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Where have all the people gone?

Posted on 9 August 2011 by Daniel Bailey

There was a time when the crumbling towers around me held people. 

The world was a much different place, then.  SFIt was a time when the deserts of Braska and Gowga were verdant fields, when the rains fell in just the right amounts at just the right time, when people soared like eagles in their metal sky-kites and walked the streets now below my keel.   They say men even crossed across the then-frozen Sea of Northern Lights from Canda to Rusha on sleds pulled by dogs over the ice.  Some even say that people once went to the Moon and trod its surface (Oh, the things some people say!).  The fields, the rains which watered them, the sky-kites, the city below me and the people who lived then, all gone now.

That was before the world changed.  Sorry, that wasn’t quite right.  Before WE changed the world.  Before we knew that the way people lived back then, the lifestyle they led, came at a price.  A price that would end up being paid in human blood.  What they didn’t realize then was the tiny byproducts of their energy sources, the carbon, accumulated in the air, the water and the soil.  Not a lot, but enough to change things.

It happened slowly, at first.  Nights stayed a little warmer, the autumns would last a little longer, the winters would start a little later, spring would come a little earlier.  Not every year, but more and more, the seasons changed.  The great ice in the North was the first to yield, they say.  The thick crust covering the Sea of Northern Lights, the Arctic they called it, thinned.  Eventually it melted in summer, only to regrow in winter.  But each winter it was less than the last and soon it was gone.

The once-frozen ground in Canda and Rusha turned soft, like warm butter, yielding up vast stores of even more carbon.  Greenland’s great glashurs stirred to life, flooding the sea with immense blocks of ice the size of mountains.  And soon the Land at the Bottom of the World began to stir.  They say its Western part, the Wace, slid into the sea in the lifespan of a man.

The world-ocean began to rise, reaching hungrily for the works of man.  Man fought back, building great walls to keep the wolf at bay.  But soon the rising tide proved too much.  And one-by-one, the great cities of the coast, like the one under me, Myame, were left to their end.

The forests, once vast (before man a squirrel could travel from sea-to-sea via branch and vine without stepping paw on the ground), finally succumbed to timbering, drought, pestilence and disease, yielding their own carbon.

The fields dried, producing less food.  The rains, when they came, fell in great cloud-bursts, washing away the best soils for crops.  Food, once abundant, became scarce.  Mankind began to quarrel over what was left.  No one knows who started it, but war came.  First in skirmishes, then great battles were fought.  The number of man, once almost beyond count (it is said men could walk 4 abreast in rank and file around the entire world and the line would never end), began to dwindle.  And the Bombe itself was used, repeatedly.

The world, once home to billions, now barely supports not much more than once lived in the city below me.  For the oceans were also changed by the tiny carbon, becoming wet deserts with little life.  Sometimes the sea itself turns red like blood.  This event, once rare, is happening more often, now.  And the waters of the Sea of Northern Lights bubble and boil...

(MP3 rendition of the Intro to this article.  Self-recorded using Audacity)

While the above is a work of fiction, studying what the effects of climate change and sea level rise will have on human populations is not.

Identifying the human impact of rising sea levels is far more complex than just looking at coastal cities on a map. Rather, estimates that are based on current, static population data can greatly misrepresent the true extent -- and the pronounced variability -- of the human toll of climate change, say University of Wisconsin-Madison researchers.

"Not all places and not all people in those places will be impacted equally," says Katherine Curtis, an assistant professor of community and environmental sociology at UW-Madison.

In a report published in the peer-reviewed journal Population and Environment, Curtis and her colleague Annemarie Schneider examine the impacts of rising oceans as one element of how a changing climate will affect humans. "We're linking economic and social vulnerability with environmental vulnerability to better understand which areas and their populations are most vulnerable," Curtis says.

They used existing climate projections and maps to identify areas at risk of inundation from rising sea levels and storm surges, such as the one that breached New Orleans levees after Hurricane Katrina, then coupled those vulnerability assessments with projections for future populations.

