The degradation of trees at the edges of tropical forests is more widespread than previously thought, according to new research.
The study, published in Nature, explains that trees near deforested or degraded areas of the forest are more vulnerable to drought, as well as to human activity such as logging. These “edge effects” are measurable up to 1.5km into the forest, the authors find.
This is an “amazing result”, a study author tells Carbon Brief, because previous studies detected these effects only within the first 120 metres of the forest edge. The new figure indicates that 18% of the remaining tropical moist forests are impacted by edge effects – an area more than 200% larger than previously estimated.
Experts not involved in the study tell Carbon Brief that quantifying tropical forest degradation is “frustratingly elusive”. And while some praise the methods used in the paper, others advise caution when interpreting the conclusions.
Two Brazilian scientists also tell Carbon Brief that the study overlooks important work from institutions in the global south who are also working on this problem. They advise that scientists from local groups should be invited to contribute to research in this area.
Forest height
Tropical forests account for around 45% of forest cover globally. These forests are well-known for their high biodiversity and the crucial ecosystem services that they provide. They also hold around one-quarter of all land-based carbon.
The new study assesses how deforestation and degradation affect “moist tropical forests” – tropical forests in the equatorial belt with a fairly consistent annual temperature and high levels of rainfall. Tropical dry forests and deciduous forests are not included in the analysis.
Research shows that around 17% of tropical moist forests disappeared over 1990-2021, largely due to human activity such as logging and fires. Of the 1,071m hectares that remained globally in 2019, around 10% were degraded, the new study says. This means that they suffered human-induced “disturbances” that led to a partial loss of their tree cover or function.
Furthermore, trees at the edges of tropical forests have higher mortality rates than trees in the centre, because they are more exposed to disturbances such as fire and drought. When intact forest landscapes become fragmented – for example, due to logging, fire, drought or the construction of roads into the forest – these “edge effects” can lead to further forest degradation.
The authors use data collected by the Global Ecosystem Dynamics Investigation (GEDI) instrument on the International Space Station to assess the forest structure – such as canopy height and aboveground biomass – over the past four years.
To measure canopy height, the authors calculate the “RH98” value – the height of the top of the canopy or the nearest tallest vegetation in the area. This is an important measure of forest health and maturity. Aboveground biomass measures the aboveground woody biomass per unit area and is also a good measure of forest health.
They combine this with data from the Tropical Moist Forest dataset, which uses Landsat satellite imagery to show how tropical moist forests have changed over 1990-2022.
The plot below shows the canopy height for different types of moist tropical forests. The rows show intact forests at least 3km from a forest edge (top row), degraded forests (second row), the edges of forests (third row) and forest regrowth (bottom row), as shown in the maps below.
Darker blues indicate taller forest canopies. The map shows where the forests are located, and the bar charts on the right hand side show the overall distribution of different tree heights.
The tallest intact moist tropical forests are found in south-east Asia, where the average canopy height is 34m, the study finds. West and central Africa and Central and South America have average forest heights of 29m. This is because intact tropical forests in Asia, which are typically dominated by “hardwood wind-dispersed species”, are typically taller, the authors say.
The map also shows that degraded forests, forest edges and areas of forest growth have a greater proportion of shorter trees on average.
The forest edge
The study investigates two different types of forest edge effects, exploring how areas of deforested and degraded land impact nearby trees.
Dr Lilian Blanc is an author on the study and researcher at the French Agricultural Research Centre for International Development. He tells Carbon Brief that the effect of nearby degraded land “was not considered in previous studies”.
The graphs below show how areas of deforested land affect tree canopy height. The charts at the top show the average distribution of canopy heights of undisturbed forests in the Americas, Africa and Asia. The line colours indicate the distance of those trees from the forest edge, with yellow indicating a short distance and blue indicating a large distance.
The bottom map shows how far into the forest edge effects are present, by measuring the distance from the forest edge at which the height of the forest reaches 95% of the height of the intact, undisturbed forest.
The authors find the greatest edge effects from deforestation along the “forestation fronts of the Amazon”, in Borneo and Sumatra coasts marked by high fragmentation levels, and on the borders of the Congo basin.
