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.

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.

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

Kohler Wants to Put a Tiny Camera in Your Toilet and Analyze the Contents

The company’s new Dekoda toilet accessory is like a little bathroom detective.

Some smart litter boxes can monitor our pets’ habits and health, so having a camera in our human toilet bowls seems inevitable. That’s just what kitchen and bathroom fixture company Kohler has done for its new health and wellness brand, Kohler Health.

The $599 Dekoda clamps over the rim like a toilet bowl cleaner, pointing an optical sensor at your excretions and secretions. It then analyzes the images to detect any blood and reviews your gut health and hydration status. Depending on the plan you choose, the subscription fee is between $70 and $156 per year.

Don’t miss any of our unbiased tech content and lab-based reviews. Add CNET as a preferred Google source.

At toilet time, you sign in via a fingerprint sensor so that the device knows who’s using the facilities. (Please wash your hands before signing out or tracking your progress.) Then, check in with the app for the day’s analysis and trends over time.

Wait until you’re off the pot, though, before you start doomscrolling your health. The device has a removable, rechargeable battery and uses a USB connection.

Kohler says it secures your data via the aforementioned fingerprint scanner and end-to-end encryption, and notes that the camera uses «discreet optics,» looking only at the results, not your body parts.

«Dekoda’s sensors see down into your toilet and nowhere else,» the company says.

Kohler warns that the technology doesn’t work very well with dark toilet colors, which makes sense. I’m sure there could be an upsell model with a light on it. Maybe the company could add an olfactory sensor, since smell reveals a lot about your gut health too. It could track «session» length or buildup under the rim to alert whoever has responsibility to clean it.

Kohler must have been straining to find appropriate lifestyle photos to include with the publicity materials. Many of the images are hilarious, featuring fit-looking men and women drinking water and staring off into space contemplatively — probably thinking about gas.

Technologies

Who’s Up to Fight Mega-Corporations in the Outer Worlds 2 on Xbox Game Pass?

Save the universe by fighting one CEO at a time in The Outer Worlds 2, plus play other great games coming to Xbox Game Pass in October.

Space is the final frontier, and it’s packed with some devious mega-corporations who are out to make a buck in The Outer Worlds 2. Xbox Game Pass subscribers can fight them in the highly anticipated sequel starting on Oct. 29.

Xbox Game Pass offers hundreds of games you can play on your Xbox Series X, Xbox Series S, Xbox One, Amazon Fire TV, smart TV and PC or mobile device, with prices starting at $10 a month. While all Game Pass tiers offer you a library of games, Game Pass Ultimate ($30 a month) gives you access to the most games, as well as Day 1 games, like Hollow Knight: Silksong, added monthly.

Here are all the games subscribers can play on Game Pass soon. You can also check out other games the company added to the service in October, including Ninja Gaiden 4.

Don’t miss any of our unbiased tech content and lab-based reviews. Add CNET as a preferred Google source.

PowerWash Simulator 2

Game Pass Ultimate and PC Game Pass subscribers can start playing on Oct. 23.

If you’ve ever spent hours watching people on YouTube clean dirty rugs, cars and other grimy objects, you should check out PowerWash Simulator 2. As the name suggests, this sequel is all about blasting away dirt and filth from pools, homes and other objects around town. You have a furry kitty companion, and yes, you can pet them when you’ve finished cleaning.

Bounty Star

Game Pass Ultimate and PC Game Pass subscribers can start playing on Oct. 23.

The American Southwest has devolved into a lawless, post-apocalyptic desert called the Red Expanse in this game. You’re out to clean the place up in this game by taking down major bounties issued by the government, and the best way to do that is by piloting and customizing a giant mech, of course. When you want to nurse your wounds, head back to your run-down garage to rest, grow and cook food and raise animals. It’s like a cozy Armored Core game.

Super Fantasy Kingdom (game preview)

Game Pass Ultimate and PC Game Pass subscribers can start playing on Oct. 24.

After returning from a hunting trip, you find your 8-bit kingdom wrecked in this game. You must rebuild your domain in this roguelite, city builder. But as night falls, hordes of monsters emerge to tear everything back down. Build, mine, cook and grow your home, and prepare to defend it from all dangers.

Halls of Torment

Game Pass Ultimate, Game Pass Premium and PC Game Pass subscribers can start playing on Oct. 28.

Get ready to descend into the deadly Halls of Torment in this retro, horde survival game. You can choose between 11 playable characters, each with their own playstyle, and equip various items and abilities to survive waves of enemies. This game is like Vampire Survivors, so if you like that game give this one a shot.

The Outer Worlds 2

Game Pass Ultimate and PC Game Pass subscribers can start playing on Oct. 29.

Clear your calendar for this sequel to the award-winning sci-fi adventure, The Outer Worlds. This time, you’re an Earth Directorate agent investigating the cause of devastating rifts that could destroy humanity. You have a new ship, new crew, new enemies and mega-corporation goons standing between you and the answers.

1000xResist

Game Pass Ultimate, Game Pass Premium and PC Game Pass subscribers can start playing on Nov. 4.

One thousand years in the future, humanity is hanging on by a thread after a disease spread by alien occupation forces people to live underground in this sci-fi adventure game. You play as Watcher, and you fulfill your duties well, until one day you make a shocking discovery. This game won a Peabody Award in 2024, and it was nominated for the Nebula Award for Best Game Writing that same year, so get ready for a story like no other.

Football Manager 26

Game Pass Ultimate and PC Game Pass subscribers can start playing on Oct. 29.

