Sea level rise rate leads global temperature?

October 19, 2009

I have noticed a surprising (to me) correlation between the global average sea level and the global temperature.  It appears to me that the sea level rise rate leads the temperature.  The following plot shows sea level rise rate from the Jason and TOPEX satellites (from the University of Colorado web site) and the global temperature (from UAH) with a 1.1 year offset added to the temperature data to align it with the sea level rise data. 


This data shows that the sea level rise rate leads the temperature – just the opposite of what I expected.  Perhaps this is already obvious to other people and there is some simple, well understood explanation.  I don’t know.

I started out looking at this data for an entirely different reason: to show that in today’s world a temperature increase followed by constant (or nearly constant) temperature will result in an initial sea level rise rate increase, and a subsequent dropping sea level rise rate.  In other words, the equilibrium time is short.  This is in contrast to Stefan Rahmstorf’s claim that a temperature increase, followed by a constant temperature will result in increased sea level rise rate that will last a millenium.   I have been critical of Rahmstorf’s claim for over two years.  I will deal more with this issue in a later post.

Here is how the data for this post is reduced:

First, here is the raw sea level data from CU and temperature data from UAH

Sea level and T

Next, both sets of data were smoothed using a 1 year FWHM Gaussian filter  and the sea level data was interpolated to 1 month intervals…

Sea level and T filtered and interpolated

Then the sea level rise rate (mm/year)  (time derivative of the sea level) was calculated…

Sea level rise rate and T filtered and interpolated

The first thing that jumps out is that the temperature peak at 1998 came about one year after the corresponding sea level rise peak,  and three major temperature troughs occur about one year after sea level rise rate troughs.


  1. That’s an extremely interesting – and surprising – observation. Still, I don’t think that it would impossible. After all, the oceans have a huge heat capacity. The randomly coming “packages” of heat stored in the oceans are migrating to the surface, and then affect the atmosphere. At least the wiggles on the graph could be determined by such things – even though temperature changes at other frequencies could be dominated by other drivers. Who knows.

    However, I guess that this inverse lag will have a simpler explanation. How is the “annual sea level rise rate” exactly measured and what is the date where they attribute it?

    I kind of feel that the rise is computed from year-on-year values, and the difference from January 2008 and January 2009 is attributed to January 2008 in the graph – which would explain why this function of time is “ahead” of temperature because the average moment where the sea level rise occurs is in mid 2008 (but it is already drawn above January 2008).

    That could explain half a year of a lag which doesn’t seem to be a perfect explanation so far… So it would be nice to see the right answer.

    • Dear Lubos Motl,

      It is very kind of you to comment.

      I got the “sea level” data from CU. But I calculated the “rise rate” myself after smoothing the sea level data and interpolating to one month increments.

      The original CU data was in about 1/30 of a year increments. I interpolated it to the lower resolution of 1/12 of a year because my original intention was to match it up with the UAH temparature data, which is monthly.

      Delta(T) is always one month for each Delta(Z)/Delta(T) (i.e. rise rate) data point. So, the rise rates here are not “computed from year-on-year values.”

      I am looking closer at this. Any further comments would be appreciated.

      Best Regards,

  2. Steve Forbes touched on the sea levels rising around NYC about one foot last night on Huckabee. His thoughts were- we should prepare for what is happening not what might happen 150 years from now. Crap n Trade and the Climate Treaty w/ U.N. are holding the U.S. for ransom.

  3. Hi Tom, I suspect we are looking at ENSO effect mainly, which distorts the sea lens with apparent sea level rise. The heat accumulated in the upper few meters of the sea during El Nino reduced cloud levels and diminished trade winds is transferred to the atmosphere over time, an affect apparent in all the main temperature time series, not just UAH MSU: see http://www.junkscience.com/Greenhouse/ElNino.gif.

    I don’t think you have discovered any mysterious source of sub-sea heating 😉


  4. I’m not an expert or anything, but could phase change have anything to do with this? I.E Heat of Fusion, the required energy to melt ice to liquid. Kinda like a pot of water can never go above 212f until its turned to vapor, and can then increase in temp again.

    So what I’m getting at, is (assuming solar output causes this) that slight increase in energy goes mostly into melting the ice and raising sea-levels, and the atmospheric temps play catchup as the ice cover lessens and more energy finally goes into raising the air temps..

  5. Just one observation: the huge drop in sea-level rise rate of 1994 does not fit (temperature rises during that period). Seems we need more observations that 10years. Is there longer dated data?

    • David,

      Thank you for your comment.

      I used a gaussian smoothing technique on the sea level rise data. This can cause a distortion of the start and end of time series data. The first and last six months are suspect since I used a one year FWHM. That is why I colored the first and last six months of the sea level and sea level rise data gray, as opposed to the rest of the data which was colored blue. Perhaps I should have chosen better contrasting colors to better make this distinction.

      best regards,

  6. Your observation are very interesting and explain why the MET Office in the UK does such a poor job of seasonal weather forecasting. The focus on CO2 has the atmoshere driving weather and climate. However, if you regularly check out the seasonal forecasts from meteorologists like Joe D’Aleo of Intellicast, their seasonal forecast is aways based on how the oceans are set up. In other words, you’ve validated what they do, the oceans drive climate. Until the the AGW global circulation model climate wizards realize this, their predictive skills will be lacking.

  7. I highly enjoyed reading your post, keep up making such interesting articles.

  8. It looks like you are a real expert. Did ya study about the theme? lawl

    • Dear JatStraikarFan,


      Best Regards,

  9. This shows that the small variations in the annual sea-level rise rate correlate reasonably with the global temperature variations, but intriguingly lead them by just over a year. If the variation of rise rate is proportional to variation of sea temperature (and how else can you explain it?), then sea temperature must be governing atmospheric temperature, not the other way around. Sounds reasonable if you consider that most of the globe’s surface is water taking a whole season to warm/cool depending on how much of the sun’s energy is trapped by the ocean each year. Obviously, the air rapidly circulates around the globe so its average temperature will be governed mainly by the slowly reacting ocean surface temperature and much less by the rapid land temperature changes. The consensus view as I understand it maintains that greehouse gases heat the atmosphere directly and are the main cause of warming. But wouldn’t this mean sea temperature should lag rather than lead the mean atmospheric temperature as it appears to do. This seems quite a simple but significant point, or have I missed something?

    • Dear HawthornDweller,

      You have not missed something. It does seem “simple and significant.”

      I do not have an explanation.

      Best Regards

  10. CLIMATEGATE HOAX. it makes sense now that we know man made global warming is a hoax

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