They also record a decrease in canopy height up to 350, 400 and 1,500 metres from the deforested edge in the Americas, Africa and Asia, respectively.
The authors find that within 120 metres of trees that have been degraded due to logging and burning, the average canopy height in undisturbed forests is 15% and 22% lower, respectively.
The authors also investigate how quickly the forest can recover from logging and fires, concluding that while there is “fast regrowth of pioneer and understory species”, there is “no significant recovery in canopy height in the 30 years following the creation of a forest edge”.
Forest degradation can also increase the likelihood of deforestation, the authors say. They warn that forest height and distance to the edge of the forest are “strong predictors of deforestation”, as forest fragmentation makes the interior of the forest more accessible to loggers.
It adds that there has been selective logging 500 metres from the forest edge in Africa and the Americas, and even deeper in Asia.
Agriculture and road expansion trigger a 20-30% reduction in canopy height and biomass at the forest edge, with “persistent effects” measurable up to 1.5km inside the forest, the authors find. Blanc tells Carbon Brief that this is “an amazing result” as previous studies only looked for edge effects up to 120 metres from the forest edge.
The authors also calculated the edge effect using total above ground woody biomass, instead of canopy height. Using this metric, the authors conclude that the total area of forest with this edge effect is 18% of total global forest area in 2022 – an area more than 200% larger than previously estimated.
Prof Simon Lewis – a professor of global change science at University College London’s department of geography – tells Carbon Brief that this is a “striking new result”.
It implies that “the negative impacts on remaining forest from the creation of forest edges are much more extensive than has been commonly documented”. It also means that “forest protection of large blocks of forest is going to be more important than we previously thought”, he says.
Overall, the study is “an important step forward in monitoring forest disturbance, which is a very tough problem”, Lewis says. However, he adds that “care is needed” when looking at some of the observational data, saying that he “trust[s] the broad patterns of biomass loss following logging, edge creation and fires, but not the specific biomass loss values from these disturbances”.
Dr Peter Potapov – a researcher in the department of geographical sciences at the University of Maryland, whose work was cited extensively in the new study – says “the conclusion that edge effects are degrading 18% of the remaining humid tropical forest is an overstatement”.
He says that forest degradation depends on other factors, such as land-use regulations, and argues that “the assumption that all forests 1.5km away from the edges are degraded may undermine ongoing conservation efforts.
Expert response
These comments reflect the mixed response that the new study has received.
Prof Matthew Hansen – a remote sensing scientist at the University of Maryland’s department of geography – tells Carbon Brief that forest degradation is “a frustratingly elusive dynamic to quantify”. However, he praises the study for being “very clear and ambitious”.
Potapov, who has published research with Hansen, tells Carbon Brief that the results broadly confirm existing findings, but warns that there are some “major limitations” with the study.
For example, he says the method does not include a “matching technique” to separate the effect of human management on tree height from the natural factors such as elevation, soil quality and floods. He also warns that the observations “failed to correctly map anthropogenic disturbances in humid tropical forests”, adding:
“The authors greatly underestimate selective logging in Gabon, while the natural non-fire disturbances like river meandering and windfalls in South America were probably treated as human-caused degradation.”
Dr Flávia de Souza Mendes, a programme manager in forest and land use at satellite imagery firm Planet Labs, says the study is “well written”. However, she laments that “there are several local groups from the global south that have been studying this topic and are not part of this study”. She suggests that scientists carrying out similar studies should “invite more local researchers to take part”.
She also tells Carbon Brief that this paper “did not take into account studies carried out by local researchers on the relationship between degradation and deforestation”.
For example, she highlights a report by Brazilian researchers which finds that, in some regions of the Amazon, 86% of degraded areas were not subsequently cleared in the following decades. This is not in line with the findings of the new study, where degradation “has a crucial role in predicting future deforestation”, she says.
Prof Celso Silva-Junior – a research scientist in amazon ecology and remote sensing at Brazil’s Universidade Federal do Maranhão – tells Carbon Brief that the study “reproduces the findings of our research group, which has been investigating large-scale forest edge effects, using remote sensing technologies, since 2016”.
