Technologies

As a ‘Sea Ice Free’ Arctic Looms, the Climate Consequences Are Mounting

Research points to a milestone in the 2030s, but sea ice is already disappearing at an unprecedented rate. And that affects all of us.

The sound of ice cracking underneath the hull of a 25,500-ton icebreaker is unmistakable. No matter where you are — shuffling along the lunch line in the galley or sitting on the observation deck with a pack of cards — the wincing of steel and crunching of ice can shriek through the ship. It’s almost ghostly; undeniably haunting.

The sight of the ice? That’s mesmerizing. From the deck of Australia’s icebreaker, the RSV Nuyina, on which I sailed to Antarctica for more than five weeks at the start of 2022, it’s like looking out over a Martian landscape that’s been covered in a coat of stark white paint. In the distance, castles of ice rise from the vast, unbroken ice sheet. At the foot of one fortress, a battalion of King penguins lurks, unfazed by the freezing temperatures. Behind the ship, smaller Adelie penguins avoid a scrap with a leopard seal by climbing onto an island of ice and scurrying away.

Sea ice is vital to the Antarctic ecosystem. It’s not just a refuge for penguins and other animals, but a fundamental facet of life for creatures further down the food chain too, like Antarctic krill. It means life. The ice is also critical for heat because it’s more reflective than water, bouncing back more sunlight than the ocean, and it can act as a physical barrier, impacting the exchange of gases between the ocean and the atmosphere and protecting the continent’s ice shelves.

The Antarctic is currently experiencing the lowest level of sea ice since satellites began taking measurements in 1979. It’s an anomaly scientists are concerned about and monitoring closely. It was just a decade ago that sea ice in the Antarctic reached record highs, but generally low extents have been observed since 2016. It’s worrying, and could signal a shift in the sea ice dynamics down south, but the situation is more dire at the opposite end of the planet.

There, at the Earth’s northern extreme, the Arctic is experiencing an increase in temperatures two to four times higher than anywhere else in the world, and sea ice has decreased by about 12% per decade since the beginning of the satellite era. About 548,000 square miles of sea ice has been lost since 1979, equivalent to losing an area of ice roughly half the size of India. It’s seen a more rapid decline since 2000.

It’s one of the most obvious signs that greenhouse gas emissions are shifting the planet’s equilibrium. Researchers say we can take steps to slow the changes, but we need to act with urgency.

The 4 million people who call the Arctic home rely on the Arctic Ocean for food and transportation. The Indigenous peoples of the Arctic, who make up about 10% of the population, have a vibrant and longstanding cultural connection to the region that is slowly dripping away as regions become free of sea ice for the first time in millennia.

Meanwhile, the distribution of wildlife is shifting and behaviors are changing, altering the interactions between predators and prey. The Arctic’s famous polar bears rely on the ice to hunt and now have to travel further to eat, whereas the narwhal, a near-mythic, tusked whale, faces increased threats from killer whales lingering in exposed, warmer waters and disruptions to its migratory patterns.

Our best models currently predict the Arctic will be «sea ice free» within the next few decades, perhaps as soon as the 2030s. Antarctica’s sea ice is more of a mystery. But at both poles, sea ice is disappearing at an unprecedented rate.

And when the ice ends it’s not just the ends of the Earth that will change. It’s the entire planet.

An already changed Arctic

The Arctic Ocean’s sea ice expands during the winter, peaking in March, before retreating toward the North Pole. It typically reaches its lowest extent in mid-September. It never completely melts away — the North Pole itself is typically surrounded, and up to a fifth of the ice in the Arctic is so-called multiyear ice, persisting for more than a year.

Our understanding of this rhythmic pulse in the Northern Hemisphere stretches back for millennia. Indigenous peoples of the Arctic have passed down knowledge of the sea ice’s extent for thousands of years, particularly around coastal communities. Iceland’s government has been keeping detailed records since the 1600s, while log books and diaries kept during early exploration by ship provide a surprising amount of detail on where and when the Arctic Ocean froze over.

Our ability to understand the ice changed dramatically with the launch of the Nimbus-7 satellite in late 1978. The NASA and NOAA polar-orbiting satellite was fitted with an instrument that provided a way to observe the extent of the sea ice all year round, no matter the weather conditions, by studying the microwave energy bounced back from the surface. Continuous records have been taken since 1979, and the analysis has been deeply troubling. The extent of Arctic sea ice has been decreasing across those four decades, with each of the last 16 years the lowest on record.

