Critical transitions in the Amazon forest system

Nature, Journal Year: 2024, Volume and Issue: 626(7999), P. 555 - 564

Published: Feb. 14, 2024

Abstract The possibility that the Amazon forest system could soon reach a tipping point, inducing large-scale collapse, has raised global concern 1–3 . For 65 million years, Amazonian forests remained relatively resilient to climatic variability. Now, region is increasingly exposed unprecedented stress from warming temperatures, extreme droughts, deforestation and fires, even in central remote parts of 1 Long existing feedbacks between environmental conditions are being replaced by novel modify ecosystem resilience, increasing risk critical transition. Here we analyse evidence for five major drivers water on forests, as well potential thresholds those that, if crossed, trigger local, regional or biome-wide collapse. By combining spatial information various disturbances, estimate 2050, 10% 47% will be compounding disturbances may unexpected transitions potentially exacerbate climate change. Using examples disturbed across Amazon, identify three most plausible trajectories, involving different conditions. We discuss how inherent complexity adds uncertainty about future dynamics, but also reveals opportunities action. Keeping Anthropocene depend combination local efforts end degradation expand restoration, with stop greenhouse gas emissions.

Language: Английский

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Cerrado deforestation threatens regional climate and water availability for agriculture and ecosystems

Global Change Biology, Journal Year: 2022, Volume and Issue: 28(22), P. 6807 - 6822

Published: Sept. 8, 2022

The Brazilian Cerrado is one of the most biodiverse savannas in world, yet 46% its original cover has been cleared to make way for crops and pastures. These extensive land-use transitions (LUTs) are expected influence regional climate by reducing evapotranspiration (ET), increasing land surface temperature (LST), ultimately precipitation. Here, we quantify impacts LUTs on ET LST combining MODIS satellite data with annual use maps from 2006 2019. We performed regression analyses effects six common across entire gradient landscapes. Results indicate that clearing forests cropland or pasture increased average ~3.5°C reduced mean 44% 39%, respectively. Transitions woody 1.9°C 27% 21%, Converting native grasslands 0.9 0.6°C, Conversely, grassland-to-pasture 15%. To date, changes have caused a 10% reduction water recycled atmosphere annually 0.9°C increase biome, compared historic baseline under vegetation. Global atmospheric greenhouse gas concentrations will only exacerbate these effects. Considering potential future scenarios, found abandoning deforestation control policies allowing legal continue (at least 28.4 Mha) would further reduce yearly (by -9% -3%, respectively) +0.7 +0.3°C, 2050. In contrast, encouraging zero restoration 5.2 Mha illegally deforested areas partially offset warming drying change.O brasileiro é uma das savanas mais biodiversas do mundo. Apesar disso, da sua cobertura foi desmatada para dar lugar cultivos agrícolas e pastos. Estas extensas transições de uso solo (LUT) têm o potencial influenciar clima regional, reduzindo evapotranspiração aumentando temperatura superfície terrestre (LST) por fim precipitação. O objetivo deste estudo quantificar os impactos sobre no Cerrado, combinando dados satélite com mapas anuais 2006-2019. Foram realizadas análises regressão efeitos seis usuais LST, ao longo todo gradiente paisagens Cerrado. Os resultados indicaram que retirada florestas à agricultura ou pastagem aumentou média em reduziu anual respectivamente. Transições formações savânicas aumentaram reduziram A conversão campos nativos Em contrapartida, campestres nativas pastagens Até momento, as mudanças causaram redução água reciclada atmosfera anualmente aumento bioma, comparação linha base histórica sob vegetação nativa. As climáticas globais decorrentes concentrações atmosféricas gases efeito estufa irão exacerbar esses efeitos. Considerando potenciais cenários futuros, observou-se abandono políticas controle desmatamento avanço (ao menos reduziriam (em −9% −3%, respectivamente) aumentariam +0.3ºC, até Por outro lado, promovam restauração dos áreas ilegalmente desmatadas compensariam parte aquecimento seca causados alterações solo.