He says that the paper’s findings concerning biomass loss beyond 120 metres from the forest edge are “critical”. However, he emphasises the importance of the “local knowledge of tropical scientists” who are “deeply involved in the establishment of the conceptual framework for treating this relevant problem”.
The post Tropical forest degradation due to ‘edge effects’ is 200% higher than thought appeared first on Carbon Brief.
Tropical forest degradation due to ‘edge effects’ is 200% higher than thought
SYDNEY, Wednesday 26 August 2026 — New 2026 Sustainability Reports released by supermarket giants Coles and Woolworths this week demonstrate the retailers are failing on their commitments to end deforestation in their supply chains.
Adele Chasson, Nature Policy Lead at Greenpeace Australia Pacific said:
“These so-called sustainability reports are revealing. Despite their public commitments in 2024 and 2025, neither Coles nor Woolworths have taken deforestation-linked beef off their shelves. Meanwhile, bulldozers continue to tear up forests and bushland, pushing wildlife closer to extinction and causing mass toxic runoff to flow into the Great Barrier Reef. Millions of native animals like koalas are losing their homes to beef pastures each year, while the big supermarkets put off action.
“Australians would be shocked to know that beef on the shelves of our biggest supermarkets could be pushing threatened species to the brink of extinction. Collectively Coles and Woolworths have made more than $2 billion in profits in the last year, profiting from the destruction of wildlife and precious Australian nature. Coles and Woolworths owe it to shoppers to deliver on their promises and end deforestation in their supply chains now.
“As big beef buyers, Coles and Woolworths have an essential role to play in keeping Australia’s unique forests standing. They can help stop the Great Barrier Reef from being poisoned by runoff and protect iconic forest wildlife by taking deforestation off their shelves. It’s time these big companies put their money where their mouths are and follow through on their promise of sourcing and supplying deforestation-free beef.”
New Zealand’s parliament has adopted a controversial new law blocking a whole avenue of climate litigation and shutting down its most advanced corporate lawsuit, which has been blamed by the government for shaking business confidence and investment.
The Climate Change Response (Tort Liability) Amendment Bill, expected to take effect in the coming days after it is formally signed by the Governor-General, prevents all current and future civil claims for climate loss or harm under tort law.
Justice minister Paul Goldsmith said last week that the aim was to give businesses “certainty around their climate change obligations”, noting it would not alter the government’s responsibilities under the Climate Change Response Act 2002 nor business obligations under the Emissions Trading Scheme.
“Our response to climate change is best managed by the Government at a national level and not through piece-meal litigation in the courts,” he added in a statement.
Such litigation, he said, “risks developing a new regime that contradicts the framework Parliament has already enacted” to tackle climate change.
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Experts say that despite dismissing the lawsuit, the ruling sets a precedent by confirming that climate science can establish legal liability for the damage caused by emissions
Goldsmith singled out a key domestic climate lawsuit brought by Northland iwi leader and activist Mike Smith against six big companies: dairy firms Fonterra and Dairy Holdings, energy firms Genesis Energy and Z Energy, New Zealand Steel and coal mining firm BT Mining. A seventh original defendant, Channel Infrastructure, was dropped after it permanently decommissioned its Marsden Point oil refinery.
Smith argued that these companies had caused him harm under public nuisance and negligence law, as well as a third breach of a duty to cease contributing to climate change that has yet to be tested domestically. He did not seek financial compensation, instead asking for the companies to immediately stop emitting or contributing to net greenhouse gas emissions.
In one of the most advanced corporate climate accountability lawsuits in the world, a trial had been scheduled for April 2027 after the Supreme Court unanimously allowed the case to continue.
Corporate lobbying in the shadows
Smith described the passing of the bill as “deeply concerning”, particularly as it coincided with the Supreme Court hearing another of his climate lawsuits. In that case, Smith v Attorney-General, he argues that the government’s response to climate change and its impacts on Māori communities in particular breaches rights to life and culture.
“That timing raises profound questions about the separation of powers and the rule of law,” said Smith. “Whatever one’s view of the merits of these cases, it is deeply troubling when parliament intervenes to remove a legal pathway while the courts are actively considering fundamental questions about climate responsibility, rights and the crown’s obligations.”
