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While 2023 made headlines for smashing global temperature records, last year also saw some truly remarkable events in the Antarctic.

After crashing to a record-low summer extent in February, sea ice around the southern continent regrew extremely slowly.

By July, when sea ice should be approaching its maximum winter coverage, there was an area of ice “missing” that was bigger than Algeria – the world’s 10th largest country.

When the annual maximum extent arrived – early – it was the smallest on record by a “wide margin”.

This made 2023 the second record-breaking year in a row, continuing the recent erratic swings in sea ice cover that had otherwise been preceded by several decades of steady, gradual increase.

In our new paper, published in the Royal Meteorological Society’s journal Weather, my coauthor and I explore what happened to sea ice in 2023, what caused the dramatic events and what the implications are for the future.

The importance of Antarctic sea ice

Antarctic sea ice is a critical puzzle piece in the regional and global climate picture.

The frozen continent as a whole acts as the Earth’s principal refrigerator, reflecting the sun’s energy from its bright, white mirror-like surface, helping keep temperatures cool.

Sea ice formation around its coastline acts as an engine for ocean currents and influences weather patterns that can have far-reaching effects.

Floating ice also acts as a buffer that can protect the exposed edges of the ice sheet from the destructive action of waves, meaning that it can curb Antarctica’s contribution to sea level rise. ​​By influencing the availability of water from the open ocean, it also affects how much snow can fall to replenish the ice sheet’s losses.

And sea ice is vitally important for marine life, as demonstrated by the “catastrophic breeding failure” of Emperor penguin chicks following the (then) record-low sea ice coverage in 2022.

Long-term trends

Thanks to satellite data, scientists have a detailed picture of how Arctic and Antarctic sea ice have behaved since the late 1970s. And for Antarctica, this picture has been something of a puzzle.

Between 1979 and 2015, average Antarctic sea ice extent – the area of ocean with at least 15% sea ice cover – increased slightly, but fairly steadily. This is in stark contrast to the Arctic, where sea ice at the minimum summer extent plummeted by nearly 12% per decade.

Then, after a record high year in 2014, Antarctic sea ice extent dropped to a record low in 2017. Several years of low sea ice came after that, with the summer minimum record smashed in 2022, when it fell below 2m square kilometres for the first time.

How extreme was 2023?

Antarctic sea ice waxes and wanes throughout the year, reaching a minimum in February at the end of the southern-hemisphere summer and a maximum in September after a long, cold winter.

This seasonal expansion causes the area covered by sea ice to grow six-fold within a single year – as the chart below shows. It depicts Antarctic sea ice extent for each day of 2023 (blue line), along with how it compares to the historical range (blue shading) and the record low for the time of year (dotted line).

Antarctic daily sea ice extent from the US National Snow and Ice Data Center. The bold lines show daily 2023 values, the shaded area indicates the two standard deviation range in historical values between 1979 and 2010. The dotted line shows the record low. Chart by Carbon Brief.

Antarctic daily sea ice extent from the US National Snow and Ice Data Center. The bold lines show daily 2023 values, the shaded area indicates the two standard deviation range in historical values between 1979 and 2010. The dotted line shows the record low. Chart by Carbon Brief.

As the chart shows, 2023 was an exceptional year in the satellite record, remaining well below average for the entire year. 

The year started with a record-breaking minimum extent of 1.79m km2 in February 2023, which was 10% lower than the already record-breaking 2022.

Although the autumn freeze-up started off as usual, from April the seasonal expansion of sea ice was very slow. By July, the total sea ice extent was 13.5m km2 – 15% lower than average for the month.

The area of “missing” sea ice for the month of July, relative to the 1981–2010 average, was nearly two-and-a-half million square kilometres – an area larger than Algeria.

The period of extreme departure from average persisted from mid-May until mid-November, with conditions recovering a little, meaning that by the end of the year, they were no longer record-breaking.

Overall, the largest deviations from average conditions in 2023 were recorded in winter (June to August). To see this in context, the chart below shows winter sea ice extent from 1979 to 2023 and highlights how dramatically low winter sea ice was last year.

Record low average winter Antarctic sea ice extent in 2023
Timeseries of average winter (June, July and August, JJA) sea ice extent over 1979-2023 as observed by satellites (data from the National Snow and Ice Data Centre). Note that the y-axis does not begin at zero. Chart by Carbon Brief.