It's a deceptively challenging process, the authors say. "Time scales for climate models and time scales for human demography are completely different," explains Schneider, part of the Center for Sustainability and the Global Environment at UW-Madison's Nelson Institute for Environmental Studies. "Future climate scenarios typically span 50 to 100 years or more. That's unreasonable for demographic projections, which are often conducted on the order of decades."

The current study works to better align population and climate data in both space and time, allowing the researchers to describe social and demographic dimensions of environmental vulnerability.

The analysis focuses on four regions they identified as highly susceptible to flooding: the tip of the Florida peninsula, coastal South Carolina, the northern New Jersey coastline, and the greater Sacramento region of northern California, areas that span a range of population demographics. (New Orleans was not included as a study site due to major population changes since the 2000 census.)


Figure 1.  Maps of the four study areas examined in this research: a Northern California, b New Jersey, c South Carolina, and d Southern Florida. The counties of each sample area are shown in dark green, while potential inundation is shown in orange (1-m sea-level rise) and red (4-m sea-level rise). For reference, urbanized areas are shown in yellow

With help from the UW-Madison Applied Population Laboratory, the researchers used 2000 census data and current patterns of population change to predict future population demographics in those areas. By 2030, they report, more than 19 million people may be affected by rising sea levels just in their four study areas.


Figure 2.  Observed and estimated population in 2000, 2008, and 2030 for the four study areas impacted by sea-level rise in 2030

And many of those people may be in unexpected places. The case studies clearly reveal the importance of considering people's patterns of movement.

"No area is completely isolated, and migration networks are one of the ways we think about connections across places. Through these networks, environmental impacts will have a ripple effect," Curtis says.

In one example, if Florida floods, New York and Los Angeles will feel the effects -- in 2000, 14,000 people from three New York counties and another 5,500 from Los Angeles moved to Miami-Dade County, Fla. Under the environmental scenarios in the study, those people would have to remain where they started or move elsewhere, consequently shifting their resources and needs to new sites.


Figure 3.  Population projections in 2030 for the four study areas based on three net migration scenarios (growing economy, declining economy, and natural disaster)

Curtis and Schneider designed their approach with an eye toward helping local authorities identify and best respond to their own needs.

"Adaptation and mitigation strategies are developed and implemented at a local level. Part of the problem with large-scale population and environmental impact estimates is that they mask the local variation that is necessary in order for a local area to effectively respond," Curtis says.

A population's demographic, social, and economic profile affects the ways in which people can respond to local disaster, she adds. For example, children or elderly require a different approach to evacuation and resettlement than a largely working-age population, while workers from the agricultural lands of northern California will face different post-displacement labor challenges than those from the industrial corridor of New Jersey.

Even using rough estimates of sea level rise, their analysis makes clear that planning ahead for mitigation and adaptation will be crucial, Schneider says.

"As we anticipate future events, future natural disasters, we've learned how dramatic it can be -- and there are things that can be done in advance to mitigate the extent of damage in a location," Curtis says.


Where have all the people gone, long time passing?
Where have all the people gone, long time ago?
Where have all the people gone?
Gone to graveyards, everyone.
Oh, when will they ever learn?
Oh, when will they ever learn?

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Comments 1 to 38:

  1. Yooper,

    I would say "chilling!" but that just doesn't seem appropriate.

    Here is a link to the presentations given last year in Corpus Christi about 'adaptations' and 'planning'.

    BTW, did you know that the US Coastal Zone Management Act has been in place since 1972?

    The program objectives are derived from the CZMA goal to "preserve, protect, develop, and where possible, to restore or enhance the resources of the nation's coastal zone."

    Feel better now?
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  2. MuonCounter,
    Doubt there is anything you can do about it, but FYI,

    " expired on 07/28/2011 and is pending renewal or deletion."

    is on your link to the presentations.
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  3. On the weekend I saw a current events article showing the difficulties the people of Taraqwa in Kiribati are encounterring already with salt water from increased storm surges contaminating fresh water sources.

    And still the denial machine rolls on....
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  4. Didn't the US Congress recently vote to outlaw funding for climate change mitigation programs?

