New predictions for sea level rise
Sea level graph from the University of Colorado is shown below:
University of Bristol Press release issued 26 July 2009
Fossil coral data and temperature records derived from ice-core measurements have been used to place better constraints on future sea level rise, and to test sea level projections.
The results are published today in Nature Geoscience and predict that the amount of sea level rise by the end of this century will be between 7- 82 cm (0.22 to 2.69 feet)
– depending on the amount of warming that occurs – a figure similar to that projected by the IPCC report of 2007.
Placing limits on the amount of sea level rise over the next century is one of the most pressing challenges for climate scientists. The uncertainties around different methods to achieve accurate predictions are highly contentious because the response of the Greenland and Antarctic ice sheets to warming is not well understood.
Dr Mark Siddall from the Earth Sciences Department at the University of Bristol, together with colleagues from Switzerland and the US, used fossil coral data and temperature records derived from ice-core measurements to reconstruct sea level fluctuations in response to changing climate for the past 22,000 years, a period that covers the transition from glacial maximum to the warm Holocene interglacial period.
By considering how sea level has responded to temperature since the end of the last glacial period, Siddall and colleagues predict that the amount of sea level rise by the end of this century will be similar to that projected by the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC).
Dr Siddall said: “Given that the two approaches are entirely independent of each other, this result strengthens the confidence with which one may interpret the IPCC results. It is of vital importance that this semi-empirical result, based on a wealth of data from fossil corals, converges so closely with the IPCC estimates.
“Furthermore, as the time constant of the sea level response is 2,900 years, our model indicates that the impact of twentieth-century warming on sea level will continue for many centuries into the future. It will therefore constitute an important component of climate change in the future.”
The IPCC used sophisticated climate models to carry out their analysis, whereas Siddall and colleagues used a simple, conceptual model which is trained to match the sea level changes that have occurred since the end of the last ice age.
The new model explains much of the variability observed over the past 22,000 years and, in response to the minimum (1.1 oC) and maximum (6.4 oC) warming projected for AD 2100 by the IPCC model, this new model predicts, respectively, 7 and 82 cm of sea-level rise by the end of this century. The IPCC model predicted a slightly narrower range of sea level rise – between 18 and 76 cm.
The researchers emphasise that because we will be at least 200 years into a perturbed climate state by the end of this century, the lessons of long-term change in the past may be key to understanding future change.
Please contact Cherry Lewis for further information.
Further information:
The paper: Constraints on future sea-level rise from past sea-level reconstructions. Mark Siddall, Thomas F. Stocker and Peter U. Clark. Nature Geoscience .
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Steve S. (20:50:02) :
How is it that people making such asinine claims can rise to head an organization like NOAA?
I will make a prediction for 100 years from now:
The Dinosaurs will reapper and there won’t be humans on the Earth’s face. Failures on weather prognoses will continue. Insects will become intelligent and will dominate the planet.
If my predictions are unsuccessful, you have the right to argue before my tomb.
I think those people are living the “here and now” in pursuit of money and power.
Well, I predict that polar ice will increase in Antarctica and will gain 7 to 82 million square miles by this time, depending on how much warming there is not.
Furthermore, I predict the winning lottery numbers will be the ones you do not have.
Also, I predict that any complaints about my predictions will result in a full refund.
I love posts like this because of the animosity they instantly generate. At the most we are all here for another 100 years or so. The sun rises and falls just as it has done since the beginning of time. Life your life and stop worrying about things you can’t control. Just a thought.
Is Svensmark right?
http://www.landscheidt.info/oulu.jpg
Its been warming quite a bit in July according to AMSU. I think this where Leif Svaalgard tries to prove that he is correct (solar does not affect temps). However, I don’t think he right, because there is obviously quite a time lapse re ocean SST which can take many years. ie A cooling is coming because of solar activity but its long term (just surmising BTW)
Talk about a bold prediction!
I predict the high temp in Phoenix today will be between 80° and 140°F.
I tell ya, it’s not easy being a scientist and making all these precision models which yield such profound results.
“Phil M: – no, another way to express it 44.5cm +/- 37.5cm”
So if 37.5cm is one Standard Deviation, we can be 95% sure that it will be between minus 30.5 cm and plus 119.5 cm.
“Nogw: This makes me remember that it is a silly thing for americans to change from their system of measures to SIM which has foolish measures as a circle of 400 degrees instead of one of 360 degrees. 360 comes from nature’s cycles while the 400 degrees figure comes from a fevered french revolutionary (Mssr.Tayllerand), with quite other objectives than those of a measuring system.”
