(Satellite rendering of the vulnerable Indonesia Archipelago — a system composing 17,000 islands. Image source: Commons)
From a climate-wrecking human warming spurring the melting of glaciers and ice sheets to the thermal expansion of the world’s oceans, sea level rise, to some degree or another over the next century is a given. How rapid this expansion progresses and how much land it devours will ultimately depend upon the amount of heat trapping gas we belch into the atmosphere and how sensitive the Earth’s climate system is to our increasingly traumatic insults.
Current conservative assessments from the Intergovernmental Panel on Climate Change (IPCC) estimate a total of 90 centimeters (nearly 1 meter) additional sea level rise before the end of this century. Today’s rate of sea level rise gets us to about 30 centimeters over the same period, so the IPCC is projecting that the pace of rising seas will more than triple over the coming years and decades.
(Global Sea Level Rise from 1993 to 2014. Image source: AVISO.)
Despite the fact that the rate of sea level rise and related glacial melt would have to rapidly uptick to meet the IPCC estimate, it remains a conservative case. Temperatures, over the next century under business as usual fossil fuel emissions or a moderate mitigation scenario, are likely to increase by between 5 and 9 degrees Celsius. This range of global heating is enough to eventually melt all or nearly all the glacial ice on Earth. So the heat forcing to the world’s glaciers is expected to be extreme, a blow at least equaling the temperature change between now and the last ice age. A temperature change that took 10,000 years to complete now crammed into an exceptionally brief period from 1880 to 2100.
Under such an outrageous pace of warming, a warming that could propel Earth to near Permian and PETM temperatures within 85 years, it is likely that the rate of sea level rise could be double or more that of IPCC predictions, possibly equaling or exceeding peak rates of sea level rise during the end of the last ice age at 10 feet per century. So the range of increase may well be between 1 and 3+ meters, making the IPCC case quite an underestimation if business as usual fossil fuel emissions continue.
(Survey of scientist projections of sea level rise in centimeters by 2100 under a high emissions scenario (RCP 8.5). Note that a majority of scientists project sea level rise in the range of 1 to 3 meters by 2100 with some scientists projecting as much as a 3 to 6 meter rise over the same period. Image source: Real Climate’s Excellent November Report on Sea Level Rise)
Stresses to glacial systems are already extreme even at the current human forcing of 400 ppm CO2, 1835 ppb methane, and at rising levels of a host of other greenhouse gasses. Current CO2 levels alone, during the Pliocene, were enough to establish seas as much as 75 feet higher than today. A fact that raises the question — if we already have 15-75 feet of sea level rise locked in, how swiftly will that rise occur? And the answer to that question depends on how rapidly the world’s largest glacial and ice sheet systems respond to human greenhouse gas forcing.
Very Large Glaciers Already on the Move
In a recent study one of the world’s largest ice sheets, the Pine Island Glacier, was found to be undergoing the first stages of an irreversible collapse. In other words, over the coming decades, the Pine Island Glacier (PIG) is due to complete an unstoppable slide into the Southern Ocean. And loss of the Pine Island Glacier alone commits the world to about 1 meter of additional sea level rise.
Unfortunately PIG is the first of many glacial systems from West Antarctica to Greenland that are likely to suffer the same fate. For from these vulnerable regions, mass losses from glacial melt have more than doubled over the past decade. In total, by 2008, about 90% of the world’s glaciers were in retreat. And since that time, warming has continued to advance with melt episodes becoming ever-more predominant.
Melt lakes, many larger than 5 kilometers across, form over Western Greenland, August 4, 2013. Summer of 2012 saw Greenland mass loss hit 600 cubic kilometers. Image source: Lance-Modis.
Greenland, for example, has exhibited increasingly severe melt stress over past summers with large stretches of lakes, many measuring 5-10 kilometers wide, forming over an ever-less-stable ice sheet. A towering ice sheet that boasts an average altitude of two kilometers, Greenland’s vast glacial system contains an immense volume of frozen water. But as great and mighty as this mountainous pile of ice may seem, human caused warming continues to deliver a series of ever-more damaging blows. By 2012Â Greenland had experienced a record wasting with 97 percent of its surface area showing melt during July and over 600 cubic kilometers of ice lost throughout the entire year. Yet as warmth continues to advance poleward, the 2012 melt season is likely to seem tame with far greater annual losses in store.
So there are many reasons to believe the IPCC estimates for glacial melt rates and related sea level rise, as with Northern Hemisphere sea ice losses, are too conservative and that science, in general, is still coming to grips with a dramatic and geologically unprecedented pace of change. That said, even IPCC findings are becoming increasingly stark.
