Guest post by Steven Goddard
One of the most cited “proofs” of global warming is that sea level is rising, as can be seen in the graph below.
http://sealevel.colorado.edu/current/sl_noib_global_sm.jpg
This is a nonsensical argument, because sea level would be rising even if temperatures were going down, as they have been since 2002. The main reason why sea level rises is because the equilibrium between glacial ice and temperature is out of balance, and has been for the last 20,000 years.
http://www.globalwarmingart.com/wiki/Image:Post-Glacial_Sea_Level_png
Note that from 15,000 years ago to 8,000 years ago, sea level rose about 14mm/year – which is more than four times faster than the current rise rate of 3.3mm/year, as reported by the University of Colorado. During the last ice age, sea level was so low that people were able to walk from Siberia to Alaska across the Bering Strait. One of the more stunning pieces of evidence of this is the remarkable similarity of appearance and culture between the indigenous peoples of Eastern Siberia and North America.
In 2002, the BBC reported that a submerged city was found off the coast of India, 36 meters below sea level. This was long before the Hummer or coal fired power plant was invented. It is quite likely that low lying coastal areas will continue to get submerged, just as they have been for the last 20,000 years. During the last ice age, thick glaciers covered all of Canada and several states in the US, as well as all of Northern Europe. As that ice melts, the water flows into the ocean and raises sea level.
http://uk.encarta.msn.com/media_461527006/ice_extent_during_the_last_ice_age.html
The IPCC has stated that sea level may rise two meters this century, which would be a rate of 22mm/year, nearly seven times faster than current rates. Do we see such an acceleration? The simple answer is no. There has been very little change in sea level rise rates over the last 100 years, certainly nothing close to the immediate 7X acceleration which would be required to hit 2 meters.
Sea level is rising, and the abuse of this information is one of the most flagrantly clueless mantras of the alarmist community.
Even if we returned to a green utopian age, sea level would continue to rise at about the same rate – just as has done since the last glacial maximum.
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Steven,
“State something specific or cut the ad hominem attacks.”
My criticism is very much ad verecundiam – and your response is to accuse me of ad hominem attacks! I’d rather you responded to the very specific point I’ve made:
Where is the evidence in the plots you present that the trend in the last seven thousand years is much more than 0.6 mm/year, way below the current trend of 3.3 mm/year?
Tom P,
The graph you linked shows periods when sea level rose quickly and slowly over the last 8,000 years. Did global warming cause sea level to rise 15 meters from 8,000 to 7,000 years ago? Sea level rose quickly from 3,000 to 2,000 years ago. Was that caused by Hummers? From 1900 to 1950, sea level rose at 2mm/year – similar to current levels, yet that was before most of the rise in CO2 levels.
But the really astonishing thing is that you are willing to accept the IPCC claims of 10-20cm/year, yet you quibble over noise in the 1-3mm range. That is why I describe the thought process as “astonishingly clueless.”
You said the data is posted “can’t be trusted.” Which data? But you trust the IPCC when they claim 2,000mm/century? Give me a break.
and “IPCC claims of 10-20mm/year” instead of “IPCC claims of 10-20cm/year”
Sea level in Hawaii has hardly risen at all since 1980, and since 1950 only at 1.5mm.year.
http://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?stnid=1611400
“I have B.S. in Geology and many years professional experience.” I think it’s reasonable to expect something a bit more specific.
“Are you trying to suggest that sea level has not risen nearly continuously since the peak of the last ice? Good luck with that theory” You’re trying to put words into my mouth. My unanswered criticism is that you are drawing conclusions using only half a cycle of data. As far as the limited data you present here, I see an uncontroversial sea level increase that came to practical end somewhere around 6000 years ago.
“My advice is don’t write a paper on it.” Apparently you take your own advice to heart.
Steven,
The rise up to 7,000 years ago was obviously the last part of the melt from the previous ice age caused by naturally induced global warming. From 7,000 onwards there is in comparison no rapid increase. The trend line from 3,000 to 2,000 years ago is about 1mm/year, the trend to present is 0mm/year, both less than the current 3.3mm/year. I’m actually rather surprised you’re paying any attention to the trend line, which you previously dismissed.
Where have I stated I’m willing to accept IPCC claims of 10-20cm/year, if indeed such claims have ever been made? I am concentrating solely on the data you have presented, with a current trend of 3.3 mm/year. Why do you now consider 3.3mm/year as noise? It certainly seems a clear trend from the first plot you presented, and indeed you presented it as such in your original posting:
“Note that from 15,000 years ago to 8,000 years ago, sea level rose about 14mm/year – which is more than four times faster than the current rise rate of 3.3mm/year, as reported by the University of Colorado.”
