On 18 March, 2022, scientists at the Concordia research station on the east Antarctic plateau documented a remarkable event. They recorded the largest jump in temperature ever measured at a meteorological centre on Earth. According to their instruments, the region that day experienced a rise of 38.5C above its seasonal average: a world record.

This startling leap – in the coldest place on the planet – left polar researchers struggling for words to describe it. “It is simply mind-boggling,” said Prof Michael Meredith, science leader at the British Antarctic Survey. “In sub-zero temperatures such a massive leap is tolerable but if we had a 40C rise in the UK now that would take temperatures for a spring day to over 50C – and that would be deadly for the population.”

This amazement was shared by glaciologist Prof Martin Siegert, of the University of Exeter. “No one in our community thought that anything like this could ever happen. It is extraordinary and a real concern,” he told the Observer. “We are now having to wrestle with something that is completely unprecedented.”

Poleward winds, which previously made few inroads into the atmosphere above Antarctica, are now carrying more and more warm, moist air from lower latitudes – including Australia – deep into the continent, say scientists, and these have been blamed for the dramatic polar “heatwave” that hit Concordia. Exactly why these currents are now able to plunge so deep into the continent’s air space is not yet clear, however.

Nor has this huge temperature hike turned out to be an isolated event, scientists have discovered. For the past two years they have been inundated with rising numbers of reports of disturbing meteorological anomalies on the continent. Glaciers bordering the west Antarctic ice-sheet are losing mass to the ocean at an increasing rate, while levels of sea ice, which float on the oceans around the continent, have plunged dramatically, having remained stable for more than a century.

These events have raised fears that the Antarctic, once thought to be too cold to experience the early impacts of global warming, is now succumbing dramatically and rapidly to the swelling levels of greenhouse gases that humans continue to pump into the atmosphere.

These dangers were highlighted by a team of scientists, led by Will Hobbs of the University of Tasmania, in a paper that was published last week in the Journal of Climate. After examining recent changes in sea ice coverage in Antarctica, the group concluded there had been an “abrupt critical transition” in the continent’s climate that could have repercussions for both local Antarctic ecosystems and the global climate system.

“The extreme lows in Antarctic sea ice have led researchers to suggest that a regime shift is under way in the Southern Ocean, and we found multiple lines of evidence that support such a shift to a new sea ice state,” said Hobbs.

The dramatic nature of this transformation was emphasised by Meredith. “Antarctic sea ice coverage actually increased slightly in the late 20th and early 21st century. However, in the middle of the last decade it fell off a cliff. It is a harbinger of the new ground with the Antarctic climate system, and that could be very troubling for the region and for the rest of the planet.”

The continent is now catching up with the Arctic, where the impacts of global warming have, until now, been the most intense experienced across the planet, added Siegert. “The Arctic is currently warming at four times the rate experienced by the rest of the planet. But the Antarctic has started to catch up, so that it is already warming twice as quickly as the planet overall.”

A key reason for the Arctic and Antarctic to be taking disproportionate hits from global warming is because the Earth’s oceans – warmed by fossil-fuel burning – are losing their sea ice at their polar extremities. The dark waters that used to lie below the ice are being exposed and solar radiation is no longer reflected back into space. Instead, it is being absorbed by the sea, further heating the oceans there.

“Essentially, it is a vicious circle of warming oceans and melting of sea ice, though the root cause is humanity and its continuing burning of fossil fuels and its production of greenhouse gases,” said Meredith. “This whole business has to be laid at our door.”

As to the consequences of this meteorological metamorphosis, these could be devastating, researchers warn. If all the ice on Antarctica were to melt, this would raise sea levels around the globe by more than 60 metres. Islands and coastal zones where much of the world’s population now have homes would be inundated.

Such an apocalypse is unlikely to occur for some time, however. Antarctica’s ice sheet covers 14m square kilometres (about 5.4m square miles), roughly the area of the United States and Mexico combined, and contains about 30m cubic kilometres (7.2m cubic miles) of ice – about 60% of the world’s fresh water. This vast covering hides a mountain range that is nearly as high as the Alps, so it will take a very long time for that to melt completely, say scientists.

