Above, James Hansen’s recent statement to me re sea level rise.
No one is more deeply concerned about SLR than Hansen, and he has ventured some of the largest numbers we’ve seen for what the potential might be. He does tell us that those numbers rest on certain assumptions:
“..Our record of precise knowledge of the changes in the mass of the ice sheets is rather short, it really began with the gravity satellite, which now has a record of only 12 years, but over that period the mass loss has increased rapidly …if it continues to double at the rate that it has in the last decade, then we could get, within 50 years, meter scale sea level rise, and you’d rapidly, within another one or 2 decades, get multimeter sea level rise. So that’s an enormous threat.”
So, multimeter sea level rise possible if his calculations are accurate, if his mechanism is real, and if the short record of accurate accounting is consistent decades into the future.
Those caveats should give us caution in assigning too much cred – yet – to the newest story on sea level being passed around.
Think sea level rise will be moderate and something we can all plan for? Think again.
Sea levels could rise by much more than originally anticipated, and much faster, according to new data being collected by scientists studying the melting West Antarctic ice sheet – a massive sheet the size of Mexico.
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Margaret Davidson, NOAA’s senior advisor for coastal inundation and resilience science and services, and Michael Angelina, executive director of the Academy of Risk Management and Insurance, offered their take on climate change data in a conference session titled “Environmental Intelligence: Quantifying the Risks of Climate Change.”Davidson said recent data that has been collected but has yet to be made official indicates sea levels could rise by roughly 3 meters or 9 feet by 2050-2060, far higher and quicker than current projections. Until now most projections have warned of seal level rise of up to 4 feet by 2100.
These new findings will likely be released in the latest sets of reports on climate change due out in the next few years.
“The latest field data out of West Antarctic is kind of an OMG thing,” she said.
So there’s quite a bit of discussion among knowledgeable folks that this is overdoing it a bit, and the article cites no new research numbers to support the direst estimates.
Readers and viewers know that I’ve produced a number of videos on the issue and interviewed some of the best experts in the field – but I caution those tweeting this new meme around that, so far as I know, “the latest field data” cited here do not give us anything like 3 meters by 2050, and even Hansen’s worst case quoted above gives something like a meter by mid century, scary enough – with multi-meter rise more toward 2100.
So, plenty of reason for concern, but recall the kerfuffle with a stray sentence in the 2007 IPCC report, claiming that “Glaciers in the Himalaya are receding faster than in any other part of the world and, if the present rate continues, the likelihood of them disappearing by the year 2035 and perhaps sooner is very high.”
This statement turns out to have escaped the rigid review process, and became a talking point for climate deniers seeking to undermine the reports solidly based major conclusions.
So, bottom line, always look for specific published, peer reviewed sources for claims as important and sweeping as these. Sea level rise is already an emergency, but dealing with it means scientists and citizens have to maintain high standards for the information they rely on and disseminate.
UPDATE: Clarification from NOAA official quoted in article, to Eric Holthaus of Slate.
Right-clicking should get you a larger version.
Reblogged this on A Green Road Daily News.
Observational data will always be smooth and nearly linear, both because there’s a desire to filter out noise, and because the observational path is one realization out of several possible futures, perhaps many possible futures.
This may be beyond the state of the art, but what’s wanted is a detailed model of the physics of ice sheets, or perhaps just the WAIS and Greenland. Then, to obtain the necessary posterior predictive distribution of SLR, such a model needs to be integrated against a range of priors on its parameters, constrained by the observational data.
No doubt this is a huge task. However, in a personal communication with Suki Manabe (see https://www.princeton.edu/aos/people/faculty/manabe/) when he recently gave a lecture at Harvard (see http://environment.harvard.edu/file/special-climate-seminar-syukuro-%E2%80%9Csuki%E2%80%9D-manabe), I asked him about this difficulty, and he said the next IPCC round would *have* to do this. I probably made a face like “Wow, that’s HARD.” He said “Computers are really fast, and getting faster. They’ll do it.”
