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JPL bombshell: Polar ice sheet mass loss is speeding up, on pace for 1 foot sea level rise by 2050

By Joe Romm on March 10, 2011 at 12:45 pm

"JPL bombshell: Polar ice sheet mass loss is speeding up, on pace for 1 foot sea level rise by 2050"


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The Greenland and Antarctic ice sheets are losing mass at an accelerating pace, according to a new NASA-funded satellite study. The findings of the study — the longest to date of changes in polar ice sheet mass — suggest these ice sheets are overtaking ice loss from Earth’s mountain glaciers and ice caps to become the dominant contributor to global sea level rise, much sooner than model forecasts have predicted.

The study, led by the U.S. Jet Propulsion Laboratory, was just published in Geophysical Research Letters here (subs. req’d).

It’s been clear for a while that the  polar ice sheet mass loss is accelerating (see Large Antarctic glacier thinning 4 times faster than it was 10 years ago: “Nothing in the natural world is lost at an accelerating exponential rate like this glacier”).

But the new study is a bombshell because of its credibility and thoroughness — and because it provides perhaps the most credible estimate to date of the sea level rise we face in 2050 on our current emissions path, 1 foot.

The JPL news release runs through the calculation that leads to the 1-foot estimate:

The authors conclude that, if current ice sheet melting rates continue for the next four decades, their cumulative loss could raise sea level by 15 centimeters (5.9 inches) by 2050. When this is added to the predicted sea level contribution of 8 centimeters (3.1 inches) from glacial ice caps and 9 centimeters (3.5 inches) from ocean thermal expansion, total sea level rise could reach 32 centimeters (12.6 inches). While this provides one indication of the potential contribution ice sheets could make to sea level in the coming century, the authors caution that considerable uncertainties remain in estimating future ice loss acceleration.

It is always worthwhile to make clear that the projections are uncertain.  On the other hand, one would have to say that the uncertainty is greater on the high side — since the rate of human-caused warming is itself projected to accelerate, and the poles are the place where the planet is heating up the most, much faster than expected (see “Deep ocean heat is rapidly melting Antarctic ice:  Oceanographer at AGU: Western Antarctic Peninsula is seeing “the highest increase in temperatures of anywhere on Earth”).

“That ice sheets will dominate future sea level rise is not surprising — they hold a lot more ice mass than mountain glaciers,” said lead author Eric Rignot, jointly of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., and the University of California, Irvine. “What is surprising is this increased contribution by the ice sheets is already happening. If present trends continue, sea level is likely to be significantly higher than levels projected by the United Nations Intergovernmental Panel on Climate Change in 2007. Our study helps reduce uncertainties in near-term projections of sea level rise.

So if you are asked how much sea levels are likely to rise by midcentury on our current emissions path, I think a reasonable reply now is “about 1 foot — assuming the current rate of ice mass loss doesn’t accelerate further.”

UPDATE:  This work is consistent with other recent sea level rise projections — Sea levels may rise 3 times faster than IPCC estimated, could hit 6 feet by 2100 [see figure]:

What makes this new study so credible is not just the groups involved — JPL, the Institute for Marine and Atmospheric Research in The Netherlands, and NCAR — and not just the 18-year dataset examined.  Impressively, the authors were able to compare and reconcile two completely different approaches, the mass budget method (MBM) and the gravity method:

The study compared two independent measurement techniques. The first characterized the difference between two sets of data: interferometric synthetic aperture radar data from European, Canadian and Japanese satellites and radio echo soundings, which were used to measure ice exiting the ice sheets; and regional atmospheric climate model data from Utrecht University, The Netherlands, used to quantify ice being added to the ice sheets. The other technique used eight years of data from the NASA/German Aerospace Center’s Gravity Recovery and Climate Experiment (Grace) satellites, which track minute changes in Earth’s gravity field due to changes in Earth’s mass distribution, including ice movement.

The team reconciled the differences between techniques and found them to be in agreement, both for total amount and rate of mass loss, over their data sets’ eight-year overlapping period. This validated the data sets, establishing a consistent record of ice mass changes since 1992.

The team found that for each year over the 18-year study, the Greenland ice sheet lost mass faster than it did the year before, by an average of 21.9 gigatonnes a year. In Antarctica, the year-over-year speedup in ice mass lost averaged 14.5 gigatonnes.

“These are two totally independent techniques, so it is a major achievement that the results agree so well,” said co-author Isabella Velicogna, also jointly with JPL and UC Irvine. “It demonstrates the tremendous progress that’s being made in estimating how much ice the ice sheets are gaining and losing, and in analyzing Grace’s time-variable gravity data.”

You may have heard about that 2010 study (Wu et al.) suggesting that earlier estimates of ice mass loss using the GRACE data were too high.  That study turns out to have had a number of issues, not the least of which is the short timeframe it examined:  “mass losses between 2002 and 2008 in Greenland, Alaska/Yukon and West Antarctica.”

As the JPL-led study notes:

The excellent agreement of the GRACE and MBM records over the last 8 years validates the 18″year MBM record. The results also indicate that an observation period of 8 years is probably not sufficient for these methods to separate the long”term trend in ice sheet acceleration from temporal variations in SMB [surface mass balance], especially in Antarctica. When we use the extended time period 1992-2009, the significance of the trend improves considerably.  The MBM record indicates an acceleration in mass loss of 21.9 ± 1 Gt/yr2 for Greenland and 14.5 ± 2 Gt/yr2 for Antarctica. The lower uncertainty reflects the reduced influence of temporal variations in SMB for the longer record. The uncertainty in acceleration is thus reduced to 5% for Greenland and 10% for Antarctica. When the mass changes from both ice sheets are combined together (Figure 2c), the data reveal an increase in ice sheet mass loss of 36.3 ± 2 Gt/yr2.

I emailed Rignot to ask him about Wu et al., since I heard he had some issues with it.  He wrote me back:

Wu et al. employed a rather complex technique to infer mass losses all over the world combining GRACE and GPS. While the approach is promising, there is not enough GPS data near the ice sheets today to constrain their solution well. Their study was somewhat premature in terms of concluding about ice sheet mass balance. Their reconstruction of postglacial rebound in Greenland is at odds with what we know about the local glaciology or with prior reconstructions of the GIA [Glacial Isostatic Adjustment].

So Wu et al. used too short of a time frame to get a good picture of what’s happening in Antarctica and appears to have a flawed reconstruction of what’s happening in Greenland.

Finally, it bears remembering that even this study’s projections for 2050 and beyond assume a basically continuous process, whereas the West Antarctic ice sheet is fundamentally unstable because most of it is grounded far below sea level.  The warmer it gets, the more unstable WAIS outlet glaciers will become. Since so much of the ice sheet is grounded underwater, rising sea levels may have the effect of lifting the sheets, allowing more-and increasingly warmer-water underneath it, leading to further bottom melting, more ice shelf disintegration, accelerated glacial flow, and further sea level rise, and so on and on, another vicious cycle. The combination of global warming and accelerating sea level rise from Greenland could be the trigger for catastrophic collapse in the WAIS (see, for instance, here).

