New predictions for sea level rise

Jul 27, 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 - 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 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 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 , 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. END

More information: Constraints on future from past reconstructions. Mark Siddall, Thomas F. Stocker and Peter U. Clark. Nature Geoscience: http://dx.doi.org/10.1038/NGEO587 .

Source: University of Bristol (news : web)

Explore further: Sea-level surge at Antarctica linked to icesheet loss

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3432682
2.2 / 5 (13) Jul 27, 2009
Warming depends on how much positive feedback from CO2 there is upon water vapor and clouds. Current UN IPCC models use positive feedback factors of about 3 to 6.

I'm betting
1. CO2 has a small effect, half of which has already happened
2. There is no positive feedback, there is negative feedback.
3. We will discover other causes of warming

We should cool our jets for a couple of decades to continue the research in the infant field of long-range climate, and to see if temperatures resume rising.
mikiwud
1.8 / 5 (10) Jul 28, 2009
Comment by prof Roger Pielke Jnr. on his website says it all.
Yawn
From Nature Geoscience comes this less-than-titillating abstract:


Nothing to see here, move along.
Posted by Roger Pielke, Jr. at 7/26/2009 08:43:00 PM
ArtflDgr
1.8 / 5 (10) Jul 28, 2009
I shall find my self bounded in a nutshell and call myself a king of infinite space.

whoops... guys missed the fad, been cooling for a decade... no sunspots... they now are going to look like those throwback 60s hippies, or 80s punks wandering aroudn where they used to exist and basically come late to the party.

as the global warmers turned into the climate changers, they have not realized that they have signed on to the ideas and goals of a collective, and completely poisoned their work.

in 10 more years when the cooling cycle is a done deal till next warming cycle, ALL these scientists will have been proved to be shoddy scientists.

and science itself will take a huge hit because they went out to find ideological answers, rather than empirical ones.

they ended up like the lysenkoists...

working hard on a science that doesnt exist... now they are so wedded to their bad choices the only way out is to get others to believe lies, rather than accept that they screwed their lives and careers by signing on to a fad bandwagon and a unfalsefiable ideology.
lengould100
3 / 5 (8) Jul 29, 2009
"been cooling for a decade" -- flat wrong. You're repeating a misconception based on a carefully crafted statement designed to mislead people by a fanatic denier. The statement was "The year 2007 has had an average temperature which is the coldest this century, and cooler than ten years ago".







When you analyse it, you find that the statement is true but says nothing. In fact EVERY YEAR except 2007 in this young 21st century has been warmer than ANY year in the 20th century EXCEPT for 2007 which was just slightly cooler than the one year 1998.

lengould100
3 / 5 (6) Jul 29, 2009
http://data.giss..../graphs/ NASA Global average Temperature data.

http://data.giss..../graphs/Fig.A2.gif
ArtflDgr
2.6 / 5 (10) Jul 29, 2009
lengould

i am old enough to remember hanson when he was pushign ice ages... (read newsweek from 1975).


hanson has been caugt several times cooking the numbers in the ipcc data...

your wrong lengould... and quoting a group that has lf late been acting more like soviet pravda than brittanica is not really a way to debate. if your source is crappy, then your debate position is crappy. and hansen is a crappy source..

my family was in russia when lysenkos biology was similar. you would have been a lysenkoist... but today we know what about that russian genetics?

collectivists are not truth tellers, they are end justifies the measn people, and so they lie. if they are wiling to steal other peoples earned property, then they are willign to lie. (or havnet you notived the most corruption and worst budgets are inthe most neo liberal states?)


www.leif.org/EOS/...-pip.pdf
Lindzen's and Choi's paper shows that the combination "reality and models" is logically inconsistent, so one can derive anything - both correct and incorrect statements - from such an inconsistent set of axioms. Whatever you derive is therefore inevitably untrustworthy.


by the way lengould can you tell me how they corrected for the rounding errors injected in each iteration using binary math?






