical forests on the southern edge of the Amazon Basin. Biol. Conserv. 144, 1419–1429 (2011). source

In the paper

“Liana forests are expected to expand with increasing aridity, disturbance regimes and CO2 fertilization90.”

What the sources say

• ?Could not verify

  The available indexed passages contain bibliographic information and keywords, including “elevated atmospheric co2,” but no discussion of whether liana forests will expand. Searches for aridity, disturbance, CO2 fertilization, and increasing liana abundance returned no passage stating the claimed relationship. (LLM, conf=0.72)

  cites [90] Schnitzer, S. A. & Bongers, F. Increasing liana abundance and biomass in tropical forests: emerging patterns and putative mechanisms: Increasing lianas in tropical forests. Ecology Letters 14, 397–406 (2011). sourceExperimental — accuracy not yet measured

In the paper

“Among the remaining old-growth forests, at least 38% have been degraded by land use disturbances and repeated extreme droughts39, with impacts on moisture recycling that are still uncertain.”

What the sources say

• Partly supported

  The Extended summary and Spatial extent and severity section estimate that 38% of remaining Amazonian forests were affected by fire, edge effects, timber extraction, or extreme drought during 2001–2018 (page not provided). But the estimate includes single drought events, not just repeated ones: Changes in carbon stocks and basin-wide emissions says only about one-third of drought-affected area experienced multiple droughts. The paper describes the denominator as remaining Amazonian forest, rather than specifically old-growth forest. (LLM, conf=0.88)

  cites [39] Lapola, D. M. et al. The drivers and impacts of Amazon forest degradation. Science 379, eabp8622 (2023). sourceExperimental — accuracy not yet measured

In the paper

“Other more recent models incorporating fire disturbances support a potential broad-scale transition of the Amazon forest, simulating a biomass loss of 30–40% under a high-emission scenario5,82 (SSP5–8.5 at 4 °C).”

What the sources say

• Partly supported

  The Results section ('Projected Changes in Tropical Tree Biomass'; page unavailable) reports that GFDL-ESM4.1 projects Neotropical forest biomass falling to 40% below its initial stock under SSP5-8.5, and describes fire-driven declines in Amazon grid cells. This supports the potential broad-scale transition, but our copy does not give a 30–40% biomass-loss range or tie that loss to 4 °C of warming. It also notes that another fire-capable model projects forest growth under high emissions. (LLM, conf=0.86)

  cites [5] Cano, I. M. et al. Abrupt loss and uncertain recovery from fires of Amazon forests under low climate mitigation scenarios. Proc. Natl Acad. Sci. USA 119, e2203200119 (2022). sourceExperimental — accuracy not yet measured
• Partly supported

  Section 4.3 (Vegetation impacts; page unavailable) projects a 30% reduction in vegetation carbon under SSP5-8.5 at 4 °C. The Discussion says fire feedbacks can shift forest-dominated ecosystems toward grasses and shrubs, including impacts in Amazonia. But the 30% figure is for South America as a whole, not specifically the Amazon, and the paper does not give the claimed 30–40% range. (LLM, conf=0.88)

  cites [82] Burton, C. et al. South American fires and their impacts on ecosystems increase with continued emissions. Clim. Resil. Sustain. 1, e8 (2022). sourceExperimental — accuracy not yet measured

In the paper

“In a remote landscape far from large agricultural frontiers, within a stable forest region of the Amazon (Extended Data Fig. 1b), satellite and field evidence revealed that white-sand savannas are expanding where floodplain forests were repeatedly disturbed by fires95.”

What the sources say

• Partly supported

  Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  cites [95] Flores, B. M. & Holmgren, M. White-sand savannas expand at the core of the Amazon after forest wildfires. Ecosystems 24, 1624–1637 (2021). sourceExperimental — accuracy not yet measured

In the paper

“In bistable regions of the Amazon forest with annual rainfall below 1,800 mm (Extended Data Fig. 1b), shifts to degraded open-canopy ecosystems are relatively common after repeated disturbances by fire45,96.”