The time to act is most definitely now, before we all but guarantee unimaginable levels of polar warming post-2050:

Related Posts:


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The Stern Interview, Part One: Climate Inaction Risks A New World War

73 Responses to JPL bombshell: Polar ice sheet mass loss is speeding up, on pace for 1 foot sea level rise by 2050

  1. Macro Tel says:

    It hit me like a bolt of lightning seared my shoulder retreating from a VC ambush into my own tripwire: proximate river deltas, bogs, and continuous permafrost, can be used as case studies to guess the future thaw behaviour of Arctic permafrost in the presence of purposeful flooding (to grow sphagnum fuscum). Text says coastal land from Hudson’s Bay’s 6 to 3 o’clock, is underlain by permafrost perhaps tens of metres thick. Atlas says is a bog south of Hayes river at York Factory, and a bog from Churchill to north of North River, encompassing 3 river mouths. I’d like to know the behaviour of taliks here. What is the soil profile where bog and permafrost overlap, compared to nearby control? Did the river mouths meander in past or since satellites (which would suggest a thaw timeline)? If no overlap of river and permafrost, are they 50m apart, 500m?
    “Effect of Beaver Dams on Subarctic Wetland Hydrology” connotes the aquifers under HB coastal areas are connected at least 100-200m. If instead of only measuring 2 nearby depressions; if more puddles further away were measured the paper would’ve charted a region of, or an entire aquifer. Cheap water table measurements needed.
    Unknown if thick permafrost will be thawed by lateral flows or surface heat. If the latter catalyzes melt, especially in the presence of 33% (+100mm/yr) more precipitation, it might be cost effective to crop dust or winter road some insulating fuscum. 45m deep. assuming 20m of c and a $50/t 21st century c price, is $1000/m^2 of northern real estate. A wide variety of non-flammable insulation options may be cost effective. If precursor R+D. BAU will thaw permafrost 2020-2050 and hijack (tax) nearly every industry towards preventing other feedbacks: wartime quality-of-life

  2. Peter M says:

    1 foot (third a meter) still seems conservative. Hansen feels 1-2 meters.

  3. Robert In New Orleans says:

    Great Post Joe!!

    The information is important in that at least there now is some sort of measuring stick to look at, even if the knowledge is very depressing.

    It makes me wonder what is going to happen if and when this information becomes availible to a wider audience?

  4. ToddInNorway says:

    Unfortunately the key assumption of assuming constant, continued ice mass loss is probably optimistic. We can place a probability estimate that the 1-foot sea level rise will come many years earlier than 2050. If we look at ice loss in a longer time perspective, it is very rapid, approximately non-linear, and once it is clear the ice loss process has momentum, it will be clear that it will accelerate and cannot be stopped.

  5. Dickensian American says:

    @Peter M.

    1 foot (third a meter) still seems conservative. Hansen feels 1-2 meters.

    By 2050? Or by 2100? My understanding is that estimate was for end of century, not 30 years from now.

  6. Michael says:

    Hansen recently published a paper that shows 5 meters of SLR by 2100, yet less than a foot (looks like around 20 cm/8 inches) by 2050, underscoring the expected acceleration; he assumes a doubling time of 10 years for Greenland/Antarctic ice loss.

    http://www.columbia.edu/~jeh1/mailings/2011/20110118_MilankovicPaper.pdf (see pages 14-17)

  7. Barry says:

    sea level rise is just one of the climate loaded dice that determine coastal flooding. others include:

    * lower pressures (inverse barometer effect)
    * higher winds driving water ashore
    * increasing big wave heights
    * increasing river outflows in storms
    * bigger el nino kelvin waves (on W.coast N.A.)
    * larger el nino thermal expansion
    * loss of coastal wetlands from sea level rise reduces impedance

    Every storm event is a role of the dice. With so many dice being loaded by climate change, static sea level is just one of the teeth that bite and not even the biggest one in magnitude.

  8. MapleLeaf says:

    I agree with Todd, the best fits for the ice loss data are quadratics– that is the rate of loss is accelerating. It is difficult to imagine it now with annual increase sin global sea levels averaging about 3 mm per year in recent decades (still higher than earlier in the 20th century), but the global sea level rise is going to start accelerating in the near future.

    The predictions by Vermeer and Rahmstorf (2009) are calling for up to 1.9 m rise above 1990 levels by 2100. Yet again, the IPCC’s predictions have been shown to be too conservative, not alarmist as the “skeptics” falsely claim.

    Joe, have you seen this disturbing paper by Rohling et al. (2009), it is probably worth featuring Joe:


    I do not want to this post to sound like fear mongering, but we have to be prudent and consider these plausible worst-case scenarios.

  9. Joan Savage says:

    We might better assume that it won’t be at a constant rate.

    A catastrophic meltwater event occurred near the end of the continental deglaciation in eastern North America, about 13,350 cal BP. Meltwater broke through an ice dam and flushed into the Atlantic via the Hudson River estuary, releasing at an estimated rate of ~0.46 Sv (0.46 million cubic metres per second) for ~80 days (Thieler et al. 2007, Donnelly et al. 2005). It has been suggested that the flush of cold fresh water may have interrupted the thermo-haline ocean patterns sufficiently to initiate the Intra-Allerød Cold Period.

    The deniers of {anthropogenic} climate change who smugly suggest we are headed to another cold period might be enthusiastic, but a flush of meltwater from either Greenland or Antarctica that interrupted currents could be catastrophic to many.

  10. Pbo says:

    This new study confirms the study by Vermeer and Rahmstorf, which is a good indication that the semi-empirical methods provided in this study was basically correct.


  11. Stephane says:

    The graph of artic sea ice volume anomaly and trend had been updated :

    the graph show a linear regression trend but when you examine the last 10 years, you may draw a new line…

  12. john atcheson says:

    The problem with this is that most people don’t understand how much horizontal impact a 1 foot vertical rise will have — in some areas it can mean a mile or more infiltration, and of course, for many islands, it is a death knell.

  13. Kota says:

    Anyone know of a map that will show the impact in cm or in? Most of the ones I know of start at 1 meter

  14. mike roddy says:

    John, you’re correct. Deniers will look at the water from Malibu or the Hamptons and conclude that a foot is no big deal- and that by then Gates will have this problem geoengineered. Ward of UW sees much higher levels, btw.

  15. Colorado Bob says:

    Question ……
    Am I correct in assuming that none of the projections take into account the CH4 out gassing that is coming between now and 2050 ?

  16. jfwells says:

    Could someone point me to a previous post or a study showing what 1′ of mean sea level rise would mean for the US, specifically south Florida and the gulf coast? I assume there is a higher probability of catastrophic flooding from hurricane storm surges, but would like to see the details.

    Thanks in advance.

  17. Colorado Bob says:

    Seas ‘will swamp Sydney yearly’

    In the report, major cities – particularly Sydney – are shown to be under much more immediate threat from sea level rises than previously predicted. It warned that there had already been a three-fold increase in inundation events in Sydney, according to data taken from Fort Denison in Sydney Harbour.

