Critical transitions in the Amazon forest system

May combine two claims.

Drought regimes are intensifying across the region, possibly due to deforestation that continues to expand within the system.

“Drought regimes are intensifying across the region41, possibly due to deforestation42 that continues to expand within the system (Extended Data Fig. 5).”

• cites [41] Anderson, L. O. et al. Vulnerability of Amazonian forests to repeated droughts. Phil. Trans. R. Soc. B 373, 20170411 (2018). sourceDisputed

  The Discussion (section 4(a)) says increasing dry and very dry events appear to be occurring in southern Amazonia, but explicitly says the proposed broader trend toward more frequent and intense droughts is not supported by its observed long-term patterns in other regions. The Conclusion (section 5) likewise reports wetter conditions in some regions and no increase in drought intensity or duration in central areas. Citation 41 is attached to the region-wide drought claim, not the separate deforestation claim attached to citation 42. (LLM, conf=0.86)

  Checked by a reasoning model — may be wrong.

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

May combine two claims.

Beyond 20% deforestation, forest mortality accelerated, causing large reductions in regional rainfall and consequently an ecosystem transition of 50−60% of the Amazon, depending on the emissions scenario.

“Beyond 20% deforestation, forest mortality accelerated, causing large reductions in regional rainfall and consequently an ecosystem transition of 50−60% of the Amazon, depending on the emissions scenario.”

• 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). sourceDisputed

  In “Climate Change: Global and Regional Perspectives” (page unavailable), the paper places a proposed forest-loss tipping point at 40% deforestation and says regional precipitation is expected to decrease beyond around 30%, not 20%. In “Impacts of Anthropogenic Drivers of Change in the Amazon” (page unavailable), it projects over 60% forest-area reduction by 2050 under combined climate, deforestation, and fire effects; it does not describe accelerated mortality beyond 20% deforestation causing a 50–60% transition. (LLM, conf=0.88)

  Checked by a reasoning model — may be wrong.

  Experimental — accuracy not yet measured

May combine two claims.

Past drier climatic conditions were very different from current climatic conditions, in which observed warming trends may exacerbate drought impacts on the forest by exposing trees to unprecedented levels of water stress.

“Past drier climatic conditions were therefore very different from the current climatic conditions, in which observed warming trends may exacerbate drought impacts on the forest by exposing trees to unprecedented levels of water stress31,32.”

• 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). sourcePartly supported

  The Results (Drought and land cover changes) report that recent warming and drying suggest increasing water stress on vegetation in the eastern Amazonia–Cerrado transition zone. The paper does not establish that past drier climates were very different from current conditions or that trees face unprecedented levels of water stress. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• 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). sourcePartly supported

  The Main section says rising temperatures are likely to intensify water stress in Amazonian forests, and Implications and conclusions says higher temperatures and vapour pressure deficit will probably reduce trees’ hydraulic safety margins. The paper does not establish that past drier conditions were very different from current conditions or that trees will face unprecedented levels of water stress. Page numbers are unavailable in our copy. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

May combine two claims.

Increasing rainfall variability is causing extreme drought events to become more widespread and frequent across the Amazon, together with extreme wet events and convective storms that result in more windthrow disturbances.

“Increasing rainfall variability is causing extreme drought events to become more widespread and frequent across the Amazon (Fig. 1c), together with extreme wet events and convective storms that result in more windthrow disturbances40.”

• cites [40] Feng, Y., Negrón-Juárez, R. I., Romps, D. M. & Chambers, J. Q. Amazon windthrow disturbances are likely to increase with storm frequency under global warming. Nat. Commun. 14, 101 (2023). sourceSupported

May combine two claims.

Maximum temperatures during the dry season follow a similar trend, rising across most of the biome, exposing the forest and local peoples to potentially unbearable heat.

“Maximum temperatures during the dry season follow a similar trend, rising across most of the biome (Extended Data Fig. 2), exposing the forest34 and local peoples35 to potentially unbearable heat.”

• cites [34] Doughty, C. E. et al. Tropical forests are approaching critical temperature thresholds. Nature 621, 105–111 (2023). sourceSupported
• cites [35] Xu, C., Kohler, T. A., Lenton, T. M., Svenning, J.-C. & Scheffer, M. Future of the human climate niche. Proc. Natl Acad. Sci. USA 117, 11350–11355 (2020). sourcePartly supported

  In Results > Projected Change (page not provided), the paper projects that billions of people could be exposed to extremely hot mean annual temperatures. This supports the concern for people, but it does not establish that dry-season maximum temperatures across the cited biome will expose local peoples to potentially unbearable heat. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

May combine two claims.

The Amazon forest contributes up to 50% of rainfall in the region and is crucial for moisture supply across South America.

“The forest contributes up to 50% of rainfall in the region and is crucial for moisture supply across South America4, allowing other biomes and economic activities to thrive in regions that would otherwise be more arid, such as the Pantanal wetlands and the La Plata river basin1.”

• cites [4] Staal, A. et al. Forest-rainfall cascades buffer against drought across the Amazon. Nat. Clim. Change 8, 539–543 (2018). sourceCould not verify

  The supplied passages are bibliographic metadata, and searches for “50% of rainfall,” “moisture supply,” and rainfall recycling did not surface a substantive passage from the paper’s body. Our accessible copy therefore cannot verify the 50% figure or the claim about moisture supply across South America. (LLM, conf=0.70)

  Experimental — accuracy not yet measured
• cites [1] Science Panel for the Amazon. Amazon Assessment Report 2021 (2021); www.theamazonwewant.org/amazon-assessment-report-2021/.Not checked yet

  Not checked in the free run.

May combine two claims.

Throughout the core of the Amazon forest biome, patches of white-sand savanna expanded in the past 20,000-7,000 years, driven by sediment deposition along ancient rivers, and more recently (around 800 years ago) owing to Indigenous fires.

“Throughout the core of the Amazon forest biome, patches of white-sand savanna also expanded in the past 20,000–7,000 years, driven by sediment deposition along ancient rivers26, and more recently (around 800 years ago) owing to Indigenous fires27.”

• 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). sourcePartly supported

  The History of vegetation and time of the present-day forests section reports evidence of broader savanna areas at different times between about 20,000 and 7,578 years ago. The Potential driver section links vegetation changes in the southwestern Amazonian study area to sedimentation and ancient river channels. Citation 26 attaches to that earlier expansion, not to the later Indigenous-fire claim. The paper does not establish expansion throughout the Amazon biome or identify all those past savannas as white-sand savanna. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [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). sourceNot checked — no full text of the source

May combine two claims.

The difference between both ensembles is possibly related to the forest-rainfall feedback included in the five coupled models, which increases total annual rainfall and therefore the stable forest area along the southern Amazon, but only when deforestation is not included in the simulations.

“The difference between both ensembles is possibly related to the forest–rainfall feedback included in the five coupled models, which increases total annual rainfall and therefore the stable forest area along the southern Amazon, but only when deforestation is not included in the simulations4,37.”

• cites [4] Staal, A. et al. Forest-rainfall cascades buffer against drought across the Amazon. Nat. Clim. Change 8, 539–543 (2018). sourceCould not verify

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

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

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

  Experimental — accuracy not yet measured

May combine two claims.

These impacts would involve irreversible loss of biodiversity, socioeconomic and cultural values.

“These impacts would also involve irreversible loss of biodiversity, socioeconomic and cultural values1,7–9.”

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

  Not checked in the free run.

• cites [7] Bromham, L. et al. Global predictors of language endangerment and the future of linguistic diversity. Nat. Ecol. Evol. 6, 163–173 (2022). sourcePartly supported

  The Main section says biodiversity is under threat, and ‘Safeguarding language diversity’ warns that language loss could erase unique expressions of human cultural diversity. The paper does not say these impacts would irreversibly destroy biodiversity or socioeconomic values; it discusses socioeconomic change chiefly as a factor in language loss. The cited passages have no page numbers in our copy. (LLM, conf=0.78)

  Experimental — accuracy not yet measured
• cites [8] Gomes, V. H. F., Vieira, I. C. G., Salomão, R. P. & ter Steege, H. Amazonian tree species threatened by deforestation and climate change. Nat. Clim. Change 9, 547–553 (2019). sourceNot checked — no full text of the source
• 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). sourcePartly supported

  The Abstract reports that the combined loss of plant species and cultural knowledge erodes indigenous knowledge networks, and that lost knowledge may jeopardize livelihoods. It does not establish that the resulting losses of biodiversity, socioeconomic values, and cultural values are all irreversible. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

May combine two claims.

Past drought periods were usually associated with much lower atmospheric CO2 concentrations, which may have reduced water-use efficiency of trees.

“Past drought periods were usually associated with much lower atmospheric CO2 concentrations, which may have reduced water-use efficiency of trees29 (that is, trees assimilated less carbon during transpiration).”

• 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). sourceSupported

May combine two claims.

Past drought periods also coincided with cooler temperatures, which probably reduced water demand by trees.

“However, these periods also coincided with cooler temperatures20,21, which probably reduced water demand by trees30.”