What the sources say

• Partly supported

  The Discussion (page unavailable) reports that, after three consecutive fires, over half of the forests studied in the Território Indígena do Xingu entered a degraded state that could persist for years or decades. This supports the repeated-fire and degradation part of the claim, but the paper does not establish that such shifts are relatively common across Amazonian bistable regions. The 1,800 mm rainfall boundary is attributed in the citing sentence to its own Extended Data figure, not specifically to this source. (LLM, conf=0.84)

  cites [45] Silvério, D. V. et al. Intensification of fire regimes and forest loss in the Território Indígena do Xingu. Environ. Res. Lett. 17, 045012 (2022). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [96] Veldman, J. W. & Putz, F. E. Grass-dominated vegetation, not species-diverse natural savanna, replaces degraded tropical forests on the southern edge of the Amazon Basin. Biol. Conserv. 144, 1419–1429 (2011). source

In the paper

“At the regional scale, a self-reinforcing feedback between forest loss and reduced atmospheric moisture flow may increase the resilience of these open-canopy degraded ecosystems42.”

What the sources say

• Partly supported

  The Abstract describes a regional feedback in which forest loss reduces recycled moisture and intensifies dry seasons. The Discussion says fire-related feedbacks may favor open vegetation and that forest loss could become self-perpetuating. It does not establish that reduced atmospheric moisture flow increases the resilience of open-canopy degraded ecosystems. (LLM, conf=0.83)

  cites [42] Staal, A. et al. Feedback between drought and deforestation in the Amazon. Environ. Res. Lett. 15, 044024 (2020). sourceExperimental — accuracy not yet measured

In the paper

“In the ‘degraded open-canopy ecosystem’ trajectory, feedbacks involve interactions among low tree cover and fire97, soil erosion60, seed limitation105, invasive grasses and opportunistic plants96.”

What the sources say

• Partly supported

  The Introduction and ‘Fire-induced loss of canopy cover’ section describe a feedback in which fire reduces tree cover, grasses invade, and grass fuels intensify subsequent fires. The ‘Persistence of fire-promoting grasses’ section also mentions vines, resprouts, and pioneer trees in fire-degraded forests, but presents them as possible alternatives to grass dominance, not as participants in the described feedback. (LLM, conf=0.84)

  cites [97] Silvério, D. V. et al. Testing the Amazon savannization hypothesis: fire effects on invasion of a neotropical forest by native cerrado and exotic pasture grasses. Phil. Trans. R. Soc. B 368, 20120427 (2013). sourceExperimental — accuracy not yet measured
• ?Could not verify

  The citation is attached specifically to soil erosion, not to the other feedbacks listed in the sentence. Searches for soil erosion and its feedback with reduced tree cover returned only an abstract and bibliographic material, with no full-text passage on which to base a verdict. (LLM, conf=0.70)

  cites [60] Flores, B. M. et al. Soil erosion as a resilience drain in disturbed tropical forests. Plant Soil https://doi.org/10.1007/s11104-019-04097-8 (2020). sourceExperimental — accuracy not yet measured
• Supported

  Citation 105 is attached to “seed limitation,” not to the other feedbacks listed in the sentence. The Discussion (page unavailable) describes a possible destabilising feedback in which a lack of large-seeded fruiting trees deters their animal dispersers, limiting the immigration and dispersal of large-seeded species. (LLM, conf=0.86)

  cites [105] Hawes, J. E. et al. A large‐scale assessment of plant dispersal mode and seed traits across human‐modified Amazonian forests. J. Ecol. 108, 1373–1385 (2020). source

In the paper

“An additional 38% of the forest biome has been damaged by extreme droughts, fires, logging and edge effects38,39.”