    “The increase in incidence of extreme sea level events for some of Australia’s largest cities is a factor of 1000, and for Sydney it is 10,000,” the report said.

    “For a multiplying factor of 100, events with a current occurrence of once every hundred years would occur every year.


  18. Dickensian American says:

    Thanks for clarification and links regarding my question. Always appreciated.

  19. Richard Brenne says:

    I’ve always said that “We’ve been measuring sea level in inches, but over a small number of decades we’ll be measuring it in feet and by the end of the century or if Americans come to understand the metric system, in meters.”

    This is a great study, but I’d say that we can expect to see “at least a foot” of sea level rise by 2050.

    At a USGS talk about climate change and uncertainties I attended last Friday one of the scientists made the excellent and all-too-rare point that whenever there are uncertainties; scientists invariably tend toward the most conservative estimates.

    Barry has an excellent and concise list of other factors affecting sea level rise, which means how sea level relates to land. All land is generally rising or falling. Because of the isostatic rebound of being under mile-thick ice during the last Ice Age, Finland is rebounding at a rate that grows the country 2.7 square miles a year.

    This is true for much of Scandinavia, Scotland, Canada and the Northeast U.S.

    But often the land acts like a teeter-totter or see-saw and the low lands to the south or subsiding at comparable rates, and this is true for the fens east of London (including the Cambridge area), the Chesapeake Bay area of the U.S. (including D.C.), and so forth.

    Then when there is subduction for instance the Pacific plate subducting under the North American plate, much of the West Coast is rising (including most of the Washington Coast) but can subside in other areas like the mouth of the Columbia River where the Pacific plate doesn’t have the same push.

    Unfortunately during the next Cascadia Subduction Zone earthquake (due anytime during the next two centuries), much of the Northern California, Oregon, Washington and Vancouver Island coastline will immediately subside a meter or two (three to six feet in the metrically-challenged U.S.).

  20. Mike says:

    Sea level rise will not be uniform. Some coastal areas will see much large increases than others. But, I have not seen a study that gives estimates of which areas will see higher than average increases and which lower. Has anyone else?

    Another point about sea level is that salt water will creep up deltas and coastal swaps. This can affect wild life and rice production in for example the Mekong Delta.

  21. Scrooge says:

    This is interesting but by 2050 the US will have more significant problems. We can just write off places like Miami and New Orleans. Will be interested to see what happens to Oahu.
    So apologies to islands of the world and to places like the Netherlands. Even though this is a global problem with our political system it is almost impossible for anything constructive to be done.
    As we have seen in most issues the conservatives are involved in, ideology trumps civil rights and science. If they don’t want to believe 2+2 equals 4 there is no way to change their childish minds.
    Also to future climate refugees we have already built one wall. We like Canada though, maybe because some of us will end up there. So I don’t think we will build one there. Just hope Canada doesn’t.

  22. Richard Brenne says:

    Then there are the many sad factors that together doom New Orleans and most of Southern Louisiana and many Gulf Coast and Atlantic landscapes that will soon become seascapes.

    The bayous act as the speed bumps slowing and lessening the storm surge from hurricanes before they can reach New Orleans. That is how New Orleans has survived for most of 300 years. The French Quarter is seven feet above sea level, the highest point nearest the mouth of the Mississippi, so one can see how it was chosen.

    But now much of the city is at or below sea level, the land there is naturally subsiding, the weight of the city increases the subsidence as does the pumping of water, oil and natural gas from the city and area.

    Then the levees on the Mississippi prevent the bayous from being rebuilt by silt during floods, thousands of miles of canals have been built through the bayou for shipping and to install and service oil and natural gas wells and pipelines, the large rodent nutria was introduced from South America that can eat 25,000 acres of marshland a year, and the BP and other oil spills and toxins kill bayou grass.

    All this while sea level will rise at least a foot and sea surface temperatures are increasing to record levels along with temperatures, further fueling the biggest hurricanes that have more open water than land to draw their strength from all the time.

    It’s very sad to say this about what might be America’s most culturally-rich and diverse city per capita, but it’s going under. It will be in the Gulf of Mexico, if not by 2050 then by 2100. There might be sea walls around the French Quarter and boats take people to have a Disneyland-type experience, but by that time the real pirates of the Caribbean might not be as charming and humorous as their audio-animatronic brethren.

  23. Michael says:

    Colorado Bob (16) – Any study that doesn’t account for methane is pretty much pointless. Especially if the results of one recent study are anywhere close to the truth:

    Methane release from the East Siberian Arctic Shelf and the Potential for Abrupt Climate Change

    Interpretation of acoustical data recorded with deployed multibeam sonar allowed moderate quantification of bottom fluxes as high as 44 g/m2/d (Leifer et al., in preparation). Prorating these numbers to the areas of hot spots (210×103 km2) adds 3.5Gt to annual methane release from the ESAS. This is enough to trigger abrupt climate change (Archer, 2005).

    http://symposium.serdp-estcp.org/content/download/8914/107496/version/1/file/1A_Shakhova.pdf (see page 34)

    3.5 GTs of methane annually is about ten times the annual human GHG emissions (CO2 equivalent, using methane’s GWP of 105 over 20 years, as one recent estimate put it, up from 72). So if true, we are already past the point where a total cessation of human emissions won’t have any effect…

  24. Flin says:

    Wanted to mention Vermeer Rahmstorf as well, but pbo was faster.

  25. Ron Broberg says:

    Re: Southern FL
    Southern Florida’s coastal flood-control structures, counted on to protect low-lying communities from getting swamped, already are at risk from sea level rise due to climate change, according to scientists for the South Florida Water Management District.

  26. Richard Brenne says:

    Lastly (or secondly, if my previous comment is delayed in moderation), Barry makes many good points about sea level impacts compounded by additional factors.

    During record or near-record low barometric pressure events (the lower the barometric pressure, the more energy the storm has), it is as if a giant soda straw was sucking the ocean higher, in the case of a January, 2010 storm the Pacific was two feet higher than the tide tables indicated at Neah Bay and Astoria, Oregon.

    Since 1970 the one degree Fahrenheit increase has meant more evaporation and 4% more water vapor in the atmosphere. During that same time the estimates (done in these comments by Leif and others) are that we’ve added the energy output equivalent to 190,000 nuclear power plants operating 24/7/365, with 10 additional power plants coming on line each day.

    (Imagine even the conservative IPCC report’s estimate that we could see 11 degree increase by 2100, which would mean 44% more water vapor and the energy output of over two million nuclear power plants! There would or will be storms no human can even begin to imagine.)

    Since 90 per cent of global warming goes into the oceans, that means far more energy in the system. Thus a 1996 Oregon State study estimated that a 100-year storm would generate swells of 33 feet on Oregon’s Pacific Coast (these can double in wave height as the swells reach shallow water on their way to the shore).