• cites [20] Wang, X. et al. Hydroclimate changes across the Amazon lowlands over the past 45,000 years. Nature 541, 204–207 (2017). sourceNot checked — no full text of the source
• cites [21] Kukla, T. et al. The resilience of Amazon tree cover to past and present drying. Global Planet. Change 202, 103520 (2021). sourceCould not verify

  Citation 30 is attached to the suggestion that cooler temperatures reduced trees’ water demand; the preceding citations support the timing of cooler temperatures. The Introduction discusses mid-Holocene drying and tree-cover resilience, but the passages retrieved for cooler temperatures, water demand, and evapotranspiration do not address that proposed effect. (LLM, conf=0.72)

  Experimental — accuracy not yet measured
• 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). sourceCould not verify

  The available indexed passage contains only the paper’s title and bibliographic details, with no section or page text addressing this claim. Searches for cooler temperatures during drought and reduced tree water demand found no relevant passage, so our copy cannot verify what the citation attributes to this source. (LLM, conf=0.70)

  Experimental — accuracy not yet measured

May combine two claims.

Since the early 1980s, rainfall conditions have changed; peripheral and central parts of the Amazon forest are drying significantly, such as in the southern Bolivian Amazon, where annual rainfall reduced by up to 20 mm yr−1.

“Since the early 1980s, rainfall conditions have also changed31. Peripheral and central parts of the Amazon forest are drying significantly, such as in the southern Bolivian Amazon, where annual rainfall reduced by up to 20 mm yr−1 (Extended Data Fig. 3a).”

• 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). sourceSupported

May combine two claims.

Although palaeorecords suggest that a large-scale Amazon forest collapse did not occur within the past 65 million years, they indicate that savannas expanded locally, particularly in the more seasonal peripheral regions when fires ignited by humans were frequent.

“Although palaeorecords suggest that a large-scale Amazon forest collapse did not occur within the past 65 million years19, they indicate that savannas expanded locally, particularly in the more seasonal peripheral regions when fires ignited by humans were frequent23,24.”

• cites [19] Hoorn, C. et al. Amazonia through time: Andean uplift, climate change, landscape evolution, and biodiversity. Science 330, 927–931 (2010). sourcePartly supported

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

  Experimental — accuracy not yet measured
• cites [23] Mayle, F. E. & Power, M. J. Impact of a drier Early–Mid-Holocene climate upon Amazonian forests. Phil. Trans. R. Soc. B 363, 1829–1838 (2008). sourcePartly supported

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

  Experimental — accuracy not yet measured
• cites [24] Montoya, E. & Rull, V. Gran Sabana fires (SE Venezuela): a paleoecological perspective. Quat. Sci. Rev. 30, 3430–3444 (2011). sourceCould not verify

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

  Experimental — accuracy not yet measured

May combine two claims.

Satellite observations of climatic variability confirm model projections, showing that since the early 1980s, the Amazonian region has been warming significantly at an average rate of 0.27 °C per decade during the dry season, with the highest rates of up to 0.6 °C per decade in the centre and southeast of the biome.

“Satellite observations of climatic variability31 confirm model projections2, showing that since the early 1980s, the Amazonian region has been warming significantly at an average rate of 0.27 °C per decade during the dry season, with the highest rates of up to 0.6 °C per decade in the centre and southeast of the biome (Fig. 1a).”

• 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). sourcePartly supported

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

  Experimental — accuracy not yet measured
• cites [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 yet

  Not checked in the free run.

May combine two claims.

Rising temperatures will increase thermal stress, potentially reducing forest productivity and carbon storage capacity and causing widespread leaf damage.

“Rising temperatures will increase thermal stress, potentially reducing forest productivity and carbon storage capacity36 and causing widespread leaf damage34.”

• cites [36] Sullivan, M. J. P. et al. Long-term thermal sensitivity of Earth’s tropical forests. Science 368, 869–874 (2020). sourceSupported
• cites [34] Doughty, C. E. et al. Tropical forests are approaching critical temperature thresholds. Nature 621, 105–111 (2023). sourceSupported

May combine two claims.

Large parts of the Amazon forest are projected to experience mass mortality events due to climatic and land use-related disturbances in the coming decades, potentially accelerating climate change through carbon emissions and feedbacks with the climate system.

“Large parts of the Amazon forest, however, are projected to experience mass mortality events due to climatic and land use-related disturbances in the coming decades5,6, potentially accelerating climate change through carbon emissions and feedbacks with the climate system2,3.”

• 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). sourcePartly supported

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

  Experimental — accuracy not yet measured
• cites [6] Parry, I. M., Ritchie, P. D. L. & Cox, P. M. Evidence of localised Amazon rainforest dieback in CMIP6 models. Earth Syst. Dynam. 13, 1667–1675 (2022). sourcePartly supported

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

  Experimental — accuracy not yet measured
• cites [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 yet

  Not checked in the free run.

• cites [3] Armstrong McKay, D. et al. Exceeding 1.5 °C global warming could trigger multiple climate tipping points. Science 377, abn7950 (2022). sourceNot checked — no full text of the source

May combine two claims.

Savannas expanded in peripheral parts of the southern Amazon basin during the LGM and mid-Holocene, as well as in the northeastern Amazon during the early Holocene, probably influenced by drier climatic conditions and fires ignited by humans.

“Nonetheless, savannas expanded in peripheral parts of the southern Amazon basin during the LGM and mid-Holocene23, as well as in the northeastern Amazon during the early Holocene (around 11,000 years ago), probably influenced by drier climatic conditions and fires ignited by humans24,25.”

• cites [23] Mayle, F. E. & Power, M. J. Impact of a drier Early–Mid-Holocene climate upon Amazonian forests. Phil. Trans. R. Soc. B 363, 1829–1838 (2008). sourcePartly supported

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

  Experimental — accuracy not yet measured
• cites [24] Montoya, E. & Rull, V. Gran Sabana fires (SE Venezuela): a paleoecological perspective. Quat. Sci. Rev. 30, 3430–3444 (2011). sourcePartly supported

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

  Experimental — accuracy not yet measured
• cites [25] Rull, V., Montoya, E., Vegas-Vilarrúbia, T. & Ballesteros, T. New insights on palaeofires and savannisation in northern South America. Quat. Sci. Rev. 122, 158–165 (2015). sourceNot checked — no full text of the source

May combine two claims.

Satellite observations from across the Amazon suggest that forest resilience has been decreasing since the early 2000s, possibly as a result of global changes.

“Satellite observations from across the Amazon suggest that forest resilience has been decreasing since the early 2000s33, possibly as a result of global changes.”

• 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). sourceSupported

May combine two claims.

New fire regimes are burning larger forest areas, emitting more carbon to the atmosphere and forcing IPLCs to readapt.

“As a result, new fire regimes are burning larger forest areas43, emitting more carbon to the atmosphere44 and forcing IPLCs to readapt45.”

• cites [43] Alencar, A. A., Brando, P. M., Asner, G. P. & Putz, F. E. Landscape fragmentation, severe drought, and the new Amazon forest fire regime. Ecol. Appl. 25, 1493–1505 (2015). sourceNot checked — no full text of the source
• cites [44] Aragão, L. E. O. C. et al. 21st century drought-related fires counteract the decline of Amazon deforestation carbon emissions. Nat. Commun. 9, 536 (2018). sourceSupported
• 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). sourceSupported

May combine two claims.

Amazonian forests are heterogeneous in their resilience to disturbances, which may have contributed to buffering large-scale transitions in the past.

“Amazonian forests are heterogeneous in their resilience to disturbances, which may have contributed to buffering large-scale transitions in the past37,61,62.”

• cites [37] Zemp, D. C. et al. Self-amplified Amazon forest loss due to vegetation-atmosphere feedbacks. Nat. Commun. 8, 14681 (2017). sourceSupported
• cites [61] Longo, M. et al. Ecosystem heterogeneity and diversity mitigate Amazon forest resilience to frequent extreme droughts. New Phytol. 219, 914–931 (2018). sourcePartly supported

  The Regional patterns of vulnerability section describes differences in drought resilience across Amazonian regions, and the Impacts of climate variability section says canopy reorganization can make responses to climate change more gradual. These passages support heterogeneous resilience and a possible buffering mechanism, but they do not establish that it buffered large-scale transitions in the past. (LLM, conf=0.83)

  Experimental — accuracy not yet measured
• 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). sourcePartly supported

  The Significance section describes heterogeneous responses to a drying climate and says forest reorganization can buffer against drastic threshold changes in vegetation state. It discusses predicted future changes, however, not evidence that heterogeneity buffered large-scale transitions in the past; its analysis also focuses on climate-related water stress rather than disturbances generally. Page numbers were not provided in our copy. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

May combine two claims.

As a result of low exposure to water deficit, most northwestern forests have trees with low drought resistance and could suffer massive mortality if suddenly exposed to severe water stress.

“As a result of low exposure to water deficit, most northwestern forests have trees with low drought resistance and could suffer massive mortality if suddenly exposed to severe water stress32.”

