Goodbye coastline: we are beyond the point of no return



We are committed to a watery future. The coastline we grew up with — the coastline that humanity grew up with — will soon be history. The giant ice sheets of Antarctica and Greenland are melting fast, and have passed the point of no return. Substantial sea level rise is now unstoppable.

It’s been a big week for glaciologists and watchers of the planet’s ice sheets. Last week NASA held a press conference to announce a new study showing that the biggest glaciers of West Antarctica are in rapid retreat, and have now passed the point of no return. They will collapse and add metres to sea level whatever we do – however much we reduce carbon emissions, or manage to restrain global warming. A separate study showed the unstoppable collapse process of one the glaciers — the Thwaites — could take as little as a century or two, if we’re lucky. Once it’s gone, the whole of the West Antarctic ice sheet will be primed to disappear.

That’s somewhere between three and five metres of sea level rise. Before you start to count in any melting of the Greenland ice sheet or the impact on the huge East Antarctic ice sheet – which also has glaciers like the Thwaites, poised for rapid retreat.

Meanwhile, the latest measurements made by the European Space Agency’s Cryosat-2 satellite show that Antarctica is now losing 160 billion tonnes of ice every year — twice as much as in 2005-10. On parts of the Thwaites and Pine Island glaciers the ice surface is dropping by as much 8 metres every year.

The news from Greenland isn’t good either. A new study looking at the shape of the land underneath the ice finds that there are deep valleys extending under the ice, which will help warm sea water to penetrate further towards the middle of the sheet. Another finds that summer fires in the rapidly warming tundra regions around the Arctic are sending smoke and soot up on to the ice and helping the summer melt to intensify.

Some historical context: the last time atmospheric CO2 was around 400 ppm — where we are today — global sea level was about 20 metres higher than today. What we’re seeing in West Antarctica is something that climate scientists have long feared — the first signs that the ice sheets are adjusting to the rapid warming of the planet that our coal and oil burning and forest felling has brought about. The first signs that we’re heading for a radically different coast, with drowned cities and flooded deltas.

The big question is how long it will take. There are tantalising signs in the sea level record from the last interglacial period — 125,000 years ago, when ice sheets were roughly the same size as now — that an ice sheet collapse caused sea levels to rise by several metres in a century or so. But we don’t have ice sheet models good enough (yet) to give us more than a general idea of how the Pine Island and Thwaites glaciers might behave as warming progresses over coming decades.

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The IPCC’s fifth report, released last year, suggests that if emissions are not constrained, sea level rise could get close to one metre by the end of this century, and that ice sheet melt could a few tens of centimetres more on top. What we’re seeing today, thanks to satellite sensors and diligent analysis, is the first signs that the ice sheets are starting the long march to our watery future.

We are certainly going to see many metres of sea level rise over the next few human generations. The map of the planet is going to be redrawn as cities are drowned and the megadeltas of Asia flooded. Florida will disappear. Holland will be in trouble. Banks Peninsula will return to what Captain Cook first took it to be — Banks Island.

This is now unavoidable, to all intents and purposes, because once the marine ice sheet instability comes into play it doesn’t matter much what you do to cool the plant, the ice is going to melt before it has a chance to reform. We can only hope that the process is slow enough to allow us to adapt — to move before the waves wash our coastal cities away.


  1. I’m afraid the world economic juggernaut is now going too fast to be stopped. It will continue until the earth becomes unihabitable in many areas. It is a now just a question of how quickly it will become noticeable. The children of tomorrow will ask the questions “why, when we knew what was happening, did we do nothing?”. We did nothing because it was too inconvenient to do anything and then we told ourselves “it will not happen in our lifetimes, so why should be care what happens when we are dead and gone?” Perhaps thousands of years in the future the dead earth will be visited by intelligent ETs who will wonder at the human’s eagerness to destroy itself by sheer greed.

    • Oh Martin. ‘we did nothing’

      well what should anyone have done?