What the sources say

• ?Not checked — no full text of the sourcecites [38] Bullock, E. L., Woodcock, C. E., Souza, C. Jr & Olofsson, P. Satellite-based estimates reveal widespread forest degradation in the Amazon. Global Change Biol. 26, 2956–2969 (2020). source
• Supported

  The Extended summary reports that adding extreme drought to fire, edge effects and timber extraction raises the estimated degraded area to 38% of remaining Amazonian forests. The Spatial extent and severity section likewise gives 38% after accounting for overlap among all four disturbances. (LLM, conf=0.94)

  cites [39] Lapola, D. M. et al. The drivers and impacts of Amazon forest degradation. Science 379, eabp8622 (2023). source

In the paper

“In the ‘white-sand savanna’ trajectory, the main feedbacks result from interactions among low tree cover and fire, soil erosion, and seed limitation106.”

What the sources say

• Partly supported

  The Conclusions (page unavailable) describe repeatedly burnt floodplain forests slowly transitioning toward a white-sand savanna state. Section 4.5 and Figure 5 describe feedbacks involving seed limitation, fire and flood erosion, but present the erosion and fire feedbacks as expected or possible rather than established as the trajectory’s main feedbacks. (LLM, conf=0.84)

  cites [106] Flores, B. M. & Holmgren, M. Why forest fails to recover after repeated wildfires in Amazonian floodplains? Experimental evidence on tree recruitment limitation. J. Ecol. 109, 3473–3486 (2021). sourceExperimental — accuracy not yet measured

In the paper

“Liana forests can also be relatively stable, because lianas self-perpetuate by causing physical damage to trees, allowing lianas to remain at high density90,91.”

What the sources say

• ?Could not verify

  The supplied passages contain bibliographic metadata but no discussion of liana-dominated forest stability. Further searches for physical tree damage, self-perpetuation, and feedbacks affecting liana density returned no substantive passage, so this claim cannot be checked against our copy. (LLM, conf=0.72)

  cites [90] Schnitzer, S. A. & Bongers, F. Increasing liana abundance and biomass in tropical forests: emerging patterns and putative mechanisms: Increasing lianas in tropical forests. Ecology Letters 14, 397–406 (2011). sourceExperimental — accuracy not yet measured
• Partly supported

  The Abstract reports that the studied liana-infested forest remained stable in extent from 2007 to 2012 and that fast forest dynamics maintained high liana infestation. The “Influence of Lianas on Forest Dynamics” section links tree mortality and resulting canopy gaps to liana maintenance, but attributes faster tree dynamics probably to species composition and competition; it does not establish physical damage to trees as the mechanism. The study also concerns a single forest patch, rather than liana forests generally. (LLM, conf=0.87)

  cites [91] Tymen, B. et al. Evidence for arrested succession in a liana-infested Amazonian forest. J Ecol 104, 149–159 (2016). sourceExperimental — accuracy not yet measured

In the paper

“Satellite observations of tree cover distributions across tropical South America suggest a critical threshold in rainfall seasonality intensity at −400 mm of the maximum cumulative water deficit37,80 (MCWD).”

What the sources say

• Partly supported

  The Results section (“Forest shifts”; page unavailable) says that forest probability across rainfall regimes is derived from satellite data and that forest resilience decreases as MCWD decreases. The Methods section (“Potential landscapes”; page unavailable) examines tree-cover states across MCWD values, but the retrieved passages do not identify a critical threshold at −400 mm. That numerical threshold is unsupported by our copy. (LLM, conf=0.86)

  cites [37] Zemp, D. C. et al. Self-amplified Amazon forest loss due to vegetation-atmosphere feedbacks. Nat. Commun. 8, 14681 (2017). sourceExperimental — accuracy not yet measured
• Partly supported

  In “Hydrological Thresholds on Current Forest Extent” (page unavailable), the paper uses satellite-derived maps and reports that savannas predominate below −400 mm MCWD when annual precipitation is below 1,500 mm. It explicitly says there is no sharp vegetation threshold: the forest–savanna transition spans −400 to −200 mm MCWD. The claim omits both the precipitation condition and the broad transition. (LLM, conf=0.88)

  cites [80] Malhi, Y. et al. Exploring the likelihood and mechanism of a climate-change-induced dieback of the Amazon rainforest. Proc. Natl Acad. Sci. USA 106, 20610–20615 (2009). sourceExperimental — accuracy not yet measured

In the paper

“Simulating individual trees can improve the representation of growth and mortality dynamics, which ultimately affect forest dynamics (for example, refs. 61,62,99).”