• 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). sourcePartly supported

  The Hydraulic traits distribution section reports that ever-wet forests, which have little drought exposure, have the least embolism-resistant xylem. It also says they face the lowest apparent risk of hydraulic failure under observed conditions. The paper does not establish that most northwestern forests would suffer massive mortality if suddenly exposed to severe water stress. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

May combine two claims.

Smaller areas with high transition potential were found scattered within deforestation frontiers, where most forests have been carved by roads.

“Smaller areas with high transition potential were found scattered within deforestation frontiers, where most forests have been carved by roads50,51.”

• cites [50] Botelho, J., Costa, S. C. P., Ribeiro, J. G. & Souza, C. M. Mapping roads in the Brazilian Amazon with artificial intelligence and Sentinel-2. Remote Sensing 14, 3625 (2022). sourcePartly supported

  The Discussion reports that roads cut through or lie within 10 km of some remaining Amazon forest, supporting the road-impact part of the cited clause. It does not establish that most forests specifically within deforestation frontiers have been carved by roads; across the remaining forest it reports 41% affected and 59% roadless. The finding about smaller areas with high transition potential appears to be the citing authors’ own result, not a finding attributed to this source. (LLM, conf=0.84)

  Experimental — accuracy not yet measured
• cites [51] Matricardi, E. A. T. et al. Long-term forest degradation surpasses deforestation in the Brazilian Amazon. Science 369, 1378–1382 (2020). sourceNot checked — no full text of the source

• AssumptionRests on an assumption: The additive sum of warming/drying slopes, ecosystem stability classes, drought impacts, road proximity, and governance can serve as a proxy for ecosystem transition potential.

May combine two claims.

These strategies may allow seasonal forests to resist current levels of rainfall fluctuations, but seasonal forests are also closer to the critical rainfall thresholds and may experience unprecedented water stress in the coming decades.

“These strategies may allow seasonal forests to resist current levels of rainfall fluctuations32, but seasonal forests are also closer to the critical rainfall thresholds (Extended Data Fig. 1) and may experience unprecedented water stress in the coming decades (Fig. 1).”

• 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). sourceSupported

May combine two claims.

Soil fertility is another heterogeneity factor that may affect forest resilience, and which may be undermined by disturbances that cause topsoil erosion.

“Soil fertility is another heterogeneity factor that may affect forest resilience59, and which may be undermined by disturbances that cause topsoil erosion60.”

• cites [59] Quesada, C. A. et al. Basin-wide variations in Amazon forest structure and function are mediated by both soils and climate. Biogeosciences 9, 2203–2246 (2012). sourceSupported
• 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). sourcePartly supported

  Citation 60 is attached to the clause about disturbances and topsoil erosion. The indexed Abstract says disturbances leave organic topsoil vulnerable to erosion and identifies soil fertility as a condition affecting the erosion feedback. It does not explicitly say that erosion reduces soil fertility. (LLM, conf=0.78)

  Experimental — accuracy not yet measured

May combine two claims.

Amazonian forests are home to more than 15,000 tree species, of which 1% are dominant and the other 99% are mostly rare.

“Amazonian forests are home to more than 15,000 tree species, of which 1% are dominant and the other 99% are mostly rare107.”

• cites [107] ter Steege, H. et al. Biased-corrected richness estimates for the Amazonian tree flora. Sci. Rep. 10, 10130 (2020). sourcePartly supported

  The Discussion estimates 15,874 Amazonian tree species and describes hyperdominance by a few abundant species. It does not establish that exactly 1% of species are dominant or that the other 99% are mostly rare. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

May combine two claims.

Observations from across the Amazon suggest that CO2-driven accelerations of tree growth may have contributed to increasing tree mortality rates, which could eventually neutralize the forest carbon sink in the coming decades.

“However, observations from across the Amazon46 suggest that CO2-driven accelerations of tree growth may have contributed to increasing tree mortality rates (trees grow faster but also die earlier), which could eventually neutralize the forest carbon sink in the coming decades55.”

• cites [46] Brienen, R. J. W. et al. Long-term decline of the Amazon carbon sink. Nature 519, 344–348 (2015). sourcePartly supported

  The paper reports Amazon-wide increases in productivity and mortality (p. 4) and suggests that faster growth may shorten tree lifespans and contribute to mortality (p. 5). But it says the factors driving the observed changes remain unclear (p. 5), so it does not establish that CO2 drove the growth acceleration. The sentence separately cites source 55 for the possibility that the sink could be neutralized in coming decades. (LLM, conf=0.84)

  Experimental — accuracy not yet measured
• cites [55] Brienen, R. J. W. et al. Forest carbon sink neutralized by pervasive growth-lifespan trade-offs. Nat. Commun. 11, 4241 (2020). sourceSupported

May combine two claims.

Roads carving through the forest are sources of illegal activities such as logging and burning, which increase forest flammability.

“For instance, roads carving through the forest are well-known sources of illegal activities, such as logging and burning, which increase forest flammability38,39.”

• cites [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). sourceNot checked — no full text of the source
• cites [39] Lapola, D. M. et al. The drivers and impacts of Amazon forest degradation. Science 379, eabp8622 (2023). sourcePartly supported

  In “Projecting Amazon forest degradation” (page unavailable), the paper says roads promote degradation and deforestation. “Spatial extent and severity” says logged forests can be more flammable than undisturbed forests, and elsewhere notes that some timber extraction is illegal. It does not establish the more specific claim that roads are sources of illegal logging and burning, or that those road-linked activities increase flammability. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

May combine two claims.

IPLCs defend their territories against illegal deforestation and land use disturbances, and they also promote forest restoration by expanding diverse agroforestry systems.

“IPLCs defend their territories against illegal deforestation and land use disturbances49,113, and they also promote forest restoration by expanding diverse agroforestry systems121,122.”

• cites [49] Nepstad, D. et al. Inhibition of Amazon deforestation and fire by parks and Indigenous lands: inhibition of Amazon deforestation and fire. Conserv. Biol. 20, 65–73 (2006). sourceNot checked — no full text of the source
• 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). sourcePartly supported

  The 'Consequences of Indigenous influence on land management' section says Indigenous Peoples protect biodiversity on their lands, and the 'Fig. 2 around here' section reports that most Indigenous lands have low-intensity land uses. Neither passage establishes that IPLCs defend their territories specifically against illegal deforestation or land-use disturbances. The agroforestry clause is attached to other citations, so it is not assessed here. (LLM, conf=0.79)

  Experimental — accuracy not yet measured
• cites [121] Schmidt, M. V. C. et al. Indigenous knowledge and forest succession management in the Brazilian Amazon: contributions to reforestation of degraded areas. Front. For. Glob. Change 4, 605925 (2021). sourcePartly supported

  The Discussion describes indigenous agroforestry management practices that can accelerate forest recovery. But the Assisted Natural Regeneration section says traditional agroforestry management in the studied villages is being replaced, not expanded. The paper therefore supports a restoration role for these practices, but not the claim that communities are expanding diverse agroforestry systems. (LLM, conf=0.87)

  Experimental — accuracy not yet measured
• cites [122] Tomioka Nilsson, M. S. & Fearnside, P. M. Yanomami mobility and its effects on the forest landscape. Hum. Ecol. 39, 235–256 (2011). sourceNot checked — no full text of the source

May combine two claims.

Continued loss of ecological knowledge will undermine the capacity of IPLCs to manage and protect Amazonian forests, further reducing their resilience to global changes.

“Continued loss of ecological knowledge will undermine the capacity of IPLCs to manage and protect Amazonian forests, further reducing their resilience to global changes9.”

• 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). sourcePartly supported

  The Abstract says progressive loss of biocultural heritage may undermine the resilience of the communities studied, and that knowledge loss constrains their ability to benefit from nature’s services. It does not establish that knowledge loss undermines their capacity to manage or protect Amazonian forests; the Study Area section also includes communities outside Amazonia. No page numbers are provided in our copy. (LLM, conf=0.87)

  Experimental — accuracy not yet measured

May combine two claims.

Other key heterogeneity factors include topography, which determines plant access to groundwater, and seasonal flooding, which increases forest vulnerability to wildfires.

“Other key heterogeneity factors (Extended Data Fig. 6) include topography, which determines plant access to groundwater64, and seasonal flooding, which increases forest vulnerability to wildfires65.”

• cites [64] Mattos, C. R. C. et al. Double stress of waterlogging and drought drives forest–savanna coexistence. Proc. Natl Acad. Sci. USA 120, e2301255120 (2023). sourceSupported
• cites [65] Flores, B. M. et al. Floodplains as an Achilles’ heel of Amazonian forest resilience. Proc. Natl Acad. Sci. USA 114, 4442–4446 (2017). sourceSupported

May combine two claims.

By creating new cultural niches, humans partly modified the Amazonian flora, increasing their food security even during times of past climate change without the need for large-scale deforestation.

“By creating new cultural niches, humans partly modified the Amazonian flora117,118, increasing their food security even during times of past climate change119,120 without the need for large-scale deforestation117.”