      The environmental alarmists say we should stop using oil, but they also tell us that even if we did it would take 100 years for any change – so that would have made no difference.

      The REAL problem is that with all this concentration on oil and greenhouse gases all the alarmists have diverted everyones attention away from the only thing that will help – and thats to prepare to handle the problem.

      As for my self I have few concerns. In 1970 the world was claimed to be heading for a new ice age, yet here we are 40 years later – well 25 really because there has been little or no increase last 16 years – all worried about being fried.
      So what will be happening in another 25 years – another ice age perhaps?

      Ive chosen to ignore the made scientists and have moved inland to a house 130 metres above sea level – so Im going to be OK even if the sea rise. Stiff shit for the beach lovers and their costly houses built on sand……….

  2. And I’m not sure about the timeframe for significant SLR. The last interglacial came on over centuries if not millennia, with a very slow change in GHG levels. There has never been a situation with such a rapid rise in CO2 so it would hardly be surprising if changes to the planet’s ice aren’t much faster than envisaged.

  3. Some historical context: the last time atmospheric CO2 was around 400 ppm — where we are today — global sea level was about 20 metres higher than today. –
    And it was 6 degrees warmer than per-industrial which = end of human habitat.
    The thing is, during the past rise to 400 ppm (we are @402 ish now and growing exponentially) the methane was released slowly ie the planet sat at lower CO2ppms for longer periods of time, so areas high in methane were affected gradually, and as methane only has an 8 year life before it ‘converts’ to CO2 the planet went through probably thousands of methane lifetimes. Where as now we have pushed CO2 up so fast we have a 40 year lag , and in that time the methane (as we are seeing) will be released faster than any time in the past.
    Instead of the methane being released a little bit at a time we are going to see maybe a million years worth leach out of the tundra, from under the Antarctica, from fracking, and from heating swamps, inside of only 40 years, I think it will more than likely happen inside of 15 years.
    All this guarantees Near Term Human Extinction, that’s if the John Keys of the world don’t get us first )
    All hail the growth god.
    This is a ‘readers digest’ version of a great informative lecture only 8 min.
    Facts like – there is more (an fing lot more) CO2 in the ‘trapped’ methane than in ALL the fossil fuels, and we have used less than half of them, to get to this point.
    Currently CO2 and CO2e = about 800ppm
    We should paint that on the walls of the maternity wards.

    • It’s worth noting that Prof Guy McPherson who has sought to popularise the Near Term Human Extinction hypothesis has chosen to not publish this idea in any respectable scientific journals as a scientist should. McPherson is widely disrespected amongst scientists who study AGW who are frustrated with his disregard for the idea that extravagent claims require extravagent amounts of evidence. McPherson has chosen to not debate with these scientists as he should and he has instead turned to the internet where he preys upon the fears of people who know that AGW is bad but who also lack the expertise to critique his extrapolations of just how bad. As such, I consider McPherson to be the leader of a death-cult. NTHE alarmism is the mirror image of denialism. Both demotivate commitment to action. I think the Arctic Methane Emergency Group belong in this category too. Despite growing volumes of methan being released in the Arctic there is not good evidence for the clathrate gun hypothesis, and there is strong evidence against it. Unfortunately it is not going to be all over for us in a few decades so therefore the onus is on us to get off our lazy rear end and get busy without the excuse “it’s helpless we’ll all soon be dead.”

      • Sorry Peter but 402.6ppm + a 40 year time lag = NTHE, regardless of what anyone says.
        McPherson isn’t a scientist he is a professor, but yes sometimes he gets a few things wrong, I challenge you to give as many off the cuff talks as Guy has and not miss a beat.
        I suppose you think this guy is a clown 2 ?
        Ho hum

    • Robert, although the huge stores of methane in clathrate sediments and permafrost have the potential to cause catastrophic greenhouse forcing, the evidence is pretty clear that they did not play a role in the natural swings of climate and greenhouse gas concentrations over the ice ages. There is an event some 55 million years ago when they probably did, but the suggestion in your post that methane controls levels of CO2 in the atmosphere does not fit with the ice core records (compare the timing of methane and CO2 peaks).
      It is not useful to fret about a catastrophe that is very uncertain to occur. The problem is serious enough given the ever-rising greenhouse gas emissions from human kind. I think that is what we should focus discussion and political decisions on.