Video: Changes in Arctic sea ice

Video credit: NASA’s Scientific Visualization Studio

For decades, scientists have tried to pinpoint when the total extent of Arctic sea ice will drop below 1 million square kilometers (or about 386,000 square miles) — the marker denoting a «sea ice-free» summer. In 2009, for instance, one study used climate models to determine that this mark would be hit by 2037. Other research has shown that the timing is unpredictable, with analyses suggesting we might still be decades away.

In June, a study in the journal Nature Communications analyzed 41 years of satellite data, from 1979 to 2019, reiterating that human greenhouse gas emissions are the dominant force in reduction of Arctic sea ice. It also generated a flurry of worrying headlines focused on the first ice-free summer, citing the near end of a range that it said had shifted to as early as the 2030s to 2050s. But those headlines gloss over a critical point: The current losses of summer sea ice are already having devastating effects.

«Although the first ice-free Arctic summer has constantly been a point of interest for understanding and communicating climate change, it’s more a symbolic threshold in some sense,» says Zachary Labe, a climate scientist at Princeton University and the National Oceanic and Atmospheric Administration. «Arctic climate change is already happening now and in all months of the year.»

An Antarctic paradox

From the beginning of the satellite era until 2010, Antarctic sea ice experienced a slight increase, with an acceleration in winter sea ice extent between 2012 and 2014. This was unexpected. Global temperatures have unequivocally risen in this time, largely due to human-induced climate change, raising ocean temperatures. Sea ice should’ve been melting. It didn’t.

The phenomenon was dubbed the Antarctic paradox.

Many climate models haven’t been able to reproduce these effects, though at least one high-resolution model has had success. Though explaining the paradox has been difficult, scientists have several hypotheses.

A visit to Antarctica

Natalie Robinson, a marine physicist at New Zealand’s National Institute of Water and Atmospheric Research, points out that changing wind patterns, release of freshwater from Antarctica, and ocean stratification could all have played a role over the last four decades, but she says that pointing to one variable as a driver of the increase is virtually impossible. «In reality, all of these processes act simultaneously and influence each other,» she notes.

About seven years ago, the story began to change. Antarctic sea ice extent plummeted in 2016 and hasn’t totally recovered since. In 2023, winter sea ice extent is dramatically lower than we’ve ever seen in the satellite era.

«Antarctic sea-ice extent has now adopted a downward trajectory as expected under warming and is congruent with observations of surface warming in the Southern Ocean,» says Petra Heil, a polar ice scientist with the Australian Antarctic Division. Graphs generated by Labe show the stark decline.

A line graph of Antarctic sea ice extent in 2023 generated by Zachary Labe

The record low extent has scientists concerned. Understanding the paradoxical increase over the past four decades could help unlock the reasons behind this sudden change. Does it represent a shift to a worrying new normal? Or is it merely a blip that can be attributed to the normal range of variability?

«There is certainly a fair bit of concern in the scientific community that it’s the former,» says Robinson.

«And we are racing to find out.»

When the ice ends

The great white sheets at either end of the Earth are particularly good at reflecting sunlight. Sea ice covers about 15% of the world’s oceans across the year, and up to 70% of the heating energy is reflected back into space. Cover that ice with a dusting of snow and up to 90% can be reflected.

When the sea ice disappears, the energy is absorbed by the ocean, raising its temperature. «In a positive feedback loop this ocean warming leads to even more ice loss and global warming,» says Heil. She suggests conceptualizing the impact of sea-ice loss by thinking about sea ice as the air conditioning unit of the Earth.

When the sea ice disappears, our planetary AC unit is being switched off. It becomes harder to reflect that heat into space and we lose the ability to «self-regulate» the Earth’s climate.

The change doesn’t affect just the ocean surface and the Earth’s air temperatures, though. Sea ice also plays one of the most critical roles on the planet in the ocean’s depths. As seawater freezes into ice, salt is expelled, making the surrounding water denser. This heavier, colder water sinks and gets whisked around the planet. Warmer waters are predominantly pushed by wind into the polar regions, then freeze up into ice. The cycle is known as thermohaline circulation.

«This process can be regarded as the starting point/engine of the global oceans’ overturning circulation,» says Jan Lieser, a sea ice scientist with the Australian Bureau of Meteorology and University of Tasmania.

image of the global conveyor belt with red arrows signifiying warmer water pushing around into the poles and blue arrows signifying colder deep currents

As the oceans continue to warm at both poles and sea ice extent decreases, this deep ocean current is likely to be disturbed. The knock-on effects could disrupt the polar ecosystems as nutrients and ocean biogeochemistry are altered, particularly in the Southern Ocean, where circulation is also heavily influenced by Antarctic meltwater and the currents already show signs of slowdown.