Indonesia to Lose 10% of its Islands by Mid-Century
For if only the very conservative IPCC estimates bear out, we are still likely to see dramatic loss of lands and displacement of human beings.
A glaring example appears in new report from Maplecroft’s Climate Change Vulnerability Index which found that more than 1,500 islands in Indonesia would disappear after just a half meter of sea level rise. The study also found that the same amount of sea level rise would flood up to half of the capital city of Jakarta. Meanwhile, the 90 centimeters of sea level rise projected by the IPCC for the end of this century would put 42 million people along the coastline at risk of losing their homes.
Ancha Srinivasan, principal climate change specialist with the Asian Development Bank (ADB) noted in an interview that:
This archipelago’s biggest threat is rising sea levels, where 42 million people living three kilometres from the coast are vulnerable if estimated sea level rise reaches up to 90 centimetres by the end of the century.
Indonesia is composed of over 17,000 islands, many of which are low lying or feature sprawling and vulnerable coast lines. It is located in a region of the world where ocean levels are among the most rapidly rising. It is among a growing number of islands and low-lying coastal regions that are under increasing threat from what would seem even a modest change in sea level.
But as we went at length to illustrate above, Indonesia and other regions may be lucky to see only a 90 centimeter rise. So these projected impacts, though seemingly stark, may be at the low end of what we are likely to experience. Add just one more meter and most of Jakarta is flooded while 42 million of Indonesia’s people are almost certain to be members of a vast global migration away from the world’s coastlines.
Links:
Indonesia Risks Losing 1,500 Islands by 2050
Indonesia: Rising Seas Threaten 1,500 Islands
Maplecroft’s Climate Change Vulnerability Index
Real Climate’s Excellent November Report on Sea Level Rise
What does a World at 400 PPM CO2 Look Like?
Pine Island Glacier Undergoing Irreversible Collapse
Greenland Experiences 97 Percent Surface Melt in July of 2012
robertscribbler 
Robert A. Vella
/ February 27, 2014Reblogged this on The Secular Jurist.
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mikkel
/ February 27, 2014One question about statements like “during the Pliocene, were enough to establish seas as much as 75 feet higher than today.”
Not sure what to search for, but I was astonished to learn how much the ocean basins deepen over time. Now I’m not sure the Pliocene is far enough to contribute that much, but I think it’s still like 5m or something. If I remember, the Eocene was more like 25m.
Anyway, I can’t remember the numbers that well, but whenever I read statements like the one above I do wonder how much of it would be counteracted by this. In some ways it doesn’t matter because all the infrastructure on the coast is toast — so it’s only when discussing if inland seas, etc will return..but still.
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robertscribbler
/ February 27, 2014Eocene was closer to 80 meters higher than today. The Pliocene ranged from 15-75 feet higher than today. And you must understand that my estimate is conservative.
According to Dwyer, G. S.; Chandler, M. A. (2009). “Mid-Pliocene sea level and continental ice volume based on coupled benthic Mg/Ca palaeotemperatures and oxygen isotopes”:
“estimates of maximum sea-level elevations during the Mid-Pliocene range from 10 to 35 m above present, perhaps higher, which would have inundated many low-lying coastal regions.”
Click to access 33-30-million-years-ago-sea.pdf
This was during the period 3 -3.3 million years ago when CO2 ranged from 390 to 405 ppm.
I can’t emphasize this enough. Even my estimates are conservative.
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mikkel
/ February 27, 2014Right that is about the depth of the water right? My point is that the basin of the oceans is getting deeper over time and so the same volume of water leads to less maximum sea elevation.
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robertscribbler
/ February 27, 20143 million years isn’t long enough for ocean basin depth to make much of a difference.
In any case, all the ice in Antarctica gets you 61 meters, all the ice in Greenland gets you seven and thermal expansion gets you to about 80 meters in pretty much every assessment I’ve looked at. 220 to 250 feet if all the ice melts.
Have fun.
390 to 405 ppm melts all of Greenland and West Antarctica eventually. That gets us 7 meters from Greenland, 5 meters from West Antarctica, 1 meter from thermal expansion, 5 meters from additional glacial melt in other regions of Antarctica and around the world for around 18 meters or nearly 60 feet give or take about 20.
My estimate undershoots this by 15 feet average. And the ‘as much as 75 feet’ could well be as much as 120 feet (given some reports).
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mikkel
/ February 27, 2014Yup, I guess in the scheme of things the basin hollowing is a rounding error.