      • Hinrich
        I know methane hasn’t played a big part in past ‘events’ that is my point …….. in the past CO2 has never gone from 320ish to 402.6 ish in less than 50 years, so the methane was released …. s l o w l y …. over thousand of methane lifetimes, it may have never gone much over where it is now ie 1.8ish ppm (and growing)
        Though according to something I watched on YT last night, there have been methane burps in the past. It might have been on this ?

        And ” The problem is serious enough given the ever-rising greenhouse gas emissions from human kind. I think that is what we should focus discussion and political decisions on”

        You aren’t listening sorry, we are @ 402.6 ppm now, and next year around this time we will be at 406ish ppm. And as this stuff hangs around for 1,000, and as we are 40 years behind what 402.6ppm= it doesn’t matter now if we burn every tyre on the planet (which we will do once the final curtain goes down), or if we all piss off tonight, within the next 40 years the current CO2 that is up there for 1,000 years is going to kick humans off the planet.
        It might take another 5 years before people get it, but you will.
        Exponential anything, is hard to hide eventually. ie the doubling of ice melt in Antarctica within 4 years.
        We are toast.

        • Robert, I don’t quite understand what you are pushing for. Are you saying we shouldn’t, or don’t need to, take any action on reducing greenhouse gas emissions? It’s all too hard and too late anyway? Personally, I’ll rather focus on the scientific evidence (summarised by courtesy of the IPCC): there is still a chance of keeping the warming to 2 degrees C with drastic cuts in emissions. I am aware that this requires political will on a scale that we have not seen and that we are already at a point where our mitigation scenarios have to include as yet unproven technical solutions like carbon capture and storage. However, if only for the sake of my 2-year old, I refuse to sit back and bury my head in the pillows. Doing that turns it into a certainty that we will see climate change bigger than the difference between ice ages and interglacials. In case I misunderstood you, what do you suggest we should do?

          • 2 degrees became a target once it was realised that 1 degree wasn’t attainable. The “safety” of 2 degrees is highly suspect – especially as that is an average – some parts of earth will get much hotter than that.
            The political discussion is still years away from a point where meaningful action will even begin. As a species we didn’t evolve with the ability to respond to a problem of this nature. NZ on track for 48% increase in GHG emissions over the next ten years – how much would a change in government impact on that?

            As a society we are addicted to oil/carbon and need bigger fixes to get our hits. There is no “methadone” or other alternative – there’s only cold turkey.

            If you’re in a flood and the waters are rising faster than you’re sandbagging and most of your neighbours are untroubled watching TV, what would you do? That’s where you might find your answer as to what to do. It’s most certainly an acute question.