• cites [117] Levis, C. et al. Persistent effects of pre-Columbian plant domestication on Amazonian forest composition. Science 355, 925–931 (2017). sourceNot checked — no full text of the source
• cites [118] Coelho, S. D. et al. Eighty-four per cent of all Amazonian arboreal plant individuals are useful to humans. PLoS ONE 16, e0257875 (2021). sourcePartly supported

  The Introduction (page unavailable) says Indigenous management practices may have changed the abundance of useful Amazonian plants and describes practices that created domesticated forest landscapes. It does not establish that this occurred without large-scale deforestation. The food-security and past-climate-change clause is attached to other citations in the citing sentence, not to this source. (LLM, conf=0.82)

  Experimental — accuracy not yet measured
• cites [119] de Souza, J. G. et al. Climate change and cultural resilience in late pre-Columbian Amazonia. Nat. Ecol. Evol. 3, 1007–1017 (2019). sourcePartly supported

  In “Two models of land use” (page unavailable), the paper describes forest enrichment without large-scale deforestation and says its review suggests that polyculture agroforestry gave pre-Columbian societies resilience to climate variability. The citing sentence’s assertion that these practices increased food security during climate change is stronger than the paper’s proposed resilience finding; it does not establish a direct increase in food security. (LLM, conf=0.82)

  Experimental — accuracy not yet measured
• cites [120] Furquim, L. P. et al. Facing change through diversity: resilience and diversification of plant management strategies during the Mid to Late Holocene Transition at the Monte Castelo shellmound, SW Amazonia. Quaternary 4, 8 (2021). sourcePartly supported

  Section 5.1 says Indigenous people directly manipulated plants and co-constructed biodiversity, while section 5.2 describes diversified plant management in response to climatic change. Section 5.3 finds that fires recorded at Monte Castelo were not for vegetation clearance. That site-specific finding does not establish that modifying Amazonian flora more broadly required no large-scale deforestation; the food-security and climate-change phrase is attached to other citations in the citing sentence. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

May combine two claims.

In the rainy western Amazon, drought-resistant species are rare but present within tree communities, implying that they could replace the dominant drought-sensitive species in a drier future.

“For instance, in the rainy western Amazon, drought-resistant species are rare but present within tree communities111, implying that they could replace the dominant drought-sensitive species in a drier future.”

• cites [111] Esquivel-Muelbert, A. et al. Seasonal drought limits tree species across the Neotropics. Ecography 40, 618–629 (2017). sourceSupported

May combine two claims.

Tree species complementarity increases carbon storage, accelerating forest recovery after disturbances.

“Tree species complementarity increases carbon storage, accelerating forest recovery after disturbances108.”

• cites [108] Poorter, L. et al. Diversity enhances carbon storage in tropical forests: Carbon storage in tropical forests. Global Ecol. Biogeogr. 24, 1314–1328 (2015). sourcePartly supported

  The Discussion (page unavailable) reports a positive relationship between species richness and above-ground biomass, supporting the carbon-storage part of the claim. The Introduction presents complementarity as a proposed mechanism, not one the study establishes. The discussion of gap dynamics says richness and biomass may both rise after disturbance; it does not show that complementarity accelerates forest recovery. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Humans have been present in the Amazon for at least 12,000 years and extensively managing landscapes for 6,000 years.

“Humans have been present in the Amazon for at least 12,000 years114 and extensively managing landscapes for 6,000 years22.”

• cites [114] Morcote-Ríos, G., Aceituno, F. J., Iriarte, J., Robinson, M. & Chaparro-Cárdenas, J. L. Colonisation and early peopling of the Colombian Amazon during the Late Pleistocene and the Early Holocene: new evidence from La Serranía La Lindosa. Quat. Int. 578, 5–19 (2021). sourceNot checked — no full text of the source
• cites [22] Clement, C. R. et al. Disentangling domestication from food production systems in the neotropics. Quaternary 4, 4 (2021). sourcePartly supported

  Citation 22 is attached to the landscape-management claim, not the separate 12,000-year presence claim. Section 3, “Early Human Entanglements in the Neotropics” (page unavailable), says early-Holocene palm remains suggest management at two Amazonian sites, and Section 5, “Are the Neotropics Different?” (page unavailable), describes evidence of widespread human influence. Neither passage establishes that landscapes were extensively managed for 6,000 years. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

May combine two claims.

Consistent loss of Amazonian languages is causing an irreversible disruption of ecological knowledge systems, mostly driven by road construction.

“However, consistent loss of Amazonian languages is causing an irreversible disruption of ecological knowledge systems, mostly driven by road construction7.”

• cites [7] Bromham, L. et al. Global predictors of language endangerment and the future of linguistic diversity. Nat. Ecol. Evol. 6, 163–173 (2022). sourcePartly supported

  In “Predicting future language loss” (page unavailable), the paper identifies the Amazon rainforest as a projected hotspot, not a documented site of consistent loss. “Predictors of language endangerment” associates road density with endangerment globally but does not establish that road construction is the main cause of Amazonian language loss. The cited passages do not establish irreversible disruption of ecological knowledge systems; “Safeguarding language diversity” instead describes the predictions as possible outcomes that intervention may change. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

May combine two claims.

Through diverse ecosystem management practices, humans built thousands of earthworks and 'Amazon Dark Earth' sites, and domesticated plants and landscapes across the Amazon forest.

“Through diverse ecosystem management practices, humans built thousands of earthworks and ‘Amazon Dark Earth’ sites, and domesticated plants and landscapes across the Amazon forest115,116.”

• cites [115] Levis, C. et al. How people domesticated Amazonian forests. Front. Ecol. Evol. 5, 171 (2018). sourcePartly supported

  The Introduction and Discussion describe diverse management practices that domesticated plants and forest landscapes across Amazonia. Materials and methods says people created anthropogenic soils, and the Discussion mentions mounds and geoglyphs. However, the paper does not establish that humans built thousands of earthworks and Amazon Dark Earth sites. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [116] Clement, C. R. et al. The domestication of Amazonia before European conquest. Proc. R. Soc. B. 282, 20150813 (2015). sourceSupported

May combine two claims.

Today, IPLCs have diverse ecological knowledge about Amazonian plants, animals and landscapes, which allows them to quickly identify and respond to environmental changes with mitigation and adaptation practices.

“Today, IPLCs have diverse ecological knowledge about Amazonian plants, animals and landscapes, which allows them to quickly identify and respond to environmental changes with mitigation and adaptation practices68,69.”

• cites [68] Alexander, C. et al. Linking Indigenous and scientific knowledge of climate change. BioScience 61, 477–484 (2011). sourceNot checked — no full text of the source
• cites [69] Ford, J. D. et al. The resilience of Indigenous peoples to environmental change. One Earth 2, 532–543 (2020). sourcePartly supported

  The paper’s discussion of Indigenous knowledge (section labeled “War uet”; page not provided) says botanical and ecological knowledge helps Indigenous peoples detect environmental change and adapt their practices. The Resilience Factors section also describes fire-management practices in Latin America. These passages support the general mechanism, but do not establish the claim specifically for IPLCs’ knowledge of Amazonian plants, animals, and landscapes or their ability to respond quickly there. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

May combine two claims.

Field evidence from long-term monitoring sites across the Amazon shows that tree mortality rates are increasing in most sites, reducing carbon storage, while favouring the replacement by drought-affiliated species.

“For instance, field evidence from long-term monitoring sites across the Amazon shows that tree mortality rates are increasing in most sites, reducing carbon storage46, while favouring the replacement by drought-affiliated species47.”

• cites [46] Brienen, R. J. W. et al. Long-term decline of the Amazon carbon sink. Nature 519, 344–348 (2015). sourcePartly supported

  The main text (p. 4) reports increasing mortality across the monitoring network and a resulting decline in the rate of biomass gain. It does not establish that mortality increased in most individual sites, and it says forests remained a biomass sink rather than losing biomass overall. The drought-affiliated species clause is attached to a different citation, so it is not assessed here. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [47] Esquivel‐Muelbert, A. et al. Compositional response of Amazon forests to climate change. Glob. Change Biol. 25, 39–56 (2019). sourceSupported

May combine two claims.

Increases in tree water-use efficiency may reduce forest transpiration and consequently atmospheric moisture flow across the Amazon, potentially reducing forest resilience in the southwest of the biome.

“Moreover, increases in tree water-use efficiency may reduce forest transpiration and consequently atmospheric moisture flow across the Amazon53,56, potentially reducing forest resilience in the southwest of the biome4,37.”

