Retreating glaciers created 2,500km of “new” coastline and 35 “new” islands in the Arctic between 2000 and 2020, according to a new study.
The research uses satellite images of more than 1,700 glaciers in Greenland, Alaska, the Canadian Arctic, Russian Arctic, Iceland and Svalbard.
The findings show that 85% of these glaciers retreated over 2000-20, revealing 123km of new coastline per year on average.
The study, published in Nature Climate Change, links the acceleration in glacier melt to warmer ocean and air temperatures.
The authors find that just 101 glaciers – less than 6% of the total – were responsible for more than half of the total additional coastline length.
For example, the retreat of the Zachariae Isstrom glacier in north-east Greenland revealed 81km of new coastline alone.
The study warns that the freshly revealed coastlines are more prone to landslides, which may, in turn, create “dangerous tsunamis” that pose risks to human life and infrastructure.
A scientist not involved in the study tells Carbon Brief that it remains “unclear” what the implications of the new coastlines will be for the people and ecosystems of the Arctic.
He suggests that they “may become home to important ecosystems that play a hitherto unquantified role in the global carbon cycle”.
Glacier melt
Glaciers are slow-moving rivers of ice found on almost every continent in the world. They typically advance downhill by a few centimetres every day, driven by their own weight.
The head of a glacier is always found on land – typically at high altitude, where temperatures are low. Here, precipitation and avalanches cause snow to build up on the surface of the glacier. Over time, the snow compacts into ice, adding mass to the glacier.
Meanwhile, the tail end of the glacier is typically found at lower elevations where the air is warmer. Here, melting ice and evaporating water cause glaciers to lose mass.
As the planet warms, glaciers are melting more rapidly. This often causes the bottom of the glacier – known as the “terminus“, “snout” or “toe” – to recede, reducing the overall length of the glacier. This is known as terminus retreat.
Over 2000-19, glaciers collectively lost around 267bn tonnes (gigatonnes, or Gt) of ice every year. A recent report by the UN warned that many glaciers will “inevitably” disappear entirely over the coming decades.
A separate study estimated that even if the world successfully limits global warming to 1.5C, glaciers could lose a quarter of their total mass by 2100.
Glaciers can be broadly split into categories based on their location. For example, while “land-terminating” glaciers end on land, “marine-terminating” glaciers flow into the ocean, where they often end in a “floating glacier tongue” that sits on the surface of the water.
When marine-terminating glaciers melt and retreat, new areas of coastline are often revealed. Research shows that marine-terminating glaciers in the northern hemisphere have cumulatively lost 10Gt of mass every year over 2000-20 due to terminus retreat.
The northern hemisphere is home to around 1,500 of the world’s roughly 200,000 glaciers.
The new study assesses how much new coastline has been exposed due to terminus retreat in marine-terminating glaciers in the northern hemisphere over 2000-20.
Satellite monitoring
The authors used a pre-existing dataset to identify all the marine-terminating glaciers in the northern hemisphere. They then manually assessed satellite imagery – mainly from Sentinel-2 – to digitise the new coastline that was exposed as a result of glacier retreat around Greenland, Alaska, the Canadian Arctic, Russian Arctic, Iceland and Svalbard over 2000-20.
Dr Jan Kavan is the lead author of the study and a researcher at the University of South Bohemia’s Centre for Polar Ecology. He tells Carbon Brief that the researchers opted for a manual approach because algorithms trained to identify the position of glaciers “don’t work very well” on coastlines.
This is because Arctic coastlines tend to be highly variable, Kavan explains. For example, glaciers near the coastline may be covered in debris – making it hard for an algorithm to recognise them.
Dr Simon Cook is a senior lecturer in environmental sciences at the University of Dundee, who wrote a “news and views” piece about the study published in Nature climate change. He praises the study, telling Carbon Brief that manually identifying coastlines is “labour-intensive and slow work, but widely regarded to be robust”.
The authors inspected 1,704 marine-terminating glaciers in total. They find that 2,466km of new coastline formed between 2000 and 2020 – an average of 123km of new coastline every year.
The map below shows where the coastline was added (red) and lost (blue) due to changes in glacier terminus positions over 2000-20. The yellow circles the total length of new coastline added in different regions, where larger circles indicate greater additions.
The authors note that the rate of new coastline formation varies highly between regions. Just 101 glaciers were responsible for more than half of the total additional coastline length, they say.
Two-thirds of the new coastline identified in this study were in Greenland, the authors say. The melt of the Zachariae Isstrom glacier in north-east Greenland has resulted in the formation of 81km of new coastline – more than twice as much as any other glacier in the study – according to the paper.