The bill – which says that no person (including the government) can be found liable in tort for emissions-related climate change effects – followed major lobbying efforts by the companies defending themselves in Smith’s lawsuit. They outlined a proposed legal amendment in a briefing note to the government in 2024.
The centre-right government has been fiercely criticised over its lack of transparency in relation to this lobbying activity. The national ombudsman recently found that the Prime Minister’s Office effectively withheld information requested by the Environmental Law Initiative about meetings, discussions and conversations regarding Smith’s case.
Green groups fail to stop bill
The bill sparked huge concern among environmental campaigners in New Zealand and elsewhere. Greenpeace Aotearoa called it a “shocking abuse of executive power” and the vast majority of submissions to a parliamentary inquiry said it should be rejected.
But in the end, it was adopted with little resistance, moving relatively smoothly through parliament, passing its third reading by 67 votes to 53. Sam Bookman, climate law lecturer at Melbourne Law School, told Climate Home News he was not surprised by this, given that the coalition government has a secure majority.
A complaint has been made to the UN special rapporteur on climate change and human rights by Smith, the National Iwi Chairs Forum Pou Tikanga and youth coalition Climate Clinic Aotearoa over what they see as the government’s heavy-handed approach. Smith is also challenging the new law in yet another lawsuit.
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Bookman thinks it “very unlikely” that such a challenge will succeed, noting that New Zealand’s constitution is firmly anchored in parliamentary sovereignty.
But the expert in climate law does not see the bill as the end of legal action in the country, noting that New Zealand has a “sophisticated climate litigation landscape with a growing number of specialist and experienced lawyers and NGOs”.
The country is also approaching its next general election in November, and some opposition parties have pledged to restore access to the courts if elected.
Amanda Larsson, global project lead on agriculture for Greenpeace International, said: “This law deserves to be tested, and I strongly encourage the international climate litigation community to unite and help defend New Zealanders’ fundamental right to hold polluters accountable before this becomes a global blueprint.”
Copycat legislation on the rise
New Zealand’s move is part of a small but growing legislative effort to shut down climate litigation around the world.
In the US, Republican politicians introduced legislation in the House and Senate in April that would shield fossil fuel firms from climate liability lawsuits. Similar laws have already been passed at state level in Tennessee, Utah, Iowa and Louisiana.
The German state of Bavaria has put forward a similar proposal to the Federal Council, aiming to block private climate claims as well as the recognition and enforcement of foreign judgments imposing such liability. There are also proposals to limit available remedies and actions in the Netherlands and Belgium.
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Bookman said he expects more efforts to counter climate damages litigation and advised plaintiffs to think about how to respond, including drawing on broader support in opposing them.
“Even though it’s very hard for plaintiffs to win these types of cases, companies are very eager to avoid the expense, embarrassment and political accountability that come even with unsuccessful lawsuits,” he said.
The post New Zealand moves to protect business with law curtailing climate litigation appeared first on Climate Home News.
New Zealand moves to protect business with law curtailing climate litigation
Bhima Yudhistira Adhinegara is the Executive Director of the Center of Economic and Law Studies (CELIOS), an Indonesia-based economic think tank. Muhammad Zulfikar Rakhmat is the Director of the China-Indonesia desk at CELIOS.
Indonesia produces around 60% of the world’s nickel, a metal used to manufacture batteries for electric vehicles (EVs) – more than any other country in the world. But in 2026, the government sharply reduced how much of its nickel can be extracted from the ground.
Production quotas were reduced by around 40% this year compared to 2025. Weda Bay, the largest nickel mine on Earth, had its allowance cut by more than 70% and exhausted its full-year quota by the end of May, halting mining entirely; it cannot resume large-scale extraction until next year unless regulators grant an extension.
The policy has sparked a vivid debate in Indonesian policy circles: how can the country shift its strategy from a decade of mining vast quantities of cheap nickel to producing a high-value and low-carbon material that the rest of the world wants for EV batteries.
The cuts aren’t a silver bullet to clean up Indonesia’s nickel industry, whose smelters are powered by coal – the most polluting fossil fuels. But alongside stricter enforcement of environmental rules, it is one side of efforts to produce more sustainable nickel for a premium.