I am alarmed to see the distribution of projections…it means there aren’t enough people even contemplating how 3m+ could happen.
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robertscribbler
/ February 27, 2014Not too hard, really. You put a lot of ice sheets into irreversible collapse and those numbers stack up very quickly. It’s just a question of how quickly you start to push them off the cliff.
I’m surprised there hasn’t been much in the way of scenarios done on this yet.
Though my official is 1-3, the only limiter I see to more is ice sheet respond driving localized cooling. At that point, though, you might have tipped the scales too far into disequilibrium and end up with a lot more ice bergs in the ocean than you bargained for.
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mikkel
/ February 28, 2014“the only limiter I see to more is ice sheet respond driving localized cooling”
This is *entirely* speculative but let me lay out a scenario where it makes melting worse. Let’s say you have the ice on land, which either melts directly or moves according to internal slippage. Right now, there is a danger that as sea ice melts, it removes blockage and allows glaciers to slip into the ocean. Is it possible that if enough ice/cold water flowed into the ocean around Greenland then you may slow down that route, but also create a blocking pattern that keeps heat trapped over Greenland and contributes to direct melting?
A similar process happens inside valleys where adjacent valleys can either be much colder or warmer because a front moving in has created a major differential and the intense difference in temperature pushes the front around the entire valley instead of through it. If the front is strong enough it can break this isolation, but otherwise it takes a long time for dissipation to occur.
I could see a hypothetical scenario in which a major heat wave breaks through the “cold boundary” to add energy to Greenland but then is blocked from leaving.
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robertscribbler
/ February 28, 2014In general, the cooling effect is considered to be strong. The fresh water layer adds cooling and the ice bergs generate cold in their localized regions as the melt. There are a number of studies on the effect available.
In any case, the positive feedback to rate of ice loss, even in a localized scenario is sea level rise itself. More of the ice sheets are flooded and the grounding line moves further and further inland.
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robertscribbler
/ February 28, 2014In any case, it’s an interesting problem to think about. For my part, I don’t think the cold core systems will be very stable over Greenland for a number of reasons and you get all sorts of instabilities where warm air may over-ride on occasion.
The collapse of those ice sheets will also further degrade albedo. But I think the fresh water effect and ice berg related cooling will fight back for a time before being overwhelmed.
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james cole
/ February 28, 2014A few years back, on an international flight from Stockholm, via Iceland to New York, we passed over the heart of Greenland in September. I can’t explain what I saw, but it was a vast area of melt lakes and malt rivers that disappeared down holes. This was in marked contrast to the same flight back in the 1980’s, when all I saw was ice. It was only in early 2000’s that I noticed a massive change from white ice in Sept. to vast blue lakes.
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ccgwebmaster
/ February 28, 2014I think the scope for relatively abrupt sea level rise (inches per year) is underestimated (as seems par for the course), though my personal opinion is that most people don’t need to worry about it too much as I think civilisation (and most people) will be largely gone by the time sea level rise becomes serious.
It’s a fascinating topic though. Not only are some parts of the land rising and falling (adding to or negating sea level rise to some extent in those regions), some of this process is post glacial rebound – which is to say the crust tends to spring up where you remove loading from ice sheets (a rather slow process, but one which also increases the frequency of tectonic activity – earthquakes and volcanoes – and possibly substantially in the end).
Then we get into the often quoted figures for sea level rise and a rather important detail that is often not communicated. When we talk about 1m of sea level rise – this is not a uniform metre all over the surface of the globe (as people tend to think, apparently including almost all journalists reporting climate science).
As with global average temperature changes, the effects on the ground are far more nuanced and complex. Because of the billions of tonnes of mass being moved around the gravitational shape of the planet is effectively changed as the ice moves off the polar regions and into the ocean. For instance, the mass of the Greenland Ice Sheet (GIS) actually acts to attract more water towards Greenland. Take away the GIS mass and dump it into the oceans and the reduction in gravitational attraction locally actually means the sea level falls around Greenland (and significantly as you get near to it).
The converse implication of that however is that other regions – particularly nearer to the equator – experience a greater amount of sea level rise than that predicted as the average. Therefore if you are planning for 1m rise and are in the wrong place, you might not only fall short in terms of “worse than predicted” outcomes but also through failure to understand what the actual implications are in your region.
Want to avoid worrying about sea level rise? Try to find one of the sweet spots where it balances out (a little hard to predict due to the complex interplay of GIS vs the Antarctic ice) or get close enough to one of the big ice sheets that sea level will actually fall.
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robertscribbler
/ February 28, 2014The West Coast of Canada is probably the best place due to crustal rebound. But if rates of rise exceed one meter, everyone will be effected.