    Depressing, to say the least...

    The silver lining - with their heads firmly entrenched in the sand, they *might* be some of the first to feel the effects of the rising waters...
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    [DB] I know you speak figuratively, but 6 meters of SLR brings the sea to Congress' steps, literally:


  5. Bern#4: "with their heads firmly entrenched in the sand,"

    Interesting position, that. Washington DC was built on landfill, so head in the sand might be messy:

    1860s -- Residents of Washington, D.C., dump garbage and slop into alleys and streets, pigs roam freely, slaughterhouses spew nauseating fumes, and rats and cockroaches infest most dwellings including the White House.

    Actually, it doesn't sound like that much has changed.

    I don't think the cuts you were referring to made it all the way through the budget process into law, but you can bet they'll be back.
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  6. That was a disturbing audio, resonating too close to home.
    A futurecast, eh.

    Don't imagine that any contrarians will listen to it long enough to give it a second thought.
    Crumbling towers indeed.

    As the tragedy unfolds with relentless momentum, we are the witnesses. But, that sucks, it would have been much nicer to actually do something constructive.

    But, I guess, the Bible and that monstrous mass of people who are hooked into it, want their Armageddon no matter what it takes to achieve it.
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  7. muoncounter: Indeed, I see today that Republican presidential hopeful Michele Bachmann has vowed to shut down the EPA: "I guarantee you the EPA (U.S. Environmental Protection Agency) will have doors locked and lights turned off and they will only be about conservation."
    They are playing a political game, where they blame environmental protection for all the economic ills that the US is suffering from. Sadly, if they get their way, it wont fix the economic ills, but you can be sure it'll generate some non-economic ones...
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  8. Muon, you beat me to a response. Indeed, all true; Bachman and her supporters scare me. What I was going to say is:

    Nah, it's just hard to accept that some lifestyle changes might have to be made (no more big 4-wheel drives for commuting to the office, etc.), very hard to accept that something very bad is likely happen, and very hard to accept that one is at least partly responsible. Facing this triple-whammy, it isn't that surprising that many seek shelter in denial. It isn't even surprising that many get angry when you try to pry them out of their sheltered place.

    I was in the wilderness with a group who took a wrong turn coming down a mountain once. There was anger. There was denial. But eventually the fact set in that the only way to get back to our food and our only known sources of water was to go back over the top of the mountain. (Well, OK, we skirted around the summit.) It's a pity that thermodynamics are harder to understand than triangulating a position on a map. Because saying, "We are here; our food, our tents, and our sleeping bags are there. What do you want to do?" tends to cut through the BS.
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  9. Sorry, Bern...
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  10. Nice fiction! I always enjoy reading stuff like that (not living it though....).
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    [DB] Thanks!  Did you try the audio version of the intro?  I'm experimenting with making posts more multimedia to drive interactivity and interest.

  11. Odd that most climate scientists seem to be of the view that SLR will be less than 1m by 2100. There are of course exceptions such as Dr Hansen who predict possible decadal doubling of polar ice mass loss producing catastrophic SLR during the last 30 years of this century. I think this minority will be proven right and, on current trends, SLR of 1m is likely to result by 2050.

    By 2050, global population of ~10 billion is predicted. At least 1 billion will be directly impacted by SLR flooding and a further 5 billion affected by scarcity of life essentials, property losses and economic collapse. But not to worry, we are assured by at least one supposedly informed economists commenting on SkS posts, that humans are resilient and will learn to live with and adapt to SLR. Some may. Billions will not.
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  12. Uh oh. Based on the maps above, a 1 meter sea level rise would make the office building where I work part of the Atlantic Ocean.

    Is it bad to find oneself looking forward to some of global warming's impacts? :]
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  13. Bern#7:

    Look at the 'bright side': Suppose Bachmann (and no doubt some other of her extremists) has her way and EPA is dismantled. Within a few years of burning high sulphur coal and letting the soot fly, our air will be brown again - just like it was before the EPA could regulate pollutants. Higher albedo, global warming problem solved.