Finally, I most certainly didn’t say the data couldn’t be trusted – that was what Tallbloke implied when he wrote:
“Which do you trust more – proxy reconstructions or concrete archeological evidence?”
This is a false choice – I have no reason to doubt either as they are consistent with each other and imply the sea level was rising over the last 7,000 years far slower than the last 100 years.
Tom P,
The sea level rise rates have varied considerably over the last 7,000 years – sometimes fast and sometimes slow – just as the global temperature has varied greatly over that time. There is no valid reason to compare the 7,000 average vs a time frame as short as 100 years, as there is a significant degree of variability shown during the 7,000 year period.
Given that rates haven’t changed much from the first half of the twentieth century, it is going to be very difficult for you to construct an argument that CO2 has anything to do with the current rise rates.
So why aren’t you criticizing the IPCC for their claims?
Global warming hero Dr. James Hansen said-
As an example, let us say that ice sheet melting adds 1 centimetre to sea level for the decade 2005 to 2015, and that this doubles each decade until the West Antarctic ice sheet is largely depleted. This would yield a rise in sea level of more than 5 metres by 2095.
http://www.newscientist.com/article/mg19526141.600
That claim is more than 55mm/year, coming from the world’s most respected climatologist.
Ben Lawson,
The article uses graphs covering three time frames. 20,000 years, 100 years and 15 years. They all show that Hansen’s claims of 5mm by 2095 (55mm/year) are absurd, as is your claim that I am only considering “half a cycle.” This article is about the interglacial, which started 15,000 or so years ago. I have considered the entire period in some detail.
Steven,
You state: “There is no valid reason to compare the 7,000 average vs a time frame as short as 100 years.”
But that is EXACTLY what you did in your original post:
“Note that from 15,000 years ago to 8,000 years ago, sea level rose about 14mm/year – which is more than four times faster than the current rise rate of 3.3mm/year, as reported by the University of Colorado.”
All I did was derive the most recent trend for the last 7,000 years of 0.4+/-0.4 mm a year. Why is the trend from 15,000 to 8,000 years ago valid, while the trend from 7,000 to present invalid?
Smokey,
US tidal gauge figures are here,
http://upload.wikimedia.org/wikipedia/en/7/7f/U._S._Sea_Level_Trends_1900-2003.gif
and don’t support your view that on average the sea level around the US isn’t rising.
Of course the clear trend of the global satellite data is the basis for Steven’s post. Why do you reject the data he presented?
There’s actually been plenty of coverage about rising sea levels in the press – I’m surprised you missed it.
Tom P,
Who to believe, the NOAA, or Wikipedia?
The gif above comes from the NOAA. Complain to them if you think it’s inaccurate. Also, I don’t reject Steven Goddard’s data. Take your best guess about what I meant by “currently.”
In either case, it’s a silly argument. Any sea level rise is well within normal, historical parameters since the last Ice Age, and can not be attributed to AGW unless the well established theory of natural climate change is falsified.
So let’s just cut to the chase: are you claiming that a rise in CO2 causes a rise in the sea level?
Tom P,
Because 2 mm/year is within the range of variability for the last 7,000 years, but much lower than that from the period from 15,000 to 7,000 years ago.
Again, why are you quibbling over 1-2mm when the IPCC claims are an order of magnitude higher?
Smokey,
The sea level is currently not rising here in Texas. And the trends are between one and two feet per year rise per one hundred years. Might not be a bad idea for all you east and west coasters to move on down here to Texas. You may not know it, but we still have the right to life, liberty and the pursuit of happiness down here. Besides real estate is pretty cheap right now and we could use all the sane people we can get.
No, I don’t belong to the chamber of commerce. I just feel that the more producers we have down here the better off we’ll be. Oh yeah no income tax down here either.
Mike Bryant
Oops i meant one to two feet per one hundred years…
Mike Bryant,
How are the fire ants these days? Texas is a great state with probably the most sane populace, but 20 years ago the kids couldn’t go to the lake without getting attacked, even swimming 100 feet offshore. Has that gotten better?
Smokey,
“Who to believe, the NOAA, or Wikipedia?”
The plots I gave came originated from a dataset maintained at the UK Proudman Oceanographic Laboratory. It’s very difficult to quantify the NOAA data in the animations you linked to. The trend data from NOAA is clearly presented here:
http://tidesandcurrents.noaa.gov/sltrends/sltrends.shtml and is in good agreement with the POL data, probably as they’re based on the same tidal-gauge measurements. I have no reason to doubt either of these datasets.
“Any sea level rise is well within normal, historical parameters since the last Ice Age.”
Certainly not according to the data Steven presented. The trend for the last 7000 years has been 0.4+/-0.4 mm/year. The current rate of 3.3+/-0.4 mm/year is indeed far outside the trend for the last 7000 years.