Americans do not have a system of measures; they use a crazy mixture of different systems (can you tell me the power of a light-bulb in horsepowers, or blood-pressure in PSI, or spectacles in 1/foot ?).
The gon, used by surveyors, would have the advantage that on a great circle it equates 100 km, just as a minute of arc equates a nautical mile. There is nothing natural about the deg, but 360 can be divided by 2, 3, 4 ,5 ,6, 8, 9, 10 etc. Neither is part of the International System, which is coherent and therefore uses the rad.
Vacationing in Wildwood NJ in July I noticed there were some freakish high tides I have never seen before. Could this be changes in the AMO PDO?
http://www.wired.com/wiredscience/2009/07/hightides/
Alexej Buergin – are you French?
The Americans use the good old British Imperial system, which is why sometimes their Mars Probes miss their orbit & crash land!
Is anyone into models enough to answer this?
If water in a narrow tube is heated, it will rise in a linear manner, thermometer-wise.
If the water is in an inverted cone-shaped vessel it will rise in a less quickly with increasing heat as it has to fill a wider area.
If the water is on a flat plate, it will hardly rise at all because it will increase in area unless bounded somehow.
Do the usual models have a linear assumption? Given shallow shorelines and the like, they ought not.
Sea level models using dynamical methods should be compared against straight forward statistical models (the setting events that happened prior to sea level change in the past). This model they used in the above paper sounds like a mixed breed, part dynamical and part statistical. There is no way I would say anything about this new model’s accuracy other than to say that further research is needed to compare it to the gold standard: the statistical model, otherwise known as the control. Their conclusions go way out there in a land unsubstantiated by their research design.
” Phil M (05:50:22) :
Alexej Buergin – are you French?
The Americans use the good old British Imperial system, which is why sometimes their Mars Probes miss their orbit & crash land!”
1) No, I am not
2) No, they do not
Of the 7 basic units (m, kg, s, A, K, cd, mol) of the SI, they use s, A and mol (I don’t know about candela). Instead of m thay use foot, instead of kg they use either pound(-mass) or slug, and instead of K it is °F. But scientists use the SI, of course.
If you want to do any calculations at all, the SI is the way to go, because it is very simple and coherent (SI-units in, SI-units out, no conversions).
I’ve been doing some experimenting and it turns out Albedo changes alone are capable of explaining all the temperature change during the ice ages. Based on the estimated increase of ice and snow during the ice ages, enough sunlight would have been reflected, rather than absorbed, to drop temperatures by 6C. Milankovitch cycles kick-off and pull-back the ice-Albedo feedback and that is all that is needed.
This is what I was taught in atmospheric physics in graduate school in the 80’s. I still think it is the most probable explanation. Anyone with common sense has long realized that CO2 is a drop in the ocean compared to other first order factors. If positive feedback reinforced CO2 warming, which releases even more CO2 as oceans warm, then obviously the atmosphere would have long ago became runaway hot. Clearly other factors are at work and which cool the planet despite the historically documented fivefold increases in the tiny trace amounts of CO2 in the air.
@Alexej Buergin (06:52:25) :
You’re right. America and Americans will never accomplish anything using their archaic system. (Insert smiley face or the SI equivalent).
evanmjones (20:54:38): …He said that sea level has a direct effect on the earth’s rotation (by a small degree), and that figuring it out that way, sea level rise was being exaggerated by quite a lot. This is an excerpt of a 2007 pdf I have on file: The Ice Caps are Growing By David J. Ameling (he has commented here) “The IERS determines the rotation of the Earth. Data only exists from 1972 to the present. From 1972 thru 1998 (26 years) 21 leap seconds were added. From 1999 to the present (9 years) only 1 leap second has been added. This means since 1999 to the present the Earth’s rate of rotation has increased. There are two possible (but not mutually exclusive) causes for this.
1. Some of the Earth’s mass has moved closer to the Earth’s axis of rotation similar to a spinning skater bringing his arms closer to his sides, and thus spinning faster. For the Earth this would occur when some of its ocean water is moved to the polar ice caps to form snow and ice.
2. An electromagnetic force that would slow down the Earth’s rotation is lessening.”
I suppose #3 could be the sea level, with what I assume a tiny effect, re: mm’s of sea level relative to radius of earth. Have you seen other papers re: rotation speed Evan, I’m curious? This seems like one metric that would be hard to fudge with the atomic clock as the measure for length of day.
And I’ve ‘nailed’ that today’s temperature where I live will be between 60 and 100 F.
” Dave (08:02:35) :
@Alexej Buergin (06:52:25) :
You’re right. America and Americans will never accomplish anything using their archaic system. (Insert smiley face or the SI equivalent).”