Nevertheless, there is now a real danger that some significant sea level rises will occur in the next few decades as the ice sheets and glaciers of west Antarctica continue to shrink. These are being eroded at their bases by warming ocean water and could disintegrate in a few decades. If they disappear entirely, that would raise sea levels by 5m – sufficient to cause damage to coastal populations around the world. How quickly that will happen is difficult to assess. The Intergovernmental Panel on Climate Change has said that sea levels are likely to rise between 0.3m to 1.1m by the end of the century. Many experts now fear this is a dangerous underestimate. In the past, climate change deniers accused scientists of exaggerating the threat of global warming. However, the evidence that is now emerging from Antarctica and other parts of the world makes it very clear that scientists did not exaggerate. Indeed, they very probably underrated by a considerable degree the threat that now faces humanity.

“The picture is further confused in Antarctica because, historically, we have had problems getting data,” added Meredith. “We have never had the information about weather and ecosystem, compared with the data we get from the rest of the world, because the continent is so remote and so hostile. Our records are comparatively short and that means that the climate models we have created, although very capable, are based on sparse data. They cannot capture all of the physics, chemistry and biology. They can make predictions that are coherent but they cannot capture the sort of extremes that we’re now beginning to observe.”

The woes facing Antarctica are not merely of human concern, however. “We are already seeing serious ecological impacts that threaten to spread through the food chain,” said Prof Kate Hendry, a chemical oceanographer based at the British Antarctic Survey.

A critical example is provided by the algae which grow under and around sea ice in west Antarctica. This is starting to disappear, with very serious implications, added Hendry. Algae is eaten by krill, the tiny marine crustaceans that are one of the most abundant animals on Earth and which provide food for predators that include fish, penguins, seals and whales. “If krill starts to disappear in the wake of algae, then all sorts of disruption to the food chain will occur,” said Hendry.

The threat posed by the disappearance of krill goes deeper, however. They play a key role in limiting global warming. Algae absorb carbon dioxide. Krill then eat them and excrete it, the faeces sinking to the seabed and staying there. Decreased levels of algae and krill would then mean less carbon from the atmosphere would be deposited on the ocean floor and would instead remain near the sea surface, where it would return to the atmosphere.

“They act like a conveyor belt that takes carbon out of the atmosphere and carries it down to the deep ocean floor where it can be locked away. So if we start messing with that system, there could be all sorts of other knock-on effects for our attempts to cope with the impact of global warming,” added Hendry. “It is a scary scenario. Nevertheless that, unfortunately, is what we are now facing.”

Another victim of the sudden, catastrophic warming that has gripped the continent is its most famous resident: the emperor penguin. Last year the species, which is found only in Antarctica, suffered a catastrophic breeding failure because the platforms of sea ice on which they are born started to break up long before the young penguins could grow waterproof feathers.

“We have never seen emperor penguins fail to breed, at this scale, in a single season,” said Peter Fretwell, of the British Antarctic Survey. “The loss of sea ice in this region during the Antarctic summer made it very unlikely that displaced chicks would survive.”

Researchers say that the discovery of the loss of emperor penguins suggests that more than 90% of colonies will be wiped out by the end of the century, if global warming trends continue at their current disastrous rate. “The chicks cannot live on sea ice until they have fledged,” said Meredith. “After that, they can look after themselves. But the sea ice is breaking up before they reach that stage and mass drowning events are now happening. Colonies of penguins are being wiped out. And that’s a tragedy. This is an iconic species, one that is emblematic of Antarctica and the new vulnerability of its ecosystems.”

The crisis facing the continent has widespread implications. More than 40 nations are signatories of the Antarctic Treaty’s environmental protocol, which is supposed to shield it from a host of different threats, with habitat degradation being one of the most important. The fact that the continent is now undergoing alarming shifts in its ice covering, eco-systems and climate is a clear sign that this protection is no longer being provided.

“The cause of this ecological and meteorological change lies outside the continent,” added Siegert. “It is being caused because the rest of the world is continuing to emit vast amounts carbon dioxide.

“Nevertheless, there is a good case for arguing that if countries are knowingly polluting the atmosphere with greenhouse gases, and Antarctica is being affected as a consequence, then the treaty protocol is being breached by its signatories and their behaviour could be challenged on legal and political grounds. It should certainly make for some challenging meetings at the UN in the coming years.”

Greta Thunberg was detained by police at a demonstration in The Hague, in the Netherlands.

The climate activist was put in a bus by local police along with other protesters who tried to block a major highway into the city on Saturday.

Thunberg had joined a protest by hundreds of activists and was detained when she joined a group of about 100 people who tried to block the A12 highway.

Before she was detained, Thunberg said: “We are in a planetary emergency and we are not going to stand by and let people lose their lives and livelihood and be forced to become climate refugees when we can do something.”

