The retreat of sea ice in the Arctic has long been a prominent symbol of climate change.
Observations reveal that Arctic sea ice extent at the end of summer has halved, since satellite records began in the late 1970s.
Yet, since the late 2000s, the pace of Arctic sea ice loss has slowed markedly, with no statistically significant decline for about 20 years.
In new research, published in Geophysical Research Letters, my colleagues and I explore the reasons for the recent slowdown of Arctic sea ice – and turn to climate models to understand what might happen next.
Our findings show that, rather than being an unexpected or rare event, climate model simulations suggest we should expect periods like this to occur relatively frequently.
This current slowdown is likely caused by natural fluctuations of the climate system – just as they played a part in an acceleration of sea ice loss in the decades prior.
Were it not for human-caused warming, it is likely that sea ice would have increased over this period.
According to our simulations, the slowdown could even last for another five or 10 years – even as the world continues to warm.
Widespread slowdown
The changes in the Arctic are one of the most clear and well-known indicators of a warming climate.
With the Arctic warming up to four times the rate of the global average, the region has lost more than 10,000 cubic kilometres of sea ice since the 1980s. (The volume of ice lost is roughly equivalent to 4bn Olympic swimming pools).
Arctic sea ice reached its smallest extent on record in September 2012, dwindling to 3.41m square kilometres (km2). This triggered discussions of when the Arctic might see its first “ice-free” summer, where sea ice extent drops below 1m km2.
Research has shown that human-caused warming is responsible for up to two-thirds of this decline, with the remainder down to natural fluctuations in the climate system, also known as “internal climate variability”.
Despite the record low of 2012, satellite data reveals a widespread slowdown in Arctic sea ice loss over the past two decades.
Climate model simulations of Arctic sea ice thickness and volume further reinforce these observations, indicating little or no significant decline over the past 15 years.
This data is laid out in the charts below, which show average sea ice extent in September (left) and for the whole year (middle), as well as how annual average sea ice volume differs from the long-term average (right).
(September is typically the point in the year where sea ice reaches its annual minimum, at the end of the Arctic summer.)
The coloured lines indicate that the data originates from the National Snow and Ice Data Centre (NSIDC, orange), the Ocean and Sea Ice Satellite Application Facility (OSISAF, red) and the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS, blue).
These observational records show how the precipitous decline in sea ice seen over much of the satellite data has slowed since the late 2000s.
It also shows that the slowdown is not limited to summer months, but is occurring year-round.
Our study is not the first to highlight this slowdown – several recent studies have also examined various aspects of this phenomenon. Meanwhile, a 2015 paper was remarkably prescient in suggesting such a slowdown could occur.
Is the slowdown surprising?
The loss of sea ice around the north pole is both a cause and effect of Arctic amplification – the term given to the rapid warming in the region.
Melting snow and ice reduces the reflectiveness, or “albedo”, of the Arctic’s surface, meaning less incoming sunlight is reflected back out to space. This causes greater warming and even more melting of ice and snow.
This “surface-albedo feedback” is one of several drivers of Arctic amplification.
Given global warming is caused by the continued rise in greenhouse gas emissions, it might seem puzzling – or even impossible – that Arctic sea ice loss could slow down.
However, the recent generations of climate models used for the Coupled Model Intercomparison Project (CMIP) – the international modelling effort that feeds into the influential reports from the Intergovernmental Panel on Climate Change (IPCC) – illustrate why this might be happening.
Models from CMIP5 and CMIP6, which simulate the historical period and explore different future warming scenarios, indicate that slowdowns in Arctic sea ice loss lasting multiple decades are relatively common – happening in roughly 20% of model runs.
This is due to natural variability in the climate system, which can temporarily counteract decline of sea ice – even under high-emission scenarios.
One way that climate scientists investigate natural variability is by running multiple simulations of a model, each with identical levels of human-caused emissions of carbon dioxide, aerosols and methane. These are known as “ensembles”.
Due to the chaotic nature of the climate system, which results in different phases of natural variability, the different model runs produce different outcomes – even if the long-term climate change signal from human activity remains constant.
Large ensembles help us to understand how to interpret the Earth’s observed climate record, which has been influenced by both human-induced climate change and natural variations.
In our research, we examine how many individual model runs within the ensemble exhibit a similar or greater slowdown in sea ice loss than the observed record over 2005-24.
The models show that natural climate variability can accelerate sea ice loss, as seen during the dramatic record-lows in 2007 and 2012. However, this natural variability can also temporarily slow the longer-term downward trend.
The primary suspects behind this multi-decade variability are natural fluctuations linked to the tropical Pacific and the North Atlantic, although the precise causes are yet to be quantified.