We are not talking music or sports or politics here, but engineering. It is not a good idea to use different “systems” at the same time. See Phil M and the Mars probe that crashed (systems of measure), or the Airbus 380 (computer programs). During WW II pilots got into trouble by mixing up sm and nm, or US gallon and Imperial gallon.
Bee scale aerodynamics.
Conventional aircraft wings operate on the principle that air flowing more rapidly over the curved upper surface has a lower pressure than the air flowing under the less curved lower surface, generating lift. This requires the smooth flow of air.
Bees wouldn’t be able to fly using that principle. At their small scale, the wings instead produce turbulent vortices that keep the little guys up. Turbulent flow over aircraft wings destroys lift and has the opposite effect.
It seems the low end is a bit low if one assumes that the current satellite measured rate of about 32mm/year continues for this century yielding 32cm.
I just love that sea level graph from CU. 3.2 +/- 0.4mm/yr., such exquisite precision. But lets consider for a moment the system that provides the data from which it is derived. We have a set of radar altimeters mounted on satellites . I couldn’t find the orbital heights for the JASON units, but for the TOPEX set it’s given as 1330 km, so for purposes of discussion we’ll use that. This would indicate that to achieve 1mm accuracy the altimeters would need to be capable of reading to one part in 13 billion, hardly likely since it would require the instruments be able to differentiate to less than a single cycle at the frequencies at which they operate. After 15 years of practice and adjustment the lads are fairly confident that they can describe the orbital ephemeris for the satellites these units are riding on to something like 10 to 50 CENTIMETERS rms or more depending on who’s telling the story. These altimeters operate in the C and Ku bands which means that if the temperature, pressure and humidity of the atmosphere are not perfectly known and accounted for chaotic errors will be introduced into the measurements. At the height the sats are operating any deviation from perfect orthogonality which is likewise not perfectly known and accounted for will also introduce significant errors. Then we have the oceanic surfaces the altimeters are reading, which are subject to a variety of perturbations of height and reflectance from winds, tides, gravity, currents, etc., which also need to be accounted for. Now I know the dedicated number crunchers will tell me that the vast toolbox of modern statistical mathematics allows for the extraction of a signal from even such a noisy and error ridden data set, which may be true. And NOAA does show on their website a calibration to a set of ten Pacific tidal monitoring stations, but the differences noted generally range from 2 to 4 cm rms, which seems to me to indicate that virtually all of the difference in the graph is within systemic uncertainty. If the folks involved had a long history of disinterested pursuit of the truth, one might be tempted to grant some credence to their efforts, but since their description of the project on their website implicitly indicates that a primary goal was to verify global warming, I don’t think it is unreasonable to question whether the dramatically sloping trend line on their graph is a true reflection of the state of sea levels or a statistical fantasy founded on the conscious or unconscious biases of those doing the data adjustments. The statistical toolkit can be a powerful weapon in the pursuit of scientific truth, but, as has been demonstrated numerous times in this affair, it also offers copious opportunities for mischief.
Dave Wendt (16:49:29) :
He swings, it’s going back, way back, it’s outta here!
But, er, sea level rise of 500mm since 1993??
Where was that?
” Ian (01:44:41) :
But, er, sea level rise of 500mm since 1993??
Where was that?”
One zero too many, 50 mmm=2 inch.
And yes, where was that?
Alexej Buergin (10:07:13) :
” Dave (08:02:35) :
@Alexej Buergin (06:52:25) :
“It is not a good idea to use different “systems” at the same time.”
If you have a Russian scientist and an American scientist in collaboration on an important project, you’d better have a very good translator. How many errors of serious consequence would be made in the transition if Americans were ‘forced’ to change from their system to the metric? IOW, two systems in use at the same time. The key, IMO, is to recognize the probability of human error and to diligently search for it.
Dave Wendt (16:49:29) :
Had a brain fart while writing this, 1300km is obviously 1.3 billion mm, not 13 billion. Was going to let it slide since evidently not many people read it, but if I expect integrity in others I guess I have to have some myself, so cancel my first point, although I still suspect their actual achievable accuracy is off by at least an order of magnitude. I worked with EDM in the surveying business for many years and the topline units, even today are only good 2mm +/- 3ppm to a precision retro prism on a tripod over a couple miles and generally require regular recalibration to maintain that. Actually, even if they can only achieve centimeter level accuracy, it’s a fairly heroic accomplishment. I just resent the constant requirement to scale every graph so that barely consequential trends have slopes like an Olympic downhill track.