The vast ice sheets that cover Greenland and Antarctica have the potential to trigger catastrophic sea level rise as the climate warms.
But the ice-sheet models that scientists use to project future changes underestimate how fast sea levels are rising now and how much they have risen in the past.
This suggests the models are missing important processes driving ice-sheet retreat.
New research suggests that melting at grounding zones – where the ice transitions from sitting on land to floating on water – could be the missing piece of the puzzle.
And it is potentially a big piece. For example, when one study on the Thwaites glacier in west Antarctica included these processes, its projections of ice-sheet loss more than doubled.
In this guest post, we unpack the latest research on grounding-zone mechanisms and why they suggest that current global projections of sea level rise may be substantially underestimated.
Ice sheets are shrinking faster than models project
Scientists use ice-sheet models to project how fast – and by how much – the Earth’s ice sheets will shrink as global temperatures rise.
These models, developed by scientists at universities and national research institutes, represent physical real-world processes using sets of equations. By solving these equations, scientists gain understanding how the physical system will respond to different scenarios. There are around 20 ice sheet models in use around the world today.
The models capture what we know about how ice sheets flow and deform. Projections using these models suggest that ice sheets will contribute 10s of centimetres to sea level rise by the end of the century.
However, it increasingly looks like these models underestimate the true sensitivity of ice sheets to climate change.
First, we can look at sea level rise from ice sheets over the past 20-25 years. Over this period, we have detailed satellite observations to compare to model predictions.
The figure below shows the spread in projections from models (blue shading) for Greenland’s contribution to sea level rise compared to the satellite data (blue line). This spread is generated by a range of factors, such as how different models describe ice flow, how fine of a resolution they use to represent the real system and the initial state used for model runs. Sea levels are presented relative to 2015, as this was chosen as a benchmark year.
It is clear that the majority of models underestimated the rate of Greenland melt.
Next, we can consider whether models have succeeded in reproducing ice sheet loss from historical warm periods.
For example, proxy records, such as reconstructions of previous shorelines, indicate that during the Pliocene (5.3-2.6m years ago) sea levels were between six and 40 metres higher than today.
This extreme sea level rise would have required a substantial contribution from the world’s ice sheets. However, models are largely unable to reproduce these values, with almost all failing to even attain lower bounds.
Finally, from a different standpoint, we can ask how much climate forcing is required to reproduce current ice sheet retreat rates. Models of the west Antarctic ice sheet typically require ice shelves, which restrain the flow of grounded ice, to be melted very rapidly in order to reproduce current rates. However, recent observations of melting in these regions suggest it is in fact far smaller than models require.
Together, this evidence suggests that ice-sheet models are not entirely capturing what is going on: they should be more sensitive to changes in the climate than they currently are. Two recent papers have suggested that what happens in so-called “grounding zones” could be the missing piece of this puzzle.
Grounding zones
Ice sheets are not static; they spread out like a very thick liquid. The majority of ice in the world’s ice sheets sits on top of land, above sea level. As the ice spreads out and thins, it begins to float, transitioning into a floating ice shelf.
The boundary between ice on land and floating ice shelves – shown in the figure below – is known as the “grounding zone”.
The classical picture of grounding zones is as distinct boundaries between floating and grounded ice. It was previously thought that they migrate on annual-to-decadal timescales as ice sheets retreat and advance, and that little melting took place there.
Recently, however, a different picture has emerged, where grounding zones are actually highly dynamic regions.
In particular, two independent mechanisms – called “tidal intrusion” and “porous intrusion” – are thought to be taking place in grounding zones.
Both of these mechanisms are thought to allow relatively warm ocean water to rush under ice sheets, enabling vigorous melting to take place there.
Tidal intrusion
Antarctica has one of the largest tidal ranges in the world, with sea levels fluctuating by up to seven metres each day.
As the tide rises, water pressure under ice shelves increases, lifting the ice and creating a new cavity in the grounding zone. As a result, this newly formed cavity, which can be up to 15km long, is rapidly filled with ocean water.
When the tide falls, the reverse happens: the ice settles back down and water flushes out of the cavity. This cyclic process – named “tidal intrusion” – occurs up to twice per day, driving rapid flows of warm ocean water into and out of the grounding zone, where it can melt the ice from below.
The tidal opening and closing of grounding zone cavities can be observed using surface elevation and radar measurements from satellites. However, these observations – particularly in fast-changing regions – have typically been limited by how frequently the satellites pass over the same spot, which varies between weeks and months.
