From the National Oceanography Centre, Southampton (UK)
New study documents the natural relationship between CO2 concentrations and sea level
By comparing reconstructions of atmospheric CO2 concentrations and sea level over the past 40 million years, researchers based at the National Oceanography Centre, Southampton have found that greenhouse gas concentrations similar to the present (almost 400 parts per million) were systematically associated with sea levels at least nine metres above current levels.
The study determined the ‘natural equilibrium’ sea level for CO2 concentrations ranging between ice-age values of 180 parts per million and ice-free values of more than 1,000 parts per million.
It takes many centuries for such an equilibrium to be reached, therefore whilst the study does not predict any sea level value for the coming century, it does illustrate what sea level might be expected if climate were stabilized at a certain CO2 level for several centuries.
Lead author Dr Gavin Foster, from Ocean and Earth Science at the University of Southampton which is based at the centre, said, “A specific case of interest is one in which CO2 levels are kept at 400 to 450 parts per million, because that is the requirement for the often mentioned target of a maximum of two degrees global warming.”
The researchers compiled more than two thousand pairs of CO2 and sea level data points, spanning critical periods within the last 40 million years. Some of these had climates warmer than present, some similar, and some colder. They also included periods during which global temperatures were increasing, as well as periods during which temperatures were decreasing.
“This way, we cover a wide variety of climate states, which puts us in the best position to detect systematic relationships and to have the potential for looking at future climate developments,” said co-author Professor Eelco Rohling, also from Ocean and Earth Science at the University of Southampton.
The researchers found that the natural relationship displays a strong rise in sea level for CO2 increase from 180 to 400 parts per million, peaking at CO2 levels close to present-day values, with sea level at 24 +7/-15 metres above the present, at 68 per cent confidence limits.
“This strong relationship reflects the climatic sensitivity of the great ice sheets of the ice ages,” said Dr Foster. “It continues above the present level because of the apparently similar sensitivity of the Greenland and West Antarctic ice sheets, plus possibly some coastal parts of East Antarctica.”
According to the study, sea level stays more or less constant for CO2 changes between 400 and 650 parts per million and it is only for CO2 levels above 650 parts per million that the researchers again saw a strong sea level response for a given CO2 change.
“This trend reflects the behaviour of the large East Antarctic ice sheet in response to climate changes at these very high CO2 levels. An ice-free planet, with sea level 65 metres above the present, occurred in the past when CO2 levels were around 1200 parts per million.”
Professor Rohling said, “Sea level rises to these high values will take many centuries, or even millennia, but the implications from the geological record are clear – for a future climate with maximum warming of about two degrees Centigrade, that is with CO2 stabilized at 400 to 450 parts per million, sea level is set to steadily rise for many centuries, towards its natural equilibrium position at around 24 +7/-15 metres, at 68 per cent confidence. In Intergovernmental Panel on Climate Change terms, this is a likely rise of at least nine metres above the present. Previous research indicates that such rises above present sea level may occur at rates of roughly one metre per century.”
Based on these results, which document how the Earth system has operated in the past, future stabilization of CO2 at 400-450 parts per million is unlikely to be sufficient to avoid a significant steady long-term sea level rise.
The study is published this week online ahead of print in Proceedings of the National Academy of Sciences of the United States of America (PNAS manuscript # 2012-16073R).
Rob Boyd , like so much of climate science this ‘confidence’ trick would lead to the work failing this is was student handing in an essay for an undergraduate science course. Is it really much to ask these ‘professional’ scientists to meet the standard they would expect of their own students ?
Words fail. Beyond stupid. We know temp causes sea level, temp causes CO2 level. Therefore sea level and CO2 are correlated. But CO2 doesn’t cause temp, so industrial CO2 output doesn’t change temp, so sea level doesn’t change due to CO2 output by human industry. How did they not notice this? Or should I ask “For how much MONEY did they not notice?”
I wonder what is “normal” sea level for pre-industrial CO2 levels according to this research.
http://twitter.com/afneil/status/286602191270199296
@Mike McMillan
“When sea levels rise and fall, that changes the volume of water available to dissolve the CO2. Colder water during ice ages can hold more gas, but there is much less of it. Interglacials have much more liquid water, but it’s warmer and can hold less per volume unit. I wonder if that trade off was taken into account.”