Without such a model and calculation, we don’t know about internal state changes and potential bifurcations of these nonlinear systems. Just projecting trends, although popular in business modeling (e.g., ARIMA), just doesn’t cut it here.
They are trying to predict the ‘flow rate’ of a form of matter that gifted the English Language the word ‘avalanche’. More power to them, but frankly, any kinetic rate is possible when you’ve gotten a volume of ice the size of Mexico moving. The point of Arrhenius’ original 1896 thermodynamic warning was to NOT LEAVE IT UP to kinetics.
” “the latest field data” cited here do not give us anything like 3 meters by 2050, ”
First – thanks for looking into this, Peter. 🙂
Second – can you be more specific about the latest field data? What the two very well-placed scientists said in the Insurance Journal was that there is up to a ten year lag between an actual field measurement, and the time it is actually reported. Ten years can be a VERY long time IF we are at the very beginning of an exponential acceleration in the rate of SLR.
Past slopes – rates of SLR may be misleading. And if what Robert Scribbler has published is true, the very latest reports (I have no idea when the actual field measurements for these reports were made) show a very rapid increase in the rate of increase of SLR.
I have listed these rates here previously. 2013 -2014 was 4.4 mm/year. From the start of 2015 until the fall of 2015 – nine months – the rise was 10.0 mm! Essentially a tripling.
Now, this is at the peak of El Nino. But I am not so sure that SLR will be expected to correct toward the mean as quickly as air-land temperatures. So, it seems to this decidedly inexpert commentator, that this is a very important issue to make sure we have all the info about. This might be the biggest story of the decade.
I would LOVE to have you interview “Margaret Davidson, NOAA’s senior advisor for coastal inundation and resilience science and services, and Michael Angelina, executive director of the Academy of Risk Management and Insurance”!
The El Nino is a small bit of heat leaving the tropical Pacific for space and going through the surface film and atmosphere on the way (they just happen to be in the way). It will not warm even the topmost few metres of the oceans measurably (too little, too short). Could only affect SLR if it caused much Greenland surface melt run-off (such as topmost 1 metre thickness of all Greenland sheet for 4 mm SLR). I’m pretty sure it’s unrelated.
The exponential aspect of ice loss is greater than any exponential aspect of SLR (thermosteric must be near linear). Example with your numbers (I’ve not been keeping track).
~2000-2012 3.2 – 1.6 = 1.6 mm/year of ice loss.
2013 -2014 4.4 – 1.6 = 2.8 mm/year of ice loss.
2015 prorate 13.3 – 1.6 = 11.7 mm/year of ice loss.
So that’s an increase of 600%. However, even if your number is correct it’s needed to know whether there was a large runoff anomaly from land that needs to be subtracted.
And thermal expansion of sea water. And gravity effect away from ice masses. And probably more I have no idea about.
My “– 1.6” mm/year above is the thermal expansion of sea water to subtract “(thermosteric)”. Forget where I got it or whether I computed it from +13.7 zettajoules/year. It’s pretty good. Between 1.4 – 1.8 mm/year say. I don’t know the cause of that SLR being only in the tropics & sub-tropics, maybe temperate. The obvious thought is Earth rotating but that’s miniscule, it cannot be that.
I meant “will not warm even the topmost few metres of the high-latitude oceans measurably” (the topic is ice melt). Obviously it warms the topmost few metres of tropical Pacific measurably on its way from ocean thermocline to space because that’s what it is.
novice here w/question about thermal expansion: does El Nino actually reduce rate of slr by releasing seawater heat to space? the idea being that because ocean gives up heat, thermal expansion is reduced? (of course this says nothing about other impacts of El Nino as temp records are set, presumably melting more of Greenland, thawing permafrost, etc.)