The atmosphere and ocean systems are incredibly complex and intertwined. Though the focus has long been on the extent of the sea ice, thickness also plays a role. So does snow cover. These measurements are harder to include in models because they’ve traditionally been difficult to gather. There are also differences at either pole. The Arctic typically has had thicker sea ice lasting for years, whereas Antarctic sea ice freezes new each year.

It now seems highly unlikely that the current declines can be stopped but Heil, and her colleague Melinda Webster from the University of Washington, say «it’s possible to slow and mitigate further detrimental effects of a warming climate by reducing greenhouse gas emissions and implementing ways to reduce existing atmospheric greenhouse-gas concentrations to levels that can sustain a habitable climate.»

On June 16, Heil and Webster, and more than 60 other polar scientists responded to the changes to the poles by calling for «urgent intensification of national and international research and observational capabilities in view of rapid Arctic and Antarctic change.»

«Action is required now,» she says, «to give future generations a fighting chance to mitigate the negative consequences of a warming climate.»

The anomaly in Antarctica’s sea ice this year, as if sounding its own alarm and affirming Heil’s calls, has only continued its downward trajectory.

Technologies

Anthropic Pinky-Promises It Won’t Add Ads to Claude

Anthropic’s Super Bowl ads are funny, but can we really trust them?

In the latest chapter of Anthropic’s «We’re not like the other guys» campaign, the AI company is pledging not to introduce advertisements into conversations with its chatbot, Claude. And it’s spending big on Super Bowl ads to make sure you know that fact.

Anthropic’s announcement takes a clear shot at competitor OpenAI. The ChatGPT-maker said a few weeks ago that it would begin testing ads in its products that will be «clearly marked» as sponsored posts. The company also said that ads wouldn’t be served around sensitive or regulated topics, like mental health and politics.

The news was a stark reversal from previous statements — OpenAI CEO Sam Altman had called ads a «last resort» in 2024. But it wasn’t entirely unexpected, given the general chaos of the AI industry’s financing.

For a long time, AI startups operated at a loss, spending billions of dollars from venture capitalists and others to build their chatbots without making money. OpenAI and many others now have a complex web of circular deals to keep the lights on, but newer advanced models require more compute, better chips and generally more maintenance and money to keep up. Anthropic certainly isn’t immune to these financial pressures; the company is the the process of securing a new $10 billion funding deal.

That’s why AI companies are seeking new revenue streams. Hence the ads.

The concern with including ads in chatbots (beyond general irritation) is that it will push products at the expense of helping users. Anthropic wrote, «Users shouldn’t have to second-guess whether an AI is genuinely helping them or subtly steering the conversation towards something monetizable.»

There’s also the risk that tech companies will prioritize advertising metrics and revenue over safety or user autonomy. OpenAI did not immediately respond to a request for comment.

Anthropic, for its part, has been very outspoken about the risks posed by AI technology, so it’s not surprising to hear the company weigh in on this issue. CEO Dario Amodei has spoken at length about the potential threat that AI systems may pose to humanity.

But we have a wealth of examples to draw on — streaming services, smart TVs and now chatbots — where tech companies tried and eventually failed to resist the allure of advertiser money. We can never say never. Anthropic didn’t.

Technologies

Overwatch’s New Season 1 Is What the Game Was Always Meant to Be

A commitment to an ongoing story and more frequent new heroes, including five right now, move the game in the direction it always seemed to promise.

In late January, I was among a group of journalists from all around the world packed into the Blizzard Theater in Irvine, California, to watch the 40-minute Overwatch spotlight and hear from Blizzard execs about where the game was going next. I was not prepared for what we saw. Nor were the other journalists, who gasped, laughed and sometimes comically swore as the video showed us what’s coming next for the hero shooter franchise — which turns a decade old later this year.

What stirred up such audible reactions? An ongoing story that’s reflected directly in the game. New subroles with distinct passive abilities. Ten new heroes are coming this year, five of which are arriving next week. One of the later heroes is freaking Jetpack Cat, who was dreamed up in concept art and scrapped before the game was even released. And maybe most surprisingly, dropping the «2» so the game returns to simply being «Overwatch.»

