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
The launch of the Africa Energy Bank (AEB) has been put back yet again, raising doubts about the institution’s future ability to finance fossil fuel projects – its main objective – as global lenders retreat from such investments over climate concerns, experts told Climate Home News.
The bank, which had been billed to launch in September after a series of delays, is now scheduled to begin operations in November, according to the head of the African Energy Chamber, an advocacy body for the continent’s oil and gas sector.
Even as the world aims to transition away from fossil fuels, many African leaders have made clear they want to continue exploring and extracting the continent’s large oil and gas deposits – estimated at around 125 billion barrels of crude and over 600 trillion cubic feet of gas – to boost economic development.
As a group, Africa sided with a number of powerful oil-and-gas producing nations in blocking progress on negotiations to craft a global roadmap to transition away from fossil fuels at last year’s UN COP30 climate talks, although some countries did individually support the proposal.
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Meanwhile, major projects under development across the continent – including the 1,443-km East African Crude Oil Pipeline (EACOP) and Dangote’s 700,000-barrel-per-day Kenyan refinery – show that African governments see oil and gas as playing a significant role in meeting their energy and economic needs for many years to come.
In 2022, at a gathering of the African Petroleum Producers’ Organization (APPO) in oil-rich Angola, ministers from its member states adopted a resolution to create the Africa Energy Bank to finance projects for the production, use and trade of oil, gas and broader energy sources.
African control over energy resources
An article on the APPO website explains that the bank was conceived as a way to overcome “disenchantment” with fossil fuels among “the international community” which it said had crystallised around the “energy transition” concept.
“If Western countries, after having long taken advantage of the energy sources they now revile to develop, can afford the luxury of abandoning them, this is not the case in Africa,” it adds, noting that many of the continent’s economies are still largely dependent on oil and gas revenues.
A separate web page about the bank, also hosted on APPO’s website, says its objectives include financing the exploration, production and refining of oil and gas, as well as supporting member states in transitioning from fossil fuels to cleaner energy sources “while ensuring energy security”.
Said Addi, a former executive with Shell and energy commodities trading house Gunvor, said the new bank was judged necessary because financing for hydrocarbons from many traditional international lenders has become constrained.
In trying to fill this financing gap, Africa is not simply setting up another fund to support oil and gas, he added. “It is also an attempt to give African countries greater control over how their energy resources and infrastructure are financed,” he explained.
Nigeria to host the AEB
The energy bank – a joint initiative of APPO and the African Export–Import Bank (Afreximbank) – has so far suffered several delays and is almost two years behind schedule. The initial plan was to start operations in January 2025, with Nigeria as the host country, but the bank’s opening was delayed to June of that year to allow Nigeria time to finalise the construction of the bank’s headquarters in Abuja.
After the government announced the completion of the offices in late November 2025, a new launch date was set for January 2026, which was moved back to April, June and then September. Now it has shifted again to November, raising concerns that the institution may be losing momentum.
Former Shell executive Addi said that if the capital is eventually paid in, the bank becomes operational and its first projects are commercially credible, then the delays will be regarded as normal teething troubles in setting up a multilateral institution. But, he added, scepticism will be justified if it continues to stall.
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Baron Lamarré, an oil and gas expert and former Petronas oil trader, said that missing “three deadlines in a row is not normal”, and warned that if the timeline slips again, “the story flips from ‘ambitious institution finding its footing’ to ‘good idea that lost momentum before it found any’.”
The Nigerian government, APPO and Afreximbank did not respond to requests for comment by the time of publication.
The funding challenge
The Africa Energy Bank is targeting base capital of $5 billion, with plans to scale up to $120 billion within five years by mobilising private-sector funds. However, it is expected to start operations with initial seed capital of $500 million.
The funding plan is to have the 18 member countries of the APPO contribute $83 million each to the bank as equity for a combined $1.5 billion. Afreximbank, other non-APPO African countries and investors outside the continent are expected to provide the remaining $3.5 billion.
But even the initial $500 million has not been easy to mobilise. In May, APPO Secretary-General Farid Ghezali called on members to deliver on their pledges towards the startup goal before the end of June. But the delays suggest this may not have been met, with experts saying Africa may be finding it difficult to self-fund its oil and gas projects in the absence of international capital.
Lamarré said every extension of the deadline points to the fact that “raising fossil fuel capital in Africa without the majors and their financing networks is brutally hard”.
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Since 2020, Western lenders, export credit agencies and insurers have been in steady retreat from African hydrocarbons, he said, while oil majors are divesting their African assets, handing over fields to smaller local operators whose credit ratings are not high enough to borrow cheaply.
Even capital from China and the Gulf, which has partially filled the gap, cannot match the volume, tenor or pricing that Western investors once offered, Lamarré argued.
“If mobilising the first $500 million of seed capital [for the AEB] has taken this long, that’s the clearest signal yet of how steep the climb to $120 billion looks,” he said, noting that the continent’s energy financing gap is as large as $30 billion-$45 billion per year.
Africa’s investment landscape, meanwhile, has been shifting. While foreign direct investment dropped from a 2024 peak, inflows remained roughly one-third above the continent’s long-term average in 2025, according to the 2026 World Investment Report from UN Trade and Development (UNCTAD). They are concentrated in a few sectors including critical minerals needed for renewable energy technologies, battery manufacturing and advanced industrial production.