    In January, 2010 they amended that estimate of a 100-year event, saying they could generate waves of over 55 or even 60 feet. That revision came in 14 years (and some may be due to their measurement metrics rather than wave heights increasing during that time alone), and as more energy is added to the system those revisions will undoubtedly need to continue, always upward.

    The upshot is that my favorite restaurant in the world (for its setting, clam chowder, low cost and friendly, quick service), Mo’s Clam Chowder at Tolovana State Park just south of Cannon Beach, Oregon, will disappear within some small number of decades, or merely years. If there’s one entity you don’t want to play Russian roulette with, it’s the ocean.

    In 1999 Mo’s had its windows shattered and a watermelon-sized rock (on display) came through the window. The manager Tom took a picture of his truck blasted by a 35-foot wave that also drenched Mo’s last October, surprisingly when the storm hit at low tide.

    Combine rising sea levels with intensified storms with the soda straw effect all coming during a 10-foot high tide and the restaurant is jarred off its foundation and is lost forever.

    As with everything, enjoy it while you can. . .

  27. Solar Jim says:

    Another startling post.

    When, due to our present course of “economic development,” the West Antarctic Ice Sheet is loosened from it’s present undersea grounding by accelerating warming of seawater and flotation buoyancy due to rising sea level, we will “have lift-off” of the most spectacular and disastrous kind. It will rise sea level about twenty feet, precipitating submergence of civilization’s greatest works (the art, architecture and infrastructure of seaports) to say nothing about nature.

    We may have one foot of rise by mid-century, then an average of one foot per decade thereafter for centuries.

    I think I’ll get my fiddle, along with an atomic bailout bucket. Hope they get that three foot diameter tar-sands petroleum pipeline built from Canada to Texas soon. That should fix us good, since we must set all these geologic materials on fire. Don’t we.

  28. Colorado Bob says:

    Michael ,
    It has been my understanding that many of the past projects have never had any real handle on just what the CH4 will be. Since the permafrost on land and sea, is subject to the same margin of error as all our other guesses, the CH4 load isn’t going to be one of those things where the low ball assumption comes in on the money.

  29. Colorado Bob says:

    Richard Brenne @ 27 -
    If what you say is correct, then looking at daily rainfall records will be just as relentless as the physics behind their rise. Yesterday :

    Total Number of Records for March 9, 2011
    (out of 11,326 stations with at least 30 years of data)
    New: 219 + Tied: 5 = Total: 224


    51 stations in Alabama set new daily records.
    UNIONTOWN [PERRY COUNTY], AL. is a good example .
    4.16 in ….. 2.23 in (1909) 117 years in the record.

    These numbers aren’t being broken, they are being crushed by by far larger ones.

  30. Colorado Bob says:

    Inland sea floods outback Qld towns

    “This is an unprecedented event where there’s been up to 20 inches of rain in parts of the Diamantina Shire which happened over a two-day period,” he said.


  31. Aaron Lewis says:

    Once again, we have a rigorous academic study funded by taxpayer money that so understates the situation that it is useless for risk management, public policy, or planning.

    [JR: Well, I think planning on 1 foot in 2050 is entirely reasonable for now.]

    Being mostly empirical, this study does not address how recent and ongoing changes in Arctic albedo from loss of sea ice will affect the ice sheet melt. It does not address how recent and ongoing changes in the northern hemisphere’s polar vortex/jet stream will affect ice sheet melt by enhanced transport of water vapor. It does not address the effects of carbon feed-backs from melting permafrost and seabed clathrates. The temperature of ocean waters around and in contact with the ice sheets is changing, and recent changes in ocean currents promote those changes. It does not address changes in sea level caused by the gravitational interactions between the ice sheets and the oceans. Finally, and most importantly, it ignores that ice dynamics accelerate as the ice warms toward its melting point.

    Cumulatively, these issues ensure that current trends will not continue. I do not doubt that this study did get the past trends correct. However, that is moot. Ice sheet loss into the oceans will accelerate dramatically.

    To ignore all the above factors, and then offer up a number based on past trends, pretending it has some value, is an absolute failure to comprehend the consequences of reality. To say that these factors have not been “well modeled” is no excuse. These are known issues, and to give a number without discussion of these issues makes that number – worse than useless. It is wrong, and the prestige of institutions such as JPL ensure that their errors are accepted by managers, planners, and decision makers over better numbers put forth by less prestigious sources.

    Climate science’s concept of risk management seems to be limited to covering their ass with scientific reticence, and cheerily piping up, “We were not alarmist”. I accuse every climate scientist that does not discuss and account for the issues listed above. These factors interact and feed-back with other factors, so you cannot say, “That is not in my field.” At some point, all of these factors will impact and affect you, so you might as well deal with them now.

  32. Prokaryotes says:

    Is this the game changer? (political speaking)

  33. MapleLeaf says:

    Aaron @32,

    Excellent points. Did you read my post (and follow the link) @9 above?

  34. EFS_Junior says:

    I aims to please.

    Here’s a direct link to the aforementioned GRL paper (for anyone interested);


  35. paulm says:

    Peter @8,

    Could it be that the earth can actually flip state in a year. All dependant on the ice extent.
    It maybe possible.

    So at a given point in the near future as with bump up against these extreme global temps we will just flip over and then thats it, we are in a new wilder state that wont flip back anytime soon even if the global temp fluctuates lower in the future.

  36. EFS_Junior says:


    Kind of harsh don’t you think?

    It’s rather hard to believe a 2M SLR by 2100 given the necessary kinematics of the Greenland ice sheet alone (2M for Greenland is almost a 3rd of the total Greenland ice sheet).

    At this moment, I tend to fall within the 1M SLR camp by 2100, current SLR is still plodding along (linearly) at ~3mm/yr.

    Also, given your list, we would need some quantitative estimates with their associated uncertainties. Making such a list, without attached numbers and uncertainties, is similar to the denialists making their lists poo-pooing the SAT instrumental record (RE: WUWT’s surfacestations.org BS), a list, is just a list, if left as just a list.

    #9/33 A quadratic SLR (mm/yr/yr) alone doesn’t cut it, as the 2nd derivitive is a constant, as in constant acceleration, you need a positive mm/yr/yr/yr to get a net positive acceleration vs time.

    Now having said all that, what’s going on in the Arctic right now is serious business, a 4C SAT rise overall since the 1920′s, with 3.5C coming from just the last ~35 years (1945-75 saw a drop of 0.5C), and still accelerating into 2011 (0.25C/yr +/-0.15C/yr (current linear slope)).

    All that soot on the western Greenland ice sheet also doesn’t help the current (and future) situation(s) at all.

    At this time, predicting future SLR, with the current state-of-the-art (SOTA), will have large uncertainties associated with them IMHO.

    Having been a (now former) coastal engineer for most of my professional career, I do take future SLR quite seriously though. I just think we need to make significant improvements in current predictive capabilities, based on sound physics based modeling, and we just are not there yet IMHO.

    That is all.