Recent research, published last month, has used a unique set of sub-daily satellite observations from the ICEYE constellation to show that tidal intrusion is widespread beneath Thwaites glacier.
This research indicates that warm water is able to intrude up to 6km beneath the Thwaites ice shelf during each high tide, where it could accelerate ice melt from below.
Thwaites – nicknamed the “doomsday glacier” – holds enough ice to raise global sea levels by up to 65cm and has long concerned scientists because of its rapid present retreat, potential for runaway ice loss and possibly important role as a keystone in the west Antarctic ice sheet.
This new research suggests that Thwaites may be even more vulnerable than previously thought.
Porous intrusion
Beneath ice sheets, there are networks of channels and tunnels, as well as porous sediments, through which meltwater from the bottom of ice sheets flows.
In grounding zones, this cold, fresh meltwater meets relatively warm, salty ocean water. The ocean water is denser, allowing it to intrude beneath the meltwater and into the grounding zone. This process is called “porous intrusion”.
Recent modelling has suggested that ocean water can intrude kilometres beneath ice sheets via this mechanism.
However, previous research has not considered how the geometry of these regions change in response to melting. In our new study, published in Nature Geoscience, we show that, when this effect is considered, the porous intrusion mechanism can be far more powerful.
In particular, we show that these systems display a tipping-point like behaviour, in which a small change in ocean temperatures can lead to a dramatic change in the distance that warm water is able to intrude through grounding zones.
We also show that the porous intrusion mechanism is not only applicable to ice shelves exposed to warm water or with high melt rates at a glacier’s base, such as Thwaites, but can also influence cold water ice shelves.
The susceptibility of a glacier to porous intrusion is linked to the slope of the seabed and how quickly melted ice is replaced. This is illustrated in the figure below; glaciers in the purple-shaded area are the most susceptible.
In fact, Thwaites appears to be relatively unsusceptible to porous intrusion – despite being highly vulnerable to tidal intrusion – because it flows very rapidly and ice is replaced very quickly.
Other ice shelves, such as the Ross and Ronne ice shelves, which sit in relatively cold water may, surprisingly, be amongst the most susceptible ice shelves.
Are grounding zones the missing piece?
The majority of ice-sheet models still represent grounding zones as a distinct transition between grounded and floating ice, with no melting there from either tidal or porous intrusion.
The only models able to attain anything resembling sea level rise values during past warm periods have included a grounding-zone melting mechanism or a similar mechanism that boosts their sensitivity to climate change.
These same models have also received much attention for their pessimistic future sea level rise projections. Capturing the past requires an increased sensitivity to climatic change, meaning that they predict much higher sea level rise in future.
So, grounding zone intrusion and melting might be the missing piece to reconcile observed and modelled sea level rise.
While scientists have yet to run model simulations with grounding-zone melting included for the whole of Antarctica, studies focusing on specific regions of the continent’s ice sheets project up to twice as much sea level rise.
Current global projections of sea level rise also do not include grounding-zone melting. This means that these projections – including those that inform the reports of the Intergovernmental Panel on Climate Change (IPCC) – may be substantial underestimates.
Ice-sheet models have “known unknowns” – things we know that we do not know perfectly, but can account for imperfect knowledge of. However, they also have “unknown unknowns” – things that we do not even know are happening and therefore cannot quantify the full effects of.
Although grounding-zone melting might result in higher sea level than we expected, at least we now know that it is happening and can begin to incorporate it into our models. The devil we know is better than the devil we don’t.
The post Guest post: The critical role of ‘grounding zones’ in the retreat of Earth’s ice sheets appeared first on Carbon Brief.
Guest post: The critical role of ‘grounding zones’ in the retreat of Earth’s ice sheets
The annual World Economic Forum got underway on Tuesday in the Swiss ski resort of Davos, providing a snowy stage for government and business leaders to opine on international affairs. With attention focused on the latest crisis – a potential US-European trade war over Greenland – climate change has slid down the agenda.
Despite this, a number of panels are addressing issues like electric vehicles, energy security and climate science. Keep up with top takeaways from those discussions and other climate news from Davos in our bulletin, which we’ll update throughout the day.
From oil to electrons – energy security enters a new era
Energy crises spurred by geopolitical tensions are nothing new – remember the 1970s oil shock spurred by the embargo Arab producers slapped on countries that had supported Israel during the Yom Kippur War, leading to rocketing inflation and huge economic pain.