    Chris G#8:

    Especially when storm clouds are gathering and it looks like a hard rain's gonna fall.
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  14. Agnostic,

    What do you feel will change in the next 40 years to create 1m of SLR? That is a large leap from todays 2-2.5 mm/yr.
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  15. Eric: hmm, I thought the current rate was more like 3.2mm/yr.

    But the answer to your question is: non-linear ice-sheet dynamics. There are signs that Greenland & the WAIS are beginning to destabilise. Based on that, and paleoclimate data from previous interglacials, it seems the question is now "how long will it take" rather than "will it happen".
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  16. Agnostic @11, I am curious as to who that economist is. As you know, I am far more skeptical of the threat from sea level rise than most regular commentators here at SkS (excluding deniers). I base that skepticism both on a reasonable trust of the experts, and a belief that the past is the guide to the future. The opinion of the sea level experts (of whom Hansen is not one) can fairly be taken to be represented by that expressed by the World Climate Research Program sea level rise workshop. There estimate for end of century sea level rise including the melting of glaciers and ice sheets is for a rise between 0.6 and 0.8 meters: Church 2007 Placed in the perspective of Brisbane, that equates to a change of peak King tides from a minor to a moderate flood level, still a meter lower than the flood experienced in January of this year. Although coastal suburbs would be impacted more, that still means less than 10% of the land area of Brisbane would become untenable for commercial use or inhabitation, assuming no counter measures in the form of sea walls and levees. The cost of that would be approximately to increase the normal cost of construction in replacing aging buildings by 40%, a minor cost against the normal economic life of the city. Sydney would be effected even less by such a rise. Arguably other cities would be effected more. Indeed, I would be surprised if they did not. But purportedly one of the most vulnerable would be Miami, and even there the impact of a 0.8 meter sea rise would be relatively minor as shown by this image of Miami with a 1.25 meter sea level rise (or the impact of a 0.45 meter storm surge with a 0.8 meter sea level rise): Much as I enjoyed Daniel's fiction, I think we can safely say Miami will not be below anybody's keel in the next one hundred years. Turning to the past as the guide for the future, it strikes me that during the approximately 140 meter rise in sea levels since the last glacial maximum, sea levels rose at " average rate of about 10 mm yr-1 (1 m per century), and with peak rates of about 40 mm yr-1 4 m per century), until about 7,000 years ago" (Church et al, 2008). That one meter per century average pace represents a useful best estimate of the likely rate of sea level rise for a four degree temperature differential between initial and equilibrium temperatures, and hence for peak sea level rise at the end of this century. Going from 0.3 meters per century now to 1 meter per century at the end of the century leaves an average increase over the century of around 0.6 meters. Even in the unlikely event that sea level rises match those before the Eemian, when over a 2.5 thousand year interval, sea levels rose at approximately, 3.5 meters per century, because of the slow rises in the first part of the 21st century, whole century averages are likely to be closer to 1 meter than to 2. So, while I fully expect sea level rises of up to 8 meters in the long run, and up to 20 if, with just a bit of bad luck, we trigger a tipping point, I do not expect sea level rises to be the major climate change story of the 21st century. Compared to the impacts of ecosystem loss, ocean acidification, extreme weather, and extreme heat, the impacts of sea level rises will appear almost inconsequential, although a significant (not crippling) economic burden in their own right.

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  17. 16, Tom Curtis,

    Might it not be more correct to measure sea level rise in terms of "per degree Celsius" instead of per year, given that the current rate of temperature change will quickly outstrip that of the past? The 120m sea level rise since the last glacial goes with a roughly 20˚C temperature change in Greenland, but spread over several thousand years such that warming in Greenland appears to have been at best 1˚C per century. Using (probably unrealistically) simplistic, linear projection this implies that another 10˚C temperature change within 100 years could amount to a total sea level rise of 60m (although the annual rate of actual sea level change in response to such rate of warming could be open to argument).

