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 .
I wonder about the sources of water available to produce a rise in sea level. At the last glacial maximum, or near its end actually, ice filled the Puget Sound lowland south to near Olympia with melt water flowing to Grays Harbor via the Chehalis River. Much of this glacier was below current sea level. Melting, breakup, and flushing (to the ocean) of this low elevation ice would be less difficult than melting the ice fields now at elevations above, say, 2,000 meters. Likewise for the ice of NW Europe. It seems to me there ought to be an inflection point between the “easy-to-melt” ice and the “hard-to-melt” ice. Assuming that inflection point has been crossed, future melting ought to slow, if not stop at some point. Sea level rise should slow and then stop. (All other issue held constant.) The slowing part is already occurring, I believe.
Vincent (11:20:45) : You are not. It is all about the “new order” with which you will be blessed to live in. Enjoy it!
steven mosher (12:38:42):
What to do? Cut C02 or plan for a 82cm rise and establish building codes appropriately? Cut C02 which impacts everyone, or focus the costs on people who choose to live in low lands near water? Tax malibu.
Cutting CO2 wouldn’t work because the CO2 is not the real cause of warming or climate changes. We cannot set down the Sun, change the planet orbit, or change the mechanics of the oceans, etc., so the unique option is to plan, not for 0.82 m, but for 1.5 m and establish contingency programs before the mother nature acts.
If the current cooling continues or expands and sea levels continue to decrease, part of the adaption costs will be expanded dredging of navigation channels and harbor areas in all tidewater areas. Where would the dredge spoils be deposited? What would the price be for resultant environmental degradation? I believe these costs would amount to “serious money.”
It seems reasonable to plan and provide for what is actually occurring rather than what might happen when bumble bees learn that they cannot fly.
Nasif Nahle (13:02:08)
We will politely have to disagree about the connection between GHGs and Warming. All I am saying is that on the assumption of the connection we both know that the error bands will increase. So, all this talk about the width of the error bands is not exactly pertinent.
best regards
steve
LukeWarmer: Free the data, free the code, free the debate.
Alan the Brit –
“Thankfully, otherwise the poor little things will start to fall out of the sky! I always have a problem with a theoretical law that says something should not do what it actually does, & clealry very efficiently too!”
But this may be down to the fact that they’re not bright enough to understand the physics so they just go ahead and do it anyway.
Others who appear not to be bright enough to understand the figures just churn out claptrap instead. Give me the bumble bees any day!
“Also, since most Americans don’t know the difference between a centimeter and carrot, …”
Quick, what’s the difference between a caret and a carat?
(Gotcha!)
TIDES are a big part of all this. Anyone who has ever seen the sea or even watched movies about the sea will have noticed WAVES and also TIDES.
Have any of these modellers factored changing tides into their projections ? Tides are caused by water sloshing around the earth pulled by the moon and the sun. If we have a different volume of water sloshing around then the dynamics are totally changed – it’s not just the tide tables from 100 years ago uplifted by a number of inches. Or is it ?
Vincent, you have to read carefully. Don, knowingly or unknowningly, gave you the obvious answer. If you take ice from the FREEZER and put it back in the REFRIGERATOR, of course it will melt.
And a karat… ^ (<< caret)
Anthony: For those not wanting to cough up $18 to read the paper, here’s a link to the FREE supplementary information for Siddall et al (2009) “Paleo-constraints on future sea-level rise”. It helps clarify what Siddall et al did:
http://www.nature.com/ngeo/journal/v2/n8/extref/ngeo587-s1.pdf
Well, well. Isn’t this also good support for a natural climate variability acting on sea level? Isn’t this also good support for the notion that the climate has indeed been warmer than it is now? This may not be embraced so enthusiastically by ipcc.
So much for poor Jimmy’s twenty feet.
OT, but interesting: Forbush events confirm cosmoclimatology, Motl about a new report by Svensmark:
http://motls.blogspot.com/2009/07/forbush-events-confirm-cosmoclimatology.html
World sea level observation from satellite began only in 1992, and shows an seemingly linear rise as suggested by the top Figure. However, according to Japan Met Agency, the 100-year sea level data around Japan:
exhibits only a 20-year oscillation and absolutely NO long-range trend.
I’m a little late to the game, but are you sure they didn’t leave out a decimal point? As in “7 to 8.2 cm”?
Paddy (13:26:41) :
If the current cooling continues and sea levels drop, they had better pick up the pace on planned deeping/widening of Suez and Panama Canals, for starters.
They may soon find out that a deep-water port ain’t so deep anymore, and shallow ones become useless without clearing.
Yes, they had better make thier contingency plans. A decade or two can sneak up on lethargic beaurocrats.