• 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). sourcePartly supported

  The Local thermodynamic and circulation anomalies section says rising CO₂ can reduce stomatal conductance and forest transpiration. The Discussion also reports reduced moisture flow over the Amazon. But Differences between Amazon and Indonesian forests attributes the reduction in moisture convergence to non-local influences from Africa, rather than a direct consequence of reduced transpiration within the Amazon. The southwest-resilience clause has separate citations and is not judged here. (LLM, conf=0.83)

  Experimental — accuracy not yet measured
• cites [56] Lammertsma, E. I. et al. Global CO2 rise leads to reduced maximum stomatal conductance in Florida vegetation. Proc. Natl Acad. Sci. USA 108, 4035–4040 (2011). sourceNot checked — no full text of the source
• cites [4] Staal, A. et al. Forest-rainfall cascades buffer against drought across the Amazon. Nat. Clim. Change 8, 539–543 (2018). sourceCould not verify

  The available passages are bibliographic metadata, not substantive text from the paper (no section or page is given). Searches for water-use efficiency, transpiration, atmospheric moisture flow, and southwestern Amazon resilience returned no passage addressing the attributed claim. (LLM, conf=0.72)

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

  The Results section (‘Self-amplified forest loss under dry-season intensification’; page unavailable) links reduced evapotranspiration after forest loss with moisture recycling and declining forest resilience. But the paper studies forest loss, not increased tree water-use efficiency as a cause of reduced transpiration. The southwest-resilience clause has separate citations in the citing sentence and is not attributed to this source. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

May combine two claims.

Logging and edge effects can make a forest patch more flammable, but these disturbances are often not captured by ESMs.

“For instance, logging and edge effects can make a forest patch more flammable39, but these disturbances are often not captured by ESMs.”

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

May combine two claims.

Although these ecosystem transitions have been confirmed only in the Negro river basin, floodplain forests in other parts of the Amazon were shown to be particularly vulnerable to collapse.

“Although these ecosystem transitions have been confirmed only in the Negro river basin (central Amazon), floodplain forests in other parts of the Amazon were shown to be particularly vulnerable to collapse45,64,65.”

• 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). sourceSupported
• cites [64] Mattos, C. R. C. et al. Double stress of waterlogging and drought drives forest–savanna coexistence. Proc. Natl Acad. Sci. USA 120, e2301255120 (2023). sourcePartly supported

  In “Future Changes in Double Stress,” the paper says floodplain forests of the Amazonas, Madeira, and Upper Negro Rivers are particularly affected by simulated hydrologic stress, supporting the geographic point. It does not establish that those forests are particularly vulnerable to collapse: the same section says vegetation shifts depend on local factors and that more research is needed to determine each forest type’s vulnerability. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [65] Flores, B. M. et al. Floodplains as an Achilles’ heel of Amazonian forest resilience. Proc. Natl Acad. Sci. USA 114, 4442–4446 (2017). sourceSupported

May combine two claims.

For floodplain ecosystems covering 14% of the forest biome, a different critical threshold has been estimated at 1,500 mm of annual rainfall, implying floodplain forests may be the first to collapse in a drier future.

“For floodplain ecosystems covering 14% of the forest biome, a different critical threshold has been estimated at 1,500 mm of annual rainfall65, implying that floodplain forests may be the first to collapse in a drier future.”

• cites [65] Flores, B. M. et al. Floodplains as an Achilles’ heel of Amazonian forest resilience. Proc. Natl Acad. Sci. USA 114, 4442–4446 (2017). sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Guadua bamboo forests are common in the southwestern Amazon.

“Guadua bamboo forests are common in the southwestern Amazon92,93.”

• cites [92] da Silva, S. S. et al. Increasing bamboo dominance in southwestern Amazon forests following intensification of drought-mediated fires. For. Ecol. Manag. 490, 119139 (2021). sourceNot checked — no full text of the source
• cites [93] Carvalho, A. Lde et al. Bamboo-dominated forests of the southwest Amazon: detection, spatial extent, life cycle length and flowering waves. PLoS ONE 8, e54852 (2013). sourceSupported

May combine two claims.

In stable forest regions of the Amazon with annual rainfall above 1,800 mm, forest cover usually recovers within a few years or decades after disturbances, yet forest composition and functioning may remain degraded for decades or centuries.

“In stable forest regions of the Amazon with annual rainfall above 1,800 mm (Extended Data Fig. 1b), forest cover usually recovers within a few years or decades after disturbances, yet forest composition and functioning may remain degraded for decades or centuries84–87.”

• cites [84] Brando, P. M. et al. Prolonged tropical forest degradation due to compounding disturbances: Implications for CO2 and H2O fluxes. Glob. Change Biol. 25, 2855–2868 (2019). sourceNot checked — no full text of the source
• cites [85] Mesquita, R. C. G., Ickes, K., Ganade, G. & Williamson, G. B. Alternative successional pathways in the Amazon Basin: successional pathways in the Amazon. J. Ecol. 89, 528–537 (2001). sourcePartly supported

  The Summary describes secondary forest stands 6–10 years after clearing, and the Introduction reports that recovery to primary forest may take 100–200 years on lightly used sites or at least 500 years on heavily used sites. The Methods give mean rainfall of 2,200 mm at the study site. The paper does not establish that forest cover usually recovers within years or decades across stable Amazonian regions above 1,800 mm of rainfall, or give a general timescale for recovery of forest functioning. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [86] Jakovac, C. C., Peña-Claros, M., Kuyper, T. W. & Bongers, F. Loss of secondary-forest resilience by land-use intensification in the Amazon. J. Ecol. 103, 67–77 (2015). sourceCould not verify

  Searches for recovery times, rainfall, and species composition found no matching full-text passage. The retrieved text is labelled Abstract and cannot establish the claim under the specified evidence rule; the available passages do not verify recovery within years or decades, an 1,800 mm rainfall threshold, or degradation lasting centuries. (LLM, conf=0.70)

  Experimental — accuracy not yet measured
• cites [87] Barlow, J. & Peres, C. A. Fire-mediated dieback and compositional cascade in an Amazonian forest. Phil. Trans. R. Soc. B 363, 1787–1794 (2008). sourcePartly supported

  The Conclusion (p. not provided) says that compositional recovery after forest disturbance can take hundreds of years or longer. The Results report recruitment of smaller trees within nine years, and the Methods describe a study area averaging 2,041 mm of annual rainfall. But the paper does not establish that forest cover usually recovers within years or decades across stable Amazonian regions receiving more than 1,800 mm of rain annually. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

May combine two claims.

In the degraded forest trajectory, feedbacks often involve competition between trees and other opportunistic plants, as well as interactions between deforestation, fire and seed limitation.

“In the ‘degraded forest’ trajectory, feedbacks often involve competition between trees and other opportunistic plants85,90,92, as well as interactions between deforestation, fire and seed limitation84,87,105.”

• cites [85] Mesquita, R. C. G., Ickes, K., Ganade, G. & Williamson, G. B. Alternative successional pathways in the Amazon Basin: successional pathways in the Amazon. J. Ecol. 89, 528–537 (2001). sourcePartly supported

  The ‘what drives successional pathways in the Amazon?’ section (page unavailable) links deforestation and periodic burning to different regeneration pathways, while the ‘regeneration as a function of distance from primary forest edge’ section reports seed-dispersal limits. The paper also discusses dominant pioneer plants retarding regeneration, but it does not establish competition between trees and other opportunistic plants as a frequent feedback. (LLM, conf=0.82)

  Experimental — accuracy not yet measured
• 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). sourceCould not verify

  The citation is attached to the clause about competition between trees and opportunistic plants, not the separate clause about deforestation, fire and seed limitation. The available passages labeled Abstract contain bibliographic details and the keyword “below-ground competition,” but no substantive passage establishing the claimed feedback in degraded forests. Searches for tree–liana competition and degraded-forest feedbacks returned no relevant text. (LLM, conf=0.72)

  Experimental — accuracy not yet measured
• cites [92] da Silva, S. S. et al. Increasing bamboo dominance in southwestern Amazon forests following intensification of drought-mediated fires. For. Ecol. Manag. 490, 119139 (2021). sourceNot checked — no full text of the source
• cites [84] Brando, P. M. et al. Prolonged tropical forest degradation due to compounding disturbances: Implications for CO2 and H2O fluxes. Glob. Change Biol. 25, 2855–2868 (2019). sourceNot checked — no full text of the source
• cites [87] Barlow, J. & Peres, C. A. Fire-mediated dieback and compositional cascade in an Amazonian forest. Phil. Trans. R. Soc. B 363, 1787–1794 (2008). sourceSupported
• 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). sourcePartly supported

  The Discussion (page unavailable) links fire-related forest disturbance to changes in seed-dispersal traits and describes dispersal-limited recovery and a possible feedback between plant and animal communities. It does not establish a feedback involving deforestation, fire and seed limitation together. The competition clause has a separate set of citations and is not assessed against this source. (LLM, conf=0.78)

  Experimental — accuracy not yet measured

May combine two claims.

Vismia forests are common in old abandoned pastures managed with fire, and are relatively stable because Vismia trees favour recruitment of Vismia seedlings over other tree species.

“For instance, Vismia forests are common in old abandoned pastures managed with fire85, and are relatively stable, because Vismia trees favour recruitment of Vismia seedlings in detriment of other tree species88,89.”