Yes. Per Kevin Trenbeth “Ocean Heat Uptake: The Apparent Hiatus in Global Warming and Climate Sensitivity” by Yale University “agKayS6h6xA” @ 11:24 eye balling ORSA4 graph OHC went down by ~10 zettajoules 1998-2000 (interest note: volcanoes were much bigger). That was the El Nino. So, ~10 zettajoules departed oceans for space 1998-2000 and 137 zettajoules went into oceans from Sun 2002-2012 (the “pause”). At 15:42 ORSA4 differentiation graph shows that Earth’s energy imbalance went from the ~+0.9 w/m**2 imbalance from +CO2 to ~-0.1 w/m**2 (eye balling) for the 2 years and Kevin points out what is obvious, that Earth’s ecosphere cools during a big El Nino when the surface has its largest average temperatures (because heat is from oceans, not from Sun). I just computed ~32 zettajoules cooling of Earth’s ecosphere over 24 months 1998-2000 from that “Rates of change” graph and I cannot reconcile that with the ~10 zettajoules from the 11:24 graph so I would need to sort that out some day because that’s way too big variation to just take as an approximation.
Apparently I got this ocean thermal expansion coefficient γ from IPCC 3 years ago. I vaguely recall some scientist saying 200 ppm and I know I once used 120 ppm as an ocean average that I worked out from a temperature/salinity/γ matrix and 130 ppm for 4,000m depth pressure at 0 °C but that’s pretty rough because it wasn’t available for a variety of pressures (depths). It should really be done by assessing in several depth layers to get any reasonable accuracy. Note that the average γ of the top 250m (6.5%) is a massive 6x the average γ of deep ocean below 700m. This means that heat added but moving deep causes very little expansion.
1971-2010 IPCC
————–
0- 250m @ 22C γ = 226 11mm / 0.19C
250- 700m @ 22C to 8.5C γ = 150 avg. 29mm / 0.19C (0.03 C / m depth)
700- 2500m @ 8.5C to 4.5C γ = 37 avg. 1mm / 0.042C
I’m waiting for NOAA (I hope) to provide the number of zettajoules departing oceans to space for 2015/16 El Nino. Signs are that El Nino size increases in a warmer ecosphere than present (I hypothesize or notionize that’ll continue until tropical Pacific balances its well-mixed layer nominally 90m deep so it gets back its historical relationship with tropical Atlantic and reduces Pacific easterlies velocity to where it used to be 50% of new heat stayed above the topmost 2% depth of the oceans (what’s called the well-mixed layer” because it’s well mixed) and this affects surface temperature. Over the next 7 years ~zero of new heat stayed above the topmost 2% depth, while the portion of new heat going deeper than the topmost 15% depth of the oceans increased from 2% up until 2003 up to a large 77%. You see above that heat was being pushed in fast after the huge 1997/1998 El Nino and it’s been decreasing ever since. That’s probably partly because it’s been piling up North of Australia, maybe some gradual push back over the last 15 years leading up to the El Ninos like the 2015 one and bigger.
I think the formatting wll be a mess, not nearly wide enough.
The final 20 lines of that has an ocean heat table missing so it’s meaningless, don’t bother with it.
Update. It’s now NOAA ORAP5 plot that shows how much heat Earth’s ecosphere is gaining or losing on a quarterly basis. That’s the actual heating caused by GHGs and you can eye ball trends through it for various periods depending on whether your interest is ENSO or the underlying +GHG-induced energy imbalance.
the 10 year lag time would be an extreme estimate for how long it takes for research to show up in an IPCC report.
The individuals cited in the article are not publishing scientists.
If there were anything showing numbers like these, I think we would have heard of it from someone like Eric Rignot, Mauri Pelto, or Jason Box.
Perhaps Peter can ask Eric or Jason or Mauri …. Unless they are doing the “embargo until accepted” thing.
Unless there was a reporter’s transcription error, how else can we take the statement by Davidson? She gives a specific number for rise and a specific decade range. And then promises new unpublished data in the pipeline to buttress the claim.