    Now, admittedly, this is an apples and oranges comparison, because the amount of water locked up in ice, and the configuration by latitude and on land and water is drastically different. But by the same token, this makes an effort to predict sea level rise by year (instead of by degrees C) similarly difficult to do based purely on past sea level rise.

    I think the situations are just too dramatically different to take too far, but I take no solace in a 20˚C Greenland temperature rise yielding a 120m sea level rise, no matter what the time frame.
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  18. It might be interesting to have an article on climate change in fiction. It's one thing to get the models; it's another to develop a comprehensive narrative of the future from a human perspective. There is the established genre of eco-fiction, but I'm thinking specifically of recent stuff incorporating global warming (e.g. Kim Stanley Robinson). I simply don't have the time right now to do a thorough piece, though I suppose it could wait.

    I find it interesting that George R.R. Martin's Song of Ice and Fire fantasy series features background tension stemming from the idea that "winter is coming."
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  19. Read Asimov's 'Nightfall.'

    A highly developed planet with multiple suns and therefore continual daylight; every 2000 years or so, an eclipse causes total darkness. Scientists try to warn the population prior to the eclipse, but a quasi-religious cult interferes. Bad results.

    All that, written in 1990.
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  20. Drowned world by J.G. Ballard? Can't remember what the cause of the warming/sea level rise was, but it was published in 1962. Found it a rather dissapointing read though :-(
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  21. Tom,
    While much of Miami's waterfront will still be above sea level with a one meter sea level rise, where will they get their water from? Currently they have well fields on the back side of town where they obain water for drinking. Those are located only 3 feet above sea level. If sea level was to rise even 0.8 meters, a small storm surge (or none at all) would innundate the well fields and they would have no source of water.

    Miami is a special case that grabs the attention of Americans (like me). A better question is what to do with the 17% of Bangladesh that would be innundated by a 1 meter sea level rise. (I noticed that APiratelooksat50 did not mention Bangladesh recently when he listed countries affected by sea level rise, you can make any claims if you ignore the evidence). Millions of subsistance farmers live there. Current increases of sea level have made farmers switch from rice to shrimp. All the arable land nearby is already farmed. Where will they go?

    Your reference to the World Climate Research Program sea level rise workshop appears dated to me. Much has been learned about sea level rise in the past 2 or 3 years. I note that their graph shows measured sea level rise at or above the maximium they estimate will occur. It will be interesting to see what the next IPCC report says about sea level rise.
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  22. muoncounter #19
    Actually, Asimov wrote the short story Nightfall in 1941. 1990 was the novelization by Robert Silverberg.
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  23. A couple of other SF books with climate change themes:
    Mother of Storms - John Barnes
    Heavy Weather - Bruce Sterling
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  24. I would have to say that I also share Tom's skepticism over extreme rates of sea level rise. While this is attention-grabbing, I dont think it is supported well by science so far. Even with much higher temperatures, its hard to put much credence on projected sea level rise rates that are higher than peak rate for ice sheet collapse at the last glacial termination. On that basis, I doubt that sea level would be higher than 1m by 2100. While this doesnt have dramatic impact, it should be noted that 0.5m sealevel rise by 2100 is no laughing matter either (see the Stern report), especially for those places already having problems with coastal erosion and salt incursion. The great deltas in particular have a very delicate balance between sediment load and sealevel rise controlling dynamics.
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    [DB] Please note that I at no point (AFAIK) constructed any sort of time frame or amounts of SLR into this post.  Or at least into the intro piece.

    The intro was meant as a retrospective look at the changes that could took place at some future point in time, looking backwards from that time.  It serves(d) as an attention-getting device intended to spur dialogue.

    And yes, I was strongly influenced in this by The Road Warrior, The LOTR:FOTR and Earth Abides (by George R.R. Martin George R. Stewart).  Stories that will always live in my memories.