• cites [85] Mesquita, R. C. G., Ickes, K., Ganade, G. & Williamson, G. B. Alternative successional pathways in the Amazon Basin: successional pathways in the Amazon. J. Ecol. 89, 528–537 (2001). sourcePartly supported

  The Summary and ‘regeneration under Vismia- and Cecropia-dominated canopies’ report that abandoned-pasture stands were Vismia-dominated and that many recruits beneath Vismia were Vismia seedlings or clonal sprouts. The paper describes Vismia as persistent, but says its effect on other species’ regeneration is a possibility and that land-use history may confound it. The claim presents that proposed cause as established and calls the recruits seedlings without allowing for sprouts. (LLM, conf=0.87)

  Experimental — accuracy not yet measured
• cites [88] Jakovac, A. C. C., Bentos, T. V., Mesquita, R. C. G. & Williamson, G. B. Age and light effects on seedling growth in two alternative secondary successions in central Amazonia. Plant Ecol. Divers. 7, 349–358 (2014). sourceCould not verify

  The passages labelled Abstract contain bibliographic metadata and keywords, not findings about Vismia. Searches for Vismia recruitment, fire-managed pastures, and forest stability found no passage addressing the claim in our copy. (LLM, conf=0.72)

  Experimental — accuracy not yet measured
• cites [89] Mazzochini, G. G. & Camargo, J. L. C. Understory plant interactions along a successional gradient in Central Amazon. Plant Soil https://doi.org/10.1007/s11104-019-04100-2 (2020). sourceNot checked — no full text of the source

May combine two claims.

Although most recent models agree that a large-scale collapse of the Amazon forest is unlikely within the twenty-first century, our findings suggest that interactions and synergies among different disturbances could trigger unexpected ecosystem transitions even in remote and central parts of the system.

“Although most recent models agree that a large-scale collapse of the Amazon forest is unlikely within the twenty-first century2, our findings suggest that interactions and synergies among different disturbances (for example, frequent extreme hot droughts and forest fires) could trigger unexpected ecosystem transitions even in remote and central parts of the system101.”

• cites [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 yet

  Not checked in the free run.

• cites [101] Willcock, S., Cooper, G. S., Addy, J. & Dearing, J. A. Earlier collapse of Anthropocene ecosystems driven by multiple faster and noisier drivers. Nat. Sustain 6, 1331–1342 (2023). sourcePartly supported

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

  Experimental — accuracy not yet measured

May combine two claims.

These forests may naturally regrow through forest succession, yet because of feedbacks, succession can become arrested, keeping forests persistently degraded.

“These forests may naturally regrow through forest succession, yet because of feedbacks15, succession can become arrested, keeping forests persistently degraded (Fig. 4).”

• cites [15] Flores, B. M. & Staal, A. Feedback in tropical forests of the Anthropocene. Global Change Biol. 28, 5041–5061 (2022). sourceSupported

May combine two claims.

The Amazon biome has already lost 13% of its original forest area due to deforestation, or 15% of the biome if young secondary forests are considered.

“The Amazon biome has already lost 13% of its original forest area due to deforestation83 (or 15% of the biome if we consider also young secondary forests83 that provide limited contribution to moisture flow84).”

• cites [83] Smith, C. C. et al. Old-growth forest loss and secondary forest recovery across Amazonian countries. Environ. Res. Lett. 16, 085009 (2021). sourcePartly supported

  Table 1 reports 13.4% old-growth forest loss across the Amazon biome, supporting the rounded 13% figure. Section 2.2 reports the extent and ages of secondary forests, but does not report 15% forest loss when young secondary forests are considered. The paper defines secondary forest as regrowth on previously deforested land, so adding it to old-growth loss would double-count that area. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

May combine two claims.

After fire, the topsoil of burnt forests changes from clayey to sandy, favouring the establishment of savanna trees and native herbaceous plants.

“After fire, the topsoil of burnt forests changes from clayey to sandy, favouring the establishment of savanna trees and native herbaceous plants95.”

• 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). sourcePartly supported

  The Soil Shift section says burnt floodplain forest soil shifts from clayey to sandy, while the Vegetation Shift section reports the arrival of savanna trees and the dominance of native herbaceous plants in burnt sites. But the paper says it cannot infer how soils and plants interact during this shift; it does not establish that the sandier soil favours the establishment of both plant groups. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

May combine two claims.

Estimates from across the Amazon indicate that approximately 30% of areas previously deforested are in a secondary forest state, covering 4% of the biome.

“Estimates from across the Amazon indicate that approximately 30% of areas previously deforested are in a secondary forest state83 (covering 4% of the biome).”

• cites [83] Smith, C. C. et al. Old-growth forest loss and secondary forest recovery across Amazonian countries. Environ. Res. Lett. 16, 085009 (2021). sourceSupported

May combine two claims.

Another study using a climate-vegetation model found that with accumulated deforestation of 30−50%, rainfall in non-deforested areas downwind would decline by 40%, potentially causing more forest loss.

“Another study using a climate-vegetation model found that with accumulated deforestation of 30−50%, rainfall in non-deforested areas downwind would decline67 by 40% (ref. 67), potentially causing more forest loss4,37.”

• 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). sourceSupported
• cites [4] Staal, A. et al. Forest-rainfall cascades buffer against drought across the Amazon. Nat. Clim. Change 8, 539–543 (2018). sourceCould not verify

  The passages available from our copy are bibliographic and repository information, not the study’s findings; none reports the claimed 30–50% deforestation scenario or a 40% rainfall decline in non-deforested areas downwind. Searches for those figures and for downwind rainfall returned no relevant passage. The potential for further forest loss is attached to different citations in the citing sentence. (LLM, conf=0.74)

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

  The Results (LGM and twenty-first century; page unavailable) describe an approximately 40% dry-season rainfall reduction that could lead to self-amplified forest loss. But that scenario is driven by reduced oceanic moisture inflow, not 30–50% accumulated deforestation; the passage does not place the rainfall decline in non-deforested areas downwind. (LLM, conf=0.87)

  Experimental — accuracy not yet measured

May combine two claims.

Today, invasion by alien flammable grasses is a novel stabilizing mechanism, but the long-term persistence of these grasses in the ecosystem is uncertain.

“Today, invasion by alien flammable grasses is a novel stabilizing mechanism96,97, but the long-term persistence of these grasses in the ecosystem is also uncertain.”

• cites [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). sourceNot checked — no full text of the source
• 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). sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Their origin has been attributed to geomorphological dynamics and past Indigenous fires.

“Their origin has been attributed to geomorphological dynamics and past Indigenous fires26,27,94.”

• 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). sourcePartly supported

  The Conclusions and Ways Forward attribute the study area’s savanna and forest distribution to evolving fluvial terraces, topographic gradients, and hydrology, supporting the geomorphological part. Linkage to Past Climate mentions anthropogenic fires only as a suggested amplification of Holocene savanna in the separate Gran Sabana region; it does not attribute the origin of the study area’s vegetation to past Indigenous fires. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites [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). sourceNot checked — no full text of the source
• cites [94] Adeney, J. M., Christensen, N. L., Vicentini, A. & Cohn‐Haft, M. White‐sand ecosystems in Amazonia. Biotropica 48, 7–23 (2016). sourceNot checked — no full text of the source

May combine two claims.

At the landscape scale, secondary forests are more likely to be cleared than mature forests, thus keeping forests persistently young and landscapes fragmented.

“At the landscape scale, secondary forests are more likely to be cleared than mature forests, thus keeping forests persistently young and landscapes fragmented83.”

• cites [83] Smith, C. C. et al. Old-growth forest loss and secondary forest recovery across Amazonian countries. Environ. Res. Lett. 16, 085009 (2021). sourcePartly supported

  Section 2.2 reports that most Amazonian secondary forest was young and that 70% of cleared secondary forest was five years old or less; the Discussion also describes high turnover and short residence times. Our copy does not establish that secondary forests are more likely to be cleared than mature forests, or that their clearance keeps landscapes fragmented. Page numbers were not available in the indexed passages. (LLM, conf=0.85)

  Experimental — accuracy not yet measured

May combine two claims.

Significant effects on simulation results may emerge from increasing plant functional diversity, representation of key physiological trade-offs and other features that determine water stress on plants, and allowing for community adjustment to environmental heterogeneity and global change.

“Significant effects on simulation results may emerge from increasing plant functional diversity, representation of key physiological trade-offs and other features that determine water stress on plants, and also allowing for community adjustment to environmental heterogeneity and global change32,55,62,99.”

• 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). sourcePartly supported

  The Abstract and Implications and conclusions (page unavailable) link variation in hydraulic traits and a proposed growth–mortality trade-off to Amazon forest composition and biomass change. Hydraulic traits distribution also reports variation with rainfall and local water availability. The paper does not show that increasing functional diversity or allowing community adjustment significantly changes simulation results. (LLM, conf=0.82)

  Experimental — accuracy not yet measured
• cites [55] Brienen, R. J. W. et al. Forest carbon sink neutralized by pervasive growth-lifespan trade-offs. Nat. Commun. 11, 4241 (2020). sourcePartly supported

  In “Implications for forest demography and carbon sink” (page not provided), simulations with and without a growth–lifespan trade-off produce substantially different biomass and mortality results. The paper also notes that climate-driven shifts in species distributions may affect biomass. It does not establish simulation effects from increasing plant functional diversity, representing features that determine water stress, or allowing community adjustment to environmental heterogeneity. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• 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). sourcePartly supported

  The Significance section (page unavailable) shows that representing individual plant water stress and canopy dynamics, rather than an aggregated canopy, substantially changes simulated forest responses. It also predicts changes in forest composition following drought. Our copy does not specifically show that increasing plant functional diversity or representing key physiological trade-offs produces significant effects on simulation results. (LLM, conf=0.82)

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

  The available passages contain the title and bibliographic records, but no substantive findings. Searches for simulation effects, physiological trade-offs, water stress, and community adjustment returned no passages addressing the claim, so our copy cannot verify what is attributed to this paper. (LLM, conf=0.72)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

In 2012, Davidson et al. demonstrated how the Amazon basin was experiencing a transition to a 'disturbance-dominated regime' related to climatic and land use changes, even though at the time, annual deforestation rates were declining owing to new forms of governance.