          • Hi again Hinrich
            First apologies for posting so often, but you asked so
            ‘Are you saying we shouldn’t, or don’t need to, take any action on reducing greenhouse gas emissions?’
            Well if it would make a difference, then clearly yes.
            To make a difference, ‘we’ would need to remove maybe 300 cubic kilometers?? of crap out of the atmosphere and oceans ASAP ‘we’ would need to bring CO2 and methane down to something like 280ppm CO2 and .5-.7 ppm methane, because, ‘we’ need to more or less force a mini ice age to reverse what is in motion, as Gareth says the ice takes time to refreeze.
            Anything less than removing the past 40 -60 years worth of human extravagance isn’t going to change things.
            With 7.16 billion people on this rock, it is imposable to reverse the CO2 output, feeding this mass of flesh is UNSUSTAINABLE now, ‘we’ would have to take out something like 5 – 6.8 billion people to bring the planet back to a point it could ‘sustain’ us.
            The only way to stop the planet from going above 2 C is to keep it from going above .5C ops.
            It is already a certainty that we will see climate change bigger than the difference between ice ages and interglacials, the atmosphere hasn’t been @ 402.5 CO2 and 1.8 – 2 ppm methane for something like 25 – 55 million years, and it has NEVER been in this situation …. where CO2 has risen 100 + ppm in 1,000 years or so, with 50ppm in the last 30 – 40 years, that is worse than a meteor or several Mount Pinatubos.
            I’m bloody sorry about your daughter, it breaks my heart seeing the last generation being born. Alas if you had been listening to me over the past 15 years you might not have had her, but you, like every other breeder did, so now you face reality with a kid on a stick.
            Not liking these facts dose not change them, and clearly as I keep saying the only thing you can do is not have another child.

  4. What I want to know is where are all the people who until quite recently were saying that global warming was a myth, that the Earth was cooling, that burning coal was the way forward etc? Where are Don Brash and the rest of the lunatics? Where is Chris -‘carbon dioxide is a harmless gas” de Freitus?

    I suppose it doesn’t matter because we still have lunatics in charge anyway. Stephen -get the tar sands out of the ground and burn them even if it creates a Moonscape- Harper, Tony -dig it up and sell it to China- Abbott, John -let’s mine to conservation estate- Key.

    We won’t have to wait for ice sheets to melt; with the jet stream already buggered and California in the worst drought in history it’s going to be a very interesting Northern Hemisphere summer.

    • And think of all the nuclear power plants, and chemical plants, close to rivers and lakes and the seashores, what will happen when the water keeps rising? We may have heaps of Fukushimas, polluting the fish and other seafood, and radioactive elements seeping into ground water.

      This will become unmanageable, and it will be proved, although it will happen gradually. The floods of refugees will be immense.

  5. “We can only hope that the process is slow enough to allow us to adapt — to move before the waves wash our coastal cities away.”

    How delightfully vague.

    And for the people who are coastal and lacking cities? For whom this is a Now problem? You know – various island communities and Bangladesh?

    And aquatic species losing breeding grounds in shallow waters…

    Let’s not have any re-runs of Rio and other posturing ‘earth summits’. The human traits that lead to politicians are simply not useful, not nimble enough, to begin any process of ‘adaption’. We’re fools to think so.

    On the other hand – might they be sufficiently motivated to move away from the ‘grow the population of consumers, cannon fodder, and taxpayers’ curse that we’ve been enduring since after WW2?

    If it wasn’t for the frequent bribes and frequently moved goal-posts on pricing of basic commodities, I’m reasonably sure most women would have settled for fewer kids. (Seems to be the case in Japan.)

  6. The situation is terrible. But I have no respect for hopelessness.

    “There is a Chinese proverb: To know and not act is not to know. The greatest catastrophe in history is happening on our watch. We can either be bystanders and passive victims, letting climate change happen to us or we can actively fight for what we hold dear.”

  7. Hey, says the ostrich man, under the sand things look rather different, there is no sign of global warming and sea level rises.

    Keep on pumping the gas into the air, he says.

    He is one of many, of most out there, refusing to understand and draw the inevitable conclusions.

    Forget the Auckland Unitary Plan, other plans, forget the economic day dreams of this government, and other governments, forget it all, like turning these isles into a Noah’s Arch to save millions of humans from destruction and suffering.

    The bit of land that will be left will be fought over. Earlier predictions by doomsday adherents have told me, it may be better to be dead, than to survive the catastrophe that will come.

    Human history is actually full of examples of self destruction of cultures, and also of destruction to geological and climate changes. Just this time it will reach dimensions of “biblical” proportions.