Retreating glaciers also exposed 35 new islands with areas larger than 0.5 square kilometres (km2), according to the study.
Changing coastlines
Rising ocean and air temperatures are the main reason that marine-terminating glaciers are rapidly losing mass, the study says. However, many other factors may affect how quickly new coastline forms due to glacier melt.
According to the authors, 85% of the glaciers in the study retreated between 2000 and 2020.
However, not all of these led to the development of new stretches of coastline.
For example, glaciers that stretch out far into the sea could experience “extensive retreat” without any new coastline forming, according to the paper.
Conversely, glaciers in “deep and narrow fjords” can expose long new areas of coast by losing only a small volume of ice.
The authors note that the most “dramatic” glacier retreats are due to ice shelves or floating tongues breaking off the main glacier and collapsing into the water.
Meanwhile, glacier advances – when glaciers gain mass more quickly then they lose it, or temporarily “surge” forwards – can cause a loss of coastline. (Surges are short-lived periods when the glacier moves faster than its normal rate, often due to meltwater which builds at the base of the glacier and acts as a lubricant.)
The paper finds that more than 50 metres of coastline was lost due to glacier advances. Two-thirds of this gain was in Svalbard due to a “surge” of the Nathorstbreen glacier system, according to the paper.
Lead author Kavan tells Carbon Brief that other studies have assessed coastline gain from “individual glaciers” or “small regions”, but says this is the first paper to quantify coastline gain across the entire northern hemisphere for a uniform time period.
Dr Robert McNabb, a lecturer at Ulster University who was not involved in the study, tells Carbon Brief the study “highlights the importance and immense value of having long-term, freely available satellite archives for research”.
Tsunami risk
Glacier melt is often discussed in the context of water security, as the world’s 200,000 glaciers store around 70% of the Earth’s fresh water. However, Kavan tells Carbon Brief that the impact of retreating glaciers on the bedrock is often “neglected”.
Using a map of rock types across the Arctic, the authors analyse the changing conditions of the new coastlines. They find that most of the new coastline is formed of metamorphic bedrock – a type of rock formed from intense heat and pressure. Meanwhile, softer sedimentary rocks, which are more susceptible to erosion, dominate the newly formed coastlines in eastern Svalbard.
In his news and views piece, Cook – the University of Dundee environmental sciences lecturer – explains that the newly revealed coastlines are known as “paraglacial”. He writes:
“Paraglacial coasts differ from other established areas of Arctic coastline because permafrost will not yet have had time to develop in these freshly revealed areas, meaning that they are more easily eroded by wave action, mass wasting and other processes because of a lack of icy cement. They are, therefore, expected to be highly dynamic.”
Cook says it is “currently unclear” what the implications of the new paraglacial coastlines will be for the people and ecosystems of the Arctic. He suggests that the new coastlines “may become home to important ecosystems that play a hitherto unquantified role in the global carbon cycle”.
Freshly revealed paraglacial coastlines can be more prone to landslides, which may, in turn, cause “dangerous tsunamis”, the paper notes. As an example, it points to a tsunami on 17 June 2017 in Greenland, which caused “substantial infrastructure damage and loss of life”.
Dr Anna Irrgang is a coastal geomorphologist at the Alfred Wegner Institute and was not involved in the study. She tells Carbon Brief that the study “may help in detecting potential risk-zones” for such tsunamis.
She adds that the dataset provided in this study can be used as a “first estimation of the hazard potential”, but adds that “a more in-depth risk analysis needs to be undertaken at the local scale, where communities might be exposed to these arising dangers”.
Meanwhile, Kavan tells Carbon Brief that marine-terminating glaciers are considered “biodiversity hotspots”. Meltwater from the glacier causes upwellings at the terminus of the glacier, creating “nutrient-rich water” that is vital for many polar species, he says.
As a result, ongoing glacier retreat may result in many of these habitats being lost, putting species like bearded seals and Arctic-dwelling birds at risk, he adds.
The post Global warming is ‘exposing’ new coastlines and islands as Arctic glaciers shrink appeared first on Carbon Brief.
Global warming is ‘exposing’ new coastlines and islands as Arctic glaciers shrink
Scientists have vowed to keep working on the next flagship set of reports for the Intergovernmental Panel on Climate Change (IPCC), after a political row over the timeline for their release saw its latest session suspended on Friday evening without agreement.