At the same time, data on global energy investment from the International Energy Agency (IEA) shows that fossil fuel investment in Africa has declined over the last decade.
“Trojan horse” for fossil fuels
While the Africa Energy Bank struggles to get off the ground, climate campaigners have criticised its primary aim of financing oil and gas on the continent at a time when the world is starting to move away from high-carbon fuels to cleaner alternatives.
Bhekumuzi Dean Bhebhe, founder of Africa Change Lab, described the bank as a “Trojan horse”, arguing that its focus on fossil fuel financing runs counter to the global energy transition and the African Union’s Agenda 2063 goals of sustainable development and inclusive growth.
The energy bank, he warned, “risks locking Africa into a new cycle of debt, dependency and fossil fuel entrenchment”, adding that its financing blueprint does not pave the way for a climate-resilient future. “In truth, it is to deepen the same extractive, carbon-heavy pathways that the continent should be moving away from,” he added.
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Kenya-based climate and energy expert Joab Okanda said the AEB’s plan to finance oil and gas is “a misplaced priority” and it should instead back clean energy in line with the policies of some of Africa’s major export markets like Europe.
In addition, the new bank could struggle to mobilise enough resources to advance large-scale oil and gas projects, he added, noting that its proposed $5-billion initial capital is equivalent to the cost of the East African Crude Oil Pipeline alone.
The AEB’s aim of backing more fossil fuels should be flipped “to support countries that are oil-dependent to start working on their transition plans”, Okanda said.
The post Launch of Africa Energy Bank delayed again in blow to oil and gas hopes appeared first on Climate Home News.
Launch of Africa Energy Bank delayed again in blow to oil and gas hopes
A booklet published by the UK’s opposition Conservative party includes a “cost of net-zero” that appears to have been doubled by a spreadsheet error.
The “common sense” policy document argues that “what people ultimately want is a government competent enough to solve the problems for which it takes responsibility”.
In a section that says “sophisticat[ed]…modelling” should not be a substitute for “political judgement”, the “Right Way” document disparages various estimates of the cost of net-zero.
The Conservative document then claims – incorrectly – that the government’s official adviser, the Climate Change Committee (CCC), had put the cost of net-zero at close to £1tn. It says:
“In 2020, the CCC estimated that its route to net-zero would cost £957bn.”
In fact, the CCC’s 2020 estimate was exactly half this amount – £478bn – and last year it published a revised figure of £108bn, largely as a result of the falling cost of electric vehicles (EVs).
Spreadsheet error
The Conservative party’s erroneous claim appears to stem from another report that had accidentally added up numbers twice, using a spreadsheet published by the CCC in 2020.
The 2020 spreadsheet contains a table listing the additional investments that would be needed to build a net-zero economy, from low-carbon electricity generation through to heat pumps and EVs.
These extra capital expenditures, listed as “CAPEX”, add up to a total of £1.38tn over the 30 years of 2020-50. They are set against operational savings, listed as “OPEX”, of £0.90tn.
Added up over 2020-50, the combined CAPEX and OPEX figures come to a total of £478bn.
In addition to the annual sectoral CAPEX and OPEX figures, the CCC’s 2020 spreadsheet also has a line giving combined totals for each year. It appears that someone has added all of these numbers together, resulting in the savings and costs being counted twice.
This double-counted total for the cost of net-zero amounts to £957bn – as shown in the image below – and it appears to be the source of the claim in the Conservative booklet.
At the time of publication in 2020, the CCC said that the £478bn net cost of net-zero amounted to less than 1% of GDP over 30 years – and that the large investment needed would not only result in savings due to lower fossil-fuel imports, but that it would boost GDP overall, by around 2%.
In 2025, the CCC revised its estimates for investment costs and operating savings to £670bn and £562bn respectively, giving a net total of £108bn over 2025-50, or less than 0.2% of GDP.
Earlier this year, the committee said that cutting emissions to net-zero would cost less than a single fossil-fuel price shock and that doing so would have benefits worth £110bn per year.
Paper trail
The erroneous claim in the Conservative document is referenced to the CCC’s 2020 advice on the UK’s sixth “carbon budget”, which, as explained, does not contain the £957bn figure.
The earliest online use of the £957bn figure found by Carbon Brief is a 12 January 2026 article in the Spectator, by retired engineer and self-described “accidental energy analyst” David Turver.
A day later, Turver repeated the mistaken number in a report for the free-market Institute of Economic Affairs. His report cites figure 5.3 of the CCC’s 2020 advice.
However, as set out above, the CCC spreadsheet containing the data for figure 5.3 only adds up to £478bn, half the figure claimed by Turver.
It appears that Turver accidentally added up all of the numbers in the CCC spreadsheet, without noting that it already included a line for the annual total. This results in double-counting the cost.
(Turver’s report also triggered a slew of inaccurate headlines stating that net-zero would cost £7.6tn – or even £9tn. These figures, which came from Turver’s report, were based, among other things, on the implicit assumption that fossil fuels and the cars, boilers and power plants that use them are all free.)
After Turver’s report and article in January 2026, the erroneous £957bn figure was repeated in March by the Great British Think Tank. The organisation has the tagline “dat