Recent drying over the Amazon could be the “first warning signal” that the rainforest is approaching a tipping point, new research says.
The Amazon is the largest rainforest in the world and receives 2-3 metres of rain every year. However, intensifying droughts and human-driven deforestation mean parts of the forest are beginning to dry out.
The study, published in Science Advances, finds that deforestation is delaying the start of the South American monsoon, leading to reduced rainfall over the Amazon.
The authors warn that continued deforestation could push the region past a tipping point in which a further, rapid reduction in rainfall would kill vast swathes of trees.
Over the past 40 years, the Amazon’s dry season has already become longer, the paper finds. This might be the early warning signal that the combined rainforest and South American monsoon systems are approaching a critical threshold, the authors say.
The authors also stress the importance of ongoing experimental work to quantify the impacts of increasing temperature and CO2 on the Amazon rainforest, so that scientists can produce more accurate models of the links between deforestation and rainfall.
Amazon water cycle
The Amazon is the largest rainforest in the world.
The region contains around 400bn trees and is home to at least 10% of the world’s known species. It is also a key carbon store, holding more than 120bn tonnes of carbon in its vegetation and soil.
Tropical rainforests are warm and humid all year round. The Amazon basin receives around 2-3 metres of rainfall every year on average. It “recycles” much of this rainfall back into the atmosphere through evapotranspiration – the movement of water from the land to the atmosphere through a combination of evaporation and transpiration.
Much of this rainfall comes from the South American monsoon, which is driven in part by the temperature difference between the warm Amazon rainforest and cooler Atlantic ocean.
However, as droughts become more intense and frequent, the humid Amazon climate is beginning to dry, killing trees or making them less resilient to future changes. The ongoing drying trend is exacerbated by deforestation and wildfires.
Around 20% of the Amazon has already been deforested and a further 6% is “highly degraded”.
Dr David Lapola is a research scientist at the State University of Campinas in Brazil and a Carbon Brief contributing editor. Lapola, who was not involved in the study, tells Carbon Brief that the Southern and south-eastern Amazon are “currently experiencing a crisis in terms of changing climate and land use”.
Scientists have warned for decades that human-caused climate change could push key components of the Earth system – such as ice sheets, rainforests and monsoons – past critical thresholds and into new states.
Identifying these “tipping points” is an active area of research.
Previous studies suggest that the Amazon could be pushed beyond its tipping point if forest loss exceeds 40%. At this level of deforestation, evapotranspiration in the Amazon would reduce significantly, leading more trees to die from lack of water.
This self-perpetuating cycle could see large areas of tropical forest turn into dry grasslands in just decades, in a process called “dieback”.
Deforestation
To investigate the link between Amazon deforestation and rainfall, the study authors produce a model of moisture transport across South America that simulates how air moves through the Amazon. The model includes key feedbacks between vegetation, soil moisture and the atmosphere.
The authors find that deforestation reduces the amount of water released into the atmosphere through evapotranspiration. The drop in atmospheric moisture drives a reduction in rainfall.
To form raindrops, water vapour in the atmosphere condenses into liquid water, releasing energy in the form of heat. The reduction in rainfall means that less energy is released in this way, limiting warming in the atmosphere above the region.
As a result, the temperature difference between the warm Amazon rainforest and cooler Atlantic ocean becomes less pronounced. This can cause delays in the onset of the Amazon’s wet season and a lengthening of the dry season, resulting in drier soils and higher tree mortality.
Overall, this feedback means that deforestation in the Amazon weakens the South American monsoon, further reducing rainfall over the Amazon.
Prof Dominick Spracklen is a professor of biosphere-atmosphere interactions at the University of Leeds and co-wrote a “focus” article on the new study.
He tells Carbon Brief that including this complex feedback between the forest and atmosphere makes the rainforest-monsoon system “more sensitive to deforestation, compared to many previous studies that did not include this feedback”.
The graphic below shows the relationship between deforestation and rainfall. The dashed line shows the model used in the study with all feedbacks included, while the solid line shows a model which does not include the atmosphere-vegetation feedbacks.
The study authors find that if deforestation crosses a “critical threshold”, rainfall could drop by 30-50% over just a few years, pushing the system past a tipping point and damaging or killing large areas of the forest.
The model shows that Amazon rainfall is more sensitive to deforestation when key feedbacks between the atmosphere and vegetation are taken into account. This indicates that the tipping point could be crossed sooner than previously thought, the authors warn.
