Between October 2024 and September 2025, temperatures were 1.60 degrees Celsius above the 1991-2020 mean, the National Oceanic and Atmospheric Administration said in its annual Arctic Report Card, which draws on data going back to 1900.
Co-author Tom Ballinger of the University of Alaska told AFP it was "certainly alarming" to see such rapid warming over so short a timespan, calling the trend "seemingly unprecedented in recent times and maybe back thousands of years."
The year included the Arctic's warmest autumn, second-warmest winter, and third-warmest summer since 1900, the report said.
Driven by human-caused burning of fossil fuels, the Arctic is warming significantly far faster than the global average, with a number of reinforcing feedback loops -- a phenomenon known as "Arctic Amplification."
For example, rising temperatures increase water vapor in the atmosphere, which acts like a blanket absorbing heat and preventing it from escaping into space.
At the same time, the loss of bright, reflective sea ice exposes darker ocean waters that absorb more heat from the Sun.
- Sea-ice retreat -
Springtime -- when Arctic sea ice reaches its annual maximum -- saw the smallest peak in the 47-year satellite record in March 2025.
That's an "immediate issue for polar bears and for seals and for walrus, that they use the ice as a platform for transportation, for hunting, for birthing pups," co-author Walt Meier of the National Snow and Ice Data Center told AFP.
Modeling suggests the Arctic could see its first summer with virtually no sea ice by 2040 or even sooner.
The loss of Arctic sea ice also disrupts ocean circulation by injecting freshwater into the North Atlantic through melting ice and increased rainfall.
This makes surface waters less dense and salty, hindering their ability to sink and drive the Atlantic Meridional Overturning Circulation -- including the Gulf Stream -- which help keep Europe's winters milder.
Ongoing melt of the Greenland Ice Sheet also adds freshwater to the North Atlantic Ocean, boosting plankton productivity but also creating mismatches between when food is available and when the species that depend on it are able to feed.
Greenland's land-based ice loss is also a major contributor to global sea-level rise, exacerbating coastal erosion and storm-driven flooding.
- More Arctic blasts -
And as the Arctic warms faster than the rest of the planet, it weakens the temperature contrast that helps keep cold air bottled up near the pole, allowing outbreaks of frigid weather to spill more frequently into lower latitudes, according to some research.
The Arctic's hydrological cycle is also intensifying. The October 2024 - September 2025 period -- also known as the 2024/25 "water year" -- saw record-high spring precipitation and ranked among the five wettest years for other seasons in records going back to 1950.
Warmer, wetter conditions are driving the "borealization," or greening, of large swaths of Arctic tundra. In 2025, circumpolar mean maximum tundra greenness was the third highest in the 26-year modern satellite record, with the five highest values all occurring in the past six years.
Permafrost thaw, meanwhile, is triggering biogeochemical changes, such as the "rusting rivers" phenomenon caused by iron released from thawing soils.
This year's report card used satellite observations to identify more than 200 discolored streams and rivers that appeared visibly orange, degrading water quality through increased acidity and metal concentrations and contributing to the loss of aquatic biodiversity.
Thousands of glaciers to melt each year by mid-century: study
Paris, France (AFP) Dec 15, 2025 -
Thousands of glaciers will vanish each year in the coming decades, leaving only a fraction standing by the end of the century unless global warming is curbed, a study showed on Monday.
Government action on climate change could determine whether the world loses 2,000 or 4,000 glaciers annually by the middle of the century, according to the research.
A few degrees could be the difference between preserving almost half of the world's glaciers in 2100 -- or fewer than 10 percent.
"Our results underscore the urgency of ambitious climate policy," said the study published in the journal Nature Climate Change and led by glaciologist Lander Van Tricht.
Researchers usually focus on the loss of mass and area of the world's ice giants, but Van Tricht and his colleagues set out to determine how many individual glaciers could melt away annually in this century.
While the melting of smaller individual glaciers may have less impact on sea-level rise than larger ones, their loss can significantly harm tourism or local culture, the scientists said.
"The disappearance of each single glacier can have major local impacts, even if its meltwater contribution is small," Van Tricht from ETH Zurich and Vrije Universiteit Brussel, told reporters.
Co-author Matthias Huss, also a glaciologist at ETH Zurich, took part in 2019 in a symbolic funeral for the Pizol glacier in the Swiss Alps.
"The loss of glaciers that we are speaking about here is more than just a scientific concern. It really touches our hearts," he said.
- 'Peak extinction' -
The scientists examined the satellite-derived outlines of 211,490 glaciers from a global database to determine the year when the largest number will disappear -- a concept they coined "peak glacier extinction".
They used glacier computer models under several different warming scenarios -- ranging from a world in which temperatures rise by 1.5C from pre-industrial levels to one where they climb by 4C.
Today, the world is losing around 1,000 glaciers every year but the study warned that the pace is set to accelerate.
The number of glaciers disappearing annually will peak at 2,000 by 2041, even if warming is limited to 1.5C -- the threshold countries pledged to pursue under the Paris Agreement to avoid the worst impacts of climate change.
At that pace, 95,957 glaciers would be left standing around the planet by 2100, or just under half.
The United Nations, however, has warned that warming is on track to exceed 1.5C in the next few years.
Using projections showing temperatures would rise 2.7C under government policies, around 3,000 glaciers would disappear every year between 2040 and 2060, the glaciologists said.
By 2100, only one in five glaciers, or 43,852, would have survived in a 2.7C world.
Under a worst-case scenario where temperatures rise by 4C, as many as 4,000 glaciers would disappear each year by the mid-2050s.
Only nine percent of glaciers, or 18,288, would remain by the end of the century.
- Almost zero -
The timing of peak glacier disappearance varies between regions, depending on their size and location.
In areas with predominantly smaller glaciers, such as the European Alps and subtropical Andes, half could be gone within two decades.
In parts of the world with larger glaciers, such as Greenland and the Antarctic periphery, peak glacier disappearance will occur later in the century.
The researchers stressed that while glacier disappearances will peak in every scenario, the pace only begins to decline because there are fewer glaciers left and the bigger ones take more time to melt away.
For example, Van Tricht said, the loss rate in the Alps will fall to almost zero by the end of the century "just because there are almost no glaciers left".
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