One of the first questions to that group of execs was about changing the title from Overwatch 2 back to Overwatch — why change, and what does it mean? Johanna Faries, president of Blizzard Entertainment, said the team thought it was the right time for Overwatch to turn the corner in a big way. «It sets us up for a much broader conversation on where the future of this universe [is] and where these characters are going to go.»

Blizzard’s big swing to revitalize Overwatch comes as the game approaches its 10th anniversary in May. Gaming is different in 2026, as newer live-service games can disappear in an instant, and even more tenured franchises like Call of Duty and Battlefield can struggle to retain players. Even Overwatch finally has a major, direct competitor in the team hero shooter genre in Marvel Rivals. So for Blizzard to step up and commit so boldly to this vision is a jolt, a burst of life into a game that has already spent the past couple of years solidifying and expanding its identity with new game modes and features like perks and map voting.

The announcements are both a celebration of the game’s history and a statement that the game is building a bolder future for itself.

Across my own nine-year history playing Overwatch, I’ve experienced its ups and downs, from the heights of queuing with a full six-stack and joining organized team play to the lows of the seemingly interminable double shield meta. And after talking to hero designers, narrative designers, systems designers, artists and voice actors, I left the Blizzard campus reflecting on the idea of playing Overwatch and following its larger story after all these new initiatives launch. One thought stuck with me.

This is how the game was always supposed to feel.

The emotion of a new cinematic driving the story of Overwatch forward, of puzzling over 10 hero silhouettes and learning that five of them would be ready to play almost immediately… it kindled the same kind of anticipation I had in the movie theater where I first awed over an early Overwatch trailer.

Best of all, fans won’t have to wait for this new era of Overwatch, as its fittingly rebadged Season 1 is launching next week with five heroes up-front and another new hero roughly every other month in each new season. We’ll get two new maps later in the year, alongside the return of postmatch accolades, which updated the old voting cards that let you show some love to players on either team who performed particularly well in a match.

I got an early look at the journey awaiting Overwatch fans this year during my time at Blizzard. And while I have some lingering questions about how certain elements will play out, here’s why I’m more excited about the game than I’ve ever been.

Overwatch embraces storytelling directly in the game

The world of Overwatch has always felt vibrant and pulsing with lore, but the game has struggled to tell a story outside of an impressionistic narrative you could vaguely piece together between cinematics, comics and occasional in-game events.

Season 1 promises to change that by kicking off the year-long Reign of Talon storyline, beginning with a cinematic that shows major upheaval in the villainous organization and longtime antagonist to Overwatch. The rest of that story will play out over the course of the year, through traditional avenues like hero trailers, short stories and comics, as well as more immersive methods like new voice lines and map changes that reflect story events.

The Overwatch Spotlight video includes a clip of Talon aircraft assaulting Overwatch’s Gibraltar base, home of operations for genius ape hero Winston. In the media playtest, I fought across a Watchpoint: Gibraltar map that showed the damage of that attack. The bridge outside the starting attacker spawn was partially collapsed, and a flaming beam had crashed down on the airship in the hangar. These map changes breathe life into the larger narrative of a new, more aggressive Talon and make sure players see the consequences of these story beats.

In addition to map changes that illustrate the ongoing story, Overwatch’s narrative and audio designers said that character interactions will also change to reflect the story’s progression, noting an «outrageous amount» of voice lines being added to the game.

Collectively, these changes help bridge the gameplay with the wider world of conflicts and characters that have been the initial point of interest for so many players.

Five new heroes headline a massive influx over the next year

Overwatch 2 launched with three new heroes and has added another 10 in the three-plus years since then. Now we’re getting 10 heroes in a single year, starting with five who all have connections to existing characters and factions in the game.

Domina, the new ranged tank and ally of Talon, is the heiress of Vishkar Industries, the same company that damage hero Symmetra works for and that also suppressed and exploited support hero Lucio’s hometown with technology his father had developed.
Anran, a new fire-themed damage hero, is the older sister of support hero Wuyang. She wields hand fans that can shoot fire, and is a new Overwatch recruit alongside her brother.
Emre, a damage hero wielding multiple weapons, is a former Overwatch agent now turned to Talon’s aims. He’s an old friend of damage hero Freja, though the person she found in their recent reunion is very different from the friend she remembers.
Mizuki, an offensively focused support hero, is part of the Talon-aligned Hashimoto clan, which has been facing opposition from the support hero Kiriko and her allies in Japan.
Jetpack Cat, a cat wearing a jetpack, is based on an early Overwatch hero concept long thought to be scrapped. Overwatch support hero Brigitte builds the kitty a jetpack to let her support allies from the skies by towing teammates and trolling enemies.