The road has been blocked for several hours dozens of times in recent months by activists demanding an end to all subsidies for the use of fossil fuels.

At previous protests, police drove detained protesters to another part of the city, where they were released without further consequences.

Thunberg was seen flashing a victory sign as she sat in the bus used by police to take detained demonstrators from the scene.

The Extinction Rebellion campaign group said before the demonstration that the activists would block a main highway into The Hague, but a heavy police presence, including officers on horseback, initially prevented the activists from getting on to the road.

A small group of people managed to sit down on another road and were detained after ignoring police orders to leave.

Extinction Rebellion activists have blocked the highway that runs past the temporary home of the Dutch parliament more than 30 times to protest against subsidies.

The demonstrators waved flags and chanted: “We are unstoppable, another world is possible.”

One held a banner reading: “This is a dead end street.”

In February, Thunberg, 21, was acquitted by a court in London of refusing to follow a police order to leave a protest blocking the entrance to an oil and gas industry conference last year.

Her activism has inspired a global youth movement demanding stronger efforts to fight the climate crisis since she began staging weekly protests outside the Swedish parliament in 2018.

She has repeatedly been fined in Sweden and the UK for civil disobedience in connection with protests.

In the early 1960s, Canada’s fisheries ministry installed a .50-calibre machine gun on an island in British Columbia. The weapon, typically used against armoured vehicles and low-flying aircraft, was mounted with the sole purpose of killing orcas. The high-powered gun was never used, but the message was clear: the whales, derisively called “blackfish”, were the enemy.

Now, six decades later and less than 100 miles away from where the gun was mounted, that same ministry has joined residents of a remote community in a frantic attempt to rescue a stranded orca calf.

For the last two weeks, the two-year-old calf has been trapped in a lagoon off the wind-battered west coast of Vancouver Island. Immense resources from Indigenous communities and Canada’s federal fisheries department have been marshalled to rescue the calf, which has been named kʷiisaḥiʔis (pronounced kwee-sahay-is), by local First Nations – a name that roughly translates to Brave Little Hunter. Amid the intensifying effort to free her, the outpouring of community support highlights a dramatic shift in public perceptions of the whales, from nuisances to be culled into beloved individuals worthy of a challenging and costly rescue.

The saga began on 23 March when residents of a coastal community along the north-western reaches of Vancouver Island spotted an orca trapped on shore. It is unclear why the orcas entered the lagoon, but the remains of a harbour seal nearby suggest to experts the stranding may have been the result of a hunt gone wrong. Locals worked, unsuccessfully, for hours to rescue the 14-year-old mother, named Spong, who was trapped in a trough-like depression on the shore. Kʷiisaḥiʔis watched helplessly as her mother struggled, and cries of distress were heard from hydrophones placed in the water. Glen McCall, one of the first on scene, called the immense emotional and physical toll of the failed rescue an “absolutely horrible” experience.

In the weeks since, every attempt to lure her out, including the use of vocalisations from family members, banging metal pipes and laying ropes with floats attached, have all failed. But the calf desperately needs nutrition. While she seems healthy, experts caution that her health could decline quickly in the coming days.

In the days since Spong’s death and the collective rescue effort, kʷiisaḥiʔis has carried the weight of a community’s hope. Every few minutes, her narrow black dorsal fin breaks the surface of the lagoon near the village of Zeballos. What follows is a misty exhalation from the orca – and a collective sigh of relief from the dozens of experts glued to her every movement, and from the global audience heavily invested in the whale’s plight.

“I was out there the day the mother got stranded, and it really left a mark on me,” said Chris Copeland, who uses the Facebook page of a local inn to chronicle the health of the calf. The updates, he’s learned, are read all over the globe. “With the way the world is these days, I think people just really want something to hope for. We’re all cheering for the little whale.”

On the bridge that separates the lagoon from the Little Espinosa Inlet, cedar boughs hung by the Ehattesaht First Nation highlight the high cultural stakes of the rescue: the origin stories of the Nuu-chah-nulth people tell of a killer whale coming on to land and transforming into a wolf, which itself transforms into a human.

Last week, the Ehattesaht First Nation, alongside the neighbouring Nuchatlaht First Nation, launched a canoe into the lagoon in an attempt to draw the calf closer with their drumming, a “powerful” moment on the water. “Every discussion and the resulting decisions are guided by one single principle: what is the safest for [the calf] and has the most probability for success,” the Ehattesaht chief and council said on Thursday.

