Antarctic sea ice has reached its maximum extent for the year, clocking in at the second lowest in a record stretching back to 1979, according to provisional data from the US National Snow and Ice Data Centre (NSIDC).
Over the past two years, Antarctic sea ice has been “way outside anything we have witnessed in our satellite record for their winter months”, an expert tells Carbon Brief.
Meanwhile, at the Earth’s other pole, the Arctic reached its summer minimum extent on 11 September, ranking as the seventh lowest on record, according to the NSIDC.
The organisation notes that “the last 18 years are the lowest 18 Arctic sea ice extents in the satellite record”.
The combination of below-average Arctic and Antarctic sea ice extents means that global sea ice extent has been at near-record lows over the past six months.
Antarctic maximum
For decades, scientists have been using satellite data to track the annual cycle of sea ice growth and melt at the world’s poles. This is a key way to monitor the “health” of sea ice in both the Arctic and Antarctic.
This year, Antarctic sea ice extent reached its annual maximum extent of 17.2m square kilometres (km2) on 19 September, according to the NSIDC. This is the second lowest in a satellite record stretching back 46 years, and 1.6m km2 smaller than the 1981-2010 average maximum, the NSIDC notes.
However, the NSIDC cautions that there is “some uncertainty in the estimate and date of the maximum because of an outage in the input source data” over 12-18 September.
Dr Zack Labe is a research physical scientist at NOAA’s Geophysical Fluid Dynamics Laboratory. He tells Carbon Brief that there is ongoing research in the polar community to understand whether Antarctic sea ice is undergoing a “regime shift”.
He adds that the past two years have been “way outside anything we have witnessed in our satellite record for their winter months” for Antarctic sea ice.
For example, Dr Ariaan Purich – from the school of Earth, atmosphere and environment at Monash University – explains to Carbon Brief:
“Our research suggests ocean warming has been important in pushing sea ice into this low-coverage state, and we also see preliminary indications of changed sea ice behaviour, suggesting that the underlying processes controlling Antarctic sea ice coverage may have altered.”
Global sea ice extent – a metric that combines Arctic and Antarctic sea ice extent – is currently tracking near the record low extent set last year.
The graphic below shows global sea ice extent over 1978-2024, where red indicates the 2024 extent and shades of blue indicate different years over 1978-2023 (darker colours indicate more recent years).
Labe tells Carbon Brief that global sea ice extent is an “unconventional metric”, but says it “really summarises the state of polar climate right now, which is that sea ice is unusually low all across the high latitude regions of our planet”.
Record-breaking Antarctic season
The Antarctic has seen a record-breaking year. In September 2023, Antarctic sea ice reached a new all-time low maximum extent, sparking widespread media attention. In the year that followed, sea ice extent has since continued to track near record lows.
On 20 February 2024, the Antarctic hit its annual minimum, tying with 2022 for the second-lowest minimum in the 46-year satellite record. Dr Mark Serreze, director of the NSIDC told Carbon Brief at the time that more warm ocean water was reaching the surface, melting ice and keeping more ice from forming.
He said that we “must wait and see” whether this is a “temporary effect” or if the Antarctic has entered a “new regime”.
Antarctic sea ice extent “expanded slowly” throughout March, and ended the month tied with several other years for third-lowest sea ice extent on record for the time of year, according to the NSIDC.
Throughout April, Antarctic sea ice extent continued to grow “relatively uniformly”. The continent saw temperatures of 3-5C above average in the west, while in the east, temperatures were 4-7C below average, the NSIDC adds.
Throughout May 2024, the rate of growth was slow relative to the 1981-2010 average, but “still much faster than last year”, the NSIDC says. And into June, Antarctic sea ice continued to track “well below all previous years except for 2023”, it adds.
The NSIDC finds that by the end of June, sea ice extent was more than 2m km2 below the 1981-2010 average, but still 500,000km2 above the exceptionally-low 2023 extent for the time of year.
By late July, Antarctic sea ice extent was “very close to the levels” seen in 2023. By the end of July, Antarctic sea ice was more than 2.1m km2 below the 1981-2010 average, and 190,000 km2 above 2023 levels, the NSIDC says.
The graphic below shows Antarctic sea ice extent between 1978 and 2024, where red indicates the 2024 extent and shades of blue indicate different years over 1978-2023 (darker colours indicate more recent years).