But, a Davos panel on energy security heard, the situation has since changed. Oil now accounts for less than 30% of the world’s energy supply, down from more than 50% in 1973. This shift, combined with a supply glut, means oil is taking more of a back seat, according to International Energy Agency boss Fatih Birol.
Instead, in an “age of electricity” driven by transport and technology, energy diplomacy is more focused on key elements of that supply chain, in the form of critical minerals, natural gas and the security buffer renewables can provide. That requires new thinking, Birol added.
“Energy and geopolitics were always interwoven but I have never ever seen that the energy security risks are so multiplied,” he said. “Energy security, in my view, should be elevated to the level of national security today.”
In this context, he noted how many countries are now seeking to generate their own energy as far as possible, including from nuclear and renewables, and when doing energy deals, they are considering not only costs but also whether they can rely on partners in the long-term.
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In the case of Europe – which saw energy prices jump after sanctions on Russian gas imports in the wake of Moscow’s invasion of Ukraine – energy security rooted in homegrown supply is a top priority, European Commission President Ursula von der Leyen said in Davos on Tuesday.
Outlining the bloc’s “affordable energy action plan” in a keynote speech at the World Economic Forum, she emphasised that Europe is “massively investing in our energy security and independence” with interconnectors and grids based on domestically produced sources of power.
The EU, she said, is trying to promote nuclear and renewables as much as possible “to bring down prices and cut dependencies; to put an end to price volatility, manipulation and supply shocks,” calling for a faster transition to clean energy.
“Because homegrown, reliable, resilient and cheaper energy will drive our economic growth and deliver for Europeans and secure our independence,” she added.
Comment – Power play: Can a defensive Europe stick with decarbonisation in Davos?
AES boss calls for “more technical talk” on supply chains
Earlier, the energy security panel tackled the risks related to supply chains for clean energy and electrification, which are being partly fuelled by rising demand from data centres and electric vehicles.
The minerals and metals that are required for batteries, cables and other components are largely under the control of China, which has invested massively in extracting and processing those materials both at home and overseas. Efforts to boost energy security by breaking dependence on China will continue shaping diplomacy now and in the future, the experts noted.
Copper – a key raw material for the energy transition – is set for a 70% increase in demand over the next 25 years, said Mike Henry, CEO of mining giant BHP, with remaining deposits now harder to exploit. Prices are on an upward trend, and this offers opportunities for Latin America, a region rich in the metal, he added.
At ‘Davos of mining’, Saudi Arabia shapes new narrative on minerals
Andrés Gluski, CEO of AES – which describes itself as “the largest US-based global power company”, generating and selling all kinds of energy to companies – said there is a lack of discussion about supply chains compared with ideological positioning on energy sources.
Instead he called for “more technical talk” about boosting battery storage to smooth out electricity supply and using existing infrastructure “smarter”. While new nuclear technologies such as small modular reactors are promising, it will be at least a decade before they can be deployed effectively, he noted.
In the meantime, with electricity demand rising rapidly, the politicisation of the debate around renewables as an energy source “makes no sense whatsoever”, he added.
The post Climate at Davos: Energy security in the geopolitical driving seat appeared first on Climate Home News.
Climate at Davos: Energy security in the geopolitical driving seat
Climate Change
A Record Wildfire Season Inspires Wyoming to Prepare for an Increasingly Fiery Future
As the Cowboy State faces larger and costlier blazes, scientists warn that the flames could make many of its iconic landscapes unrecognizable within decades.
In six generations, Jake Christian’s family had never seen a fire like the one that blazed toward his ranch near Buffalo, Wyoming, late in the summer of 2024. Its flames towered a dozen feet in the air, consuming grassland at a terrifying speed and jumping a four-lane highway on its race northward.
A Record Wildfire Season Inspires Wyoming to Prepare for an Increasingly Fiery Future
Climate Change
Analysis: UK newspaper editorial opposition to climate action overtakes support for first time
Nearly 100 UK newspaper editorials opposed climate action in 2025, a record figure that reveals the scale of the backlash against net-zero in the right-leaning press.
Carbon Brief has analysed editorials – articles considered the newspaper’s formal “voice” – since 2011 and this is the first year opposition to climate action has exceeded support.
Criticism of net-zero policies, including renewable-energy expansion, came entirely from right-leaning newspapers, particularly the Sun, the Daily Mail and the Daily Telegraph.
In addition, there were 112 editorials – more than two a week – that included attacks on Ed Miliband, continuing a highly personal campaign by some newspapers against the Labour energy secretary.