  25. "I find it interesting that George R.R. Martin's Song of Ice and Fire fantasy series features background tension stemming from the idea that "winter is coming." "

    I wonder if this is favourite book for our sometime visitor - The Inconvenient "skeptic" who somehow believes a milankovich forcing can override all other forcings no matter how big.
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  26. Sphaerica @17, the problem with indicating a sea level rise per degree celsius is that the paleo evidence clearly shows that it can take centuries, and even millenia to melt large ice sheets. The Laurentide ice sheet (over North America) for example, did not fully retreat until about 6,500 years ago, even thought the last glacial ended 10,000 years ago. Therefore the expectation that the Greenland Icesheet or the West Antarctic Ice Sheet should fully melt in 90 years is unrealistic.

    Should they melt completely, which seems likely with business as usual, that would result in a sea level rise of around 15 meters, (approx 7 from the GIS, 5 from the WAIS and 3 from other ice caps and glaciers), but it will not do so for several centuries. That means the sea level rise will be an ongoing problem for the foreseeable future, but not a catastrophic one for most people.
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    [DB] Tom, my understanding for the WAIS is that ice sheet collapse is the postulated mechanism of loss.  And that this is thought possible due to the WAIS being almost entirely accessible to the ocean, as the majority of its bed is well-below current sea levels.  With the PIG & Thwaites being the linchpin/keystone for the entire works.

    Thus, rates of in situ melt for the WAIS are completely moot.

  27. Michael Sweet @21, I am not particularly concerned about Miami's water supply, as it can be supplied by desalinization at need. As such it represents a low order problem for the future, and one which Miami has plenty of time to deal with.

    Bangladesh, and to a lesser extent the Nile delta (and no doubt others I am less familiar with) represent serious problems, which I do not wish to down play. They are resolvable problems. Bangladesh may well be able to defeat rising sea levels by building (with international aid) large sea walls now, along with other concrete baffles through out the delta. The idea is not to hold the sea back, but to retain more silt from flooding, thus raising the delta level. Alternatively the problems could be solved by either mass migration, or by urbanization coupled with enhanced agricultural productivity.

    The point is that if sea level rise were the only problem, the problem would be resolvable, and adaption would be a more economic response than mitigation.

    Of course, even for Bangladesh, sea level rise will be one of the least of their problems from global warming. Indeed, for Bangladesh some of their problems (loss of reliable irrigation due to glacier melt in the Himalayas, for example, or reduced primary productivity of crops due to excess heat) will make solving the problem of sea level rise more difficult if not impossible. So adaption only is not a viable response to climate change.
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  28. DB @24, I certainly did not want to imply that you where suggesting Miami would be under the keel by 2100. Indeed, given the linguistic developments evidenced your story, I suspect you are placing it several hundred years in the future (without a specific number in mind). On the other hand, I do want to firmly reject Agnostic's claim @11 that we might see a 1 meter rise in sea level by 2050.
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  29. DB @26, I'm certainly happy to concede that the WAIS will melt faster than Greenland. However, I return to my point about the past being the guide to the future. Similar situations undoubtedly occurred during the last deglaciation, and may have been responsible for some of the intervals of 4 meters per century sea level rise. Consequently multimeter sea level rises by 2100 cannot be excluded. But the average rate was still 1 meter per century, which I consider a better predictor.

    With regard to the mechanics of WAIS breakup, I think the sea is going to have to melt its way in. The weight of the ice will prevent it from simply running in under the ice and floating it away. Consequently the break up of the WAIS will certainly take decades, and will probably take a more than a century. Of course, all estimates come with large implied error bars ;)
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    [DB] I believe we are in broad agreement that:

    1. Past history is a general predictor of future performance
    2. That our current understanding of about 1 meter SLR is at about the upper limit we can expect by 2100 due to melt alone
    3. That the weight of the WAIS will prevent the warming oceanic waters from running underneath it as it does ices shelves/tongues.

    That being said, the constraining factor limiting the mass-wasting of the GIS, the coastal fringe of mountains, is entirely absent from the WAIS.  What this (warming plus geomorphology) entails for the WAIS is an enhanced Zwally Effect (surface melt running through moulins lubricating the bedrock promoting ice-sheet slip), creating an unstable ice sheet sliding at increasing speed down a slope that terminates in the ocean...(we need to drag Mauri in off the glacier he's on right now to provide some proessional insights).