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The new record of drought and warmth in the Amazon in 2023 related to regional and global climatic features

Scientific Reports, Journal Year: 2024, Volume and Issue: 14(1)

Published: April 6, 2024

In 2023 Amazonia experienced both historical drought and warm conditions. On October 26th the water levels at port of Manaus reached its lowest record since 1902 (12.70 m). this region, monthly maximum minimum temperature anomalies also surpassed previous values registered in 2015 (+ 3 °C above normal considering 1981-2020 average). Here we show that dry situation is associated with two main atmospheric mechanisms: (i) November 2022-February southern anomaly vertical integrated moisture flux (VIMF), related to VIMF divergence extreme rainfall deficit over southwestern Amazonia, (ii) June-August downward motion northern conditions region. Anomalies mechanisms during event. The first mechanism significantly correlated negative sea surface (SST) equatorial Pacific (November-February La Niña events). second positive SST Pacific, impacts June-September El Niño on Walker Circulation. While droughts were linked (warmer North Tropical Atlantic SST) austral summer (winter spring), transition from 2022-23 appears be a key climatic driver record-breaking situation, combined widespread anomalous warming worldwide ocean.

Language: Английский

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Amazon savannization and climate change are projected to increase dry season length and temperature extremes over Brazil

Scientific Reports, Journal Year: 2024, Volume and Issue: 14(1)

Published: March 1, 2024

Land use change and atmospheric composition, two drivers of climate change, can interact to affect both local remote regimes. Previous works have considered the effects greenhouse gas buildup in atmosphere Amazon deforestation general circulation models. In this study, we investigate impacts Brazilian savannization global warming a fully coupled ocean-land-sea ice-atmosphere model simulation. We find that individually lengthen dry season reduce annual rainfall over large tracts South America. The combined land resulted mean reduction 44% length increase 69%, when averaged basin, relative control run. Modulation inland moisture transport due shows largest signal explain Central-West. maximum daily temperature anomalies, reaching values up 14 °C above current climatic conditions Amazon. Also, as consequence drivers, soil surface runoff decrease most country, suggesting cascading negative future on agriculture production hydroelectricity generation.

Language: Английский

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The South American monsoon approaches a critical transition in response to deforestation

Science Advances, Journal Year: 2023, Volume and Issue: 9(40)

Published: Oct. 4, 2023

The Amazon rainforest is threatened by land-use change and increasing drought fire frequency. Studies suggest an abrupt dieback of large parts the after partial forest loss, but critical threshold, underlying mechanisms, possible impacts degradation on monsoon circulation remain uncertain. Here, we use a nonlinear dynamical model moisture transport recycling across to identify several precursor signals for transition in coupled atmosphere-vegetation dynamics. Guided our simulations, reveal both statistical physical approaching reanalysis observational data. In accordance with results, attribute these characteristic nearing system induced loss due deforestation, droughts, fires. would lead substantially drier conditions, under which could likely not be maintained.

Language: Английский

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A Worrying Future for River Flows in the Brazilian Cerrado Provoked by Land Use and Climate Changes

Sustainability, Journal Year: 2023, Volume and Issue: 15(5), P. 4251 - 4251

Published: Feb. 27, 2023

In this study, we assessed the impacts of land use and climate changes on river flows 81 watersheds within Cerrado biome, Brazil, based a comprehensive analysis field secondary data acquired between 1985 2018. Complementarily, projected future deforestation scenario up to 2050 predicted their surface water in study area. We observed that direct by large-scale oriented production irrigated agricultural commodities have more significantly impacted than changes. estimated an average decrease 8.7% 6.7% streamflow due changes, respectively. Most (56.7%) were cover occurred recent decades. Climate combined responsible for total reduction −19,718 m³/s watersheds. By assuming current rates, 23,653 2050, equivalent 33.9% region. It will cause severe discontinuity many rivers strongly affect agricultural, electric power production, biodiversity, supply, especially during dry seasons

Language: Английский

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Global carbon balance of the forest: satellite-based L-VOD results over the last decade