Coastal Louisiana, on the other hand, ends up with +2-3 feet based on sinking alone. So one meter for them is more like 5-6 feet.
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ccgwebmaster
/ February 28, 2014Actually my main point was that sea level actually falls near to the gravitational masses being removed. So theoretically the effects can be avoided or greatly minimised by being in the right place.
This blog post mentions it, could try to dig papers if of any especial interest:
http://piecubed.co.uk/2013/05/31/ice-melt/
“Jerry Mitrovica of Harvard University and his colleagues published a paper detailing the changes in the world’s ocean fingerprint due to the melting ice. They simulated the effects of the ice sheets melting including all of these factors: the rebounding earth, the gravitational pull and the change in axis of rotation. They found that if all of Greenland’s ice were to disappear the global average sea level would increase by seven metres. However, in Scotland it would fall by approximately 3 m. Europe woud be lucky and see sea levels rise a lot less than the average. South america would not be as fortunate, the water that Europe doesn’t get has to go somewhere, and in some places water would rise up to 10m. Which is rather scary.”
So, assuming they’re quoting from the paper hinted at – the 7m total rise from Greenland means -3m in Scotland (sea level FALLS there) but some places it rises by 10m.
So – my argument is Scotland is a better choice than South America? If you were clever enough you could find a point of minimal change to occupy. Does it help the existing cities and infrastructure? No, not really. But if you were serious about future planning…
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robertscribbler
/ February 28, 2014Pace of crustal rebound is slow…
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ccgwebmaster
/ February 28, 2014But post glacial rebound was only listed as a minor factor.
The major factor is the shift in gravitational attraction – that is instant. Pick billions of tonnes of ice up from a sheet, dump them into the ocean – gravity is a function of mass and you just moved part of the planet somewhere else…
Not sure if I’m being clear enough? As global sea level rises, regions close to the displaced mass actually experience falling sea level – due primarily to the movement of mass, with isostatic rebound as a secondary (and as you say longer term) factor.
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ccgwebmaster
/ February 28, 2014Ie just to be clear – that 3m of sea level fall for Scotland quoted if GIS melts – is not “over thousands of years” (isostatic rebound) but rather is “as fast as the ice melts” (re-distribution of mass and hence gravitational attraction). However, one cannot take GIS in isolation and must examine the Antarctic context for a more balanced overall picture (ie in the end it might still rise in Scotland, but probably not for Greenland).
Anyway I guess it isn’t really that important, was just trying to mention one of the nuances most people don’t appreciate – that sea level rise isn’t uniform and a lot more is going on than a simple nicely global averaged rise everywhere.
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robertscribbler
/ February 28, 2014The fingerprint theory is new as it relates to sea level rise. An interesting model simulation of how gravity is altered by ice sheet collapse to effect Earth changes. As such, it is also untested and very squishy.
For my part, I don’t want to be advising people to go to Scotland and end up finding out that the gravity model got things wrong.
In any case, the current model, if valid, becomes less and less useful with sea level rises of over 30 feet.
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ccgwebmaster
/ February 28, 2014Squishier than the IPCC modelling often relied upon to report on climate change?
I’m not particularly advocating people go to Scotland, just using it as an example of the unevenness of projected change.
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robertscribbler
/ February 28, 2014LOL. Good point. I think that’s up in the air at the moment.
And you’re right, there will probably be some rather strange outcomes.
I’d like to see more work done on the gravity fingerprint. My hunch, and it’s just a hunch, is that the results at this point are pretty grainy and will smooth more over time.
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ccgwebmaster
/ February 28, 2014Actually looks as though the blog author linked to papers explaining it (albeit many paywalled).
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Tom
/ February 28, 2014Looking at pictures of coastal England from the past 2 months of inundation by the sea and ridiculous amounts of rain illustrates an approximation of what most global coastal cities and towns will experience in the coming decades. With the collapse of Earth’s ecosystem ongoing, i’m not sure we’ll have to worry about sea-level rise. Humanity will more than likely be gone by 2040 according to some sources (whereas I don’t think we’ll make it through the 2030’s due to cascading failures of civilization along the way). I hope i’m wrong. Either way, we’re in for bad times.
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robertscribbler
/ February 28, 2014I think we’ll still be around. It’s just much tougher from here on out.
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ccgwebmaster
/ February 28, 2014Can I suggest you’re conflating civilisation with survival? Civilisations have collapsed and disappeared numerous times in the past following much mild stressors and shocks. Our species however has a track record of adapting to different environments and holds plenty of evolutionary advantages compared to most species.