  8. This article is hysterical nonsense and scaremongering. Antarctic ice, as a whole, is increasing, which reduces water in the sea. Glaciers which move, are glaciers which are growing, with precipitation added far inland. Those that seem to be melting are a small section of the massive continent and are affected by underwater volcanic activity.
    The level of CO2 in the atmosphere has NO effect, it is not hot, and is not capable of melting the ice.
    People, please use your brains! The Anarctica will never melt. It is at the bottom of the globe, is in darkness a large part of the year, and the sun never shines directly on it. Soon it will be winter, the big freeze is on again,
    Over the next decade, the sun will be drifting further away from the Earth, as part of its natural cycle. A mini-iceage will become apparent with time. The Northern Hemisphere, in particular, will lose its warming trend – it has started already.
    The Arctic will regain its ice, the sea routes will close again.The amount of CO2 in the air will have no effect whatsoever.
    This is a deluded scare story from Nasa, and these lying scientists should hang their heads in shame.
    The questions you all should ask are – “Why are we all being lied to so blatantly?”
    “Why is our education so poor, that we are unable to discern that we are being treated as fools?”
    Oh how those scientists must laugh and snigger, as they publish their mad fairytales.
    This is not true science, but propaganda!

    • You have some evidence that refutes the Greenhouse Effect that was identified mid-1800s and the heat absorptive qualities of gases that was measured by Arrhenius in 1896?
      Can you provide a scientific basis for your “The level of CO2 in the atmosphere has NO effect, it is not hot, and is not capable of melting the ice.“?
      The addition of a few reputable citations might help your plausibility.

    • Aha – a visitor from Lala Land.

      Everything in this comment is nonsense – factually incorrect, misleading drivel.

      The only purpose it serves is to demonstrate how deluded some people allow themselves to become.

    • Would you please be so helpful to provide the evidence for your claims or at least provide the links to such evidence, assuming there is any.

    • Sorry, Juniper, but your comments are based more on fanciful thinking rather than hard facts. There is simply no evidence to sustain your myopic (dis)belief of global warming.

      • Frankly I suspect you’ll find there were too many “junipers” in the gin or, more likely, a serious case of Poe’s Law at work.
        As a different Poe poet said…
        “Believe only half of what you see and nothing that you hear.” ― Edgar Allan Poe

    • This post by Juniper is full of nonsense.

      Just one example. “The level of CO2 in the atmosphere has NO effect, it is not hot, and is not capable of melting the ice.”

      This is of course a silly statement. CO2 doesn’t have to be hot to absorb heat energy, and raise planetary temperatures. Google greenhouse affect.

      What’s more interesting to me is the person who wrote that post is obviously at least educated, but to say something as silly as that? This shows how cynical sceptics are. They will try any trick to fool a few gullible people but nobody is fooled any more.

  9. If there’s one thing the planet and its inhabitants do best of all is adapt . We’ll be ok . The very worst thing we can do is live in fear . Fear is more awful than death in my view . Fear infects and distorts our entire lives while death is the blink of an eye .
    That doesn’t mean we shouldn’t act to protect our future happiness however .
    I might finally get my beach front property and when the global warming refugee hoards arrive ? I say party ! In the most green and low emissions way possible of course .
    Ok . We all seem to know that we’ve fucked it up a bit , But let those who are innocent cast the first stone . Or … spare me the fucking hypocrisy will you ?
    We can whine and wring our hands and tut tut but will that stop the petulant ice from melting ? No . I don’t think so . So , fuck the ice if it can’t take a joke . Let it be the water in my coffee .
    In the mean time ? Break out the rods , there’s fishing to be done on the front lawn .

    And doesn’t it worry you that the sun will all but go out in about 5 billion years ? That’s what really freaks me out .

    • CB,
      Evolution is, well, evolving – as Monsanto and antibiotic drug manufacturers are learning- so there’s really no point worrying about our fate in five billion years because, if we’re still around, we will have evolved into a very different species by those eons of time.
      Hope that puts your mind at rest and you can go back to your fearless fishing and Antarctic iced coffee drinking.

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