Frontiers in Remote Sensing, Journal Year: 2024, Volume and Issue: 5

Published: May 10, 2024

Monitoring forest carbon (C) stocks is essential to better assess their role in the global balance, and model predict long-term trends inter-annual variability atmospheric CO2 concentrations. On a national scale, inventories (NFIs) can provide estimates of stocks, but these are only available certain countries, limited by time lags due periodic revisits, cannot spatially continuous mapping forests. In this context, remote sensing offers many advantages for monitoring above-ground biomass (AGB) on scale with good spatial (50–100 m) temporal (annual) resolutions. Remote has been used several decades monitor vegetation. However, traditional methods AGB using optical or microwave sensors affected saturation effects moderately densely vegetated canopies, limiting performance. Low-frequency passive less effects: occurs at levels around 400 t/ha L-band (frequency 1.4 GHz). Despite its coarse resolution order 25 km × km, method based L-VOD (vegetation depth L-band) index recently established itself as an approach annual variations continental scale. Thus, applied continents biomes: tropics (especially Amazon Congo basins), boreal regions (Siberia, Canada), Europe, China, Australia, etc. no reference study yet published analyze detail terms capabilities, validation results. This paper fills gap presenting physical principles calculation, analyzing performance reviewing main applications tracking balance vegetation over last decade (2010–2019).

Language: Английский

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The time since land-use transition drives changes in fire activity in the Amazon-Cerrado region

Communications Earth & Environment, Journal Year: 2024, Volume and Issue: 5(1)

Published: Feb. 21, 2024

Abstract Deforestation and climate change are expected to alter fire regimes along the Cerrado-Amazon transition, one of world’s most active agricultural frontiers. Here we tested hypothesis that time since land-use transition (age frontier) intensification also drive changes in region’s by reducing probability both drought non-drought years. We modeled as a function transitions based on MapBiomas Project datasets from 1986 2020. find that, while burned area declined pasturelands aged croplands advanced, deforestation abruptly increased activity before (Amazon: 4 years; Cerrado: 3 years) after 8 7 land clearing for pasture, especially Amazon. Additionally, combination ignition risk, drought, air-dryness likelihood large extents areas associated with deforestation. Incorporating frontier age proxy governance modeling is crucial, given ecological implications changing despite declining rates probability. Most importantly, protecting against preserving native vegetation vital.

Language: Английский

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Impacts of fire on canopy structure and its resilience depend on successional stage in Amazonian secondary forests

Remote Sensing in Ecology and Conservation, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 15, 2025

Abstract Secondary forests in the Amazon are important carbon sinks, biodiversity reservoirs, and connections between forest fragments. However, their regrowth is highly threatened by fire. Using airborne laser scanning (ALS), surveyed 2016 2018, we analyzed canopy metrics burned (fires occurred 2001 2018) unburned secondary across different successional stages ability to recover after We assessed maximum mean height, openness at 5 10 m, roughness, leaf area index (LAI) height volume (LAHV) for 20 sites South‐East Amazonia (ranging from 375 1200 ha). Compared forests, had reductions LAI, LAHV, increases roughness. These effects were more pronounced early (ES) than later (LS) stages, example, decreased 33% ES 14% LS LAI 36% 18% LS. Forests less resistant fire, but resilient (capable of recovering a disturbance) post‐fire stage forests. Data extrapolation our models suggests that structure partially recovers with time since fire six out seven metrics; however, LAHV may never fully recover. Our results indicate stage‐specific management policies mitigate against should be implemented increase success regeneration. Mitigation fires critical if continue provide wide array ecological services.

Language: Английский

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Choosing fit-for-purpose biodiversity impact indicators for agriculture in the Brazilian Cerrado ecoregion

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: Feb. 20, 2025

Understanding and acting on biodiversity loss requires robust tools linking impacts to land use change, the biggest threat terrestrial biodiversity. Here we estimate agriculture's impact Brazilian Cerrado's using three approaches-countryside Species-Area Relationship, Species Threat Abatement Restoration Habitat Index. By same input data, show how indicator scope design affects assessments resulting decision-support. All indicators agriculture expansion's increasing pressure Results suggest that metrics are complementary, providing distinctly different insight into change drivers impacts. Meaningful applications of therefore require compatibility between focal questions choice regarding temporal, spatial, ecological perspectives drivers. Backward-looking analyses focused historical accountability best served by countryside-Species Area Relationship Forward-looking risk hotspots global extinctions mitigation Restoration.

Language: Английский

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