    Basically, gravity (like physics) is a bee-otch and wins all ties.

  30. Tom Curtis: It seems we're mostly agreed that long-term (i.e. over 500-1000 years or so) sea level rises of 5-15 metres are not only plausible, but likely.

    Where I disagree with you, though, is your perception of rate. As Sphaerica stated at 17, it might be more appropriate to think in terms of ice melt per warming, rather than ice melt per century.

    After all, the end of the last glacial maximum saw a 5ºC temperature rise over 10,000 years. We're looking at matching that in 100 years. With rate of warming two orders of magnitude higher, it's not such a stretch to imagine that rate of sea level rise might be only half an order of magnitude higher.

    On that basis - I'd say that past performance is absolutely not a good indicator for what will happen over the next century, because the projected rate of warming does not appear anywhere in the paleoclimatic record, no matter how far back you go. This is the importance of models - they can give you an idea of what will happen when you venture into new territory. Models of ice sheet dynamics seem to be fairly rough & ready at the moment, but the more research done on it, the more worrying the results seem to get... (recent work on the PIG being but one example)
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  31. Tom Curtis - "On the other hand, I do want to firmly reject Agnostic's claim @11 that we might see a 1 meter rise in sea level by 2050"

    True, it seems very unlikely given the present state of knowledge, but 'suspected' rapid jumps in SLR during the height of the last interglacial, suggest that it is still possible, in principle at least.

    See: Rapid sea-level rise and reef back-stepping at the close of the last interglacial highstand - Blanchon (2009)

    If the timing/dating by Blanchon can be confirmed by other techniques, it's strong evidence of ice sheet collapse. Sure it's likely that collapse will take place further into the future, not in the next 39 years, but when you read what the bulk of scientific literature was saying 7-8 years ago, they've certainly made a habit of underestimating the speed of ice loss.
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  32. Yooper (response to #24): "meant as a retrospective look at the changes that could took place at some future point in time,"

    Here's an aptly titled movie along the same vein.

    Why didn’t we stop climate change when we had the chance?
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    [DB] Thanks for the link.  Didn't know it was wholly available on the 'net yet (I caught an open-window preview back in the spring).  Highly reccommended.

    Postlethwaite was a treasure.  He will be missed.


    Ok, didn't realize that was just a preview (saw the 1:40 and thought that was the hour/minute runtime).  Oopsy.  Very much worth buying, though.

  33. Eric @ 14

    Two things suggest a speeding-up of SLR this century

    1. Hansen et al 2011 note that we are already within “a few tenths of a degree” of the Eemian maximum when sea level was ~5m above current levels. Should we aim to limit atmospheric CO2 to 450 ppm, this would take average global temperature to well above Eemian by 2100 and so expose us to SLR similar to that pertaining at the Eemian maximum.

    2. SLR is primarily caused by melting of land based ice. At current rates of loss, it is unlikely that SLR would exceed 1m by 2100. But why should we assume that current polar land based ice loss will remain constant for the next 90 years. If warming continues (few dispute it will) the rate of land based ice mass loss will increase causing accelerated SLR.

    Hansen asserts that the effects of slow feedbacks initiated by anthropogenic CO2 emissions are such as to produce decadal doubling of ice mass loss from the GIS. This would result in ice mass loss rising from ~120 gigatonnes in 2000 to ~130,000 gigatonnes per annum by 2100. Were this to occur and be accompanied by similar rate of WAIS ice loss, the result could be SLR of 5m by 2100.

    It is useful to remember that neither ice mass loss or its effect on SLR are linear and because of this non-linearity very rapid acceleration in SLR over the next 40-50 years would not be expected. During this period it is possible that SLR per annum will increase from mm/annum to cm/annum. However, during the latter part of this century a much larger SLR should be expected from on-going decadal doubling of ice mass loss from the GIS.