When considering the huge variations in solid and liquid water they should also consider that melting ice to water absorbs a lot of CO2. I see no mention of this. Consider the mass of CO2 absorbed by ice melt sufficient to raise the oceans by 50 meters! It is far more than the mass of CO2 in the atmosphere at 400 ppm. It would appear that their “outgassing” calculation is out by several hundred per cent. They need to find a heck of a lot more CO2 to have 70 m of sea level rise AND 1000 ppm AND equilibrium. When water warms and it outgasses CO2 it stops when the atmospheric concentration balances the vapour pressure. There seems to be a belief that the oceans can get to 20 ppm and the atmosphere to 1000, the seas vomiting out their adsorbed gases.
I don’t find the paper alarmist, I find it conceptually incomplete.
Good points above. The key this time would seem to be the ocean basins and the continental arrangement. http://scotese.com/lateeoc1.htm With the shift in the continents, the ocean circulation must have been significantly different through most of the last 40 million years.
We should keep in mind that, according to Scotese, the end of the Paleocene to the beginning of the Eocene was the warmest period in earth’s history. (Note that most modern mammals came about then–we like warm just like the reptiles and dinosaurs.) And the earth has generally cooled since then. There can be no surprise, nor informative information, in the subject study.
The most amazing invention is the Thermos.It keeps hot things hot and cold things cold.How does it know which is which?(dumb joke)
CO2 at greater atmos levels makes the Earths temp rise higher.
But at the termination of interglacial temp periods ,temps dive while CO2 levels continue to rise.
Then CO2 levels drop after 800 years.
The exact same levels that once caused warming ,now cause cooling.
How does CO2 know which is which?(dumb climate science)
I have a newbee question here so don’t be too harsh. If rising CO2 causes oceans to rise, and rising oceans also cause warming of the planet, and warming of the planet causes CO2 to rise, then how would the oceans ever recede once all the ice was gone?
This should be relevant. http://en.wikipedia.org/wiki/Antarctic_circumpolar_current#Formation
Well, according to the Colorado Sea Level Research Group, average rate of sea level rise during the last decade is 2.28 mm/year. However, glacial isostatic adjustment (GIA) correction of 0.3 mm/yr is included, so this rate is in fact only 2 mm/year (8 inch/century). The guys are mixing up sea level and ocean volume a bit, figures they show you are for a hypothetical sea level rise for an ocean put into a basin with constant volume, when in fact basin volume is increasing. Anyway, to have anything close to 1 m/century, this rate should go up four or fivefold eventually.
It can only be if the sea level response function is very slow, on the order of ~3 centuries. Which means a substantial sea level rise until the end of this century can be excluded with high confidence. And it does NOT make ANY sense to calculate further than that, because technology applied that far in the future will not even resemble today’s one (as today’s technology is a bit more advanced than that of the beginning of last century).
With the advent of self replicating molecular assemblers airborne carbon will become the prime raw material for everything we would choose to manufacture, which threatens with a serious carbon dioxide depletion. Not a good thing for a large scale technology to compete with plants for a resource.
Therefore preloading the atmosphere with this stuff as much as possible now, buys us time to replenish it (from limestone) later as needed. Which will have its own repercussions of course, ocean basification, caused by lime milk, the inevitable byproduct in an aqueous environment, being one. Fortunately we have the guts to decrase ocean pH somewhat in thoughtful preparation for such an eventuality.
Their conclusions are ass-backwards (hopefully only to ensure future funding).
Ice core data indicates:
1. Temperatures increase
2. Sea levels rise
3. Atmospheric CO2 levels increase
More conclusively, this study demonstrates CO2 equilibrates between the oceans and atmosphere. The rapid Holocene sea level rise has leveled off and the oceans have warmed. Atmospheric CO2 is currently low relative to the warm full oceans. The oceans are off gassing CO2 to bring the atmosphere back into equilibrium. Rising atmospheric CO2 helps warm the planet (slightly), and increases plant growth, which in turn increases habitable areas and biodiversity. Humans are helping the process slightly.
We’re just fleas on a dog. Climate change is a natural result of a process that will continue with or without us.