During the weekend, government officials and scientists alike expressed disappointment over the inability to reach a compromise before some delegates from developing countries and small island states had to leave the week-long meeting in Ethiopia to catch flights home.
The disagreement – which has persisted since early 2024 – turns on whether the three key parts of the AR7 assessment should all be published before the conclusion of the UN’s next Global Stocktake of global climate action, which is due to be completed in late 2028.
The IPCC issued a statement after the close of the session, saying that “key agenda items” – the timelines for the three AR7 reports, as well as the IPCC budget – remain open and under discussion. It said the IPCC’s plenary session and its deliberations on the pending agenda “will resume at the earliest opportunity”, giving no further details of when.
IPCC Chair Jim Skea told delegates in closing remarks that recent months had been some of the most turbulent for the climate science panel and that, if there were stronger words than “profound disappointment” he would use them, according to a summary published by the Earth Negotiators Bulletin (ENB). IPCC discussions happen behind closed doors.
IPCC scientists remained committed
In an open letter, issued on Monday, a group of nearly 120 scientists – from a total of 664 AR7 authors – said they “stand committed to continue working to deliver the AR7 reports in a manner that is rigorous, timely and inclusive, in line with our mandate to be policy-relevant”.
“An assessment that arrives after the decisions it is meant to inform cannot serve its purpose,” they emphasised. “The second Global Stocktake in 2028 is such a decision point, and the world should not have to face it without the IPCCʼs latest assessment.”
Europe, small islands and the least developed countries, plus many Latin American and developed nations, want the IPCC to meet this deadline, arguing that the findings from the UN climate science body are irreplaceable in the UN climate policy-making process.
However, around a dozen developing countries plus Russia have argued that the reports should come later in order to allow for greater research input from the Global South – something that, in their view, would make the findings fairer. They also claim that a shorter timeline would put excessive pressure on experts.
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Who shapes climate science? The equity question facing the IPCC
Early completion of the next global climate science assessment reports risks excluding research from the Global South, which is key to ensuring the findings are fair -
Governments that support climate science must stand firm against naysayers
The IPCC is meeting to decide the timing of its next major report, as some countries try to delay it and weaken the case for faster emissions cuts
The most vocal of this group at last week’s meeting were India and Saudi Arabia, according to the ENB summary and a developed country diplomat. Critics see this push for a longer timeline as an excuse to deprive government decision-makers of the latest science and ease pressure on emerging economies to raise their ambition, particularly on cutting emissions.
Commenting on last week’s meeting, France’s ambassador for climate negotiations Benoît Faraco said a broad coalition of developed and developing countries from all five continents, “united in their support for science and the timeline proposed by scientists”, had withstood pressure “from a few countries” seeking to slow down the process of adopting the IPCC reports.
He added that France would not back down and would “continue to fight tirelessly for science, protect the integrity of information, and convince our partners that without the best available scientific data, we will be less effective in tackling climate change and protecting our populations”.
Inclusivity proposal stalled
In a bid to unlock a solution for the AR7 timeline, countries discussed ways to improve the inclusivity of the IPCC’s work. One option put on the table was for the IPCC to expand its funding for delegates from developing countries to attend some or all of its sessions from one to two participants, according to the ENB summary and a delegate speaking to Climate Home News.
That would increase the costs for the IPCC to complete AR7 by up to a quarter, according to an assessment shared by the secretariat. The panel’s budget is under severe strain and its officials have warned that, without additional voluntary contributions, it risks running out of money before it can deliver on this assessment cycle.
Climate Home News understands that some of the IPCC’s traditional donors – which mainly include European countries, Japan and Australia – indicated a willingness to support funding for an additional developing country participant. But without an agreement over the budget or the timeline for the reports, that option was ultimately not adopted.
‘Disappointed and worried’
The three reports are managed by working groups that collate and draw overall findings from the latest scientific studies and data on the physical effects of global warming around the world, how to adapt to it, and pathways for cutting planet-heating emissions in order to meet the temperature goals of the Paris Agreement.
Winston Chow, an urban climate professor at Singapore Management University who co-chairs Working Group II on adaptation, wrote in a LinkedIn post that he was “disappointed and worried” for the IPCC authors who have worked “extraordinarily hard” to assess the relevant climate science over the past two years.
He said he shared their concern that “the rigour, time and goodwill they’ve invested are now being put at risk by the Panel’s stalemate”.
As science comes under attack at UN talks, climate movement splits over how to respond
For Working Group II, a meeting for 250 experts writing that report is scheduled for January 2027, followed by the approval of a special report on cities and climate change in Singapore next March.