    I accept that most climate scientists at present regard a 1m. rise in sea level by 2100 as a maximum expectation and I remain quite ambivalent about a 5m SLR occurring by 2100. On the other hand, I see no reason to challenge the views expressed by Dr Hansen. Even taking into account uncertainties associated with slow feedbacks on Arctic amplification, it is not unreasonable to believe that SLR of no more than 1m. by 2100 is a very conservative estimate.
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  34. DB Comment on #24
    Earth Abides (a great novel) was written by George R. Stewart, not George R. R. Martin.
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    [DB] You are very much correct (facepalms).  My bad.  My copy is missing from the shelf (I can't blame the kids because the oldest doesn't read despite a perfect GPA & top entrance marks to college & the other is but 8...), else I'd have caught that.

  35. Tom, Rob, Agnostic,
    who was it said "If you want to know where the science is, read the IPCC. If you want to know where the science is going, read Hansen."? (Obviously whoever it was said it a bit differently, otherwise I'd have picked it up on a search.)

    I'm quite happy with Tom's summary of various projections, but, I spend most of my 'climate-time' looking at the Arctic. Satellite images, graphs, blogs, papers - all of which tell me that the very best science of a mere 5 years ago was way off the mark about the rate of loss of sea ice.

    Even if SLR projections are only half as far off the reality as the Arctic sea ice calculations were, we're in for a good bit more than 1 or 2 metres SLR by 2100.

    As always, if we'd just get our act together and reduce GHG concentrations we could avoid some of the worst of it. And by that I mean not just reducing emissions. We have to get serious about sequestration - not of emissions alone, but of actual atmospheric/ocean concentrations already there from current and previous emissions.
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  36. On the subject of Florida, there are some interesting vulnerabilities to sea level rise.

    A fair number of people live on barrier islands on the west coast. As it stands now, those islands are marginal for evacuation when a hurricane is predicted to hit (do note, evacuation by car; given 24 hour warning, you have the option of swimming to the mainland). The bridges and causeways all have low spots; raising sea level even half a meter gives the storm surge a head start on cutting the islands off for evacuation.

    Elevation of wells is no big deal; it's easy enough to thread another meter of pipe onto the wellhead and lift the pump. The water table underneath is what matters, and again, some areas on marginal on water supplies, to the point that Tampa was talking about running sewage through a desalinization plant (it's cheaper than purifying seawater; the energy cost is non-trivial).

    It doesn't hurt to keep a little history in mind (my GGF moved to Florida in the 20s, my wife is 3rd generation native, we learned some history in school, and I read more later). A truckload of people moved to Florida in the last century. A truckload could also leave. The decline of civilization in Florida would look not so much like the Road Warrior, and it's not quite tropical, but in the absence of mosquito control and alligator control, and with the added bonus of uncontrolled invasive species (pythons, fire ants, nile monitor lizards), and several species of poisonous snake (eastern diamondback rattler, cottonmouth, coral snake, copperhead, pygmy rattler) , life could get interesting. The climate/wildlife also is very friendly to rabies. Historically, Yellow Fever was enough of a problem that towns changed their names to avoid the word "yellow" (Yellow Bluff became Ozona, for example).

    This is also not terribly speculative -- one friend was bitten by a pygmy rattler, our vet's son bitten by a diamondback (and it was treated with veterinary antivenin!), my composition teacher caught a bad case of encephalitis from a mosquito bite, a friend of my cousin's was killed and eaten by an alligator. Another friend had to do the rabies series after an animal bite, and I recall seeing a bunch of dead (presumed from rabies) bats on another friend's driveway.
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  37. Tom Curtis @ 28

    You are quite right. Even with a decadal doubling of the ice loss from the GIS, the earliest indicated date for 1m RSL is 2065 - not 2050, unless of course the Kraken Wakes or Arctic CH4 emissions reach 1,500 million tonnes per annum before 2030. Then all bets are off!
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  38. Agnostic @37, yes then all bets are of, and our goose is already cooked.

    For policy consideration I ignore such early trigger catastrophes, not because they are unrealistic or implausible. They are certainly a real possibility. But if they are early trigger events, then it is too late to do anything about it. As no current policy can have an impact in such scenarios, such scenarios have no relevance for current policies.
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