These editorials, nearly all of which were in right-leaning titles, typically characterised him as a “zealot”, driving through a “costly” net-zero “agenda”.
Taken together, the newspaper editorials mirror a significant shift on the UK political right in 2025, as the opposition Conservative party mimicked the hard-right populist Reform UK party by definitively rejecting the net-zero target that it had legislated for and the policies that it had previously championed.
Record climate opposition
Nearly 100 UK newspaper editorials voiced opposition to climate action in 2025 – more than double the number of editorials that backed climate action.
As the chart below shows, 2025 marked the fourth record-breaking year in a row for criticism of climate action in newspaper editorials.
This also marks the first time that editorials opposing climate action have overtaken those supporting it, during the 15 years that Carbon Brief has analysed.
This trend demonstrates the rapid shift away from a long-standing political consensus on climate change by those on the UK’s political right.
Over the past year, the Conservative party has rejected both the “net-zero by 2050” target that it legislated for in 2019 and the underpinning Climate Change Act that it had a major role in creating. Meanwhile, the Reform UK party has been rising in the polls, while pledging to “ditch net-zero”.
These views are reinforced and reflected in the pages of the UK’s right-leaning newspapers, which tend to support these parties and influence their politics.
All of the 98 editorials opposing climate action were in right-leaning titles, including the Sun, the Daily Mail, the Daily Telegraph, the Times and the Daily Express.
Conversely, nearly all of the 46 editorials pushing for more climate action were in the left-leaning and centrist publications the Guardian and the Financial Times. These newspapers have far lower circulations than some of the right-leaning titles.
In total, 81% of the climate-related editorials published by right-leaning newspapers in 2025 rejected climate action. As the chart below shows, this is a marked difference from just a few years ago, when the same newspapers showed a surge in enthusiasm for climate action.
That trend had coincided with Conservative governments led by Theresa May and Boris Johnson, which introduced the net-zero goal and were broadly supportive of climate policies.
Notably, none of the editorials opposing climate action in 2025 took a climate-sceptic position by questioning the existence of climate change or the science behind it. Instead, they voiced “response scepticism”, meaning they criticised policies that seek to address climate change.
(The current Conservative leader, Kemi Badenoch, has described herself as “a net-zero sceptic, not a climate change sceptic”. This is illogical as reaching net-zero is, according to scientists, the only way to stop climate change from getting worse.)
In particular, newspapers took aim at “net-zero” as a catch-all term for policies that they deemed harmful. Most editorials that rejected climate action did not even mention the word “climate”, often using “net-zero” instead.
This supports recent analysis by Dr James Painter, a research associate at the University of Oxford, which concluded that UK newspaper coverage has been “decoupling net-zero from climate change”.
This is significant, given strong and broad UK public support for many of the individual climate policies that underpin net-zero. Notably, there is also majority support for the “net-zero by 2050” target itself.
Much of the negative framing by politicians and media outlets paints “net-zero” as something that is too expensive for people in the UK.
In total, 87% of the editorials that opposed climate action cited economic factors as a reason, making this by far the most common justification. Net-zero goals were described as “ruinous” and “costly”, as well as being blamed – falsely – for “driving up energy costs”.
The Sunday Telegraph summarised the view of many politicians and commentators on the right by stating simply that said “net-zero should be scrapped”.
While some criticism of net-zero policies is made in good faith, the notion that climate change can be stopped without reducing emissions to net-zero is incorrect. Alternative policies for tackling climate change are rarely presented by critical editorials.
Moreover, numerous assessments have concluded that the transition to net-zero can be both “affordable” and far cheaper than previously thought.
This transition can also provide significant economic benefits, even before considering the evidence that the cost of unmitigated warming will significantly outweigh the cost of action.
Miliband attacks intensify
Meanwhile, UK newspapers published 112 editorials over the course of 2025 taking personal aim at energy security and net-zero secretary Ed Miliband.
Nearly all of these articles were in right-leaning newspapers, with the Sun alone publishing 51. The Daily Mail, the Daily Telegraph and the Times published most of the remainder.
This trend of relentlessly criticising Miliband personally began last year in the run up to Labour’s election victory. However, it ramped up significantly in 2025, as the chart below shows.
Around 58% of the editorials that opposed climate action used criticism of climate advocates as a justification – and nearly all of these articles mentioned Miliband, specifically.