In addition, the table below shows the average winter sea ice extent and the anomaly – that is, the departure from the 1981-2010 average. It is clear that at 2.34m km2, the anomaly in the winter of 2023 was larger than in any other year. The next largest was 0.93m km2 in 2022.

Year JJA mean extent (million km2) JJA anomaly (million km2)
2023 13.34 -2.34
2022 14.75 -0.93
2002 14.95 -0.73
2017 14.97 -0.71
1986 15.00 -0.69

Table showing the top five years with largest negative winter sea ice extent anomalies with respect to 1981–2010, ranked from lowest sea ice extent to highest. All extents and anomalies are shown in millions of square kilometres. Source: Gilbert & Homes (2024)

Drivers of low sea ice conditions

There is no single cause of record-low sea ice conditions, but it is likely that a combination of oceanic and atmospheric factors conspired to produce 2023’s record sea ice conditions.

Recent studies have pointed to the important role of ocean processes and heat stored below the surface, which have kept sea ice extent low since 2016. Warm sea surface temperatures in the Southern Ocean during the first half of 2023 probably also partly explain both the record minimum extent in February and the slow freeze-up afterwards.

But Antarctic sea ice is also closely controlled by atmospheric circulation. One such circulation pattern is the Amundsen Sea Low, which is a low-pressure weather system that consistently forms off the coast of West Antarctica. Exactly where it is and how low the atmospheric pressure gets can control winds and temperature in the region, impacting the movement, breakup, formation and destruction of sea ice.

The pattern in sea ice in 2023 was closely tied to the behaviour of the Amundsen Sea Low, which was unusually deep and far to the east in winter when the sea ice anomalies were at their peak.

This situation tends to blow warm air towards the coast and push sea ice back, limiting sea ice growth during the freeze-up season.

Other large-scale weather patterns – such as the Southern Annular Mode and El Niño-Southern Oscillation have historically contributed to the ups-and-downs observed in Antarctic sea ice, but they do not seem to have had a major influence in 2023.

These weather patterns can interact to either amplify or suppress sea ice changes by affecting the ways that sea ice moves, melts and freezes.

Links with climate change

Deciphering the role of climate change in Antarctic sea ice trends is much more complicated than in the Arctic because conditions are impacted by so many competing factors.

However, the sheer magnitude of 2023’s sea ice lows suggests that something unusual is happening.

Sea ice conditions during 2023 were far outside the bounds of normality, but it is difficult to say exactly how far. That is because the satellite record is relatively short (45 years) and the system is highly variable. In addition, climate change is already impacting the Southern Ocean in complex ways, making an estimation of what is “normal” impossible.

Climate models project a decline in Antarctic sea ice in response to greenhouse gas emissions and rising temperatures. However, until 2015 this prediction was largely at odds with what scientists were seeing – in part due to the complexity and uncertainty of the processes involved, and the impractically high detail required to accurately represent sea ice in models.

However, despite their limitations, it seems inescapable that models will ultimately be correct about Antarctic sea ice decline. Human emissions are raising temperatures in the Southern Ocean, and studies show a link between ocean warming and low Antarctic sea-ice extents.

Several papers – including one discussed in a previous Carbon Brief guest post – have argued that recent record-low sea ice years may be a taste of what is to come.

With 2024 likely to be another year of high global average temperatures and weather extremes, it may emerge as another year of low Antarctic sea ice. Although current sea ice extent is no longer the lowest on record, conditions are still well below the 1981-2010 average, and this situation may well persist into the 2024 melt season.

So, while it is too early to say conclusively that the recent sea-ice lows are the beginning of a regime shift in Antarctic sea ice, it seems inevitable that it will eventually decline in response to human-caused climate change.

For now, all scientists can say for certain is that the events of 2023 were entirely remarkable and unlike anything seen in the satellite record.

The post Guest post: Why 2023 was an exceptional year for Antarctic sea ice appeared first on Carbon Brief.

Guest post: Why 2023 was an exceptional year for Antarctic sea ice

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More support needed to power Africa’s food systems with renewables, experts say

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As efforts to expand energy access across Africa grow, experts and policymakers have called this week for greater coordination and investment to power food production with renewables, arguing the sector has been treated separately from energy policy and therefore faces barriers in going green.