Julie L (17:26:22) :
If that was the case I believe they may have stated “7.0” instead of “7”.
Nasif Nahle (13:02:08) :
steven mosher (12:38:42):
What to do? Cut C02 or plan for a 82cm rise and establish building codes appropriately? Cut C02 which impacts everyone, or focus the costs on people who choose to live in low lands near water? Tax malibu.
Cutting CO2 wouldn’t work because the CO2 is not the real cause of warming or climate changes. We cannot set down the Sun, change the planet orbit, or change the mechanics of the oceans, etc., so the unique option is to plan, not for 0.82 m, but for 1.5 m and establish contingency programs before the mother nature acts.
Nasif Nahle,
Forbush events confirm cosmoclimatology,
Motl about a new report by Svensmark:
Quote:
“An independent set of measurements has also shown that the amount of aerosols, i.e. potential nuclei of the new clouds, also decreases. All these “strength vs decrease” graphs display a lot of noise but the negative slopes are almost always significant at the 95% level (with one dataset being an exception, at 92%).
Each Forbush decrease can therefore warm up the Earth by the same temperature change as the effect of all carbon dioxide emitted by the mankind since the beginning of the Industrial Revolution. While you might think that such an effect is temporary and lasts a few weeks only, it is important to notice that similar variations in the solar activity, the solar magnetic field, and the galactic cosmic rays take place at many different conceivable frequencies, so there are almost certainly many effects whose impact on the temperature – through the clouds – is at least equal to the whole effect of man-made carbon dioxide”.
http://motls.blogspot.com/2009/07/forbush-events-confirm-cosmoclimatology.html
I do not understand how they get a base trend for sea level measurement. They can only compare sea level with the levels of the continents. I do understand that geologically continents typically move a few centimeters horizontally every year, and vertically of the order of a few millimeters. The trend seems suspiciously large compared with the satellite temperature record, where the variations in temperature are much larger than the trend in temperature.
peter_ga (18:45:30) :
“I do not understand how they get a base trend for sea level measurement. They can only compare sea level with the levels of the continents. I do understand that geologically continents typically move a few centimeters horizontally every year, and vertically of the order of a few millimeters.”
A good point, Peter, and one that isn’t factored into AGW as far as I can see. As Bob Dylan said:
“The carpet too is moving under you”.
Why don’t they just ask Jane?
Jane Lubchenco as head of NOAA, says “climate models are robust enough to predict wind patterns 100 years from now and help municipalities locate wind farms”.
Stupid on it’s face as no one would ever locate the wind farm where wind is not currently located, but the notion that she can predict anything 100 from now is complete BS.
Of course if she was talking about with the accuracy level of this 7-82 CM spread she’s probably got a “clear” prediction of where wind will be.
No doubt it’s a wide variation centered where it is today.
Remarkeble heh?
How is it that people making such asinine claims can rise to head an organization like NOAA?
So, Jane, what’s your robust guess on sea level rise?
A good point, Peter, and one that isn’t factored into AGW as far as I can see.
“Axe” Moerner said the IPCC systematically cherrypicked areas that were subsiding and avoided factoring in areas that were uplifting, in order to fudge their sea level numbers.
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.
evanmjones (20:54:38) :
“Axe” Moerner said the IPCC systematically cherrypicked areas that were subsiding and avoided factoring in areas that were uplifting, in order to fudge their sea level numbers.”
So they do factor some of it in – the bits that fit their models. Well, no surprises there then. Not only are they cherry picking, they are picking the good bits out of the cherries!
Ron de Haan (18:21:19):
…it is important to notice that similar variations in the solar activity, the solar magnetic field, and the galactic cosmic rays take place at many different conceivable frequencies, so there are almost certainly many effects whose impact on the temperature – through the clouds – is at least equal to the whole effect of man-made carbon dioxide”.
Forbush effect is unambiguous as a measurement of the intensity of solar radiation. The decrease of thermal neutrons during Forbush events, that is, when solar flares come up, determines the frequency and velocity of Rosby waves and the formation of cyclones.
For example, El Niño should be causing a warm and dry summer over our area; however, it would seem that we are in a neutral period, i.e. without ENSO. We have undergone some thunderstorms and the temperatures have not been higher than 38 ° C.
I think this is an effect of the absence of significant solar flares through the last two years, weakening the El Niño by giving place to more and stronger Forbush events.
I would like to know how the galactic thermal neutrons have increased in the lower stratosphere and the upper troposphere during the last two years.
The last year, under La Niña influence, we didn’t see cloudless days during the summer, which is quite unusual in our region. Obviously, the incoming galactic cosmic ray are increasing. I could be wrong, of course.