Restricting Indonesia’s nickel output
Production quotas were introduced to stop the collapse of nickel prices because of oversupply in the market. Prices had fallen more than 40% in 2023 alone and kept sliding as Indonesian supply kept growing, hitting a four-year low of around $13,900 a ton in late 2025.
Critics called the recent tightening of production quotas proof that Indonesia’s nickel strategy has failed, arguing that the industry shouldn’t need to throttle its own output to survive. But when assessed against what the policy was supposed to do – push up nickel prices – it has worked. Prices jumped to $20,000 a ton in May, the highest since 2024.
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Chinese industry groups representing companies that have invested billions to mine and refine the country’s nickel were furious, warning Indonesia’s president Prabowo Subianto that the cuts put $50 billion worth of investment at risk. But much of that Chinese capital is sunk into smelters and processing plants built specifically to run on Indonesian ore, and cannot simply be moved elsewhere. That gives Jakarta more room to hold its ground than the warning suggests.
Stronger environmental enforcement
Since the start of the year, Indonesia’s forestry task force has seized more than four million hectares of land from mines and plantations operating illegally in protected forests, collecting over two trillion rupiah ($113 million) in fines.
This included 148 hectares seized from Weda Bay for lacking a forestry permit. The share of nickel produced from illegal small-scale mining also fell from about a quarter in 2022 to roughly 10% by 2024.
The crackdown responds to serious environmental damages in the nickel industry. On Obi Island, a waste pond collapsed after heavy rain in June 2025, flooding three villages and killing a resident. Internal company tests found chromium-6 – a carcinogen – in the water, in quantities far above the legal limit. The footprint of another mine near Raja Ampat, which is home to some of the world’s richest coral reefs, grew 60-fold in just eight years.
The market is responding to early cleanup efforts. Low-carbon nickel now sells for a real premium, roughly $18,800 to $19,300 a ton compared with $17,900 to $18,300 otherwise, as carmakers seek to source cleaner materials to comply with the European Union’s new emissions rules for imports.
In turn, this is incentivising the industry to do more to green its operations. Vale Indonesia’s smelter in South Sulawesi now runs almost entirely on hydropower, for example.
None of this addresses coal use, however. Major Indonesian nickel producers still emitted an estimated 15 million metric tons of greenhouse gases in 2023. Indonesia may be cracking down on illegal mining and rewarding cleaner producers but it is still running its mines on the dirtiest fuel available.
Unequal benefits
For Indonesia to truly benefit from producing cleaner and high-value nickel, it needs to reap the economic benefits too. Although the industry has boosted the country’s economic growth, the reality on the ground tells a different story.
Konawe in Southeast Sulawesi is home to a major smelting complex. Growth in the district jumped from 6% to 22% between 2015 and 2023, driven almost entirely by the nickel industry, according to a study by the Lowy Institute study. At the same time, poverty levels increased slightly and unemployment remained unchanged.
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In Halmahera, another epicentre of the nickel industry, spending by the poorest fifth grew just 5% between 2019 and 2022, compared with 28% for the wealthiest fifth, according to a separate study.
Part of the reason for this inequality is the system for transferring mining royalties to district authorities where the mines are located. In theory, they are entitled to the largest share. But in practice, payments are delayed, companies routinely dispute what they owe and royalties are pooled and distributed across a larger area.
The Natural Resource Governance Institute has found that decentralisation handed local governments power to approve new mines faster than they could build their capacity to manage them. Higher output raises national income on paper, but local governments remain constrained by fiscal rules and infrastructure costs that scale with mining.
None of this makes the 2026 quota cuts a mistake. Indonesia has every right to defend its pricing power over a resource it controls. But limiting extraction isn’t going to fix underlying issues around environmental enforcement and revenue-sharing. That requires rules that are consistently enforced, royalties that reach communities living by the mines, and a plan to wean smelters off coal.
The post Indonesia’s nickel production cuts are not enough to create a sustainable industry appeared first on Climate Home News.
Indonesia’s nickel production cuts are not enough to create a sustainable industry
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