That doesn’t seem like an uninformed misstatement.
It sounds like a lie. You do not make statements in science without having a study at hand to hand out to the people you are talking to. Remember the claims on cold fusion. Total BS when people tried to redo the experiment. New unpublished data in the pipeline is per BS.
Okay, now this is no longer in the frame of polite discourse, WHATEVER the field.
Mr Bates, all this does is make your case more difficult, because if you start hurling these accusations, people who might have taken your argument seriously will now think you are just an emotional busybody.
Willing to listen, but, first, and from MY perspective, and speaking for noone else, Clean Up Your Act.
Tom:
Try publishing this type of libel in a more high profile setting and see where that gets you. You have zero evidence that the statement is a lie, yet this seems to be the first conclusion you jump to concerning a scientist. There is a reason the term anti-science exists, for those that so vehemently attack the messengers.
The first thing that occurs to me when you mention a sudden acceleration as an El Niño gets underway is rainfall patterns. El Niño usually comes with a rise because more rain falls over the oceans and the big rain catchments like the Amazon/Indian monsoon go into relative drought. More water stays in the oceans rather than entering the terrestrial water cycle. This means a temporary upward excursion in SLR.
and vice versa
THAT, however, is the kind of skepticism that we need. SHOW us the money, but when it turns up, don’t say it isn’t there the way some people do.
The most recent time that I posted on this site was to express skepticism about this new sea level story. As I said then, even the well justified and peer reviewed projections we already have should be cause for immediate action on CO2, but this new story just doesn’t quite fit with the ice dynamics we currently understand. The new story may be based on very new observations, and those very new observations may eventually cause some upward revision to SLR estimates, but there’s a lot of work to be done in validating the interpretation of those measurements before we can be confident in their meaning.
If you look at the actual numbers, NOAA measurements of ocean level rise on land not moving up or down like New Orleans or Miami, say Johnston AToll or Sydney is 3 inches ocean rise trend in 100 years. To get to Hansen’s make believe numbers the melt would have to increase thousands of times in the next 30 some years. unlikely to happen unless the sun blew up. Antarctic overall land ice is increasing per NASA research. West Antarctic melt is offset by the increase in the rest of the continent which has not actually seen a rise in surface temperatures for 40 years. West Antarctica per NASA research seems to be losing ice due to under ice heating from volcanoes. the basalt basement rocks are warmer than other parts of Antarctica. Hansen takes a guess, uses the worst case unlikely guess and claims the sky is failing. He has been doing that his entire career both in and out of government. His contribution to global temperature measurement is the Giss data set, That data set grids the world and attempts to plug each grid with a temperature than takes an average for the world. The problem is a lot of grids have no data at some point so a lot of the temperatures are estimate, 66 percent currently, a lot more for measurement in the past back to 1880. When an actual temperature is less than surrounding estimates or actual temperatures they throw it out and plug a higher estimate in. Barrow Alaska for example this last October mean was 7 degrees less than in 1911. They threw the actual temperature out and plugged in a higher estimate, problem solved. Than the Giss folks use the fake estimate to tell us the sky is falling when alternate measurements like RSS show no warming for decades.
Tom Bates of course has some published data to support his accusations. I cam hardly wait.
I am particularly interested in the paper where Hansen says the sky is falling.
“Actual numbers” please.
What matters, of course, is variation in a signal as a multiple of the number of standard deviations it varies off a previous baseline. If there is no change, then either there has been no change, or the measurement is too insensitive to show a change.
Mr Bates cannot expect to declare things like “West Antarctic melt is offset by the increase in the rest of the continent which has not actually seen a rise in surface temperatures for 40 years” or “West Antarctica per NASA research seems to be losing ice due to under ice heating from volcanoes. the basalt basement rocks are warmer than other parts of Antarctica” without, (a) getting VERY quantitative about these claims, and (b) showing some solid evidence. There is *no* evidence vulcanism is affecting WAIS at all.