What the sources say

• Partly supported

  The Ecosystem Demography Model, version 2 section describes a size- and age-structured model, and Site-level simulations link size-dependent growth and mortality to changes in forest structure. This supports the importance of representing tree-level differences, but the paper describes structured equations rather than simulations of individual trees and does not show that individual-tree simulation improves the representation of those dynamics. (LLM, conf=0.82)

  cites [61] Longo, M. et al. Ecosystem heterogeneity and diversity mitigate Amazon forest resilience to frequent extreme droughts. New Phytol. 219, 914–931 (2018). sourceExperimental — accuracy not yet measured
• Supported

  The Significance section says that representing individual-level responses improves models’ ability to capture forest structure, composition, and dynamics. It also explains that differences among individual plants influence growth and mortality, producing forest-level responses that differ from those of an aggregated model. (LLM, conf=0.92)

  cites [62] Levine, N. M. et al. Ecosystem heterogeneity determines the ecological resilience of the Amazon to climate change. Proc. Natl Acad. Sci. USA 113, 793–797 (2016). source
• ?Could not verify

  The supplied passages and additional searches for individual trees, growth, mortality, and forest modelling returned bibliographic material rather than a passage addressing the claim. Our indexed copy therefore does not establish whether the paper says that simulating individual trees improves the representation of growth and mortality dynamics. (LLM, conf=0.72)

  cites [99] Sakschewski, B. et al. Resilience of Amazon forests emerges from plant trait diversity. Nat. Clim. Change 6, 1032–1036 (2016). sourceExperimental — accuracy not yet measured

In the paper

“Satellite observations of tree cover distributions across tropical South America suggest a critical threshold between 1,000 and 1,250 mm of annual rainfall78,79.”

What the sources say

• Partly supported

  The Results (‘Stability of tropical forests’; page unavailable) use forest-cover distributions to identify a rainfall-dependent change in South America, with bistability beginning at 1,250 mm per year. The paper does not place the threshold between 1,000 and 1,250 mm per year; it reports a bistable range of 1,250–2,050 mm per year. (LLM, conf=0.85)

  cites [78] Staal, A. et al. Hysteresis of tropical forests in the 21st century. Nat. Commun. 11, 4978 (2020). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [79] Staver, A. C., Archibald, S. & Levin, S. A. The global extent and determinants of savanna and forest as alternative biome states. Science 334, 230–232 (2011). source

In the paper

“Here we use the runs from Tuinenburg et al.134, who published monthly climatological mean (2008–2017) moisture flows between each pair of 0.5° grid cells on Earth.”

What the sources say

• Supported

  The Introduction states that the dataset contains moisture flows between every pair of 0.5° grid cells and consists of monthly multi-annual mean footprints for 2008–2017. Methods §2.2 confirms that the published output was aggregated to 0.5° resolution and provided as monthly means over that period. (LLM, conf=0.95)

  cites Tuinenburg et al. [134] Tuinenburg, O. A., Theeuwen, J. J. E. & Staal, A. High-resolution global atmospheric moisture connections from evaporation to precipitation. Earth Syst. Sci. Data 12, 3177–3188 (2020). source

In the paper

“Although MODIS VCF can contain errors within lower tree cover ranges and should not be used to test for bistability between grasslands and savannas125, the dataset is relatively robust for assessing bistability within the tree cover range of forests and savannas126, as also shown by low uncertainty (standard deviation of tree cover estimates) across the Amazon (Extended Data Fig. 8).”