  37. Sasparilla says:

    #33 Prokaryotes – “Is this the game changer? (political speaking)”

    A very valid question and in a rational world it absolutely would be (of course there were a ton of rational game changers before over these years), but this is the United States and as that saying goes…you can’t fix stupid.

    If the seal level was rising a foot this year then I think it would be a game changer (it’d be impossible not to ignore what was happening and the press would be all over it, but currently 1 of the 2 political parties in the US can make political hay by ignoring what is happening and saying its not happening and they are being very successful – of course with lots of help from people and groups with lots of money / power).

    So, sadly, my guess is that this very important study doesn’t mean anything with regards to climate change action in the US at the Federal level…just MHO..it will mean something in the future when looking back at this time period though.

  38. Flin says:

    @Mr Lewis #32: The top end of current estimates is something around 1.9 meters for 2100 (or 6 feet).
    Sea Level rise from 2003 to 2008 was about 2.5 mm/year, longterm trend is a bit higher. But nevertheless there is no indication yet for heavy acceleration. While it is plausible that it might happen, it is not yet happening.
    Therefore EFS_Junior is right, there is a dire need for improvement of predictive capabilities. Mankind can handle 6 feet in 90 years. No need to panic on the sea level front. Sea Level rise is slow.
    Food and precipitation are more dangerous and urgent. Too bad for the Maledives, though.

  39. Flin says:

    This isn’t a game changer. Sea level rise is slow. It shows that current estimates are too low, which is known for some years now.
    We know that
    - Ice Shelfs melt faster than previously thought
    - Albedo feedback is more extreme than current models account for

    And we suspect that the trends are nonlinear. Nevertheless the deveolpment is still slow, although it’s very fast on a geological scale.

  40. Peter M says:

    You know paulm #36

    The article from Australian News- but seen widely elsewhere, with Hansen and Sato- is the most aggressive of all regarding sea rise. I believe JR had it posted here 2 months ago as well.

    Its very informative reiterating Hansens reasoning that 450ppm & a 2 degree rise is a prescription for disaster.

    Hansen says ” It is hard to argue that anything above the Holocene maximum (of about 0.5 degrees above the pre-industrial temperature) can preserve a safe climate, and that we have already gone too far. The notion that 1.5C is a safe target is out the window, and even 1 degree looks like an unacceptably high risk”

  41. Mulga Mumblebrain says:

    There seems to be a tendency for the predictions of science, even the most careful and stringent, to err on the side of under-estimation when it comes to climate science. For a number of years the expression ‘worse than the most pessimistic projections’ or something similar has been pretty common in reporting of climate events. Is this because the scientists are being ‘conservative’ in order not to alarm the public, or have they been spooked by being derided by the intellectually challenged as ‘alarmists’? From the comments above, my own insufficient knowledge of the science and my general presentiment that things are far worse than the mainstream of climate science yet acknowledges, I can see several areas where these new predictions could come up short of the dreadful reality. I actually believe that the era of catastrophe is upon us. The argument made by Richard Brenne as to the unimaginable fury of future storms particularly resonates, as I have witnessed electrical storms this year of an intensity that I have only ever seen before in the tropics, and we are far from the torrid zone here. And still the rain pours down on Queensland.

  42. Richard Brenne says:

    Michael (#6) – That is a great paper by Hansen and Sato, even if it is an outlier relative to papers by Pfeffer, Overpeck, Rahmstorf, Otto-Bliesner and others.

    An IPCC Report Lead Author (who I otherwise respect a great deal) I recently had lunch with was dismissive of Hansen and the conversation and events didn’t allow me time to ask him why in detail, but I plan to, because while Trenberth and other senior scientists might like to see Hansen more involved in the IPCC Report process and have other issues, and others have issues with him about sea level and the possibility of a runaway greenhouse, I’d never heard him dismissed in that way.

    To me Hansen is looking at the big picture and plugging all factors into the extremely complex equation better than anyone, as he has often done. He’s often been a couple of decades ahead of the scientific consensus, and he’s been as right while making bold predictions as often as any scientist I know.

    Fundamentally Richard Alley (who I otherwise like a great deal for his energy, ability to communicate complex issues and generosity, especially of hand gestures) is making linear projections of sea level rise which Hansen agrees is “preposterous” when that would mean a half a meter of sea level rise in the next decade.

    But Hansen takes a much more realistic, likely and nuanced approach of looking at sea level rise in non-linear terms of exponential growth that could last for centuries until negative feedbacks like the cooling of the oceans due to all the ice-melt kick in. If the doubling time drops to less than a decade as Hansen feels it could and quite possibly already has, then only a foot or so of sea level rise by 2050 could still mean many feet, possibly as many as 15, by 2100.

    The thing that is most uncertain is the timing and the only thing we have going for us with business as usual is the inertia built into the system, which only delays the inevitable. I think Joe might’ve posted about this paper already but if not it would make a great post.

    Scientists by their natures and the nature of their specialization, work and the nature of the large and well-funded institutions who are their employers are quite conservative. If you ask them over a couple of (ideally a couple of dozen) beers what they really think is happening, many would agree with many of the bolder comments here.

    Their intuitions are more valid than any others, but they have to painstakingly show their math and all supporting evidence and use complex models, which often take decades to confirm the conclusions their intuition led them to believe years or even decades earlier.

    So keep the most-informed comments coming, because you’re at the cutting edge of understanding and communicating what is possible, especially if we don’t act appropriately, as we show virtually no signs of doing.

  43. Richard Brenne says:

    Colorado Bob (#30) – It’s not what I say; I’m just parroting Kevin Trenberth, who Joe has often quoted here.

    The link between the physics, models, broad predictions and the weather people actually experience is how many if not most people will come to understand and accept climate change, so your finding these record and near-record precipitation as well as heat events is invaluable, Colorado Bob. Keep up the good work!

    And not only are the mouths of most large rivers especially vulnerable (Nile, Mekong, Mississippi, Congo, Yellow, Yangtze, Indus and those flowing into Bangladesh and the Netherlands) to sea level rise, but flooding from rain, snow and glacier melt upstream can combine with storm surges, high tides and the other factors Barry and I mention to create greater flooding than from either direction alone in all estuaries (bays and all rivers subject to tides).

  44. Steve Bloom says:

    Joe, on one level it does makes sense to plan for 1 foot SLR by 2050, but if the rate increases such that anything like 2 meters is reached by 2100, then many of those 2050-based plans will cease to make sense. A lot of very expensive coastal infrastructure planned assuming 1 foot SLR will be lost long before the end of its design life.

    [JR: I switched to "plan on" not "plan for." I think I've been pretty clear that the seas are just going to keep rising at an accelerating rate if we keep doing nothing.]

  45. Steve Bloom says:

    Re #39: “Mankind can handle 6 feet in 90 years.”

    I wouldn’t be so sure. An awful lot of productive ag land and esturary productivity will go along with that. In addition, if indeed that’s the pace things are on the next 2 meters of SLR will be seen by 2125, and it won’t be stopping then. It begins to sound quite hard to handle.