Multiple developers reiterated that this superdrop of new heroes wasn’t the result of cutting corners or rushing the process, but instead a benefit of improved tools and systems that have shrunk the design time for new heroes from eight months down to four or five.

«We still wanted to give the characters the same level of care we give any hero that we build,» the game’s Art Director Dion Rogers said in a panel on the new Reign of Talon story’s art.

In the leadership panel, Keller noted that the team wanted to kick off this year with an update that would feel like an expansion for the game, and the best way to do that for a hero shooter was to give them a bunch of new heroes: «People play this type of game … to learn more about these heroes, pick them up and continuously master them,» he said. Launching five heroes at once gives players that much more to engage with and could substantially shake up the meta of hero picks and team compositions.

Buzzing enthusiasm among developers

There’s plenty more driving my optimism beyond the new narrative focus and influx of new heroes. It’s the vibe of the announcements, the willingness for the game to go big, chase ideas and deliver a uniquely Overwatch experience to players.

There was palpable excitement among the five groups of Blizzard developers that journalists got to hear from at the Overwatch Spotlight event. In a panel about the game’s narrative, Lead Narrative Designer Miranda Moyer buzzed with enthusiasm, speaking alongside Scott Lawson, the game’s audio and technical director, about planning a year-long story, bringing Talon into the fray and how characters and allegiances might change over the course of that story.

«I think a lot of this new story is predicated on questions that have existed since, y’know, Overwatch was an entity [before eventually being disbanded],» Moyer said. She also noted that while some characters may have felt a little out of the loop of any sort of larger narrative throughout previous years of the game’s story, in the new structure «every single character … is pertinent to the overall plot.»

Developers being excited about their game isn’t surprising, but the degree of enthusiasm was encouraging for a game that suffered a years-long content drought followed by a troubled launch for Overwatch 2, stumbling over gated hero releases and long-announced game features that never saw the light of day. The conversations with devs gave me confidence that there’s a vision and passion for Overwatch that can fuel exciting updates like this for a long time to come.

The question marks amid the coming changes

The promises of ongoing stories and new heroes every season — six per year — are two of the most exciting things the game could announce. That said, some announcements from the spotlight raise more curiosity or concern than confidence.

A major overhaul of the menus forces us to relearn where things are and how to navigate them. The systems design team asserted that the new layout will add value, minimize interruptions and give players choices in menus, and I’m hopeful that the time spent relearning how to get around is worth the payoff. I like the cleaner look, but it will take some time to see how the new layout really feels.

The team also announced that some heroes, such as Ana and Genji, would be getting their second mythic skins before others received their first. I say this as someone who plays lots of Ana and wasn’t at all excited by her mythic skin, but that feels pretty unfair to the rest of the roster, especially given how many new faces we’re getting this year.

Balancing is the other element that feels like a bigger question mark in 2026. Dropping five heroes simultaneously and adding a new hero every season is going to put a lot more pressure on the team responsible for balance.

I asked Associate Game Director Alec Dawson about the challenge of balancing five new heroes at once. He acknowledged that the team does still want heroes to feel «impactful» at launch, but said they «probably went a bit too far» with recent releases.

«It’s good to have an impactful launch. It’s not good if your hero is banned in almost every match you’re in,» Dawson said.

The hero design team told us that they’ll be keeping a close eye on Jetpack Cat, especially given that permanent flight is an entirely new element in the game, and there are very few restrictions on her Lifeline ability that lets you fly allies around the map. Hero designer Scott Kennedy added that the team knows it’s going to be difficult to figure out all at once and that they’ll react quickly if things are out of line.

A new day and a familiar feel for Overwatch

The Spotlight video alone felt like Overwatch returning to the wonder and imagination that powered its 2016 launch. And the experience of talking to a variety of developers — and particularly seeing the seemingly unseverable thread of enthusiasm that connected them — made me as hopeful for the game as I’ve been since I started playing. The promise driving a story forward seems to mirror the team’s own internal hopes for shepherding the game into something bigger and bolder.

In a group interview with global media, I asked the game’s director, Aaron Keller, whether the Spotlight announcements were a commitment to moving the game forward — not just in terms of game mechanics but using it to tell a story beyond just brief snippets we’ve gotten from cinematics and events. He referenced the «amazing, sentimental» character pieces they’ve done so far, but said the team wants the new story to go somewhere.

«We want to take players on a journey over the course of this year — and over the course of many years,» Keller said. «We want to be doing this for as long as players are going to tune in for it.»