Des says:
January 3, 2013 at 3:30 am
So why is Alaska heading for an ice age and the Berring sea ice on the increase, is it the CO2?
http://www.dailymail.co.uk/news/article-2256188/What-global-warming-Alaska-headed-ice-age-scientists-report-states-steady-temperature-decline.html#ixzz2GuWMoKCT
The interesting part about this link is the comment section. A quick run down them (and there are over 200) shows almost no CAGW support with most support being toward AGW being a scam by rent seeking academics and politicians. The real message is getting out to the population despite the efforts of ‘the Team’ to the contrary. Once the politicians who are not making money from the scam see the way the majority are moving and break ranks things will become interesting.
ferd berple says:
January 3, 2013 at 4:21 am
According to the study, sea level stays more or less constant for CO2 changes between 400 and 650 parts per million
=========
Since we are at 400, this study says it is OK to go up to 650
>>>>>>>>>>>>>>>>>>
Pretty sad, isn’t it! After concluding that nothing much changes between 400 and 650, the blatant political pressure to maintain the narrative is on full display. They babble on about 450 and 2 degrees being some sort of safe limit even though their own results say something completely different. The IPCC position? That 450 and 2 degrees is the safe limit. In other words, do whatever research you want, report any results you get, but put in some verbiage about 450 and 2 degrees being a safe limit or you get no funding.
One wonders if the safe limit wording has to be approved in advance and they don’t even bother to read the rest of the report to see if it contradicts itself.
Based on these results, which document how the Earth system has operated in the past, future stabilization of CO2 at 400-450 parts per million is unlikely to be sufficient to avoid a significant steady long-term sea level rise.
Astonishingly Al Gorean logic. They assume the higher C02 levels somehow causes sea levels to rise. For Warmists, C02 really is a magical gas.
This would be great news if Ice core rings were annual rings.
George J. says:
January 3, 2013 at 6:31 am
I got a good laugh out of your question, George–not because it was silly at all, but because as a “newbee” you hit their contradiction right on the head. Welcome to WUWT.
davidmhoffer says:
January 3, 2013 at 7:26 am
And I’ve read where if we burned all available fossil fuels, atmospheric CO2 would get to ~600ppmv. So what’s the big deal? Where’s the beef? You are absolutely correct, Mr. Hoffer.
Sea level is currently near to its historical lows and should be expected to rise regardless of human actions. http://en.wikipedia.org/wiki/File:Phanerozoic_Sea_Level.png
It has been rising for several thousand years and the rate of increase has been reasonably steady. http://www.google.com/imgres?q=exxon+sea+level+curve&hl=en&safe=images&sa=X&tbo=d&biw=998&bih=560&tbm=isch&tbnid=0I4WcalAl1L57M:&imgrefurl=http://www.theoildrum.com/node/5129&docid=6dQsZMS3jWWNYM&imgurl=http://www.theoildrum.com/uploads/12/Post_Glacial_Sea_Level_present.jpg&w=692&h=476&ei=IqnlUI78AtP82gWV9oHwAw&zoom=1&iact=hc&vpx=685&vpy=192&dur=546&hovh=186&hovw=271&tx=158&ty=87&sig=114091406124388918232&page=1&tbnh=129&tbnw=193&start=0&ndsp=18&ved=1t:429,r:11,s:0,i:123
There is no reliable data to support the notion that the rate of increase will more than triple so than it will rise by 1 meter by 2100.
We have skewed the natural Carbon dioxide concentration without skewing (very much) the temperature. The natural relationships are between temperature and CO2 and and temperature and sea level. There is no physical relationship between CO2 and sea level.
The natural temperature corresponding to natural 400ppm CO2 is higher than today’s, so of course their metric will incorrectly predict sea level.
After so too many strike outs, the team has picked a winner, correlation between two symptoms of a warming planet. Here is a correlation that will stand the test of time, team cheerleaders go crazy.
Sort of like toenail and hair growth as a correlation for the health of the body.
Reblogged this on Standard Climate.
A good example of dumbing down. I find it hard to grasp that a researcher would risk losing whatever credibility they had in publishing this. Does it remind any that of K-12 gradeschool level work?
If the data can be trusted, this is a useful study, the convoluted and egregious attribution of sea levels to CO2 notwithstanding.
IF the data can be trusted.
But confidence in the verity of the data is always a problem with authors who evince the ideological bias that all too often adulterates data as part of the “War Against Climate Change”.
Moderators – do not post this comment, but rather please review my guest post at “Digging in the clay” blog (by Verity Jones) at http://diggingintheclay.wordpress.com/2012/12/31/the-minds-of-warmist-pundits/
because I would like the same to be a guest post at WUWT.
thanks – John Bell
Elevated sea levels result in large shallow seas. Shallow seas are great for life. The concentration of atmospheric CO2 is governed by the rate of eukaryote metabolism. Why does everyone forget in discussions regarding CO2, that the composition of the atmosphere is dynamically controlled by life, swamping out physical factors?