Arctic Sea Ice Shrinks by an Area the Size of Spain Every Decade, EU Report Finds
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Image credit: Dominiklenne · Public domain · Wikimedia Commons
In brief
The Arctic has lost sea ice at a rate of roughly 490,000–500,000 square kilometres per decade since 1979 — an area nearly equal to Spain's entire territory — according to the EU's 10th Copernicus Ocean State Report. The retreat is exposing Arctic coastlines to stronger winds and waves, leaving about 60% of the region's coastal infrastructure vulnerable to erosion and rising seas.
The Arctic Ocean has been losing sea ice at a pace equivalent to wiping an area the size of Spain off the map every ten years, according to the 10th Copernicus Ocean State Report, published on 30 September 2026 by Mercator Ocean International on behalf of the European Union's Copernicus Marine Environment Monitoring Service.
The report, compiled with contributions from 125 scientists across Europe and beyond, calculates that Arctic sea-ice extent fell by about 490,000 square kilometres per decade between 1979 and 2025. Spain covers roughly 506,000 square kilometres, making the comparison almost a direct match.
How the ice loss is reshaping coastlines
Sea ice normally acts as a buffer, shielding Arctic shorelines from wind and wave action. As that buffer shrinks, previously protected coasts are increasingly exposed to erosion. The report states that around 60% of Arctic coastal infrastructure is now vulnerable to erosion and sea-level rise as a direct consequence of the retreating ice.
The authors describe the trend as rapid coastal erosion that has coincided consistently with substantial sea-ice retreat over the past four decades.
Barents and Kara seas warming fastest
The warming is uneven across the Arctic. The Barents Sea has lost 70% of its sea-ice extent since 1982, the steepest regional decline cited in the report. In the Kara Sea, north of Siberia, temperatures have climbed 6.7°C since 1982 — about 1.68°C per decade, well above the Arctic-wide average.
Across the Arctic as a whole, combined sea-surface and sea-ice-surface temperatures rose 4.2°C between 1982 and 2024, roughly 1°C per decade, according to the report.
Part of a broader warning about the world's oceans
The Arctic findings are one part of a wider set of conclusions in the report. Global oceans absorbed a record 23 zettajoules of excess heat in 2025, the ninth consecutive record year for ocean heat content, according to Mercator Ocean International. Global mean sea levels rose 3.8 mm a year on average between 1999 and 2025, but that rate accelerated to 4.2 mm a year between 2012 and 2025.
The report also found that ocean acidity increased by about 17% between 1985 and 2025, and that 84% of the world's coral reefs experienced bleaching-level heat stress between January 2023 and September 2025. The Mediterranean and Black Seas recorded marine heatwaves in 2024 with temperatures up to 4.6°C above average, some lasting more than 30 days.
The ocean is transforming before our eyes: warming, rising seas and ecosystem degradation are interconnected signs of significant and long-term change.
— Pierre Bahurel, Director General, Mercator Ocean International
In the Antarctic, the report links severe sea-ice loss in 2022 to a decline in emperor penguin populations, a species since reclassified as Endangered by the IUCN. On European coasts, it cites Storm Louis in February 2024, which produced waves exceeding 8 metres along Spain's Atlantic coast and caused one fatality, as an example of the extreme events it discusses.
Key figures from the report
Selected findings of the 10th Copernicus Ocean State Report
Metric
Figure
Period
Arctic sea-ice extent loss
~490,000–500,000 km² per decade (near Spain's size)
1979–2025
Barents Sea ice-extent loss
70%
Since 1982
Arctic surface/ice temperature rise
4.2°C (~1°C/decade)
1982–2024
Kara Sea temperature rise
6.7°C (~1.68°C/decade)
1982–2024
Ocean heat absorbed (2025)
23 zettajoules (record)
2025
Global sea-level rise rate
3.8 mm/yr → 4.2 mm/yr (accelerated)
1999–2025 / 2012–2025
Ocean acidification increase
~17%
1985–2025
Arctic coastal infrastructure at risk
~60%
Current
Questions
How much Arctic sea ice is being lost per decade?
According to the 10th Copernicus Ocean State Report, Arctic sea-ice extent fell by roughly 490,000 to 500,000 square kilometres per decade between 1979 and 2025 — an area close to the size of Spain.
Why does Arctic sea ice loss threaten coastal infrastructure?
Sea ice normally shields Arctic coasts from wind and wave action. As it retreats, coasts are more exposed to erosion, which the report says makes about 60% of Arctic coastal infrastructure vulnerable.
Which part of the Arctic is warming fastest?
The report identifies the Barents Sea, which has lost 70% of its sea-ice extent since 1982, and the Kara Sea, where temperatures have risen 6.7°C since 1982 — both faster than the Arctic-wide average.
What is the Copernicus Ocean State Report?
It is an annual assessment of global ocean conditions produced by Mercator Ocean International for the EU's Copernicus Marine Environment Monitoring Service, drawing on work from 125 scientists; the edition covered here is the 10th, published 30 September 2026.
Is global sea-level rise also accelerating?
Yes. The report finds sea levels rose 3.8 mm a year on average between 1999 and 2025, but the rate climbed to 4.2 mm a year when looking only at 2012–2025.
How the world is telling it
SpanishSpanish-language coverage (eldiario.es) framed the report with the headline phrase that climate change is 'drowning the Arctic,' emphasizing the Spain-sized comparison to make the scale concrete for domestic readers and linking the findings to the EU's broader ocean-health warnings.
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