What the sources say

• ?Not checked — no full text of the sourcecites [125] Sexton, J. O. et al. Global, 30-m resolution continuous fields of tree cover: Landsat-based rescaling of MODIS vegetation continuous fields with lidar-based estimates of error. Int. J. Digital Earth 6, 427–448 (2013). source
• Supported

  The paper reports no systematic bias in MODIS VCF at 50–75% tree cover, the intermediate range at the savanna–forest boundary (passage 4, labelled Abstract; page not supplied). It contrasts this with substantial bias at low tree cover. The Amazon uncertainty observation is attributed to the citing paper’s Extended Data Fig. 8, not to this source. (LLM, conf=0.90)

  cites [126] Staver, A. C. & Hansen, M. C. Analysis of stable states in global savannas: is the CART pulling the horse? – a comment. Global Ecol. Biogeogr. 24, 985–987 (2015). source

In the paper

“Bistable areas covering 8% of the biome may turn into stable forest in the western Amazon (Peru and Bolivia), thus becoming more resilient to disturbances.”

In the paper

“Now, the region is increasingly exposed to unprecedented stress from warming temperatures, extreme droughts, deforestation and fires, even in central and remote parts of the system1.”

What the sources say

• Not checked yetcites [1] Science Panel for the Amazon. Amazon Assessment Report 2021 (2021); www.theamazonwewant.org/amazon-assessment-report-2021/.

In the paper

“However, an ensemble with all 33 models suggests that 35–41% of the biome could become bistable, including large areas of the southern Amazon.”

In the paper

“Another 3% of the biome may pass the critical threshold in annual rainfall into stable savanna in the southern Bolivian Amazon.”

In the paper

“By combining spatial information on various disturbances, we estimate that by 2050, 10% to 47% of Amazonian forests will be exposed to compounding disturbances that may trigger unexpected ecosystem transitions and potentially exacerbate regional climate change.”

In the paper

“For example, 6% of the biome may change from stable forest to a bistable regime in parts of the southern and central Amazon.”

In the paper

“Brazil is the largest supplier of rainfall to western Amazonian countries.”

In the paper

“Currently, 86% of the Amazon biome may be in a stable forest state (Extended Data Fig. 1b), but some of these stable forests are showing signs of fragility33.”

In the paper

“Up to one-third of the total annual rainfall in Amazonian territories of Bolivia, Peru, Colombia and Ecuador depends on water originating from Brazil’s portion of the Amazon forest.”

In the paper

“Between 1,000 and 1,800 mm of annual rainfall, high and low tree cover ecosystems exist in the Amazon as two alternative stable states (see Extended Data Table 2 for uncertainty ranges).”

In the paper

“On the basis of our reanalysis using tree cover data from the Amazon basin (Extended Data Fig. 1a), we confirm a potential threshold at 1,000 mm of annual rainfall (Fig. 3a), below which forests become rare and unstable.”

In the paper

“Forest resilience is changing across the Amazon as disturbance regimes intensify (Fig. 1).”

In the paper

“Our findings also indicate that Amazon forest resilience is affected by compounding disturbances (Fig. 1).”

In the paper

“From examples of disturbed forests across the Amazon, we identify the three most plausible ecosystem trajectories related to the types of disturbances, feedbacks and local environmental conditions.”

In the paper

“Within the bistability range in annual rainfall conditions, forests are relatively more likely to collapse when severely disturbed, when compared to forests in areas with annual rainfall above 1,800 mm (Extended Data Fig. 1a).”

In the paper

“The sum of these layers revealed relative spatial variation in ecosystem transition potential by 2050 across the Amazon (Fig. 1f), ranging from −1 (low potential) to 4 (very high potential).”