Jack Simmons (01:31:34) : Said,
“Today Obama announced the saving of 25 jobs in Columbus, Ohio. As we have spent some three trillion dollars on various bailouts, that works out to about $120 billion per job.”
Failing, of course to credit the new jobs generated in the Columbus Doughnut Industry! Give credit where credit is due.
The beach I hang out at is rising due to isostatic rebound from the last ice age.
You’d think that sea level was lowering if you did not know any better.
Ben
This file has reconstructed sea level data for about 50 places around the world over the last 14,000 years (most are only about 7,000 years).
The first column is Years Before Present, and the third column is the relative sea level rise over the period.
This data has NOT been corrected for glacial rebound, uplift or land subsidence but it should tell you that it is an absolute must to take this into account for every single tide gauge around the world (inlcuding very short timelines). There are some huge differences in the rates based on this (tens of metres over just a few thousand years).
The data shows most areas have had rising sea levels over the past 1,000 to 2,000 years as well as the 120M rise since the ice age ended.
In addition, the glaciers in northern Canada and Greenland did not melt completely until about 3,500 years ago so there was still a glacial melt contribution up to this date.
Tuktoyaktuk, NWT holds the record for -42M sea level change/reduction over the last 8,000 years (glacial rebound that is).
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/paleocean/relative_sea_level/sealevel.dat
Tom P,
You are playing games with the data. For the last eight years, temperatures have been declining at a rate of several degrees per century. Does that prove global cooling using your logic? Through the last 7,000 years, there have been centuries when sea level rose faster than the average and slower. For the last three years, sea level has hardly changed at all.
http://sealevel.colorado.edu/current/sl_noib_global_sm.jpg
The rate for the last 15 years (2.4 mm/century) is within the normal variation for the last 7,000 years, and much less than IPCC claims of 22mm/year and Hansen claims of 55mm/year.
BTW – the map you linked showed higher raise rates along the Gulf Coast, where the effect is due to subsidence caused by subsurface pumping.
From a State of New Jersey sea level study-
When the data from all New Jersey sites are examined together, a linear regression from at least 7500 yBP to present provides an excellent fit, suggesting a constant rate of sea level rise for approximately the past 7500 years.
http://www.state.nj.us/dep/dsr/climate/holocene.pdf
Comparison of our sea-level data with the Barbados/Western North
Atlantic reef sea-level record of Fairbanks (1989) shows (Fig. 5) that the reef data
indicate a major decrease in rate from 12 mm/y to ~ 2 mm/y between 7000 and 8000 yBP. Data from NJ (all sources) and the reefs are consistent with a constant rate of rise
http://www.state.nj.us/dep/dsr/climate/holocene.pdf
Interesting as discussions of sea level rate rises are, the thing to bear in mind is that sea level changes lag climate changes by long periods, and it is unlikely we are seeing a substantial contribution from recent warming (however much warming occured).
There are two main contributions to sea level rises.
1. Thermal expansion from warmer temperatures – about %70 of the total. While thermal expansion is an immediate result of water warming, how long it takes for seawaters to warm takes us into the warming in the pipeline discussion. Suffice it to say, average sea water temperature changes lag atmospheric temperature changes by decades.
2. Icesheet and Glacier melt. – somewhat less than %30 of the total. No one has an accurate measure of the sea level change from ice melt and it’s little more than a guess. Anyway, glacier and icesheet melt lags atmospheric temperatures changes by long perionds – hundreds to thousands of years. The most important contribution to current icesheet melting (however much is occuring) is likely the warming up to the Holocene Optimum 6,000 or so years ago.
The frequent claims of x amount of sea level rise this century if icesheet y melts are nonsense because of the huge thermal inertia of the ice volumes involved. Even if temperatures warmed dramatically it would take many hundreds if not thousands of years for these ice volumes to melt. And hence any sea level rise would take the same amount of time.
Which BTW is why you see so many reports of glaciers accelerating. The only plausible way of melting the icesheets and glaciers is to transport them to somewhere warmer and spread them out over a much larger area.
Philip_B,
Interesting comments you made about sea level rise. You say that 70% of sea level rise is due to thermal expansion? That would imply that nearly 300 feet of the 400 feet of sea level rise since the last ice age was due to thermal expansion. I don’t think that is going to fly, since global temperatures have been going down for the last 8,000 years and are about the same as they were 10,000 years ago – when sea level was 200 feet lower.
http://commons.wikimedia.org/wiki/File:Holocene_Temperature_Variations.png
You might also remember that a basic tenet of global warming is polar amplification, where the polar ice caps are supposed to heat up much faster than the rest of the earth.
What I am trying to do is to get people to think for themselves, rather than repeat AGW catchphrases.
Fire ants are still mean… But they are only in the water after a hard rain. They don’t attack unless you step on the antpile… More of an annoyance than anything else.