For example, a shift from the positive, warm phase to the negative, cool phase of a natural cycle in the Interdecadal Pacific Oscillation is associated with bringing much cooler waters close to the North American coastline and into the Arctic. This could potentially lead to sea ice growth.
What might happen to Arctic sea ice cover next?
So how long could this current slowdown persist?
Climate model simulations suggest the current slowdown might continue for another five or 10 years.
However, there is an important caveat: slowdowns like this often set the stage for faster declines later.
Climate models suggest that when the slowdown inevitably ends, the rate of sea ice loss could rapidly accelerate.
Thousands of simulations analysed in our research reveal that September sea ice loss ramps up at a rate of more than 500,000km2 per decade after prolonged periods of minimal sea ice loss.
This would equate to more than 10% of current sea ice cover in September.
An analogy of Arctic sea ice extent behaving like a ball bouncing downhill – set out in a 2015 Carbon Brief article by Prof Ed Hawkins – is particularly apt here.
Just like the ball – which eventually reaches the bottom due to gravity, despite an erratic journey – Arctic sea ice loss may temporarily seem to defy expectations at present.
Ultimately, however, sea ice loss will resume, reflecting the underlying human-induced warming trend.
While it may seem contradictory that Arctic sea ice loss can slow even as global temperatures climb, climate models clearly show that such periods are expected parts of climate variability.
As a result, the recent slowdown in Arctic sea ice does not signal an end to climate change or lessen the urgency of cutting greenhouse gas emissions, if global goals are to be met.
While the current slowdown might persist for some years to come, when sea ice loss resumes, it could do so with renewed intensity.
The post Guest post: Why the recent slowdown in Arctic sea ice loss is only temporary appeared first on Carbon Brief.
Guest post: Why the recent slowdown in Arctic sea ice loss is only temporary
Climate Change
‘This is a fossil fuel crisis’, Greenpeace tells Senate gas tax Inquiry, citing homegrown renewables as path to energy security
CANBERRA, Tuesday 21 April 2026 — Greenpeace Australia Pacific has slammed gas corporation war profiteering and environmental damage in a scathing Senate hearing today as part of the Select Committee on the Taxation of Gas Resources, urging fair taxation of gas corporations and the transition to secure, homegrown renewable energy to protect Australian households and the economy from future energy shocks.
Speaking at the hearing, Greenpeace said the US and Israel’s illegal war on Iran has laid bare the fundamental flaws of an energy system built on fossil fuel extraction, geopolitical power plays and corporate greed, and will be a defining moment for how the world thinks about energy security.
Greenpeace’s submission and full opening remarks can be found here.
Joe Rafalowicz, Head of Climate and Energy at Greenpeace Australia Pacific, said:
“This is not an energy crisis, it’s a fossil fuel crisis. The crisis we’re all facing lays bare the dangers of fossil fuel dependence, for our energy security, our communities, and for global peace and stability.
“Gas corporations like Woodside, Santos, Shell and Chevron — the same companies whose CEOs refused to front this Inquiry — are making obscene war profits, using the illegal war on Iran to price gouge, profiteer and push for more gas we don’t need — while people and our environment pay the price.
“Australians are getting smashed by soaring bills and the impacts of climate disasters — gas corporations should be paying their fair share to help this country, instead of sending billions offshore, tax-free.
“But we’re at a turning point — while gas corporations cynically push to open up more of our oceans and land to drilling for fossil fuels, our allies like the UK are doubling down on renewables in response to the fossil fuel crisis. Our trading partners in Asia are making the same reassessment of fossil fuels.
“Which is why the hearing today is crucial: an effective and well-designed tax on the gas industry’s obscene war time profits is a chance to channel funds to people and communities, fast-track the rollout of clean, secure homegrown wind and solar energy, while holding polluters accountable.
“Our dependence on fossil fuels leave us overexposed to the whims of tyrants like Trump — it’s in Australia’s national interest to end the fossil fuel chokehold for good and usher in the era of clean energy security.”
-ENDS-
Media contact
Kate O’Callaghan on 0406 231 892 or kate.ocallaghan@greenpeace.org
HOW WOODSIDE’S BROWSE GAS PROPOSAL THREATENS SCOTT REEF’S GREEN TURTLES AND PYGMY BLUE WHALES
Woodside’s Browse to NWS gas project is under assessment by the WA and Federal Governments right now. This is a project that involved drilling up to 50 gas wells around Scott Reef off the coast of WA. Gas would be extracted directly underneath Scott Reef and Sandy Islet and pumped through a 900-kilometre subsea pipeline to the NWS gas processing facility.
Woodside’s Browse gas project’s impact on Scott Reef’s marine habitats?