Hailemariam Desalegn, former prime minister of Ethiopia, said energy is critical across the food value chain – from irrigation and processing to cold storage and transport – and should therefore be considered a key pillar of strengthening food systems for the future.

“Energy is not separate from the nutrition challenge. Irrigation needs energy. Cold storage, transport, processing, as well as markets – all need reliable energy,” Desalegn told a panel at the 20th session of the Africa Food Systems Forum in Kigali. He said investments in sustainable energy systems could help reduce post-harvest losses and make nutritious food more accessible and affordable.

Africa loses up to 30% of its food before it reaches markets annually, largely due to poor roads, weak storage and inadequate cold chains, according to a 2025 report by the Alliance for a Green Revolution in Africa (AGRA).

    Akinyi Walender, Africa director at development charity Practical Action, said poor energy supply in rural communities – where much of Africa’s food is produced – is also limiting productivity. Across the continent, about 600 million people currently live without access to electricity.

    “The lack of energy access goes well beyond the inconvenience of not having lighting at home,” Walender said, adding that renewable energy has the potential to power local economies. “When people can access this sort of energy, it can raise rural incomes, improve food security, improve resilience, empower women and stimulate enterprise while creating jobs,” she added.

    Breaking down silos

    Unlocking the potential of energy across food systems requires greater coordination, Walender argued, pointing to institutional fragmentation and isolated pilot projects as major barriers.

    “Organisations working on agriculture and energy often operate according to different modalities and the interdependence between agricultural and energy markets is often overlooked,” Walender said, adding that finance institutions also tend to work in silos.

    High level dialogue on climate resilience at the Africa Food Systems Forum in Kigali, September, 2026.(Photo: AFS Forum)

    Dana Rysankova, global lead for energy access at the World Bank, told a separate event at the forum that the bank is working to break down those barriers through its newly established Productive Use of Energy (PUE) Centre of Excellence based in Nairobi, which has a mandate to foster collaboration and help develop and design programmes across different sectors.

    Can giant batteries unlock Africa’s green industrial future?

    In June, the World Bank Group and the African Development Bank Group said that over 50 million people had been connected to electricity across 40 African countries under their Mission 300 initiative, which aims to provide electricity access to 300 million Africans by 2030.

    Rysankova said the programme has shown that energy access is just the foundation for linking with other sectors to deliver real economic transformation by boosting productivity and local incomes.

    Mission 300 also aims to electrify schools and healthcare services, as well as bringing power to farmers so that they can use it for irrigation, cold storage and other agricultural activities, she added. 

    Bridging the finance and infrastructure gap

    Experts said bigger investments are needed in infrastructure and finance to turn energy access into increased productivity and economic value.

    AGRA’s 2026 foresight report, launched at the forum, puts the annual agrifood financing gap at $180 billion, while estimating that closing Africa’s yearly $67 billion-$108 billion shortfall in infrastructure finance could halve post-harvest losses and increase farmer incomes by up to 40%.

    However, the cost of transitioning to clean energy is still a major barrier for farmers and agribusinesses.

    Delegates at the Africa Food Systems Forum, September, 2026 (Photo: AFS Forum)

    Delegates at the Africa Food Systems Forum, September, 2026 (Photo: AFS Forum)

    Atinuke Lebile, CEO of Nigerian food processing company Cato Foods, told Climate Home News she would like to switch to using renewables but has been held back by the upfront cost of setting up the systems the firm needs.

    Rwandan farmer Gezel also said she would like to invest in a solar irrigation pump, but “it is so expensive”.

    Practical Action’s Walender said the challenge is no longer whether solutions exist, but how financial support can reach the communities and businesses where it could have the greatest impact.

    “Customers are dispersed and have low incomes. Markets are fragmented, and there are high upfront costs for much energy equipment,” Walender said, adding that financial institutions also often perceive agriculture as a high-risk sector.

    Egypt seeks to unlock renewable potential to power regional clean energy hub

    For food processing, the business case for using cleaner energy more efficiently is particularly strong, said Vivian Maduekeh of Partners in Food Solutions, which has worked with more than 2,000 companies across Africa.

