Polar Ice Is Lost at Sea

Eric Holthaus, a meteorologist and contributing writer for Grist, covering climate science, policy, and solutions. He has previously written for the Wall Street Journal, Slate, and a variety of other publications. Originally published at Grist

Our planet reached another miserable milestone earlier this week: Sea ice fell to its lowest level since human civilization began more than 12,000 years ago.

That worrying development is just the latest sign that rising temperatures are inflicting lasting changes on the coldest corners of the globe. The new record low comes as the planet’s climate system shifts further from the relatively stable period that helped give rise to cities, commerce, and the way we live now.

So far, the new year has been remarkably warm on both poles. The past 30 days have averaged more than 21 degrees Fahrenheit warmer than normal in Svalbard, Norway — the northernmost permanently inhabited place in the world. Last month, a tanker ship completed the first wintertime crossing of the Arctic Ocean without the assistance of an icebreaker. Down south in the Antarctic, sea ice is all but gone for the third straight year as summer winds to a close.

The loss of Earth’s polar sea ice has long been considered one of the most important tipping points as the planet warms. That’s because as the bright white ice melts, it exposes less-reflective ocean water, which more easily absorbs heat. And that, sorry to say, kicks off a new cycle of further warming.

According to research published last fall, that cycle appears to be the primary driver of ice melt in the Arctic, effectively marking the beginning of the end of permanent ice cover there. The wide-ranging consequences of this transition, such as more extreme weather and ecosystem shifts, are already being felt far beyond the Arctic.

Data from NSIDC and NASA

There is just 6.2 million square miles of sea ice on the planet right now, about a million square miles less than typical this time of year during the 1990s, and a few tens of thousands of square miles less than just last year, which had marked the previous record low. This level of detail about the remotest parts of the planet is available thanks to our relatively newfound vantage point from space. Satellites monitoring the poles gather sea-ice data, and records only go back to 1978. But it’s a near certainty that ice levels have not been this low in a long, long time.

Proxy evidence from microscopic fossils found on the floor of the Arctic Ocean provides proof that sea ice levels there are the lowest in centuries and perhaps much longer. There’s evidence from ancient plant material in far northern Canada that the Arctic has not been as warm as it currently is for at least 44,000 years. For the Antarctic, sea ice is more variable and no reliable ancient reconstructions currently exist — though there’s convincing evidence that there was less sea ice there about 128,000 years ago. For context, humans first mastered agriculture about 12,000 years ago in the Middle East, once temperatures stabilized near the end of the last ice age.

The middle of February is the usual time of the annual low for the planet’s sea ice (the Antarctic almost always has more ice than the Arctic, because there’s less land mass in the way); lately, however, the February lows have been much lower than normal on both poles. The Arctic and the Antarctic mostly operate as separate entities in the Earth’s climate system, but at the moment they’re in sync — a bit of a puzzle for researchers.

According to Zack Labe, a sea ice researcher at the University of California-Irvine, thinks there might be more than one cause. Arctic sea ice has been declining rapidly for decades, which Labe and other scientists are sure is the result of human-caused warming.

Antarctic ice, by contrast, began falling in 2016, which suggests the drop could be connected to natural swings in the climate. “It is too early to say whether losses in the Antarctic are representing a new declining trend,” says Labe.

Although the loss of sea ice is troubling, the overall pace of change is even worse. Global temperatures are rising at a rate far in excess of anything seen in recent Earth history. That means, in all likelihood, these latest records were made to be broken.

Print Friendly, PDF & Email


  1. Jeff

    Your regular reminder that about 90% of global warming goes into hiding into the world’s oceans. Around 7% melts the ice mentioned in the article, and only 3% serves to heat up the atmosphere (which has already warmed by ~1,3°C/~2°F, with more to come).

    I haven’t read an article yet that predicts what might happen when this oceanic heat starts having its effects.

    1. Michael

      In the short term the worldwide casualty of a melting Arctic is the jet stream, which has already been altered. Rather than flowing smoothly around the planet acting as boundary between cold Arctic air and warm tropical air, it has become wavy, causing many more polar vortexes, more droughts, more wildfires, more heat waves, more flooding, and more climate change. This is because the reduction in the temperature differences between the Arctic and the tropics. The political/social consequence of an increase in these events will be more famines, mass migrations, and wars, as described by the US military.