So, I’m prepared to listen, Mr Bates, if you have the calculations, evidence, ALL quantitative, to back your claims up.
Don’t hold your breath.
We know the IPCC estimates of SLR are exceedingly conservative. James Hansen’s paper should be treated seriously, even if the figures do need to be amended later. However given his track record he will probably be on the money.
I concur.
Of all the people involved in this drama, James Hansen has, historically, along with people like Wally Broecker and the late Steve Schneider, been dead on.
Exactly. Hansen was not believed in the early 1980s and look how that turned out. Rignot in in the video posted recently here said he’s been projecting linear increases in Antarctic melt but Hansen is projecting exponential increases in the melt. Rignot also made it clear they don’t yet have a long enough time series to be sure who is right. Track record says don’t write off Hansen’s conclusions.
I concur. Scientists are going to publish what is demonstratively supported by the evidence. Note the publisher of the article that warranted this climatecrocks item: Insurance corporations have to worry about WHAT IS ACTUALLY GOING TO HAPPEN. They have billions of dollars riding on that, how are they supposed to wait around for ‘demonstrable evidence’ to support what we all know is going on? To use an analogy, if you overload a bridge, the insurer will tell you its going to fail ‘now’. Science will wait until the demonstrable evidence indicates imminent failure. For policy purposes, the rest of us are stuck somewhere in the middle. The insurer is probably too alarmist, but the Scientist, in matters such as these, is ORDERED BY SCIENCE, to be too conservative. So we’re ‘stuck in the middle with you’…
The rate of sea level rise over the past ~120 years was 1.7 mm/year. But satellite data from the last ~10 years shows that this number has doubled to 3.4 mm/year. Without engaging in any speculation about the increased melting of ice sheets, we “know” that the next 100 years will bring us a minimum rise of 340 mm or 13 inches.
https://en.wikipedia.org/wiki/Sea_level_rise
The question here is when are we going to do something about this?
I’m very much of the view that – regardless of what we do to reduce emissions and to lower atmospheric concentrations of CO2 – we’re stuck with whatever the amount/rate of sea level rise will be for at least this century.
The polar sea ice melt and the thinning of glacier tongues has been due (in my completely non-expert view) as much to constant contact from beneath the ice with waters that are/were constantly a bit warmer during the second half of the 20th century and these recent decades than the warming air currents above the ice during summers. It took a hell of a long time for those small changes in water temperatures to have their accumulated effect which we now see so plainly.
If we magicked an instant, overnight reduction of anthropogenic CO2 emissions to nil, along with a simultaneous absorption and sequestration of accumulated excess emissions to bring atmospheric concentrations below 350 ppm, it will take more than 8 decades for the whole of the circulating ocean waters to lower temperatures back to 1980 levels or better. If we could do it we should, because air temperatures and storm systems _would_ fairly promptly move downwards and allow seasonal formation of more extensive and thicker winter sea ice. But that can only slow down, not stop, massive land-based glaciers and ice sheets in their current rapid movement seawards.
We have to prepare to both reduce CO2 concentrations as far and as rapidly as possible (I think below 300 ppm should be the target rather than 350, btw) _and_ to deal with at least an eventual, minimum 2 metres of sea level rise before that slows or stabilises enough to begin a pretty slow retreat. That will take until at least 2200 to show up. However long it takes for the waters to slow their rise and begin their retreat, we have to deal with at least a dozen, probably 20, major cities around the world being massively affected by the encroaching waters and, no matter when the water goes back where it belongs, long-term loss of sea level agricultural lands.
The one huuuuuge, planet-sized advantage we have in this project is the current stage of the Milankovitch cycles. If we do this fast enough on a large enough scale, the planet will help us not work against us.
It’s all very sad for the next few generations of our own and other species. But we can do it if we’d only make up our collective minds and get started.
I would not anticipate Glacier and ice sheet melt to remain linear.