  46. Vic says:

    Dead man walking.

    According to the United Nations, the average Australian male is dead by 78.9 years of age. This result can be sped up slightly by moving to the USA where the figure is 75.6 years.
    Either way you look at it, global king of crap Rupert Murdoch who turns 80 today is surely living on borrowed time.
    I’m sure everyone here would like to join me in wishing him a very merry last birthday.

  47. Leif says:

    Another effect that is not being taken into account is that the sea level does not rise uniformly the world over. The ice mass in Greenland for instance currently has a significant gravitational attraction and water level is higher in that vicinity than it will be as that mass is reduced. Thus the “water bulge” will in turn seek a new level some place else. Compounding the melt water of the ice melt. Also as the ice melts the land surrounding Greenland, not just the land directly under the ice cap, begins to rebound as well. This is land under the sea bed and extends for some distance from the shore line, further compounding the problem for others. I have recently seen a report attempting to take some of these variables into consideration but cannot recall where. However my recollection is that an extra doubling or more of sea level increase might be experienced in some areas while other areas actually lower.

  48. Leif says:

    Here is a link relating to my above comment. (Google is magic.)


  49. Aaron Lewis says:

    Re #34 Yes, I looked at your link. However, people agree on the final numbers, but they fudge on how fast we could get there. It is not how much we warm, but how fast we warm. It is not how much sea level rises, but how fast it rises. And, since 1995, we have been forecasting such slow rates of change that most people are not taking the required actions.

    OK, people “plan” on at least a foot of SLR by 2050. The tendency is to “plan” on jacking everything up in 2040 or 2045. However, planning on a foot in 2050 means that you have to plan on half a foot by 2040, and at least 3 inches by 2030. That means you really have to start jacking operations circa 2020. That means writing design and construction contracts and filing permit applications in 2015. Are you going to jack every thing up, all at once or are you going to go back and jack stuff up a little more every few years?

    Now remember that your “stuff” is major cities and the world’s industrial infrastructure. Are you going to jack NYC city up a foot, and go back 30 years later and jack it up another 2 feet? Or, do you jack it up 3 feet in 2020 and call it good for 40 years? (What is the margin of error in your 30 year sea level forecast?) Or, do you jack it up 6′ and hope that will hold you for 60 years?

    And, the error bars are huge. Remember, nobody has published a good ice dynamics model. It might be only a foot by 2050, or it might be more. Your engineer will want to design for the maximum credible sea level rise in the design lifetime of the structure plus a margin of error.

    So you may plan on at least a foot of sea level rise by 2050, but you are going to end up, jacking stuff up a lot more than a foot, well before that time. This is a much higher economic cost as a result of global warming than any of the economic analysis show.

    How much money is in the federal budget for design and construction to deal with sea level rise? And, we have how many climate scientists in federal agencies? Are they helping the government get ready? As I said, we are not planning for it.

  50. K. Nockels says:

    How angry will the denier masses be and who will they blame and what action will they take when denial is no longer an option? What do you want to bet it will go something like this “Kill the Messanger” not “Our Prophets Lied to Us” how can we help. And what happens to emmision levels if we have another war for oil, which would involve burning hugh amounts of fossil fuels to gain control of dwindling supplies. The Saudi police are shooting their own people in the streets. There are a whole lot of things besides tipping points in the climate system that will also be affecting our ability to respond if we can ever get to that point. Non-liner events will come to define the era of Climate Change.

  51. Colorado Bob says:

    This report needs to be paired with another out today -

    Study Says Navy Must Adapt to Climate Change

    The 15-month study, conducted by the National Research Council, accepts the scientific consensus that the climate is changing and that the effects are being felt now. Of particular consequence to American naval forces – the Navy, Marine Corps and Coast Guard – are the melting polar ice cap, rising seas and increasingly frequent severe storms and droughts that could lead to famine, mass migration and political instability.

    The report from research council, an arm of the National Academy of Sciences, builds on previous work by the Pentagon, State Department, the intelligence community and independent research groups that have concluded that climate change is a “threat multiplier” that adds new and unpredictable dangers to global physical and political stability.


  52. Leif says:

    Speaking of jacking stuff up as Aaron Lewis, @ 50 asks. How do we go about jacking up the subway tunnels, sewer systems and other underground utility infrastructure of a city like NY? Remember sea level does not stop in 2100. In fact it is just starting to get it on. And on and on…

  53. Colorado Bob says:

    Another stunning report :

    Warming in Taiwan twice the global average: weather bureau

    Taipei, March 9 (CNA) The Central Weather Bureau (CWB) released a stark report Wednesday on how climate change has affected Taiwan over the last century.


  54. Richard Brenne says:

    Leif (#48 and #49) – As always you do a great job of pointing out what hasn’t been considered. In this one case however that Harvard Magazine article wasn’t that great – this is much truer of the West Antarctic Ice Sheet that largely rests on the water than Greenland, which is mostly an ice cap on land.

    Here’s the paper this was based on, and a better piece of science writing at live science:



    These two links do a better job of explaining how when most or all of the West Antarctic Ice Sheet melts, the loss of gravitational pull from the ice sheet will move water to other parts of the oceans, and the U.S. is at the latitude that might see about the most additional sea level rise, in some cases of 25 per cent (so another five feet on top of the 20 or so the melting ice of the WAIS itself could cause).

    Part of this also comes, as you say, from isostatic depression of the ice sheet becoming isostatic rebound, taking up additional volume like a person does when lying in a bathtub to raise the water level.

    There is conjecture that the additional weight of rising sea levels, which is considerable, could help trigger tectonic activity that could result in the uplift of underwater mountain ranges and volcanoes that could further add to sea level rise. As far as I know this is fairly conjectural (anyone have a link?) and certainly all the concerns mentioned here pale in time scale and relevance to the ones we’ve been discussing earlier, though they are fascinating and will ultimately have large added impacts.

  55. Richard Brenne says:

    Aaron (#50) – I second Leif’s motion about jacking stuff up, though I think you might have been facetious. Jacking cars up to steal their wheels was a popular pastime in parts of Manhattan, especially during the 1980s, but jacking up all of Manhattan will take, well, some pretty big jacks.

    Aaron you make excellent points about the engineering aspects. In recent conversations with several engineers and USGS scientists I get the feeling most are simply extrapolating, assuming the next century will be mostly like the last century, when most of us here don’t think that will be the case. Anyone else know how engineers are approaching this? My guess is that it varies, but that most are far too conservative, and thinking more about getting paid than about what will truly be encountered during the 100-year life span of what they’re building. This relates to sea level rise and 100, 500, 1000 and 10,000 year floods all becoming increasingly likely over the next century and beyond.

  56. adelady says:

    we can handle 6 feet (2 metres) in 90 years?

    I don’t know how many other cities are like Adelaide, beach to hills is a fairly narrow strip, but at 2 metres we lose the airport and the sewage treatment plant as well as the port facilities. Along with a quarter to a third of all our suburbs.