Get ready for a more immersive matchday experience in the latest installment of the Football Manager franchise. You can build a star-studded squad with new transfer tools, and this entry features official Premier League licenses and women’s football for the first time in the series’ history.

Game Pass subscribers can play the standard or Console edition of this game.

Games leaving Game Pass on Oct. 31

While Microsoft is adding those games to Game Pass, it’s also removing three others from the service on Oct. 31. So you still have some time to finish your campaign and any side quests before you have to buy these games separately.

Jusant
Metal Slug Tactics
Return to Monkey Island

For more on Xbox, discover other games available on Game Pass now and check out our hands-on review of the gaming service. You can also learn about recent changes to the Game Pass service.

Technologies

Does Charging Your Phone Overnight Damage the Battery? We Asked the Experts

Modern smartphones are protected against overcharging, but heat and use habits can still degrade your battery over time.

Plugging your phone in before you head to bed might seem like second nature. That way by the time your alarms go off in the morning, your phone has a full charge and is ready to help you conquer your day. However, over time, your battery will start to degrade. So is keeping your phone plugged in overnight doing damage to the battery?

The short answer is no. Keeping your phone plugged in all the time won’t ruin your battery. Modern smartphones are built with smart charging systems that cut off or taper power once they’re full, preventing the kind of «overcharging damage» that was common in older devices. So if you’re leaving your iPhone or Android on the charger overnight, you can relax.

That said, «won’t ruin your battery» doesn’t mean it has no effect. Batteries naturally degrade with age and use, and how you charge plays a role in how fast that happens. Keeping a phone perpetually at 100% can add extra stress on the battery, especially when paired with heat, which is the real enemy of longevity.

Understanding when this matters (and when it doesn’t) can help you make small changes to extend your phone’s lifespan.

Don’t miss any of our unbiased tech content and lab-based reviews. Add CNET as a preferred Google source.

The science behind battery wear

Battery health isn’t just about how many times you charge your phone. It’s about how it manages voltage, temperature and maintenance. Lithium-ion batteries age fastest when they’re exposed to extreme levels: 0% and 100%.

Keeping them near full charge for long stretches puts additional voltage stress on the cathode and electrolyte. That’s why many devices use «trickle charging» or temporarily pause at 100%, topping up only when needed.

Still, the biggest threat isn’t overcharging — it’s heat. When your phone is plugged in and running demanding apps, it produces heat that accelerates chemical wear inside the battery. If you’re gaming, streaming or charging on a hot day, that extra warmth does far more harm than leaving the cable plugged in overnight.

Apple’s take

Apple’s battery guide describes lithium-ion batteries as «consumable components» that naturally lose capacity over time. To slow that decline, iPhones use Optimized Battery Charging, which learns your daily routine and pauses charging at about 80% until just before you typically unplug, reducing time spent at high voltage.

Apple also advises keeping devices between 0 to 35 degrees Celsius (32 to 95 degrees Fahrenheit) and removing certain cases while charging to improve heat dissipation. You can read more on Apple’s official battery support page.

What Samsung (and other Android makers) do

Samsung offers a similar feature called Battery Protect, found in One UI’s battery and device care settings. When enabled, it caps charging at 85%, which helps reduce stress during long charging sessions.

Other Android makers like Google, OnePlus and Xiaomi include comparable options — often called Adaptive Charging, Optimized Charging or Battery Care — that dynamically slow power delivery or limit charge based on your habits. These systems make it safe to leave your phone plugged in for extended periods without fear of overcharging.

When constant charging can hurt

Even with these safeguards, some conditions can accelerate battery wear. As mentioned before, the most common culprit is high temperature. Even for a short period of time, leaving your phone charging in direct sunlight, in a car or under a pillow can push temperatures into unsafe zones.

Heavy use while charging, like gaming or 4K video editing, can also cause temperature spikes that degrade the battery faster. And cheap, uncertified cables or adapters may deliver unstable current that stresses cells. If your battery is already several years old, it’s naturally more sensitive to this kind of strain.

How to charge smarter

You don’t need to overhaul your habits but a few tweaks can help your battery age gracefully.

Start by turning on your phone’s built-in optimization tools: Optimized Battery Charging on iPhones, Battery Protect on Samsung devices and Adaptive Charging on Google Pixels. These systems learn your routine and adjust charging speed so your phone isn’t sitting at 100% all night.

Keep your phone cool while charging. According to Apple, phone batteries perform best between 62 and 72 degrees Fahrenheit (16 to 22 degrees Celsius). If your phone feels hot, remove its case or move it to a better-ventilated or shaded spot. Avoid tossing it under a pillow or too close to other electronics, like your laptop, and skip wireless chargers that trap heat overnight.

Use quality chargers and cables from your phone’s manufacturer or trusted brands. Those cheap «fast-charge» kits you find online often deliver inconsistent current, which can cause long-term issues.

Finally, don’t obsess over topping off. It’s perfectly fine to plug in your phone during the day for short bursts. Lithium-ion batteries actually prefer frequent, shallow charges rather than deep, full cycles. You don’t need to keep it between 20% and 80% all the time, but just avoid extremes when possible.

The bottom line

Keeping your phone plugged in overnight or on your desk all day won’t destroy its battery. That’s a leftover myth from a different era of tech. Modern phones are smart enough to protect themselves, and features like Optimized Battery Charging or Battery Protect do most of the heavy lifting for you.

Still, no battery lasts forever. The best way to slow the inevitable is to manage heat, use quality chargers and let your phone’s software do its job. Think of it less as «babying» your battery and more as charging with intention. A few mindful habits today can keep your phone running strong for years.