So sure, inasmuch as most people rely upon modern civilisation to survive, and likely cannot without it – most people don’t need to worry about this. But our species does. It’s still going to happen and still going to affect people post civilisation as they struggle to survive and rebuild.
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Miep
/ February 28, 2014It’s also important to distinguish between civilization and culture. It is possible to have human cultures that are very different from civ, and integrated into natural communities. It’s even possible to have plant-based technologies. Instead of thinking “we can’t live without civilization’ we should be thinking about how to reshape culture into something that is long-term sustainable.
This does not begin to address the population overshoot problem, though.
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robertscribbler
/ February 28, 2014Now I like this thinking!
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ccgwebmaster
/ March 1, 2014When an animal population breeds in excess of the ability of the environment to support it, it crashes, typically with erosion of limits. There is no reason to suppose humans are different – mass mortality will correct population overshoot.
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robertscribbler
/ March 1, 2014Confrontation with boundary limits results in growth shock. One natural systems response is population collapse.
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Miep
/ March 1, 2014We’re the only animals that invented mining, though. Or learned to voluntarily burn things. Or what could burn. So we have created our own artificial context. And people have been talking about population crashes ever since I can remember.
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ccgwebmaster
/ March 1, 2014The thing is – we only postponed Malthus by using the stored energy of fossil fuels at grossly unsustainable rates to produce more food and hence people (aka the “green” revolution). Many people cling to the notion that we can continue to defy the issue indefinitely as a result of this rather questionable “success” story (how can it be a success given the long term price?).
In practice I think we will find that all we did was blow the bubble up bigger before it bursts (ie fossil fuels are finite resources, even setting aside the climate change damage in the equation). A bigger bursting bubble in this case means a much greater conflict for limited resources.
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Miep
/ March 1, 2014There are times I think that if we don’t somehow get this under control we are going to burn or eat every last living thing on this planet, unless we manage to make the air sufficiently unbreathable first.
We are just so adaptable.
And it is the ultimate in crazy-making to see hope predicated on a huge population crash.
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ccgwebmaster
/ March 1, 2014I see it more as a question of inevitability than of hope.
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robertscribbler
/ March 1, 2014The everything based on fossil fuels thesis is too limited for my taste. Either we will overcome that boundary limit, which isn’t as in owner rabble as people imagine, or there will be a regression.
In my opinion, sans climate change, the winnowing away from fossil fuel use would be a major advancement and allow for the development of far more healthy base inputs to economies.
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Miep
/ March 1, 2014Autocorrect win.
Paradigm shifts are possible. It’s not clear to me what will drive this one, though. People will want something new to latch onto for survival. That’s where mikkel is coming from.
The debate between “build something new” and “work for change within existing systems” has been going on for a long time, as to where better to put one’s energy.
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robertscribbler
/ March 1, 2014Hah. The iPhone scores!
Should have been impenetrable.
As for outside vs inside… I don’t understand why it shouldn’t involve both.
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Miep
/ March 1, 2014Yes, I agree. The whole inside/outside-the-system debate is kind of an energy suck.
I really do like “owner rabble.” It’s like a social class designation.
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robertscribbler
/ March 1, 2014The owner rabble does have a nice ring, I agree. I’m sure Bob could make something of that.
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Miep
/ March 1, 2014It’s the English translation of petit bourgeoisie.
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Colorado Bob
/ March 2, 2014“Melt lakes, many larger than 5 kilometers across, form over Western Greenland, August 4, 2013. ………….. ”
It’s no accident that these lakes are forming in the dirtiest part of the ice cap . That image really shows what the word albedo is all about.
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robertscribbler
/ March 2, 2014You have it sir. Melting snow is dirty snow.
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Colorado Bob
/ March 2, 2014January 20, 2014
Welcome to the Totten Project website. This week, our team of researchers will be heading toward our departure point of Hobart Australia, for our journey south to study the Totten Glacier and Moscow University Ice Shelf, East Antarctica. The goal of our project is to advance our understanding of this poorly understood glacial system and its potentially sensitive response to environmental change. This system is of critical importance because it drains one-eighth of the East Antarctic Ice Sheet and contains a volume equivalent to nearly 7 meters of potential sea level rise. This nearly completely unexplored region is the single largest and least understood marine glacial system that is potentially unstable.
29 days later –
We already have surprising preliminary findings from the oceanographic data collected on this cruise. Warm water temperatures were measured on the continental shelf here, perhaps an important factor driving the large amount of glacial ice loss occurring in this region.
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