    Maduekeh said food processing firms account for between 42 and 70% of energy use across food systems, while energy represents 15-22% of their total production costs. African food businesses also use roughly twice as much energy per kilogramme of product as their global competitors, putting them at a competitive disadvantage.

    The problems they face in shifting to clean energy are “risk, perception of risk and the cost”, she explained, adding that financial mechanisms are needed to help businesses overcome those issues.

    Maduekeh encouraged policymakers to consider measures like tax rebates on imported equipment and spending more on research and development to bring down the cost of productive-use technologies.

    Making a range of affordable equipment available – such as smaller irrigation pumps – could also help make the transition more accessible, she said. The evidence in favour “is very clear”, she added. “We just need to package it and communicate it to the priorities of investors.”

    The post More support needed to power Africa’s food systems with renewables, experts say appeared first on Climate Home News.

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    UK’s budget juggling trick with rainforest loan for bus-fare cap needs transparency

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    Andy Burnham, the UK’s latest prime minister, has suggested reducing the amount the British government gives as climate finance grants and providing some of its climate finance through loans instead, in a move it anticipates will save £400 million. 

    The government plans to use the savings to fund a cap on bus fares in the UK, triggering accusations from the development sector that Burnham’s proposal “throws Global South countries under the bus”. One likely destination for these new loans is the Tropical Forest Forever Facility (TFFF). 

    Will new UK PM’s green measures at home cause climate finance pain overseas?

    The TFFF is a new initiative designed to provide payments to countries that protect their rainforests by raising money from governments and private investors, channeling that money into riskier and therefore higher return assets, and using the returns it earns to fund forest protection. But there is a catch.

    The UK has committed to provide around £6 billion in climate finance funded through aid (or official development assistance, ODA) over the next three years. If switching from grants to a loan to the TFFF reduces government spending, it will likely reduce the amount that counts as ODA as well. 

    In other words, the government can make the £400 million saving, or meet its £6 billion aid budget-funded climate finance commitment, but it probably cannot do both. The UK cannot have its cake and eat it.

    How will it score as ODA?

    Whether any loan to the TFFF scores as ODA depends on the OECD’s Development Assistance Committee (DAC) which is currently deliberating on this topic

    A plain reading of the DAC’s current reporting rules suggests that the TFFF would count as a multilateral organisation: the independent investment arm, the Tropical Forest Investment Fund, would ultimately be a global, official entity (with sovereign governments appointing the board and being sole equity holders), which pools capital from sponsor governments. This would mean that to count as ODA, any loan to it would have to charge less than 5% interest.

    Tropical forest protection fund at risk after UK stalls on pledge

    The current concept note suggests a return for sponsor capital equivalent to US borrowing costs of a similar duration: currently around 5.2%, which would make any such loans ineligible. The UK could choose to charge less, but if the UK charges less than it borrows (also above 5%), the difference will add to the deficit in future years. And ODA accounting is not binary: if the UK charges just under 5%, only a small fraction of the loan would count.

    At the same time, the risk profile of TFFF is not the same as your average multilateral, and there is speculation that the DAC could allow higher interest loans to TFFF to partially count (by changing the ‘discount rate’ used to measure how concessional the loan is). The TFFF’s own modelling suggests that the risk of the UK losing money on the loan would be fairly limited: roughly a 1% chance of some capital impairment in the riskiest scenario. But some analysts doubt the accuracy of this model and view the risk as much greater.

    Launch event of the Tropical Forest Forever Facility (TFFF) fund in Belem during COP30. (Photo: Alex Ferro/COP 30)

    Launch event of the Tropical Forest Forever Facility (TFFF) fund in Belem during COP30. (Photo: Alex Ferro/COP 30)

    Would it really save money?

    If the risk really is higher, then it might justify counting more ODA on a loan to the TFFF, but it also undermines the arguments that this would create savings for the government. Loans generally don’t count towards the deficit because they create an asset. But that only works if the loan is expected to be fully repaid. If there is a material risk of losing money, then at least some of the transaction will also count towards the deficit.

    One possibility is that the loan will be ‘partitioned’ into a financial asset (the part which is expected to be repaid and wouldn’t count towards the deficit) and a ‘capital transfer’ (the part not expected to be repaid). The greater the risk, the larger that second component, and the bigger the impact on the deficit.

