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

Bochow, Nils; Boers, Niklas

doi:10.1126/sciadv.add9973

Cited by 15 publications

(11 citation statements)

References 97 publications

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“…Hence, the equilibrium assumption of CSD, whereby a slow change in the external forcing only changes the equilibrium state, but does not keep the system in disequilibrium for long, may be violated. Nevertheless, studies have found that the Amazon rainforest may approach a tipping point due to deforestation [76,77].…”

Section: Discussionmentioning

confidence: 99%

Measuring tropical rainforest resilience under non-Gaussian disturbances

Benson,

Donges,

Boers

et al. 2024

Environ. Res. Lett.

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The Amazon rainforest is considered one of the Earth's tipping elements and may lose stability under ongoing climate change. Recently a decrease in tropical rainforest resilience has been identified globally from remotely sensed vegetation data. However, the underlying theory assumes a Gaussian distribution of forest disturbances, which is different from most observed forest stressors such as fires, deforestation, or windthrow. Those stressors often occur in power-law-like distributions and can be approximated by α-stable Lévy noise. Here, we show that classical critical slowing down indicators to measure changes in forest resilience are robust under such power-law disturbances. To assess the robustness of critical slowing down indicators, we simulate pulse-like perturbations in an adapted and conceptual model of a tropical rainforest. We find few missed early warnings and few false alarms are achievable simultaneously if the following steps are carried out carefully: First, the model must be known to resolve the timescales of the perturbation. Second, perturbations need to be filtered according to their absolute temporal autocorrelation. Third, critical slowing down has to be assessed using the non-parametric Kendall-τ slope. These prerequisites allow for an increase in the sensitivity of early warning signals. Hence, our findings imply improved reliability of the interpretation of empirically estimated rainforest resilience through critical slowing down indicators.

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Section: Discussionmentioning

confidence: 99%

Measuring tropical rainforest resilience under non-Gaussian disturbances

Benson,

Donges,

Boers

et al. 2024

Environ. Res. Lett.

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“…These events are taking place at a time when the Amazon rainforest is moving towards a "tipping point", especially those regions undergoing intense forest degradation and deforestation, characterized by a warming trend 3,4 , a lengthening of the dry season 5,7 and a decline of the Amazon carbon sink 1,8 . Both, climate change and Amazon deforestation, are considered as main drivers of this biophysical transition in Amazonia [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] .…”

Section: Conclusion and Final Commentsmentioning

confidence: 99%

“…High deforestation rates regionally affect the hydrological cycle in the Amazon basin [41][42][43] . Deforestation reduces the latent heat (evapotranspiration) and increases the sensible heat, contributing to the heating of the lower atmosphere and reducing the amount of water vapor in the atmosphere [33][34][35][36] . In addition, the hot and www.nature.com/scientificreports/ dry conditions favor the occurrence of anthropogenic large-scale fires 7,44 .…”

Section: Conclusion and Final Commentsmentioning

confidence: 99%

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

Espinoza,

Jimenez,

Marengo

et al. 2024

Sci Rep

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

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“…Evidence is all around us that we are nearing or have already crossed CTPs associated with critical parts of the Earth system-we see catastrophic fires in rainforests, spreading deserts, degrading ecosystems, and shrinking sea ice (e.g., Walsh, 2016;Bochow and Boers, 2023;Kim et al, 2023).…”

Section: Introductionmentioning

confidence: 99%

Bad science and good intentions prevent effective climate action

Taylor,

Wadhams,

Visioni

et al. 2024

Preprint

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Although the 2015 Paris Agreement climate targets seem certain to be missed, only a few experts are questioning the adequacy of the current approach to limiting climate change and suggesting that additional approaches are needed to avoid unacceptable catastrophes. This article posits that selective science communication and unrealistically optimistic assumptions are obscuring the reality that greenhouse gas emissions reduction and carbon dioxide removal will not prevent climate change in the 21st Century. It also explains how overly pessimistic and speculative criticisms are behind opposition to considering potential climate cooling interventions as a complementary approach for mitigating dangerous warming. There is little evidence supporting assertions that: current greenhouse gas emissions reduction and removal methods can and will be ramped up in time to prevent dangerous climate change; overshoot of Paris Agreement targets will be temporary; net zero emissions will produce a safe, stable climate; the impacts of overshoot can be managed and reversed; Intergovernmental Panel on Climate Change models and assessments capture the full scope of prospective disastrous impacts; and the risks of climate interventions are greater than the risks of inaction. These largely unsupported assumptions distort risk assessments and discount the urgent need to develop a viable mitigation strategy. Owing to political pressures, many critical scientific concerns are ignored or preemptively dismissed in international negotiations. As a result, the present and growing crisis and the level of effort and time that will be required to control and rebalance the climate are severely underestimated. The paper concludes by outlining the key elements of a realistic policy approach that would augment current efforts to constrain dangerous warming by supplementing current mitigation approaches with climate cooling interventions.

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

Cited by 15 publications

References 97 publications

Measuring tropical rainforest resilience under non-Gaussian disturbances

Measuring tropical rainforest resilience under non-Gaussian disturbances

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

Bad science and good intentions prevent effective climate action

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