The decrease in surface compressing mass has consequences in the geologically/volcanically active areas such as Iceland, the WAIS and to a lesser but still concerning amount due to its Geology Greenland where the ice is to a large degree sitting in hot rock
http://onlinelibrary.wiley.com/doi/10.1002/jgrb.50273/abstract
Effects of present-day deglaciation in Iceland on mantle melt production rates
Abstract
[1] Ongoing deglaciation in Iceland not only causes uplift at the surface but also increases magma production at depth due to decompression of the mantle. Here we study glacially induced decompression melting using 3-D models of glacial isostatic adjustment in Iceland since 1890. We find that the mean glacially induced pressure rate of change in the mantle increases melt production rates by 100–135%, or an additional 0.21–0.23 km3 of magma per year beneath Iceland. Approximately 50% of this melt is produced underneath central Iceland. The greatest volumetric increase is found directly beneath Iceland’s largest ice cap, Vatnajökull, colocated with the most productive volcanoes. Our models of the effect of deglaciation on mantle melting predict a significantly larger volumetric response than previous models which only considered the effect of deglaciation of Vatnajökull, and only mantle melting directly below Vatnajökull. Although the ongoing deglaciation significantly increases the melt production rate, the increase in melt supply rate at the base of the lithosphere is delayed and depends on the melt ascent velocity through the mantle. Assuming that 25% of the melt reaches the surface, the upper limit on our deglaciation-induced melt estimates for central Iceland would be equivalent to an eruption the size of the 2010 Eyjafjallajökull summit eruption every seventh year.
For the WAIS
“Rapid bedrock uplift in the Antarctic Peninsula explained by viscoelastic response to recent ice unloading”
Greenland
“Heat flow from Earth’s mantle contributes to Greenland ice melting”
“Hot spot’ under Greenland accelerating ice sheet melting
Geothermal activity creates network of rivers, speeds up flow of ice to North Atlantic
Mon, Apr 4, 2016, 16:00 ”
Note in all these case the Geothermal activity has been the norm and a Natural part of the environment for millions of years, like the hot springs in many glacier areas such as NZ etc.
However they are far more delicate than we realised and we don’t know the tipping points
I’ve wondered about this for several years, too.
However, what’s the time constant of mantle rebound and unloading? That is, if an impulse of unloading is applied to a burdened mantle, how quickly is it’s initial response and, thereafter, how fast does it relax?
While the mantle is plastic, it is also viscous, so I would expect it to move slowly.
Accordingly, elastic heating of a plate can only be as much as there is flexing of it at a rate.
And mantle flow, such as in hotspots or even Kimberlite pipes is certainly no faster than tens of centimeters per year, and in most instances much less.
Worth considering in conjunction.
Remember the mantle is thin under these hotspots, especially Greenland and Iceland.
http://www.albanydailystar.com/science/biggest-glacier-in-greenland-is-crumbling-in-to-north-athlantic-ocean-escondido-daily-science-9873.html
“But ice sheets are a good example of how rising temperatures can tip natural systems into unknown territory. The warmth leads to repeating loops of cause and effect that can force ice sheets to flow faster, break faster, melt faster. Glaciologists may not be able to decipher the mysteries of ice sheets, to model their behavior and sensitivity, before calamity becomes inevitable.”
“to regard the prospect of a future glacial collapse with only modest concern is to disregard what has happened in earth’s past, and what might happen again. ‘‘We know the ice can change fast,’’ Eric Rignot, a professor of earth sciences at the University of California, Irvine, told me in May, as we talked at a campus picnic table on a sunny afternoon. ‘‘We’ve never seen it. No human has ever seen it.’’ Rignot is fairly confident, however, that we are seeing it now — a conclusion borne out by the ice-sheet data he scrutinizes every week. A few decades from now, he said, we may look back with regret, wondering why more of us didn’t acknowledge the signs all around us, why we didn’t see ‘‘that the collapse had already started.’’