“In 2012, Davidson et al.102 demonstrated how the Amazon basin was experiencing a transition to a ‘disturbance-dominated regime’ related to climatic and land use changes, even though at the time, annual deforestation rates were declining owing to new forms of governance103.”

• cites [102] Davidson, E. A. et al. The Amazon basin in transition. Nature 481, 321–328 (2012). sourceNot checked — no full text of the source
• cites [103] Hecht, S. B. From eco-catastrophe to zero deforestation? Interdisciplinarities, politics, environmentalisms and reduced clearing in Amazonia. Envir. Conserv. 39, 4–19 (2012). sourceSupported

Classified as probably not a substantial claim.

Aggregating the monthly moisture flows from Tuinenburg et al. resulted in mean annual moisture flows between all Amazonian countries during 2008-2017.

“We aggregated these monthly flows, resulting in mean annual moisture flows between all Amazonian countries during 2008–2017.”

• 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). sourceSupported

May combine two claims.

Aircraft measurements of vertical carbon flux between the forest and atmosphere reveal how southeastern forests are already emitting more carbon than they absorb, probably because of deforestation and fire.

“Aircraft measurements of vertical carbon flux between the forest and atmosphere reveal how southeastern forests are already emitting more carbon than they absorb, probably because of deforestation and fire48.”

• cites [48] Gatti, L. V. et al. Amazonia as a carbon source linked to deforestation and climate change. Nature 595, 388–393 (2021). sourceNot checked — no full text of the source

May combine two claims.

47% of the biome has a moderate transition potential (more than 1 disturbance type), including relatively remote parts of the central Amazon where warming trends and repeated extreme drought events overlap.

“Moreover, 47% of the biome has a moderate transition potential (more than 1 disturbance type; Fig. 1f), including relatively remote parts of the central Amazon where warming trends and repeated extreme drought events overlap (Fig. 1a,c).”

• AssumptionRests on an assumption: The additive sum of warming/drying slopes, ecosystem stability classes, drought impacts, road proximity, and governance can serve as a proxy for ecosystem transition potential.

May combine two claims.

10% of the Amazon forest biome has a relatively high transition potential (more than 2 disturbance types), including bistable forests that could transition into a low tree cover state near savannas of Guyana, Venezuela, Colombia and Peru, as well as stable forests that could transition into alternative compositional states within the central Amazon, such as along the BR319 and Trans-Amazonian High

“We found that 10% of the Amazon forest biome has a relatively high transition potential (more than 2 disturbance types; Fig. 1f), including bistable forests that could transition into a low tree cover state near savannas of Guyana, Venezuela, Colombia and Peru, as well as stable forests that could transition into alternative compositional states within the central Amazon, such as along the BR319”

• AssumptionRests on an assumption: The additive sum of warming/drying slopes, ecosystem stability classes, drought impacts, road proximity, and governance can serve as a proxy for ecosystem transition potential.

May combine two claims.

Large remote areas covering 53% of the biome have low transition potential, mostly reflecting the distribution of protected areas and Indigenous territories.

“By contrast, large remote areas covering 53% of the biome have low transition potential, mostly reflecting the distribution of protected areas and Indigenous territories (Fig. 1e).”

• AssumptionRests on an assumption: The additive sum of warming/drying slopes, ecosystem stability classes, drought impacts, road proximity, and governance can serve as a proxy for ecosystem transition potential.

May combine two claims.

Our reanalysis suggests a critical threshold at eight months of DSL, with a bistability range between approximately five and eight months, in which forests are more likely to collapse when severely disturbed than forests in areas with DSL below five months.

“Our reanalysis of the Amazon basin (Extended Data Fig. 1d) suggests a critical threshold at eight months of DSL (Fig. 3a), with a bistability range between approximately five and eight months (see Extended Data Table 2 for uncertainty ranges), in which forests are more likely to collapse when severely disturbed than forests in areas with DSL below five months.”

May combine two claims.

Our reanalysis confirms a critical threshold at approximately −450 mm in MCWD, and suggests a bistability range between approximately −350 and −450 mm, in which forests are more likely to collapse when severely disturbed than forests in areas with MCWD below −350 mm.

“Our reanalysis of the Amazon basin (Extended Data Fig. 1c) confirms the critical threshold at approximately −450 mm in the MCWD (Fig. 3a), and suggests a bistability range between approximately −350 and −450 mm (see Extended Data Table 2 for uncertainty ranges), in which forests are more likely to collapse when severely disturbed than forests in areas with MCWD below −350 mm.”

May combine two claims.

Long existing feedbacks between the forest and environmental conditions are being replaced by novel feedbacks that modify ecosystem resilience, increasing the risk of critical transition.

“Long existing feedbacks between the forest and environmental conditions are being replaced by novel feedbacks that modify ecosystem resilience, increasing the risk of critical transition.”

May combine two claims.

Both model ensembles agree that bistable regions will expand deeper into the Amazon, increasing the risk of critical transitions due to disturbances.

“Nonetheless, both model ensembles agree that bistable regions will expand deeper into the Amazon, increasing the risk of critical transitions due to disturbances (as implied by the existence of alternative stable states; Extended Data Fig. 1).”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The Amazon is home to more than 40 million people, including 2.2 million Indigenous peoples of more than 300 ethnicities, as well as afrodescendent and local traditional communities.

“The Amazon is home to more than 40 million people, including 2.2 million Indigenous peoples of more than 300 ethnicities, as well as afrodescendent and local traditional communities1.”

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

  Not checked in the free run.

May combine two claims.

The Amazon forest stores 150-200 Pg C, equivalent to 15-20 years of global CO2 emissions.

“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.”

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

  Not checked in the free run.

• cites [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 yet

  Not checked in the free run.

• cites [3] Armstrong McKay, D. et al. Exceeding 1.5 °C global warming could trigger multiple climate tipping points. Science 377, abn7950 (2022). sourceNot checked — no full text of the source

May combine two claims.

Recent CMIP6 models agree that in the coming decades, rainfall conditions will become more seasonal in the eastern and southern Amazonian regions, and temperatures will become higher across the entire Amazon.

“Recent climate models of the 6th phase of the Coupled Model Intercomparison Project (CMIP6) agree that in the coming decades, rainfall conditions will become more seasonal in the eastern and southern Amazonian regions, and temperatures will become higher across the entire Amazon1,2.”

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

  Not checked in the free run.

• cites [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 yet

  Not checked in the free run.

May combine two claims.

When stressing conditions intensify, some ecosystems may change their equilibrium state gradually, whereas others may shift abruptly between alternative stable states.

“When stressing conditions intensify, some ecosystems may change their equilibrium state gradually, whereas others may shift abruptly between alternative stable states10.”

• cites [10] Scheffer, M., Carpenter, S., Foley, J. A., Folke, C. & Walker, B. Catastrophic shifts in ecosystems. Nature 413, 591–596 (2001). sourceNot checked — no full text of the source

May combine two claims.

If these trends continue, ecosystem stability will probably change in parts of the Amazon by 2050, reshaping forest resilience to disturbances.

“If these trends continue, ecosystem stability (as in Extended Data Fig. 1) will probably change in parts of the Amazon by 2050, reshaping forest resilience to disturbances (Fig. 1b and Extended Data Fig. 3b).”

May combine two claims.

By 2050, models project a significant increase in the number of consecutive dry days by 10−30 days and in annual maximum temperatures by 2-4 °C, depending on the greenhouse gas emission scenario.

“By 2050, models project that a significant increase in the number of consecutive dry days by 10−30 days and in annual maximum temperatures by 2–4 °C, depending on the greenhouse gas emission scenario2.”

• cites [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 yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

The Amazon forest holds more than 10% of Earth's terrestrial biodiversity.

“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.”

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

  Not checked in the free run.

• cites [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 yet

  Not checked in the free run.

• cites [3] Armstrong McKay, D. et al. Exceeding 1.5 °C global warming could trigger multiple climate tipping points. Science 377, abn7950 (2022). sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S4 (based).

Tropical terrestrial ecosystems are a well-known case in which critical transitions between alternative stable states may occur.

“Tropical terrestrial ecosystems are a well-known case in which critical transitions between alternative stable states may occur (Extended Data Fig. 1).”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Human greenhouse gas emissions continue to intensify global warming, but the warming rate also depends on feedbacks in the climate system that remain uncertain.