      The longer term result is a runaway climate due to the melting of permafrost and frozen methane (CH4) hydrates in the Arctic. The release of 1% of the material frozen would probably result in human extinction. See reference for research in this area. This link is the layman’s description of that research.

      The background level of CH4 prior to industrialization was approximately 670 ppb. Currently, the worldwide level is approximately 1800 ppb, with highest levels from 2400 ppb to 2700 ppb, depending upon the day. Inasmuch as CH4 on 5 year scale is 100 times more potent than CO2 you can do the math and show that we are actually at a equivalent CO2 level of around 550 ppm (adding the two together), or at 650 ppm in the Arctic. One can use a five year rather than a 100 year multiplier (27x), as it appears we are on an acclerating curve, and a 100 year multiplier is irrelevant in the current situation.

      The timing of these releases are unknown. If there is not a means to refreeze the Arctic, then extinction is probably inevitable.

      There are several research projects in geo-engineering to attempt to solve this problem, but solutions are probably at least 10 years out, and which may be too late to avoid a population crash. Additionally, current solutions such as High Altitude Aerosol Injection are purely theoretical and may produce worse results than solutions.

      It should be pointed out that the Paris Climate Accords, when declaring a two degree C or even 4 degree C average increase in temperature make the assumption that CO2 will have to be removed from the atmosphere. That is to say, CO2 reductions alone will not stop us from exceeding 2-4 degrees C. Currently there are no workable mechanisms to remove CO2 nor CH4 on a cost affordable industrial level.

      Additionally, the climate models used in the predictions made by IPCC do not take into account a melting Arctic or a release of Arctic methane.

      1. ToivoS

        This is because the reduction in the temperature differences between the Arctic and the tropics.

        Well you have described the bad news. But let us consider the good news: namely the intensity of tornados in the American plains have become less severe. Also the severity of the winds from hurricanes that hit the US coast are likely to be less severe — even if the water content in those storms might be higher.

    2. drumlin woodchuckles

      Well . . . it already is. It is melting the edges of whatever ocean-edge ice it is touching. It is shifting the ranges of certain sea creatures into new places. It is boiling off more water vapor into over-sea air here and there, stoking storms with more energy-in-play and permitting bigger better storms here and there, now and then. It is probably affecting other things as well already.

  2. Synoia

    Latent heat of fusion – converting ice to water is 80 cal/gm or 80 cal/ml

    If that heat were applied to 1 ml of water, it would rise 80 deg C.

    Melting ice is a sink for heat. See that curve of global warming (wherever)? When polar ice melts it rises exponentially, not linearly over time.

    Our goose then becomes cooked.

    I’d note the the middle of the US and Canada, the prairies, will become semi-deserts and then deserts.

    Buy land near Appalachia now!

    Raleigh, NC Elevation above sea level: 99 m = 324 ft

    1. rd

      The Midwest is where warm, moist Gulf of Mexico air encounters dry cold northern Canada air. That is why it is tornado alley in the spring, summer and fall.

      Climate change is likely to put more moisture into that Gulf air. It may be that the zone where the two collide expands some. I am not convinced that the middle of the country will necessarily become a desert as I think there will still be numerous collisions between those warm wet and cold dry air masses to precipitate out lots of water. I do think it will be warmer with more evapo-transpiration and much more variable from year to year, so climate reliability will likely decline.

      The mountains that extend from the Yukon all the way down to New Mexico as well as the predominant west to east wind flow is why the Southwest is buffered from that moist Gulf air. But there are no east-west mountains in the US unlike Europe and Asia, so it is clear sailing for air to move from the Arctic Ocean to the Gulf of Mexico and back in the middle half of the country.

      BTW – during the continental glaciation, the middle of the country south of the ice sheet was an arctic and sub-arctic desert with little vegetation and lots of wind storms. That is why many areas in the Mid-West are covered by up to hundreds of feet of loess which is wind-blown silt. It is a reason why drought and poor farming practices are so devastating the mid-west causing dust storms, such as during the 1930s. The bluffs of Vicksburg Military Park are loess. https://www.nps.gov/vick/learn/education/upload/Loess.pdf Loess is the primary thing that the US has in common with China.

      1. Jim A.

        It’s certainly possible that the lattitudes where winds are Westerly or Easterly will shift with the temperatures. Lots of changes are possible with rising temps, rising sea levels, as well as changing salinity levels brought about by melting icecaps. There will be winners as well as losers as climate changes, but we really don’t know what weather patterns will look like 200-500 years from now, but they are likely to be VERY different. And while 200 years seems long on a human time-scale, it is far faster than many species will be able to adapt or move to more appropriate climates.

