The University of Colorado Sea Level Research Group updated their data in July, but oddly enough the new data was only available through mid-April. In the past these updates have tended to bring the Mean Sea Level (MSL) up to date. That is the first oddity in this update, but it is also the most trivial. This update also reversed the isostatic adjustment that they put in earlier this year. I covered the isostatic adjustment here and the previous update here. In essence they intentionally inserted a 0.25 mm/yr trend into the MSL. The result of such a ‘update’ is that it maintained the status quo 3.1 mm/yr that they have been advocating. That trend has ceased over the past 5 years.
The latest update eliminated the isostatic adjustment, but added in the following new one:
Replaced classical GDR Inverted Barometer correction on all missions with improved AVISO Dynamic Atmopshere Correction (DAC) that combines MOG2D high frequency and inverted barometer low frequency signals (Pascual et al., 2008)
They have also made previous versions of the data unavailable. Fortunately I am a pack rat and have all the original data. If the isostatic adjustment was overboard, this one is really over the top. Here is what they present for the seasonal seasons retained data which is what I will use for this article.
This chart shows that there is a 3.2 mm/yr trend in the MSL since 1993.
The first obvious difference in this data from previous data is a shift of ~10 mm for the data from 1993. There is absolutely no reason to shift data that is almost 20 years old, but they did. This chart shows the data that was available 1 year ago and the latest data. Both of them retain the seasonal signal.
The upward shift is obvious and there is no reason for such a shift upward. The only impact such a shift has, is that it gives the appearance that the sea level is higher. They can claim that the mean sea level is up to 50 mm instead of 35 mm. A direct shift would not change the trend, but what they did was no simple shift. There is also a linear trend in the difference of data that is years old. The big change starts in 2004.
The direct change is very messy and not as useful, so what I did was apply a simple 21 point moving average for both sets of data. The result is the following chart.
The gap between the two grows as time goes forward. The latest revision of the data just didn’t insert a one time shift, but a growing shift over time. Here is the difference between the two versions of what should be nearly identical data.
The difference for the available data in 2010 is 14.66 mm difference. What started out as a 10mm shift is most recently an ~15mm shift in the most recent MSL. The trend in the difference is 0.18 mm/yr for the smoothed data. The funny thing is, even with all of this monkey business, the sea level trend for the past few years is dropping. Even with an added trend, a step function shift in 2004 and the overall shift since 1993, the trend for the past 5 years is only 2.0 mm/yr.
Clearly, there is some monkey business in progress with the MSL. I decided to take my analysis a little deeper still. Since I know the trend that they are inserting into the MSL, I can revise the most up-to-date data back to the original method. The straight line in this chart is what I applied to the current version so I could update the original version of the data.
My only real concern is that this is the smoothed difference, but based on the noise level in both sets of data, I don’t feel that anything else would be suitable. When I update only the data from Aug 2010 – April 2011 and display the original data, the result is fascinating.
This might explain why they don’t want to show data using the original methodology. If the sea level stopped rising for 5 years while CO2 levels are nearly 400 ppm, the theory of global warming might lose even more steam.
I also found a new way to really compare the yearly sea level. The only portion of the following chart that uses the reconstructed data is from Aug 2010 to April 2011. The rest of it is the original data.
2011 is on track to have the same sea level as 2008. Even though the MSL in 2010 was only a smidgen higher than 2009, 2011 is very likely to be lower than both of them. Of course if they shift the trend upward even further then they might manage to hide it a little longer, but the sea levels are no longer rising.
I also went back and compared 2011 to Jan-April of 2000-2010 and on average the Jan-April average is 3.2 mm lower than the yearly average. If 2011 were to increase by 3.2 mm then the yearly average would be 28mm, which is still 3mm lower than 2009 and 2010. 2011 is tracking to finish 3mm lower than the previous two years. If they manage to insert another shift, it will have to be enormous, and I will catch it.
A pause in the sea level rising does not mean global warming is not real. The problem is that instead of dealing with the facts and the data in a straightforward manner, they tinker and mess with the data so that it always fits with their conclusions. When I find so much upward revision in the MSL, I lose trust in their conclusions. That they are altering the data to make the MSL show an increase is so obvious that it cannot be denied. That is the problem with what they are doing.