After slow growth from May to July, Antarctic sea ice began to “rapidly expand” in August, according to the NSIDC. It says “ice growth for the first two weeks of August was 1.5m km2 per day, among the fastest ice growth rates seen in the 46-year record for this time of year”.
However, growth “stalled” over 16-25 August and, by the end of the month, Antarctic sea ice extent stood at 16.86m km2 – the second lowest in the satellite record for that date ,the NSIDC says.
It notes that sea ice extent is “particularly low in the far eastern Weddell Sea, the south-west Indian Ocean and in the Amundsen Sea”.
Arctic minimum
At the other end of the world, Arctic sea ice extent has been melting towards its annual minimum for the past six months. It reached its minimum in September, and has now begun to grow again.
Back on 14 March, the Arctic hit its annual maximum, which was the 14th lowest in the satellite record. The NSIDC finds that despite favourable winds that encouraged sea ice formation, the maximum sea ice extent was 640,000km2 smaller than the 1981-2010 average maximum.
As temperatures warmed in the Arctic, sea ice continued to melt. By the start of April 2024, Arctic sea ice extent had dropped by about 278,000km2 below the March maximum, the NSIDC says.
April sea ice loss in the Arctic proceeded at a near-average rate overall, with most ice loss in the Bering Sea and Sea of Okhotsk, according to the NSIDC. The average Arctic sea ice extent for April 2024 was 14.12m km2, placing it 16th lowest in the satellite record.
The NSIDC says that although average global temperatures in April were at a record high, temperatures in the Arctic were “well below average” by up to 3-5C in some regions.
“This May, early ice loss in the eastern part of Hudson Bay was striking,” the NSIDC says. Usually, the Hudson Bay is “nearly completely ice covered through May”, it adds. However, this year saw unusually “strong and persistent” winds from the east push ice from the eastern coast into open water, resulting in record low sea ice extent in the Hudson Bay.
The NSIDC notes that by 1 June 2024, sea ice extent in the Hudson Bay was 205,000km2 below the 1981-2010 average – 65,000km2 below the previous record low set in 2015.
Arctic sea ice extent in June retreated more slowly than usual and, by the end of the month, it was “tracking above all years since 2012 except for 2013 and 2015”, it adds.
July is the warmest month in the Arctic and sees the most rapid sea ice loss, the NSIDC says. It finds that Arctic sea ice “retreated rapidly” in July. The region lost 113,000km2 of ice per day throughout the month – faster than the 1981-2010 average pace of 87,000km2 per day.
Ice loss during the month was greatest in the Kara and East Siberian Seas, Baffin Bay, Hudson Bay, and the Canadian Archipelago, the NSIDC says. Meanwhile, unusually for the time of year, a small patch of ice remained in the Hudson Bay by the end of the month. It adds that air temperatures were near average overall, with several areas slightly cooler than average.
By the end of July, Arctic sea ice extent was the third-lowest extent in the 46-year satellite record by the end of the month. Rapid Arctic ice loss continued into the first week of August, and by mid-August, sea ice extent was the fourth lowest on record, the NSIDC says.
The graphic below shows Arctic sea ice extent between 1978 and 2024, where red indicates the 2024 extent and shades of blue indicate different years over 1978-2023, where darker colours indicate more recent years.
Throughout August, ice loss slowed down in response to “waning sunlight and decreasing air temperatures”, as is typical for this time of year, the NSIDC says. By the end of August, Arctic sea ice extent was 4.55m km2 – the fourth lowest in the satellite record.
The map below shows Arctic sea ice average extent for September 2024, where the pink line shows the 1981-2010 average.
Arctic sea ice reached its annual minimum extent of 4.28m km2 on 11 September 2024, ranking as the seventh lowest in the 46-year satellite record.
The NSIDC adds that “the last 18 years are the lowest 18 Arctic sea ice extents in the satellite record”.
On thin ice
Labe tells Carbon Brief that Arctic sea ice this year has been “unusually thin”, explaining that the Arctic has seen “unusually low sea-ice concentration with the ice being more spread out and with more areas of open water found between the ice floes”.
This has resulted in near record-low total Arctic sea ice volume.