In the paper

“The Amazon forest holds more than 10% of Earth’s terrestrial biodiversity, stores an amount of carbon equivalent to 15–20 years of global CO2 emissions (150–200 Pg C), and has a net cooling effect (from evapotranspiration) that helps to stabilize the Earth’s climate1–3.”

What the sources say

• Not checked yetcites [1] Science Panel for the Amazon. Amazon Assessment Report 2021 (2021); www.theamazonwewant.org/amazon-assessment-report-2021/.
• Not checked yetcites [2] IPCC. Climate Change 2021: The Physical Science Basis (eds Masson-Delmotte, V. et al.) https://www.ipcc.ch/report/ar6/wg1/#FullReport (Cambridge Univ. Press, 2021).
• ?Not checked — no full text of the sourcecites [3] Armstrong McKay, D. et al. Exceeding 1.5 °C global warming could trigger multiple climate tipping points. Science 377, abn7950 (2022). source

In the paper

“Within the twenty-first century, global warming may cause long-term changes in Amazonian climatic conditions2.”

What the sources say

• Not checked yetcites [2] IPCC. Climate Change 2021: The Physical Science Basis (eds Masson-Delmotte, V. et al.) https://www.ipcc.ch/report/ar6/wg1/#FullReport (Cambridge Univ. Press, 2021).

In the paper

“If trends continue, these areas could potentially warm by over 4 °C by 2050.”

In the paper

“As ecosystems approach a tipping point, they often lose resilience while still remaining close to equilibrium17.”

What the sources say

• ?Not checked — no full text of the sourcecites [17] Scheffer, M. et al. Anticipating critical transitions. Science 338, 344–348 (2012). source

In the paper

“The possibility that alternative stable states (or bistability) may exist in a system has important implications, because the crossing of tipping points may be irreversible for the time scales that matter to societies10.”

What the sources say

• ?Not checked — no full text of the sourcecites [10] Scheffer, M., Carpenter, S., Foley, J. A., Folke, C. & Walker, B. Catastrophic shifts in ecosystems. Nature 413, 591–596 (2001). source

In the paper

“Within the remaining Amazon forest area, 17% has been degraded by human disturbances38, such as logging, edge effects and understory fires, but if we consider also the impacts from repeated extreme drought events in the past decades, 38% of the Amazon could be degraded39.”

What the sources say

• ?Not checked — no full text of the sourcecites [38] Bullock, E. L., Woodcock, C. E., Souza, C. Jr & Olofsson, P. Satellite-based estimates reveal widespread forest degradation in the Amazon. Global Change Biol. 26, 2956–2969 (2020). source

In the paper

“Depending on the processes involved, connectivity can either increase or decrease the risk of systemic transition17.”

What the sources say

• ?Not checked — no full text of the sourcecites [17] Scheffer, M. et al. Anticipating critical transitions. Science 338, 344–348 (2012). source

In the paper

“A single forest hectare in the central and northwestern Amazon can contain more than 300 tree species (Extended Data Fig. 7a).”

In the paper

“Most CMIP6 models agree that a large-scale dieback of the Amazon is unlikely in response to global warming above pre-industrial levels2, but this ecosystem response is based on certain assumptions, such as a large CO2-fertilization effect53.”

What the sources say

• Not checked yetcites [2] IPCC. Climate Change 2021: The Physical Science Basis (eds Masson-Delmotte, V. et al.) https://www.ipcc.ch/report/ar6/wg1/#FullReport (Cambridge Univ. Press, 2021).

In the paper

“Connectivity across Amazonian landscapes and regions can contribute to synchronize forest dynamics, causing different forests to behave more similarly17.”

What the sources say

• ?Not checked — no full text of the sourcecites [17] Scheffer, M. et al. Anticipating critical transitions. Science 338, 344–348 (2012). source

In the paper

“Moreover, as human disturbances intensify throughout the Amazon (Fig. 1), the spread of invasive grasses and fires can make the system increasingly homogeneous.”