But because the IPCC’s budget has not been confirmed due to uncertainty about the AR7 schedule, travel support for those researchers is at risk, wrote Chow. “If they cannot participate, our assessments will lose vital expertise, perspectives and scientific breadth, and the collective effort of our authors will be undermined,” he warned.
Scientific work continues
Despite the political holdups, he – together with French climate scientist Robert Vautard, co-chair of Working Group 1 – agreed with IPCC head Skea who told the IPCC’s closing session on Friday: “The engine room of the IPCC is working, and it’s healthy.”
Vautard commented in a separate post on LinkedIn after it ended: “The boat is at full steam.” Working groups I and II are due to start revising the first drafts of their reports, while Working Group III on reducing emissions is finalising its first draft which will be out soon, he wrote.
“The most exciting two years of the cycle are ahead, for the authors. The momentum in the engine room is here and now. Trust the engine room!” he added.
The IPCC and some scientists report that progress has been made towards achieving an equitable balance of authors from the Global North and the Global South.
The group of researchers who signed the open letter on Monday noted that “inclusivity is at the heart of how we work”, with author teams bringing together experts from developed and developing countries with diverse backgrounds and at different stages of their careers.
Plea to overcome political differences
The signatories include several scientists from some of the countries opposed to the alignment of all IPCC reports with the Global Stocktake.
“We are committed to an assessment in which the knowledge, experience and priorities of every region are fully reflected, a commitment we share with the leadership of the IPCC.
Equity is built into how our assessment is being drafted,” they added.
They appealed to governments that make up the IPCC “to overcome their political differences and work together as we do as a global scientific community, so that we can deliver the IPCC reports the world needs to hear”.
In a statement published on Monday, IPCC chair Skea said reaching consensus on the schedule for the reports is “vital”. He added that the assessments provide authoritative scientific evidence to inform national climate policies, strengthen adaptation and resilience and support access to climate finance, as well as helping communicate the scale of the climate crisis and the urgency of efforts to tackle it.
The post IPCC scientists vow to press on with climate reports despite political deadlock appeared first on Climate Home News.
IPCC scientists vow to press on with climate reports despite political deadlock
An Lambrechts is a biodiversity politics expert at Greenpeace International with extensive experience in biodiversity-related multilateral negotiations. She is the head of the Greenpeace delegation at the Convention on Biological Diversity (CBD) COP17 happening in Yerevan, Armenia.
In 2022, COP15 delivered the landmark Kunming-Montreal Global Biodiversity Framework to halt and reverse biodiversity loss by 2030. With COP17 starting in Yerevan, we are now halfway to the deadline, and according to the first Global Review of progress, countries are not on track to meet the biodiversity targets, and implementation must accelerate fast.
One of the main findings of the Global Review is that funding falls far short of the scale needed to halt and reverse nature loss. But the crisis facing the world’s biodiversity is not an absolute scarcity of capital – it is a profound public policy distortion.
The global economy currently spends roughly $30 destroying nature for every single dollar invested in its protection. According to a report from the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, a staggering $2.4 trillion is spent in public subsidies for fossil fuels, agriculture and water use, while global investment in biodiversity conservation and restoration stands at a mere $220 billion.
Countries urged to ramp up “insufficient” nature policies at COP17
Yet, discussions about how to close the biodiversity finance gap continue to claim that salvation lies in mobilising private capital, scaling offsets and “derisking” investments in nature. This is a fundamental misunderstanding of both the nature of ecological stewardship and of the global financial architecture.
Biodiversity conservation is not a speculative investment portfolio – it is the foundation of human survival. The health of our planet is a non-monetisable, non-excludable public good. Expecting profit-seeking private capital to protect nature perpetuates the structural drivers of ecosystem destruction in the first place.
But if private market mechanisms cannot save biodiversity, where will the necessary public resources come from?
Money going to the wrong places
The answer lies in recovering the vast public wealth currently drained by cross-border tax abuse, financial secrecy and corporate impunity. Finance and environment ministers meeting in Yerevan must give a strong political signal that, to avert ecological breakdown, countries need to take swift action to reform global tax rules, eliminate harmful public subsidies and cancel unsustainable sovereign debts for the public revenues to end up where they belong.
Extractive sectors such as industrial agriculture, fishing, timber and mining continue business-as-usual, often heavily subsidised by public treasuries, while voluntary carbon and biodiversity offset markets pose a serious risk to nature conservation. Offset schemes have delivered only a negligible fraction of the funding needed to preserve ecosystems, allowing industries to continue with their destructive business-as-usual practices.