    The ‘other’ airport, a defence facility, is not a lot better off. When we have to find suitable space for large infrastructure at the same time as a large population is on the move to find somewhere dry underfoot, I don’t see any charming, peaceful community consultation being the solution. Regardless of how pretty or ugly, it will be very, very expensive, both for governments rebuilding drainage and sewage systems and individuals buying into much more costly housing.

  57. EFS_Junior says:


    I worked my entire career for the USACE ERDC CHL, that’s the CORPS Coastal and Hydraulics Laboratory as a Research Hydraulic Engineer.

    No existing structures will be jacked up.

    However, first 10′s, then 100′s, then 1000′s of miles of coastal levees and other coastal protective structures will be built over time, the first ones will be for the most low lying critical areas.

    New builds will be on ever higher foundations, if built outside these coastal protective barriers.

    Think New Orleans, but on a truly massive scale, for hundreds of coastal cities along our Atlantic and Gulf coasts.


  58. Everett Rowdy says:

    How long do we have to wait until Wall Street goes under water?

  59. Everett Rowdy says:

    … and is there anything I can do to speed that up?

  60. Tony says:

    I can’t understand something. Two thirds or so of earth’s fresh water is in those glaciers and polar ice caps. Why aren’t people jumping up and down to point out that this fresh water is a very precious resource that’s being lost forever?

  61. Richard Brenne says:

    Below is a list of history’s 24 greatest earthquakes listed in the order of their magnitude. It’s interesting to note that on this list that goes back 426 years, two of the eight most powerful quakes have happened within the last year and two weeks, the most recent of course being the one in Japan yesterday.

    Three others on the list are within the last six and a quarter years, all around Sumatra.

    The most powerful ones are within the last half century or so. Now, earthquakes are natural events that have always occurred, seismographs have only been in use for a little over half a century, and it is human nature to try to find a pattern even when there might not be one.

    But it’s at least worth asking if just the eight-inch rise in annual sea level adding weight to the seafloor (all the most recent quakes have been at sea) or some other accelerating factor could be at least partly responsible, maybe lighting the fuse of the powder keg of plate tensions earlier or more frequently than would otherwise be the case.

    I’m not saying there’s anything to this, because even searching on-line the only reference I’ve been able to find is still in Susan Casey’s excellent and extremely well-researched book “The Wave” about increasing wave heights due to global warming.

    Many of you have better search skills and more patience than I do. Anyone find anything?

    And if eight inches of sea level rise is a contributing factor to these earthquakes, what would an additional foot in 2/5 of the time mean? What would Jim Hansen’s 5 meters (over 16 feet) by 2100 or whenever it occurs mean?

    Again, there might well be nothing to this. . .

    Largest earthquakes by magnitude
    Pos. Date Location Name Magnitude
    1 May 22, 1960 Valdivia, Chile 9.5

    2 March 27, 1964 Prince William Sound, USA 9.2

    3 December 26, 2004 Sumatra, Indonesia 9.1

    4 November 4, 1952 Kamchatka, Russia 9.0

    4 August 13, 1868 Arica, Chile 9.0

    4 January 26, 1700 Cascadia, US & Canada 9.0

    7 March 11, 2011 Tōhoku region, Japan 8.9

    8 February 27, 2010 Maule, Chile 8.8

    8 January 31, 1906 Ecuador-Colombia 8.8

    8 November 25, 1833 Sumatra, Indonesia 8.8

    11 February 4, 1965 Rat Islands, Alaska 8.7

    11 November 1, 1755 Lisbon, Portugal 8.7

    11 July 8, 1730 Valparaiso, Chile 8.7

    14 March 28, 2005 Sumatra, Indonesia 8.6

    14 March 9, 1957 Andreanof Is, Alaska 8.6

    14 August 15, 1950 Assam, India, Tibet 8.6

    17 September 12, 2007 Sumatra, Indonesia 8.5

    17 October 13, 1963 Kuril Islands, USSR 8.5

    17 February 1, 1938 Banda Sea, Indonesia 8.5

    17 February 3, 1923 Kamchatka, Russia 8.5

    17 November 11, 1922 Atacama Region, Chile 8.5

    17 May 24, 1751 Concepción, Chile 8.5

    17 October 20, 1687 Lima, Peru 8.5

    17 December 16, 1575 Valdivia, Chile 8.5

  62. Raul M. says:

    Looking at a dime, I see it says In God We Trust.
    Didn’t say religion or many other choices.
    Simply that.

  63. Richard Brenne says:

    The immense Japan 8.9 earthquake, the seventh-largest in history (or extrapolation by geologists based on evidence) going back 426 years (see my list at #59 from Wikipedia) relates to climate change in many ways.

    One is my conjecture that rising sea levels could produce just enough stress on subduction zones that they could be a contributing factor to earthquakes, perhaps lighting the fuse earlier or more often than would otherwise be the case.

    I’d guess that this earthquake oculd cost tens of billions. With Peak Oil, Climate Change and all other examples of our reaching limits to growth, how long is it before all the cumulative disasters in a year are a significant proportion of global GDP to make a real impact?

    Then there’s the way tsunamis find all the lowest land, the way sea level rise and storm surges do and will increasingly.

    Notice how from the air the tsunami seems to be approaching so slowly that it’s almost mesmerizing, and even from land people in vehicles in the footage I’ve already seen and from the India Ocean tsunamis in 2004 seem mesmerized into inaction.

    Time Magazine ran a cover story in 2008 where reporters found that in any such disaster, instead of panicking and running, most people will simply stand in place and die unless someone tells them what to do.

    This is what is going on with climate change. People like us need to alert, educate and save as many people as we can, and break their unthinking mesmerism however we peacefully can.

    In my talks especially near coastlines I’d say “Imagine you’re at the beach and suddenly the ocean retreats far out to sea, leaving fish flopping around on what had been the ocean floor. What do you do?”

    Then I tell them that what they should do is yell “TSUNAMI!” as loudly as they can to everyone they can while they run up the beach and to the top floor of the nearest, biggest and highest hotel. If a family on the beach is balking and mesmerized by something they’ve never seen before, then pick up their smallest child and run with it to the top of the highest hotel. I’ve found that when you do this, it is generally a good idea to be certain a tsunami is coming. . .

  64. Peter M says:

    #50 Aaron Lewis

    if we plan on 1 foot sea rise by 2040 (I read recently that the city of Newport Beach is planning on this- and raising their sea wall) and by 2040 they are being flooded- whats next?

    The costs for adapting to climate change and especially sea rise are going to be enormous.For those now in congress griping about deficits- what lies ahead because of climate change adaptation will make today’s puny amount look like chump change by 2050.

  65. Lewis C says:

    A paper by Prof Bill McGuire last May has a bearing on the geosphere’s destabilization by cryosphere decline.