Dr Nils Bochow – a researcher at the Arctic University of Norway and co-author of the study – tells Carbon Brief that “changes in the South American monsoon have a strong influence on the rainforest and vice-versa”. He adds:
“If we do not include these interactions and feedbacks, then we might strongly underestimate the response of the rainforest. This might give a false sense of security or undermine the urgency to act.”
Early warning signs
If an Amazon tipping point is crossed, large sections of lush rainforest could transform into a dry savannah. This process of “savanisation” would take decades to take full effect, but once underway the process is difficult to reverse. The knock-on impacts for the rest of the planet could be profound.
“Tipping points are notoriously hard to understand or predict,” Spracklen tells Carbon Brief.
However, he says there are often early warning signs when a tipping point is approaching. He likens these to the wobble of a spinning top before it falls over.
After using the models to determine what this “wobble” would look like in the Amazon, the authors analyse decades of ERA5 reanalysis data to search for it.
The map below shows the change in soil moisture between 1979 and 2019. Red indicates a drying trend over the four-decade period, while blue indicates wetting.
The authors find that over 1979-2019, soil in the Amazon has become drier. They also find that the dry season now lasts between five and 15 days longer than it used to – meaning that the region is receiving less rainfall, on average, than it was four decades ago.
This indicates that the monsoon-rainforest system has been losing stability in the last decades, the authors say. This might be the first warning signal that a tipping point is approaching, they add.
“The results of this study underline the need to double down on efforts to stop deforestation and help the Amazon region develop in a way that does not lead to additional deforestation,” Spracklen tells Carbon Brief.
Forest loss in the Amazon is beginning to slow. Deforestation in the Brazilian Amazon fell by at least 60% in July 2023 compared to the same month last year, after a new administration led by Luiz Inácio Lula da Silva took power in Brazil.
Leaders of the eight Amazon basin countries met in August 2023 to agree on the need to sustainably develop while preventing further deforestation in the region, and formally recognised that the Amazon is approaching a tipping point.
Model uncertainty
This study is “one of the first” to simulate the feedbacks between the monsoon and Amazon, according to the study authors.
Bochow tells Carbon Brief that including these “non-linear” components is key, because when small changes “reinforce each other” they can lead to significant impacts.
However, the model is unable to account for everything. Most notably, it does not include the impact of rising CO2 levels or temperatures on the forest. This omission is a notable “gap” in the study, according to Lapola.
He tells Carbon Brief that elevated CO2 levels can have a significant impact on the forest through changing evapotranspiration levels, reducing rainfall and inducing plants to use water more efficiently.
Lapola adds:
“[We should] have more experimental studies, in which we manipulate the ecosystem to test its limits in terms of resilience – for example, testing [the effects of] higher temperature and CO2.”
Spracklen tells Carbon Brief that researchers need more observational data, but warns that observations also have their “limitations”. A combination of observations and models are needed to make better predictions, he says.
Bochow points out that climate models show “a big spread in the response of the Amazon rainforest to climate change and deforestation” and agrees that there is an “urgent need to constrain the models better by doing more field experiments and observations”.
He also emphasises that “the exact numbers of our model are not to be taken for granted”. He tells Carbon Brief:
“The model simulations are used as guidance where to look for characteristic changes of stability loss in observations. Our study really focuses on the observed changes in the historical data and these do not depend on our employed model.”
The post Drying of Amazon could be early warning of ‘tipping point’ for the rainforest appeared first on Carbon Brief.
Drying of Amazon could be early warning of ‘tipping point’ for the rainforest
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Climate Change
DeBriefed 19 June 2026: Bonn talks end in ‘gridlock’ | Energy’s ‘new era’ | Oceans in climate negotiations
Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Bonn talks close
‘SIDE-STEPPING AND STALLING’: UN climate talks in Bonn have ended in “gridlock”, according to Climate Home News. The outlet reported on the failure to balance developing countries’ need for climate-adaptation finance with “richer nations’ desire to move forward” on emissions cuts. It added that both topics were subject to “rule 16”, meaning no agreement could be reached and work will be pushed to the COP31 summit in Turkey. Inside Climate News quoted UN climate executive secretary Simon Stiell, who said the talks had seen “side-stepping and stalling”.