Paul Cottrell, one of the country’s most experienced whale rescuers, told reporters he had never worked on a mission so “difficult and complex” as the attempt to free kʷiisaḥiʔis.

“Time is of the essence for this calf, we know that, and the planning is well along, but we do have a little bit more planning, equipment and logistics to work out,” he said.

On Thursday, Cottrell and Ehattesaht chief Simon John announced a plan to trap kʷiisaḥiʔis next week if the whale doesn’t escape the lagoon on her own. Using seine nets, the team would probably guide the calf into a sling, transporting her on a truck and then releasing her into an open-water pen – a series of carefully orchestrated movements that cannot take longer than a few hours.

But rescuing the calf from the lagoon is only the first step. Once safe, she needs to be reunited with family in order to survive in the open ocean. The rescue team plans to hold her in a pen used for salmon farming until relatives are close enough for a release.

While dozens of experts, including vets and drone operators, closely monitor the calf’s health, the team is also drawing on communities and whale-watching boats on Vancouver Island’s west coast in an attempt to locate the family. Whale research group Bay Cetology has opened to the public its online AI-assisted photo database of all the region’s whales in an attempt to track the calf’s relatives.

The ability to identify whales by distinct markings, a technique developed more than half a century ago, marks a pivotal moment for how the public began to understand orcas as distinct, highly intelligent and social mammals, says John Ford, a leading expert and scientist emeritus with the federal fisheries department.

“Over the years, they were feared by fishermen in the region just because they’re a large, dangerous-looking animal with big teeth,” he said. Hastily devised plans like the machine gun reflected both the frustration and fear the whales elicited. “But once you could start identifying every whale along the coast, they became individuals.”

Despite the overwhelming odds against the rescue attempt, Ford sees glimmers of hope. Brave Little Hunter is a Bigg’s killer whale, an ecotype of the species that has different social structures than the endangered southern resident whales. With movement of Bigg’s whales to different pods, the calf might be able to link up with members of its extended family if it can leave the inlet.

The tireless efforts to save the calf don’t come as a surprise to Ford, who has assisted on previous local rescue attempts. “For an individual to be orphaned and on its own, people feel empathy and want to help. It’s just human nature,” he said. “This is not just a generic whale stuck inland. We know who it is and where it should be. And many people would like to see it back with its family.”

The levels of the three most important heat-trapping gases in the atmosphere reached new record highs again last year, US scientists have confirmed, underlining the escalating challenge posed by the climate crisis.

The global concentration of carbon dioxide, the most important and prevalent of the greenhouse gases emitted by human activity, rose to an average of 419 parts per million in the atmosphere in 2023 while methane, a powerful if shorter-lasting greenhouse gas, rose to an average of 1922 parts per billion. Levels of nitrous oxide, the third most significant human-caused warming emission, climbed slightly to 336 parts per billion.

The increases do not quite match the record jumps seen in recent years, according to the National Oceanic and Atmospheric Administration (Noaa), but still represent a major change in the composition of the atmosphere even from just a decade ago.

Through the burning of fossil fuels, animal agriculture and deforestation, the world’s CO2 levels are now more than 50% higher than they were before the era of mass industrialization. Methane, which comes from sources including oil and gas drilling and livestock, has surged even more dramatically in recent years, Noaa said, and now has atmospheric concentrations 160% larger than in pre-industrial times.

Noaa said the onward march of greenhouse gas levels was due to the continued use of fossil fuels, as well as the impact of wildfires, which spew carbon-laden smoke into the air. Nitrous oxide, meanwhile, has risen due to the widespread use of nitrogen fertilizer and the intensification of agriculture.

“As these numbers show, we still have a lot of work to do to make meaningful progress in reducing the amount of greenhouse gases accumulating in the atmosphere,” said Vanda Grubišić, director of Noaa’s global monitoring laboratory.

The increasing presence of greenhouse gases is spurring a rise in global temperature – last year was the hottest ever measured worldwide – and well as associated impacts such as floods, droughts, heatwaves and wildfires.

It is also pushing the world into a state not seen since prior to human civilization. Carbon dioxide levels today are now comparable to what they were around 4m years ago, Noaa said, an era when sea were around 75ft higher than they are today, the average temperature was far hotter and large forests occupied areas of the now-frozen Arctic.

Because of a lag between CO2 levels and their impact, as well as the hundreds of years that the emissions remain in the atmosphere, the timescale of the climate crisis is enormous. Scientists have warned that governments need to rapidly slash emissions to net zero, and then start removing carbon from the atmosphere to bring down future temperature increases.