    Potential for a hazardous geospheric response to projected future climate changes

    B. McGuire*

    Aon Benfield UCL Hazard Research Centre, Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK



    Periods of exceptional climate change in Earth history are associated with a dynamic response from the geosphere, involving enhanced levels of potentially hazardous geological and geomorphological activity. The response is expressed through the adjustment, modulation or triggering of a broad range of surface and crustal phenomena, including volcanic and seismic activity, submarine and subaerial landslides, tsunamis and landslide ‘splash’ waves, glacial outburst and rock-dam failure floods, debris flows and gas-hydrate destabilization. In relation to anthropogenic climate change, modelling studies and projection of current trends point towards increased risk in relation to a spectrum of geological and geomorphological hazards in a warmer world, while observations suggest that the ongoing rise in global average temperatures may already be eliciting a hazardous response from the geosphere. Here, the potential influences of anthropogenic warming are reviewed in relation to an array of geological and geomorphological hazards across a range of environmental settings. A programme of focused research is advocated in order to: (i) understand better those mechanisms by which contemporary climate change may drive hazardous geological and geomorphological activity; (ii) delineate those parts of the world that are most susceptible; and (iii) provide a more robust appreciation of potential impacts for society and infrastructure.

    From a Guardian article at the time of the Royal Society’s publishing the above paper:


    Writing in a special series of scientific papers on the topic published today by the Royal Society, Bill McGuire, head of the Benfield Hazard Research Centre at University College London, says: “In relation to anthropogenic climate change, modelling studies and projection of current trends point towards increased risk in relation to a spectrum of geological and geomorphological hazards in a warmer world, while observations suggest that the ongoing rise in global average temperatures may already be eliciting a hazardous response from the geosphere.”

    He adds: “In order to improve knowledge and reduce uncertainty, a programme of focused research is advocated … The IPCC [Intergovernmental Panel on Climate Change] is also strongly exhorted to address more explicitly in future assessments the impact of anthropogenic climate change on the geosphere, together with its manifold potentially hazardous consequences.”

    The idea of a society under intensifying climatic destabilization of its economy finding the wealth and cohesion to construct thousands of miles of say 35ft sea-walls (worst-case scenario on 100-year design life) seems to me ludicrous.
    For a start you’d need to be able to pump the extreme-flood volumes of the rivers – such as the Yellow, Yangste, Indus, Zambesi, Nile, Rhine, St Laurence and Mississippi – over the top of those sea-walls.

    Attempts to encircle high-value city locations with such sea-walls with raised causeways to high ground would predictably impact their economic productivity, as well as massively raising their carbon debt.

    In the event of those sea-walls’ failure – due to a marine event more extreme than was designed for, or due to damage by intensified seismic activity, the entire city’s population would be trapped in a pit, and would mostly drown.

    Not a place I’d choose to live.



  66. Chris Winter says:

    So, scientists are considering the possible role of sea-level rise (increased weight of water on faults) in the greater frequency of big earthquakes.

    Also, as Leif points out above, isostatic rebound will add its bit to sea-level rise. To use a crude analogy, it’s like pushing a metal cone through the bottom of a rubber wash basin. The increasing volume of the cone inside the basin will displace more water, making the level creep up the sides. This effect is probably small compared to the addition of melt-water, but every little bit hurts.

    The bottom line is that, as with storm surge, sea-level rise will make tsunamis more damaging — and may also promote the quakes that cause them.

  67. Chris Winter says:

    Another thought: The slow rise of the sea is not destructive in the way that a tsunami is. Then again, the flood from a tsunami goes away after a short interval. Compared to a tsunami, sea-level rise is forever.

    Here’s a brief discussion of adaptation to tsunamis:

    Japan earthquake: Can you tsunami-proof a country?
    BBC News — 11 March 2011 Last updated at 07:28 ET

    Indeed, Dr Chandler adds, the only way to be free of the risks associated with a tsunami is not to live near the coast in the first place.

    It is advice that has been heeded in the past. After the Hawaiian city of Hilo was hit by successive tsunamis in 1946 and 1960, authorities moved its residents further inland.

    The costs of relocating Hilo must be a good starting point for estimating how much it would cost the world to adapt to sea-level rise.

  68. Richard Brenne says:

    Lewis C (#66) – Thanks! I’ve printed up both those excellent links and I’m biking over volcanoes in the West Hills to the Portland State Geology Department and the Portland USGS office to ask my geologist friends there about this.

    Also you’re right about building infrastructure on an unprecedented scale when 1) People can’t agree that there’s any problem, and 2) The richest people who can most afford to pay taxes to update, upgrade and build needed infrastructure refuse to pay those taxes, and 3) Peak Oil, Climate Change, the end of the Global Ponzi Scheme Economy and all other limits to growth wouldn’t allow the building of infrastructure on such a massive scale anyway, and 4) Almost any infrastructure we do build could be overtopped in their design lifetimes by the sea level rise, intensified storms of all kinds and the greater likelihood of 100, 500, 1000 and 10,000 year floods, and 5) All levees could trap water from escaping as easily as they could prevent water from entering as you suggest.

    But 6) other than that there’s no problem.

  69. paulm says:

    This article was published a few days back….


    Coincidence? Banda Aceh, Indonesia, was devastated by the December 2004 tsunami which took place two weeks before a supermoon

  70. Everett Rowdy says:

    Mr. Brenne:

    I too have wondered about the seeming increase in intense earthquakes. I wonder if the rapid melt-off of glacial ice wouldn’t be enough to cause the tectonic plates to shift. In 2006 scientists estimate that 4675 billion metric tons of ice melted off. That is a tremendous weight shift on the crust – one that is accelerating.

    Considering how land suppressed by glacial ice rebounds isostatically once the ice has melted back, I imagine that there must be some serious shifting going on as glacial ice flows into the sea.

  71. Everett Rowdy says:

    Correction: that should have read 475 billion metric tons. Apologies for the mistype.

  72. Richard Brenne says:

    Everett Rowdy (#71) – Good points. I’ve been reading as much as I can of Bill McGuire and others that share this view, including the two links Lewis C alerts us to in his great comment at #66.

    Glaciers can hold the earth’s crust more in check, while rapid melting of glaciers can create isostatic rebound that can trigger earthquakes and volcanoes that might have otherwise taken longer to develop.

    I’d say that losing weight from glaciers, icefields and especially icecaps and then shifting and adding the weight of water re-distributed around the globe (especially from Greenland and other ice in the north to all oceans, including those in the southern hemisphere, which is mostly ocean) is having and will have an increasing effect.

    It is just difficult to know which of these events would occur without any climate change and which are related. I’d say now that climate change is becoming so dramatic, both climate change and tectonic forces are responsible, with the tectonic forces themselves being at this point far more responsible.

    The best metaphor I’ve been able to come up with so far is that every subduction zone and other major fault is like a powder keg, waiting to go off at some point. Each of these powder kegs has a fuse, and an earthquake (or volcano) will result when the fuse is lit.

    Right now climate change is like throwing millions of firecrackers just about everywhere, and some of those might light some of those fuses. But as climate change and melting accelerates toward the end of this century and many centuries into the future, it will instead be like throwing millions of increasingly large Molotov cocktails around, which of course have a greater chance of lighting those fuses, and are also delicious.