JUST TRANSITION: One “glimmer of hope” came from negotiations on achieving a “just transition”, reported Euronews. The news outlet said negotiators “made headway on operationalising the Belém-Antalya mechanism”, intended to support people in the shift to a low-carbon economy. However, Politico concluded that much of the focus in Bonn had “shift[ed] to efforts outside diplomatic talks – raising questions about the future of global climate negotiations”.
‘ATTACKING SCIENCE’: Agence France-Presse reported on the EU, Switzerland and “dozens of developing nations” warning of “attacks on science” by a “small group of fossil-fuels interests” in Bonn. Table Briefings explained that “the 1.5C target is increasingly being challenged” and the role of the UN climate-science panel – the Intergovernmental Panel on Climate Change (IPCC) – in an upcoming assessment of global climate progress “remains controversial”. See Carbon Brief’s full write-up of the talks for more detail.
US-Iran deal
PRICE DROP: The US and Iran announced that they have reached an interim agreement to halt the war and reopen the strait of Hormuz, reported Bloomberg. Oil prices have fallen, as the “long-awaited deal” began the process of “eas[ing]” the global energy crisis triggered by the conflict, according to the New York Times. The Associated Press noted that high fuel prices will “likely outlast the Iran war”.
‘OIL GLUT’: The Financial Times reported that the International Energy Agency (IEA) has forecast a “glut of oil” emerging next year, if the peace deal holds. The IEA said this would allow countries to build new strategic reserves, as they “review their energy strategies and policies in response to the crisis”, according to Reuters.
‘NEW ERA’: Agence France-Presse reported that oil and gas companies have “few illusions about a return to normal for the Gulf energy industry after more than three months of blockage”. One analyst told the newswire that the war “showed the oil and gas industry that Hormuz risk is no longer just a geopolitical headline”.
Around the world
- OCEAN MONITOR: The Trump administration is “abandoning its plan” to dismantle a $368m ocean monitoring system key for tracking climate change after a “bipartisan backlash on Capitol Hill”, reported the New York Times.
- CORAL HAVEN: The New York Times covered preliminary research, presented at the Our Ocean Conference in Kenya, suggesting there could be three times as many “coral refugia” – where corals are relatively safe from climate change – than previously thought.
- BAD CREDIT: Down to Earth reported that the first carbon credits issued under the Paris Agreement’s new Article 6.4 mechanism are “facing scrutiny over alleged links to institutions controlled by Myanmar’s military junta”.
- OIL BACKTRACK: Reuters reported that oil-and-gas company Equinor has dropped a renewable-energy target and scaled back clean investments, while another Reuters story noted that Shell is selling off its offshore wind assets.
1.1 billion
The number of children facing “at least three overlapping climate hazards”, according to a new Unicef report covered by Agence France-Presse.
Latest climate research
- Including the “permafrost carbon-climate feedback” in climate models increases the chance of exceeding “tipping elements” – such as the Greenland ice sheets, Atlantic Meridional Overturning Circulation or Amazon rainforest – by up to 50% | Environmental Research Letters
- The intensity of influenza outbreaks could decline in temperate regions, but increase in tropical areas over the next century, as the climate warms | PNAS Nexus
- European snow cover has declined by 20% for December and January since the start of the industrial era, revealing an “unprecedented ongoing shrinkage of European winters” | Communications Earth & Environment
(For more, see Carbon Brief’s in-depth daily summaries of the top climate news stories on Monday, Tuesday, Wednesday, Thursday and Friday.)
Captured
The more than 2m battery electric vehicles (BEVs), 1m “plug-in” hybrids (PHEVs) and 100,000 electric vans on UK roads are already saving drivers a total of around £3bn a year, according to new Carbon Brief analysis. This amounts to savings of more than £1,100 a year in fuel costs for each BEV driver in the UK. The analysis comes amid reports in UK media this week that the government is considering “watering down” its EV sales targets.
Spotlight
Oceans rising at UN climate talks
The state of the world’s oceans is inextricably linked to the changing climate – and many delegates at UN climate talks want to see more focus on this issue, reports Carbon Brief.
Oceans are often described as the world’s “greatest ally” against climate change – absorbing 30% of carbon dioxide (CO2) emissions and most of the heat generated by those emissions.
They are also the site of important climate solutions, such as huge offshore windfarms and the shipping industry’s transition to cleaner fuels.
At the same time, the oceans themselves present a growing danger to coastal communities and sea life due to sea level rise, marine heatwaves and ocean acidification.