![Zack Labe on X/Twitter (@ZLabe): There was an accelerated loss of sea ice volume last month in the #Arctic. We are not far from a record low. Each line represents one year from 1979 [dark blue] to 2023 [dark red]. This year is shown in yellow - now updated through all of August 2024](https://breakingclimatechange.com/wp-content/uploads/2024/12/x.com_ZLabe_status_1833478263001518490-2-29.png)
Prof Alexandra Jahn is an associate professor at the University of Colorado’s Institute of Arctic and Alpine Research. She tells Carbon Brief that natural variability has contributed to the observed loss of ice – “especially during the early 21st century”.
However, she adds that internal variability alone cannot completely explain the extent of the loss we have seen, and human-caused greenhouse gas emissions “are required to get an Arctic sea ice loss as large as observed”.
The post Antarctic sea ice maximum in 2024 is ‘second lowest’ on record appeared first on Carbon Brief.
Antarctic sea ice maximum in 2024 is ‘second lowest’ on record
Drought and heatwaves occurring together – known as “compound” events – have “surged” across the world since the early 2000s, a new study shows.
Compound drought and heat events (CDHEs) can have devastating effects, creating the ideal conditions for intense wildfires, such as Australia’s “Black Summer” of 2019-20 where bushfires burned 24m hectares and killed 33 people.
The research, published in Science Advances, finds that the increase in CDHEs is predominantly being driven by events that start with a heatwave.
The global area affected by such “heatwave-led” compound events has more than doubled between 1980-2001 and 2002-23, the study says.
The rapid increase in these events over the last 23 years cannot be explained solely by global warming, the authors note.
Since the late 1990s, feedbacks between the land and the atmosphere have become stronger, making heatwaves more likely to trigger drought conditions, they explain.
One of the study authors tells Carbon Brief that societies must pay greater attention to compound events, which can “cause severe impacts on ecosystems, agriculture and society”.
Compound events
CDHEs are extreme weather events where drought and heatwave conditions occur simultaneously – or shortly after each other – in the same region.
These events are often triggered by large-scale weather patterns, such as “blocking” highs, which can produce “prolonged” hot and dry conditions, according to the study.
Prof Sang-Wook Yeh is one of the study authors and a professor at the Ewha Womans University in South Korea. He tells Carbon Brief:
“When heatwaves and droughts occur together, the two hazards reinforce each other through land-atmosphere interactions. This amplifies surface heating and soil moisture deficits, making compound events more intense and damaging than single hazards.”
CDHEs can begin with either a heatwave or a drought.
The sequence of these extremes is important, the study says, as they have different drivers and impacts.
For example, in a CDHE where the heatwave was the precursor, increased direct sunshine causes more moisture loss from soils and plants, leading to a drought.
Conversely, in an event where the drought was the precursor, the lack of soil moisture means that less of the sun’s energy goes into evaporation and more goes into warming the Earth’s surface. This produces favourable conditions for heatwaves.
The study shows that the majority of CDHEs globally start out as a drought.
In recent years, there has been increasing focus on these events due to the devastating impact they have on agriculture, ecosystems and public health.
In Russia in the summer of 2010, a compound drought-heatwave event – and the associated wildfires – caused the death of nearly 55,000 people, the study notes.
The record-breaking Pacific north-west “heat dome” in 2021 triggered extreme drought conditions that caused “significant declines” in wheat yields, as well as in barley, canola and fruit production in British Columbia and Alberta, Canada, says the study.
Increasing events
To assess how CDHEs are changing, the researchers use daily reanalysis data to identify droughts and heatwaves events. (Reanalysis data combines past observations with climate models to create a historical climate record.) Then, using an algorithm, they analyse how these events overlap in both time and space.
The study covers the period from 1980 to 2023 and the world’s land surface, excluding polar regions where CDHEs are rare.
The research finds that the area of land affected by CDHEs has “increased substantially” since the early 2000s.
Heatwave-led events have been the main contributor to this increase, the study says, with their spatial extent rising 110% between 1980-2001 and 2002-23, compared to a 59% increase for drought-led events.
The map below shows the global distribution of CDHEs over 1980-2023. The charts show the percentage of the land surface affected by a heatwave-led CDHE (red) or a drought-led CDHE (yellow) in a given year (left) and relative increase in each CDHE type (right).
The study finds that CDHEs have occurred most frequently in northern South America, the southern US, eastern Europe, central Africa and south Asia.
Threshold passed
The authors explain that the increase in heatwave-led CDHEs is related to rising global temperatures, but that this does not tell the whole story.