“Human greenhouse gas emissions continue to intensify global warming, but the warming rate also depends on feedbacks in the climate system that remain uncertain2,3.”

• cites [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 yet

  Not checked in the free run.

• cites [3] Armstrong McKay, D. et al. Exceeding 1.5 °C global warming could trigger multiple climate tipping points. Science 377, abn7950 (2022). sourceNot checked — no full text of the source

May combine two claims.

Protected areas and Indigenous territories are areas with high forest governance, where deforestation and fire regimes are among the lowest within the Amazon.

“We also included protected areas and Indigenous territories as areas with high forest governance, where deforestation and fire regimes are among the lowest within the Amazon49 (Fig. 1e).”

• cites [49] Nepstad, D. et al. Inhibition of Amazon deforestation and fire by parks and Indigenous lands: inhibition of Amazon deforestation and fire. Conserv. Biol. 20, 65–73 (2006). sourceNot checked — no full text of the source

May combine two claims.

Future changes in rainfall regimes will probably affect hydrological regimes, exposing plateau (hilltop) forests to unprecedented water stress, and floodplain forests to extended floods, droughts and wildfires.

“Future changes in rainfall regimes will probably affect hydrological regimes66, exposing plateau (hilltop) forests to unprecedented water stress, and floodplain forests to extended floods, droughts and wildfires.”

• cites [66] Marengo, J. A. & Espinoza, J. C. Extreme seasonal droughts and floods in Amazonia: causes, trends and impacts. Int. J. Climatol. 36, 1033–1050 (2016). sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Rising atmospheric CO2 concentrations are expected to increase the photosynthetic rates of trees, accelerating forest growth and biomass accumulation on a global scale.

“Rising atmospheric CO2 concentrations are expected to increase the photosynthetic rates of trees, accelerating forest growth and biomass accumulation on a global scale52.”

• cites [52] Ainsworth, E. A. & Long, S. P. What have we learned from 15 years of free‐air CO2 enrichment (FACE)? A meta‐analytic review of the responses of photosynthesis, canopy properties and plant production to rising CO2. New Phytol. 165, 351–372 (2005). sourceNot checked — no full text of the source

May combine two claims.

The impacts of pervasive disturbances on biodiversity and on IPLCs will probably affect ecosystem adaptability, and consequently forest resilience to global changes.

“The impacts of these pervasive disturbances on biodiversity and on IPLCs will probably affect ecosystem adaptability (Box 1), and consequently forest resilience to global changes.”

Probably not a substantial claim: may not pass S3 (load-bearing).

The simple additive approach does not consider synergies between compounding disturbances that could trigger unexpected ecosystem transitions.

“This simple additive approach does not consider synergies between compounding disturbances that could trigger unexpected ecosystem transitions.”

May combine two claims.

Northwestern forests are relatively more resilient than southeastern forests and are less likely to shift into a low tree cover state.

“Northwestern forests rarely experience water stress, which makes them relatively more resilient than southeastern forests that may experience water stress in the dry season, and therefore are more likely to shift into a low tree cover state.”

• AssumptionRests on an assumption: Northwestern Amazon forests rarely experience water stress.

May combine two claims.

Forest responses to CO2 fertilization depend on scale, with resilience possibly increasing at the local scale on relatively more fertile soils, but decreasing at the regional scale due to reduced atmospheric moisture flow.

“Forest responses depend on scale, with resilience possibly increasing at the local scale on relatively more fertile soils, but decreasing at the regional scale due to reduced atmospheric moisture flow.”

May combine two claims.

Considering that half of Amazonian tree species are estimated to become threatened by 2050 owing to climate change, deforestation and degradation, biodiversity losses could contribute to further reducing forest resilience.

“Considering that half of Amazonian tree species are estimated to become threatened (IUCN Red list) by 2050 owing to climate change, deforestation and degradation8, biodiversity losses could contribute to further reducing forest resilience.”

• cites [8] Gomes, V. H. F., Vieira, I. C. G., Salomão, R. P. & ter Steege, H. Amazonian tree species threatened by deforestation and climate change. Nat. Clim. Change 9, 547–553 (2019). sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

In the past, many internal mechanisms have probably contributed to ecosystem adaptability, allowing Amazonian forests to persist during times of climate change.

“In the past, many internal mechanisms have probably contributed to ecosystem adaptability, allowing Amazonian forests to persist during times of climate change.”

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

Owing to multiple interacting factors, potential responses of Amazonian forests to CO2 fertilization are still poorly understood.

“In sum, owing to multiple interacting factors, potential responses of Amazonian forests to CO2 fertilization are still poorly understood.”

Probably not a substantial claim: may not pass S4 (based).

Two internal mechanisms of ecosystem adaptability are now being undermined by global change.

“In this section we synthesize two of these internal mechanisms, which are now being undermined by global change.”

May combine two claims.

Environmental heterogeneity can reduce the risk of systemic transition because when stressing conditions intensify, heterogeneous forests may transition gradually compared to homogeneous forests that may transition more abruptly.

“Environmental heterogeneity can reduce the risk of systemic transition (large-scale forest collapse) because when stressing conditions intensify (for example, rainfall declines), heterogeneous forests may transition gradually (first the less resilient forest patches, followed by the more resilient ones), compared to homogeneous forests that may transition more abruptly17 (all forests transition in”

• cites [17] Scheffer, M. et al. Anticipating critical transitions. Science 338, 344–348 (2012). sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

At global scales, driver 1 (global warming) intensifies with greenhouse gas emissions, including emissions from deforestation.

“At global scales, driver 1 (global warming) intensifies with greenhouse gas emissions, including emissions from deforestation.”

May combine two claims.

White-sand savannas are ancient ecosystems that occur in patches within the Amazon forest biome, particularly in seasonally waterlogged or flooded areas.

“White-sand savannas are ancient ecosystems that occur in patches within the Amazon forest biome, particularly in seasonally waterlogged or flooded areas94.”

• cites [94] Adeney, J. M., Christensen, N. L., Vicentini, A. & Cohn‐Haft, M. White‐sand ecosystems in Amazonia. Biotropica 48, 7–23 (2016). sourceNot checked — no full text of the source

May combine two claims.

Degraded forests are usually dominated by native opportunistic species, and their increasing expansion over disturbed forests could affect Amazonian functioning and resilience in the future.

“Degraded forests are usually dominated by native opportunistic species, and their increasing expansion over disturbed forests could affect Amazonian functioning and resilience in the future.”

May combine two claims.

In reality, tree community adaptation to a heterogenous and dynamic environment feeds into whole-system dynamics, and not covering such aspects makes a true Amazon tipping assessment more challenging.

“In reality, tree community adaptation to a heterogenous and dynamic environment feeds into the whole-system dynamics, and not covering such aspects makes a true Amazon tipping assessment more challenging.”

May combine two claims.

Most ESMs do not simulate a dynamic vegetation cover and biomes are represented based on few plant functional types, basically simulating monocultures on the biome level.

“For now, most ESMs do not simulate a dynamic vegetation cover (Supplementary Table 1) and biomes are represented based on few plant functional types, basically simulating monocultures on the biome level.”

• cites Supplementary Table 1Not matched

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

May combine two claims.

Bamboos self-perpetuate by causing physical damage to trees and have been expanding over burnt forests in the region.

“Similar to lianas, bamboos self-perpetuate by causing physical damage to trees and have been expanding over burnt forests in the region92.”

• cites [92] da Silva, S. S. et al. Increasing bamboo dominance in southwestern Amazon forests following intensification of drought-mediated fires. For. Ecol. Manag. 490, 119139 (2021). sourceNot checked — no full text of the source

May combine two claims.

Most updated CMIP6 models agree that droughts in the Amazon region will increase in length and intensity, and that exceptionally hot droughts will become more common.

“However, most updated CMIP6 models agree that droughts in the Amazon region will increase in length and intensity, and that exceptionally hot droughts will become more common2, creating conditions that will probably boost other types of disturbances, such as large and destructive forest fires76,77.”

• cites [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 yet

  Not checked in the free run.

Probably not a substantial claim: may not pass S3 (load-bearing).

The authors followed the precautionary principle and considered the most conservative thresholds within the ranges when confidence was low.

“We followed the precautionary principle and considered the most conservative thresholds within the ranges, when confidence was low.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Based on sensitivity tests, the authors chose intermediate values of the sensitivity parameter for each analysis, which resulted in critical thresholds most similar to previously published literature.

“Based on sensitivity tests (see below), we chose the intermediate values of the sensitivity parameter for each analysis, which resulted in the critical thresholds most similar to the ones previously published in the literature.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The UTrack model tracks the atmospheric trajectories of parcels of moisture, updates their coordinates at each time step of 0.1 h and allocates moisture to a target location in case of precipitation.

“The model tracks the atmospheric trajectories of parcels of moisture, updates their coordinates at each time step of 0.1 h and allocates moisture to a target location in case of precipitation.”

• cites UTrack132Not matched

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