In the paper

“However, this scenario seems unlikely to occur in the near future (Fig. 1).”

In the paper

“If these estimates, however, considered projections from CMIP6 models and their relatively broader areas of bistability (Extended Data Fig. 4), the proportion of the Amazon forest that could transition into a low tree cover state would be much larger.”

In the paper

“Such tremendous tree species diversity can increase forest resilience by different mechanisms.”

In the paper

“At the regional scale, a fundamental heterogeneity factor is rainfall and how it translates into water stress.”

In the paper

“This international connectivity illustrates how policies related to deforestation, especially in the Brazilian Amazon, will affect the climate in other countries.”

In the paper

“As bistable forests expand deeper into the system (Fig. 1b and Extended Data Fig. 4), the distribution of compounding disturbances may indicate where ecosystem transitions are more likely to occur in the coming decades (Fig. 1f).”

In the paper

“Rare species provide ‘ecological redundancy’, increasing opportunities for replacement of lost functions when dominant species disappear109.”

What the sources say

• ?Not checked — no full text of the sourcecites [109] Walker, B., Kinzig, A. & Langridge, J. Plant attribute diversity, resilience, and ecosystem function: the nature and significance of dominant and minor species. Ecosystems 2, 95–113 (1999). source

In the paper

“Conceptual model showing how the five drivers may interact (arrows indicate positive effects) and how these interactions may strengthen a positive feedback between water stress and forest loss.”

In the paper

“Palaeorecords from the northern Amazon98 show that burnt forests may spend centuries in a degraded open-canopy state before they eventually shift into a savanna.”

What the sources say

• ?Not checked — no full text of the sourcecites [98] Rull, V. A palynological record of a secondary succession after fire in the Gran Sabana, Venezuela. J. Quat. Sci. 14, 137–152 (1999). source

In the paper

“The intensification of these drivers may cause widespread tree mortality for instance because of extreme droughts and fires76.”

What the sources say

• ?Not checked — no full text of the sourcecites [76] Brando, P. M. et al. Abrupt increases in Amazonian tree mortality due to drought-fire interactions. Proc. Natl Acad. Sci. USA 111, 6347–6352 (2014). source

In the paper

“Shifts from forest to white-sand savanna (Fig. 4) are probably stable (that is, the ecosystem is unlikely to recover back to forest within centuries), based on the relatively long persistence of these savannas in the landscape94.”

What the sources say

• ?Not checked — no full text of the sourcecites [94] Adeney, J. M., Christensen, N. L., Vicentini, A. & Cohn‐Haft, M. White‐sand ecosystems in Amazonia. Biotropica 48, 7–23 (2016). source

In the paper

“At local scales, driver 5 (accumulated deforestation) intensifies with land use changes.”

In the paper

“Drivers 2 to 4 (regional rainfall conditions) intensify in response to drivers 1 and 5.”

In the paper

“Five critical drivers of water stress on Amazonian forests affect (directly or indirectly) the underlying tipping point of the system.”

In the paper

“Satellite observations of tree cover distributions across tropical South America suggest a critical threshold at 7 months of dry season length79 (DSL).”

What the sources say

• ?Not checked — no full text of the sourcecites [79] Staver, A. C., Archibald, S. & Levin, S. A. The global extent and determinants of savanna and forest as alternative biome states. Science 334, 230–232 (2011). source

In the paper

“The southeastern region has already turned into a source of greenhouse gases to the atmosphere48.”

What the sources say

• ?Not checked — no full text of the sourcecites [48] Gatti, L. V. et al. Amazonia as a carbon source linked to deforestation and climate change. Nature 595, 388–393 (2021). source

In the paper

“Recent policy and approaches to Amazon development, however, accelerated deforestation that reached 13,000 km2 in the Brazilian Amazon in 2021 (http://terrabrasilis.dpi.inpe.br).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites http://terrabrasilis.dpi.inpe.br