In the earlier 22-year period of 1980-2001, the study finds that the spatial extent of heatwave-led CDHEs rises by 1.6% per 1C of global temperature rise. For the more-recent period of 2022-23, this increases “nearly eightfold” to 13.1%.
The change suggests that the rapid increase in the heatwave-led CDHEs occurred after the global average temperature “surpasse[d] a certain temperature threshold”, the paper says.
This threshold is an absolute global average temperature of 14.3C, the authors estimate (based on an 11-year average), which the world passed around the year 2000.
Investigating the recent surge in heatwave-leading CDHEs further, the researchers find a “regime shift” in land-atmosphere dynamics “toward a persistently intensified state after the late 1990s”.
In other words, the way that drier soils drive higher surface temperatures, and vice versa, is becoming stronger, resulting in more heatwave-led compound events.
Daily data
The research has some advantages over other previous studies, Yeh says. For instance, the new work uses daily estimations of CDHEs, compared to monthly data used in past research. This is “important for capturing the detailed occurrence” of these events, says Yeh.
He adds that another advantage of their study is that it distinguishes the sequence of droughts and heatwaves, which allows them to “better understand the differences” in the characteristics of CDHEs.
Dr Meryem Tanarhte is a climate scientist at the University Hassan II in Morocco, and Dr Ruth Cerezo Mota is a climatologist and a researcher at the National Autonomous University of Mexico. Both scientists, who were not involved in the study, agree that the daily estimations give a clearer picture of how CDHEs are changing.
Cerezo-Mota adds that another major contribution of the study is its global focus. She tells Carbon Brief that in some regions, such as Mexico and Africa, there is a lack of studies on CDHEs:
“Not because the events do not occur, but perhaps because [these regions] do not have all the data or the expertise to do so.”
However, she notes that the reanalysis data used by the study does have limitations with how it represents rainfall in some parts of the world.
Compound impacts
The study notes that if CDHEs continue to intensify – particularly events where heatwaves are the precursors – they could drive declining crop productivity, increased wildfire frequency and severe public health crises.
These impacts could be “much more rapid and severe as global warming continues”, Yeh tells Carbon Brief.
Tanarhte notes that these events can be forecasted up to 10 days ahead in many regions. Furthermore, she says, the strongest impacts can be prevented “through preparedness and adaptation”, including through “water management for agriculture, heatwave mitigation measures and wildfire mitigation”.
The study recommends reassessing current risk management strategies for these compound events. It also suggests incorporating the sequences of drought and heatwaves into compound event analysis frameworks “to enhance climate risk management”.
Cerezo-Mota says that it is clear that the world needs to be prepared for the increased occurrence of these events. She tells Carbon Brief:
“These [risk assessments and strategies] need to be carried out at the local level to understand the complexities of each region.”
The post Heatwaves driving recent ‘surge’ in compound drought and heat extremes appeared first on Carbon Brief.
Heatwaves driving recent ‘surge’ in compound drought and heat extremes
Greenhouse Gases
DeBriefed 6 March 2026: Iran energy crisis | China climate plan | Bristol’s ‘pioneering’ wind turbine
Welcome to Carbon Brief’s DeBriefed.
An essential guide to the week’s key developments relating to climate change.
This week
Energy crisis
ENERGY SPIKE: US-Israeli attacks on Iran and subsequent counterattacks across the Middle East have sent energy prices “soaring”, according to Reuters. The newswire reported that the region “accounts for just under a third of global oil production and almost a fifth of gas”. The Guardian noted that shipping traffic through the strait of Hormuz, which normally ferries 20% of the world’s oil, “all but ground to a halt”. The Financial Times reported that attacks by Iran on Middle East energy facilities – notably in Qatar – triggered the “biggest rise in gas prices since Russia’s full-scale invasion of Ukraine”.
‘RISK’ AND ‘BENEFITS’: Bloomberg reported on increases in diesel prices in Europe and the US, speculating that rising fuel costs could be “a risk for president Donald Trump”. US gas producers are “poised to benefit from the big disruption in global supply”, according to CNBC. Indian government sources told the Economic Times that Russia is prepared to “fulfil India’s energy demands”. China Daily quoted experts who said “China’s energy security remains fundamentally unshaken”, thanks to “emergency stockpiles and a wide array of import channels”.
‘ESSENTIAL’ RENEWABLES: Energy analysts said governments should cut their fossil-fuel reliance by investing in renewables, “rather than just seeking non-Gulf oil and gas suppliers”, reported Climate Home New