Scott Reef is one of Australia’s most ecologically significant marine environments, where green turtles breed, pygmy blue whales feed, and an array of at-risk species, including sharks, dolphins, whale sharks, rays, sawfish and sea snakes thrive. It is home to many threatened species, including some found nowhere else on Earth or in genetically isolated groups, magnifying its importance from a conservation perspective.
This delicate reef’s ecosystem faces multiple threats if Woodside’s Proposed Project goes ahead, including seismic blasting, gas flaring, noise pollution, artificial lighting, pipe laying and fast-moving vessels. The reef also faces the risk of a gas well blowout, which could have catastrophic and irreversible consequences for the region’s reefs and marine parks.
Woodside’s woeful marine impacts management plan
To secure their approvals, Woodside had to develop a plan for how they would manage the significant risks to threatened green turtles and endangered pygmy blue whales if the project proceeds. We’ve had two independent scientists provide a technical assessment of Woodsides management plan for whales and turtles and their findings are gobsmacking.
Their assessment found that Woodsides management plans for these species misrepresents or does not assess the risks the Browse project poses to Scott Reef’s pygmy blue whales and green turtles. They’ve also surmised that if the project goes ahead the impacts contradict the Australian government’s own recovery plan for turtles and Conservation Management Plan (CMP) for Blue Whales.
The State and Federal Governments now have the opportunity to define their legacies on nature protection and save Scott Reef from Woodside’s dirty gas.
Technical Assessment of Woodside’s Browse Pygmy Blue Whale Management Plan
Prepared for Greenpeace Australia Pacific by Dr Ben Fitzpatrick of Oceanwise Australia with Dr Olaf Meynecke of Griffith University.
The full technical assessment is available HERE
Scott Reef is a vital feeding, foraging and resting habitat for pygmy blue whales.
Pygmy blue whales feed, forage and rest in the Scott Reef region every year. Scott Reef is recognised as a Biologically Important Area for the pygmy blue whale and is an important stop-over on their annual migration.
Woodside’s Browse gas project could delay or prevent the population recovery of the endangered pygmy blue whales that rely on Scott Reef, heightening their extinction risk.
- Woodside’s management plan claims of “no credible threat of significant impacts” are not supported by scientific evidence.
- The management plan relies on outdated whale population information.
- Woodside has claimed it is unclear whether Scott Reef is a foraging habitat for pygmy blue whales, despite the presence of pygmy blue whales and significant concentrations of krill being documented in the area.
- The PBWMP ignores the impacts of industrial noise on whale-to-whale communication. This is especially concerning as mother-calf pairs migrate through the Scott Reef Biologically Important Area shortly after calves are born. Mother-calf pairs rely on continuous, uninterrupted communications to maintain their connection.
Woodside’s Browse gas project could delay or prevent the population recovery of the endangered pygmy blue whales that rely on Scott Reef, heightening their extinction risk.
Technical Assessment of Woodside’s Browse Turtle Management Plan
Prepared for Greenpeace Australia Pacific by Dr Ben Fitzpatrick of Oceanwise Australia.
The full technical assessment is available HERE
Scott Reef is a vital nesting ground for unique green turtles.
The green turtles that nest at Scott Reef’s low-lying Sandy Islet sand cay and nearby Browse Island are genetically unique and are classified as ‘Extremely Vulnerable’ in Australia’s Recovery Plan for Marine Turtles.
Woodside’s Browse gas project could make Scott Reef’s unique green turtles extinct.
- The Browse project would operate within 20 kilometres of nesting habitat that’s critical to the survival of Scott Reef’s genetically unique and vulnerable green turtle population.
- Woodside’s Browse Turtle Management Plan (TMP) misrepresents the risks the Browse project poses to Scott Reef’s green turtles.
- Claims in Woodside’s TMP about Scott Reef’s green turtle population size, nesting success and hatchling numbers are not backed by scientific evidence.
- The TMP proposes gathering updated data after the Browse project is approved.
- Woodside’s TMP proposes adding sand sourced elsewhere to Sandy Islet to counter subsidence and erosion, but fails to properly assess the associated risks.
To save Scott Reef and protect our oceans and animals, the State and Federal Governments must reject Browse.
Technical Assessment of Woodside’s Browse Pygmy Blue Whale Management Plan
To secure their approvals, Woodside had to develop a plan for how they would manage the significant risks to threatened green turtles if the project proceeds. We’ve had two independent scientists provide a technical assessment of Woodside’s management plan for whales and turtles and their findings are gobsmacking.
Woodside’s Browse gas project could make Scott Reef’s unique green turtles extinct.
Woodside’s Browse gas project could delay or prevent the population recovery of the endangered pygmy blue whales that rely on Scott Reef, heightening their extinction risk.
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