UPDATE: I received a reply tonight from Pieter Tans, who is the manager for the MLO data, it is another error in presenting the data, similar to what happened with GISS in October, a monthly data value was carried over. In this case, November to December. – Anthony
From: “Pieter Tans” <Pieter.Tans@xxxxx.xxx>
Sent: Sunday, January 11, 2009 7:24 PM
To: “Anthony Watts ” <email@example.com>
Subject: Re: Questions on currently posted 2008 MLO data
> The posted December figure is an error. It will probably be fixed
> tomorrow. The error does not appear on my computer. Our web site is
> run by a separate server dedicated to communicate outside the firewall.
> At this moment I don’t know why it repeated the November value for December.
> Sorry about this mishap.
> Pieter Tans
The year end CO2 data for the Mauna Loa Observatory is out, and it shows that the trend of Co2 increase has slowed. This year saw the lowest increase in the annual mean growth rate ever in the Mauna Loa Co2 Record: 0.24 parts per million.
Whether this is real, a data error, or something else remains to be seen. As we’ve learned previously, the Mauna Loa record is not infallible and can be adjusted post facto. To MLO’s credit, they have been responsive to queries from myself and others, and have pledged to make improvements to the process. They now have a change log, but there is no mention of the December 2008 data in it.
Here is the graph recently posted by MLO. Notice the two dips in 2008.
The blue line represents the mean value, while the red line is the monthly values. Note that the red line shows seasonal variance related to earth’s own processes that emit and absorb CO2. In the case of the 2008 value of 0.24 ppm/yr it comes on the heels of 2007’s strong year of 2.14 ppm/yr which by itself isn’t that remarkable, being only the seventh highest year in the record.
What is interesting though is the correlation of lower CO2 to a cooler 2008, suggesting that natural mechanisms, particularly the oceans, played a role in the the lower Co2 value for 2008. There are also other likely drivers of this change. For the layman reader, this is essentially the “soda pop effect”. As anyone knows, warm soda pop tends to ‘fizz’ vigorously, while cold soda pop is more tame. This is because colder water can absorb more Co2 than warmer water, and warmer water releases it more easily, especially when agitated. Lesson here, and citing from experience; don’t leave a 12 pack of Coke in your car on a hot summer day. ;-)
Here is a graph of Carbon Dioxide solubility in water versus temperature:
Here is the entire annual mean growth rate MLO data set:
Here a copy of the CO2 values of the last three months:
Source data from MLO is here
Note the identical months of November and December. It could be a GISS October2008 kind of carryover error, it could also be real. The global values for December 2008 are not yet out. Mauna Loa is only one of many CO2 reporting stations.
If the data is real, there is a dead stop in the monthly numbers, which results, when seasonally corrected, in a considerable decrease, not seen in previous Decembers through the entire record.
As MLO points out:
“The last year of data are still preliminary, pending recalibrations of reference gases and other quality control checks.”
As I previously mentioned, some reasons could be cooling of oceans. In particular the Pacific where we’ve had a La Nina event. See this guest post from Dr. Roy Spencer on how the oceans could be driving the observed Co2 changes. The other possibility is the global economic crisis. This has led to lowered consumption of fossil fuels, particularly gasoline, which saw a significant drop in miles driven this past year due to high prices and other economic uncertainties.
Most probably it is a combination of events or possibly an error. Stay tuned.
h/t to Werner Weber and many other people who notified me