Editorials denounced Miliband as a “loon” and a “zealot”, suffering from “eco insanity” and “quasi-religious delusions”. Nicknames given to him include “His Greenness”, the “high priest of net-zero” and “air miles Miliband”.
Many of these attacks were highly personal. The Daily Mail, for example, called Miliband “pompous and patronising”, with an “air of moral and intellectual superiority”.
Frequently, newspapers refer to “Ed Miliband’s net-zero agenda”, “Ed Miliband’s swivel-eyed targets” and “Mr Miliband’s green taxes”.
These formulations frame climate policies as harmful measures that are being imposed on people by the energy secretary.
In fact, the Labour government decisively won an election in 2024 with a manifesto that prioritised net-zero policies. Often, the “targets” and “taxes” in question are long-standing policies that were introduced by the previous Conservative government, with cross-party support.
Moreover, the government’s climate policy not only continues to rely on many of the same tools created by previous administrations, it is also very much in line with expert evidence and advice. This is to prioritise the expansion of clean power and to fuel an economy that relies on increasing levels of electrification, including through electric cars and heat pumps.
Despite newspaper editorials regularly calling for Miliband to be “sacked”, prime minister Keir Starmer has voiced his support both for the energy secretary and the government’s prioritisation of net-zero.
In an interview with podcast The Rest is Politics last year, Miliband was asked about the previous Carbon Brief analysis that showed the criticism aimed at him by right-leaning newspapers.
Podcast host Alastair Campbell asked if Miliband thought the attacks were the legacy of his strong stance, while Labour leader, during the Leveson inquiry into the practices of the UK press. Miliband replied:
“Some of these institutions don’t like net-zero and some of them don’t like me – and maybe quite a lot of them don’t like either.”
Renewable backlash
As well as editorial attitudes to climate action in general, Carbon Brief analysed newspapers’ views on three energy technologies – renewables, nuclear power and fracking.
There were 42 newspaper editorials criticising renewable energy in 2025. This meant that, for the first time since 2014, there were more anti-renewables editorials than pro-renewables editorials, as the chart below shows.
As with climate action more broadly, this was a highly partisan issue. The Times was the only right-leaning newspaper that published any editorials supporting renewables.
By far the most common stated reason for opposing renewable energy was that it is “expensive”, with 86% of critical editorials using economic arguments as a justification.
The Sun referred to “chucking billions at unreliable renewables” while the Daily Telegraph warned of an “expensive and intermittent renewables grid”.
At the same time, editorials in supportive publications also used economic arguments in favour of renewables. The Guardian, for example, stressed the importance of building an “affordable clean-energy system” that is “built on renewables”.
There was continued support in right-leaning publications for nuclear power, despite the high costs associated with the technology. In total, there were 20 editorials supporting nuclear power in 2025 – nearly all in right-leaning newspapers – and none that opposed it.
Fracking was barely mentioned by newspapers in 2023 and 2024, after a failed push by the Conservatives under prime minister Liz Truss to overturn a ban on the practice in 2022. This attempt had been accompanied by a surge in supportive right-leaning newspaper editorials.
There was a small uptick of 15 editorials supporting fracking in 2025, as right-leaning newspapers once again argued that it would be economically beneficial.
The Sun urged current Conservative leader Badenoch to make room for this “cheap, safe solution” in her future energy policy. The government plans to ban fracking “permanently”.
North Sea oil and gas remained the main fossil-fuel policy focus, with 30 editorials – all in right-leaning newspapers – that mentioned the topic. Most of the editorials arguing for more extraction from the North Sea also argued for less climate action or opposed renewable energy.
None of these editorials noted that the UK is expected to be significantly less reliant on fossil-fuel imports if it pursues net-zero, than if it rolls back on climate action and attempts to squeeze more out of the remaining deposits in the North Sea.
Methodology
This is a 2025 update of previous analysis conducted for the period 2011-2021 by Carbon Brief in association with Dr Sylvia Hayes, a research fellow at the University of Exeter. Previous updates were published in 2022, 2023 and 2024.
The count of editorials criticising Ed Miliband was not conducted in the original analysis.
The full methodology can be found in the original article, including the coding schema used to assess the language and themes used in editorials concerning climate change and energy technologies.
The analysis is based on Carbon Brief’s editorial database, which is regularly updated with leading articles from the UK’s major newspapers.
The post Analysis: UK newspaper editorial opposition to climate action overtakes support for first time appeared first on Carbon Brief.
Analysis: UK newspaper editorial opposition to climate action overtakes support for first time
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