GrayMouser
2.1 / 5 (7) Jul 31, 2009
"been cooling for a decade" -- flat wrong. You're repeating a misconception based on a carefully crafted statement designed to mislead people by a fanatic denier. The statement was "The year 2007 has had an average temperature which is the coldest this century, and cooler than ten years ago".

When you analyse it, you find that the statement is true but says nothing. In fact EVERY YEAR except 2007 in this young 21st century has been warmer than ANY year in the 20th century EXCEPT for 2007 which was just slightly cooler than the one year 1998.

Your guilty of what you accuse ArtflDgr of.

If you ignore the prognostication of the computer models you are left with 2 sources of data: satellite and the historical climate network.

The satellite data has consistently refuted global warming forecasts. From the satellite date we have lost most, if not all, of the temperature increases of the 20th century.

The HCN has some problems:
1) a large number of measuring sites have dropped out of the network in the last decade or two.
2) an unknown number of sites have moved over the last 100 years, some time multiple times, which ruin their baselines.
3) of the HCN network surveyed in the US 90% of them are no longer in locations that meet the requirements for NOAA gound stations.
4) government employees apply "corrections" to the HCN measurements regardless of whether they are correctly or incorrectly sited and the corrections have been oddly uniform in adding a bias to the data (and they are reluctant to release the raw data.)
ArtflDgr
2.3 / 5 (6) Jul 31, 2009
thank you graymouser (and i loved the stories of said mouser... :) )
brianweymes
2.3 / 5 (4) Jul 31, 2009
ArtflDgr I am also old enough to remember the 70's, when newspapers had no idea what climate science was (it was stil a baby back then) and had the unluck to listen to a couple on the fringe.

In the real world though, Hansen never predicted a future ice age. http://www.columb...ther.pdf
Velanarris
5 / 5 (3) Jul 31, 2009
ArtflDgr I am also old enough to remember the 70's, when newspapers had no idea what climate science was (it was stil a baby back then) and had the unluck to listen to a couple on the fringe.

In the real world though, Hansen never predicted a future ice age. http://www.columb...ther.pdf

Climate science is still immature, and it's funny that the "couple on the fringe" are now "mainstream scientific geniuses".

Especially when Hansen was the modeler for the papers that launched the Ice age forecasts. (Rasool 1971), (Budyko, 1967), (Ramanathan, 1975)
And uses the very same modeling basis for his AGW hypothesis.
GrayMouser
2.6 / 5 (5) Aug 02, 2009
ArtflDgr I am also old enough to remember the 70's, when newspapers had no idea what climate science was (it was stil a baby back then) and had the unluck to listen to a couple on the fringe.

In the real world though, Hansen never predicted a future ice age. http://www.columb...ther.pdf

While using Hansen's model doesn't make Hansen a predictor of an ice age (though he was a research associate at the time and may have had a significant role in the generating the prediction) it does show that computer models are not generators of fact.
ArtflDgr
1 / 5 (3) Aug 31, 2009
NASA Scientists Predicted a New Ice Age in 1971

NASA scientist James E. Hansen, who has publicly criticized the Bush administration for dragging its feet on climate change and labeled skeptics of man-made global warming as distracting "court jesters," appears in a 1971 Washington Post article that warns of an impending ice age within 50 years.

----

The scientist was S.I. Rasool, a colleague of Mr. Hansen's at the National Aeronautics and Space Administration. The article goes on to say that Mr. Rasool came to his chilling conclusions by resorting in part to a new computer program developed by Mr. Hansen that studied clouds above Venus.

The 1971 article, discovered this week by Washington resident John Lockwood while he was conducting related research at the Library of Congress, says that "in the next 50 years" - or by 2021 - fossil-fuel dust injected by man into the atmosphere "could screen out so much sunlight that the average temperature could drop by six degrees," resulting in a buildup of "new glaciers that could eventually cover huge areas."


there is a lot more...
but we forgot what happened when i was a young man...