    This would be the ODA and public accounting rules working as intended. ODA is a measure of ‘donor effort’, usually taken to mean fiscal impact. If it counts as ODA, it should have an impact on the deficit. And the fiscal treatment itself is governed by numerous international accounting standards, a key purpose of which is preventing politically motivated obfuscation of how governments spend their money. If it costs money, there should be an impact on the deficit even if it is a loan. If it doesn’t, it shouldn’t count as ODA (even if there have been exceptions in the past).

    UK halves Green Climate Fund contribution, as it spends more on security

    Base funding on need, not accounting

    We still know too little about the details to be sure how a loan to the TFFF (or a more exotic transaction) would count towards either ODA or the UK’s headline measures of debt and deficit. The key parameter for each is risk: the lower risk, the more likely it is that the transaction will save money, but the greater the chance that the government would have to spend more ODA elsewhere to meet its climate finance target.

    If the UK believes in the TFFF business model and wants to preserve tropical forests, then it should invest. But this decision should not be driven by optimistic accounting tricks. The government cannot expect to reduce the real value of climate finance to partner countries by giving less in grant money, without this having an impact on commitments to spend that money.

    The post UK’s budget juggling trick with rainforest loan for bus-fare cap needs transparency appeared first on Climate Home News.

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    Coal mine approval as Albanese meets Pacific leaders undermines Pacific partnership, as UN warns of 1.5C overshoot

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    SYDNEY, Thursday 3 September 2026 — Greenpeace Australia Pacific has branded the Albanese government’s approval of BHP’s coal mine extension in Central Queensland an affront to Pacific leaders and communities grappling with climate disasters, and a reckless move that undermines Australia’s partnership with the Pacific as the PM meets regional leaders at the Pacific Islands Forum.

    The approval of BHP’s coal Saraji Mine Grevillea Pit Continuation Project, an extension of one of Australia’s largest coal mines, would allow mining to continue for another 30 years, locking in the production and export of polluting coal and fuelling dangerous extreme weather disasters and sea level rise in Australia and across the Pacific. It will be the 10th fossil fuel project approved during this term of government and the 37th new fossil fuel project approved since the Albanese government was elected in 2022. 

    The announcement comes as a UN report warns of dangerous climate overshoot, and just two months before Federal Climate and Energy Minister Chris Bowen is due to take the reins of UN climate negotiations at COP31 — a moment that will test the government’s climate credibility and bring global attention to Australia’s fossil fuel exports. It also comes as fracked gas from the Beetaloo Basin climate bomb started flowing.

    Speaking from Palau, Dr Simon Bradshaw, COP31 Lead at Greenpeace Australia Pacific, said: “It is deeply insincere for Prime Minister Albanese to meet Pacific leaders here in Palau to discuss security, the energy crisis, and regional threats, while his government fast-tracks the biggest security threat to the Pacific, the climate crisis.

    “As leaders meet, thousands remain missing or dead in the Nepal-Tibet floods. Parts of Australia are bracing for a heatwave that will see temperatures approach 40 degrees, just days out of winter, and a new report finds 2,000 kilometres of coral reefs along the WA coast experienced the worst coral bleaching on record.

    “We are witnessing dangerous climate change driven by the production, export and burning of fossil fuels, wreaking havoc across the world. Continuing down the path of fossil fuels and approving new coal is an act of recklessness at a pivotal moment in the world’s energy transition and response to the climate crisis. Communities must not pay the price for fossil fuel greed.

    “No more double talk. Australia must get squarely behind longstanding Pacific leadership on climate change, fight to protect the all-important goal of limiting warming to 1.5°C, and ensure that COP31 builds further momentum in the global transition away from fossil fuels.

    “A pathway back to 1.5°C is possible. The Pacific Pre-COP and COP31 in Türkiye are critical moments for Australia to work with Pacific leaders to better align energy, climate and trade policies towards a prosperous shared future beyond fossil fuels.”

    -ENDS-

    Media contact

    Kate O’Callaghan on 0406 231 892 or kate.ocallaghan@greenpeace.org

    Coal mine approval as Albanese meets Pacific leaders undermines Pacific partnership, as UN warns of 1.5C overshoot

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