These diverse issues have led to growing calls within the UN climate process for more focus on oceans. During climate negotiations this week in Bonn – known as SB64 – nations and civil society had a chance to air these views during an “ocean and climate change dialogue”.
‘Elevate action’
Oceans first entered UN climate outcomes in 2019, when the final COP25 negotiated text requested a new “dialogue” on “the ocean and climate change to consider how to strengthen mitigation and adaptation action”.
The following years saw this dialogue established as an annual event. However, the political weight of these discussions has been limited.
COP31 is being co-led by Turkey and Australia, but with Pacific islands playing a supporting role. These small islands sometimes self-identify as “large ocean states”, stressing the ocean’s centrality in their societies.
In Bonn, figures from across the presidency threw their weight behind this issue. Chris Bowen, an Australian minister and incoming COP31 “president of negotiations”, told attendees:
“Australia, Turkey and the Pacific see an important opportunity to elevate ocean-based climate action.”
Strategies and finance
The two-day dialogue in Bonn involved a series of panels, statements and breakout groups.
One of the main topics was how oceans are integrated into national climate plans under the Paris Agreement, known as “nationally determined contributions” (NDCs).
Three-quarters of the latest round of NDCs mention oceans, with conservation of “blue carbon” ecosystems the most frequently described action. (Landscapes such as mangroves can both absorb CO2 and protect coastal areas.)
Delegates also discussed alignment with the UN biodiversity process, as well as ocean finance, which currently makes up less than 1% of all climate finance.
(As discussions were taking place in Bonn, country officials also gathered in Mombasa, Kenya for the 11th Our Ocean Conference. Carbon Brief’s associate editor Giuliana Viglione attended the conference and will publish a full summary shortly.)
Developing countries were clear that many of the ocean-related actions in their NDCs would depend on receiving more financial support.
‘Political momentum’
With the backing of the COP31 presidency, delegates were hopeful about where this year’s dialogue could lead.
Charles Hamilton, an advisor for the Bahamas who spoke for the Alliance of Small Island States (AOSIS) in the dialogue, told Carbon Brief that island representatives “are not traveling thousands of miles to just talk and pat ourselves on the back”. He added:
“A dialogue that just remains a dialogue is just more talk – no action.”
Given that, he said “discussions in the dialogue must move into COP decisions and the decisions must be actioned”, noting the importance of finance.
Marina Corrêa, oceans lead at WWF-Brazil, pointed to an upcoming UN climate change Standing Committee on Finance forum as a space to ramp up pressure on ocean finance.
More broadly, she wanted to see the presidencies translate their support into a “leader-level ocean initiative” that could “mainstream” oceans across negotiations.
“We have a really interesting opportunity, in terms of political momentum,” Corrêa told Carbon Brief.
Watch, read, listen
‘HOTTER THAN HELL’: An episode of the BBC’s Rare Earth podcast titled “hotter than hell” considered the issue of extreme heat, with input from experts and “people facing up to the hottest temperatures on the planet”.
NOT BROKEN?: John Drake, a professor of ecology at the University of Georgia, wrote an essay for Aeon – also re-published as a Guardian “long read” – questioning the framing of ecosystems and climate systems “breaking down”.
ON COURSE: On his Volts podcast, US climate journalist David Roberts interviewed UK climate minister Katie White, quizzing her about whether the UK will “stay the course with its climate plans”.
Coming up
- 20-28 June: London climate action week
- 21 June: Colombia presidential runoff
- 24 June: UK Climate Change Committee progress in reducing emissions 2026 report to parliament
Pick of the jobs
- Mongabay, managing editor – Africa | Salary: Unknown. Location: Global
- Contexte, environment reporter – Brussels | Salary: €45,000-€60,000. Location: Brussels
- Climate 200, communications director | Salary: Unknown. Location: Australia
- Energy Tracker Asia, energy transition correspondent | Salary: $3,000-$4,000 per month. Location: South-east Asia (remote)
DeBriefed is edited by Daisy Dunne. Please send any tips or feedback to debriefed@carbonbrief.org.
This is an online version of Carbon Brief’s weekly DeBriefed email newsletter. Subscribe for free here.
The post DeBriefed 19 June 2026: Bonn talks end in ‘gridlock’ | Energy’s ‘new era’ | Oceans in climate negotiations appeared first on Carbon Brief.
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