      2. drumlin woodchuckles

        This is part of what leads me to think that the Americanadian Midwest and Plains will not become a uniform overall semi-desert to desert. What I would expect is more long droughts punctuated by more huge water-dump rain/snow events. Multispecies pasture, prairie and range may well withstand 20 inches of rain in one day, followed by 10 months of drought. Row-crop land will all wash away.

        That means that in due course, meat from animals will be the only food it will be possible to grow on that land at all. Let us pray that there will remain enough land not subject to destruction by megadroughts and megafloods to grow the plant based food that our vegan friends will need to avoid starvation.

  3. rd

    One thing to be cautious about in comparing the current period to the Pleistocene – sea levels were about 400 feet lower during the glaciation peaks, which lasted quite a while. Many areas that currently could have ice cover were actually land back then and some deep water would have been shallow water which changes freeze dynamics. Also, less fresh water would have been entering into the polar oceans from melting ice compared to the period starting 20,000 or so years ago when the continental ice sheets really melted in earnest.

    This will make it difficult to analyze data and come up with meaningful apples to apples comparisons. Peak polar ocean ice cover over the past million years could very well have been the 1600-1800s with large polar oceans and cold non-continental glacier climate leading to maximizing potential sea ice area. BTW – this would have been the same period of time when the Dutch would have been commuting to and from work on ice skates as shown in many of their paintings :)

    Similarly, areas like Florida were much, much bigger back then. Anything that has a water depth of much less than 300-400 feet of water would have been land then.

  4. Jeremy Grimm

    This post describes the decreasing extent of sea ice but I didn’t see where it noted the decreasing thickness of the ice which remains. Thin sea ice can melt quickly and thereby the extent of sea ice can quickly change. This adds a mechanism for rapid shifts in the albedo of the Arctic. Adapting to change can be difficult but adapting to rapid change is much more difficult.

  5. nonsense factory

    Another consequence of the warming melting Arctic is destabilization of the permafrost zone:

    “Permafrost is land that has been frozen stretching back to the last ice age, 10,000 years ago. As the Arctic warms at twice the global rate, the long-frozen soils thaw and decompose, releasing the trapped greenhouse gases into the air. Scientists estimate that the world’s permafrost holds twice as much carbon as the atmosphere.”

    It seems safe to conclude the Arctic will not return to a frozen state in the foreseeable future (many centuries from now, if we can figure out how to pull CO2 out of the atmosphere in large quantities, perhaps we can get back to 20th century norms). At best we can slow this process by rapidly cutting fossil fuel use, but even then, massive infrastructure investment will be needeed to move wastewater treatment plants back from coastlines, to deal with the results of major droughts and floods, to handle millions of climate refugees living in zones that can no longer support intensive agriculture, etc.

  6. JBird

    I have put this book on my very large to-read list. But after reading this, I am moving it up. Disaster capitalism on a planetary scale. I might just have found my masters thesis although that’s still a few years yet. And another reason for drinking beer.

  7. Tyronius

    Accelerating global warming will happen in steps. One of those steps will be the event of an ice free Arctic Ocean, and it’s going to happen within the next 5 years- my guess is that it won’t take even that long.

    Another factor is not only the amount of carbon dioxide and methane emissions but also dust and soot increasing the rate of ice melt. There will be climate affecting ‘steps’ associated with these, too.

    The fact that 2 degrees C is now a conservative estimate for global warming has ugly implications for coastal areas, as it will accelerate sea level rise just from the thermal expansion of ocean water, let alone the effects of ice melting in Greenland and Antarctica.

    In short, I think one meter of sea level rise will occur far sooner than 2100.

  8. drumlin woodchuckles

    Coastal reality-based global warming accepters need to sell their land as fast as possible to fantasy-based global warming deniers living inland . . . . so they can have the money to buy land from those fantasy-based inlanders who want to contrarianly-invest in the coming coastal land-boom involving land fled from by those silly “global-warming believer liberals.”

    We need a way to get the two groups of people in touch with eachother.


Leave a Reply

  • Keep it constructive and courteous
  • Criticize ideas, not people
  • Flag bad behavior
  • Follow the rules

Please read our Comments Policies here.

Your email address will not be published. Required fields are marked *