End of april sees the maximum of the CO2 cycle at Mauna Loa, there seems to be a sensor hiccup, so don't be amazed if you see some alarmist messages early May.

We finally have near real time record of CO2 at Mauna Loa

http://www.cmdl.noaa.gov/ccgg/iadv/

press the submit button for a graph

or take this direct link

http://www.cmdl.noaa.gov/ccgg/iadv/iadv_ts.php?currenttype=mlo_co2_ts_obs_03397.png

Set X Axis for All Frames to custom scale

2005.0 2007.0 2 12

press get plot (ok the error message)

Yup, there is a jump, but where's the evidence it's a fault rather than real? 

Humm, well, if we're not careful, we'll get into another of those threads where, without asking those concerned, some of us draw a conclusion. I'm not going to reach a conclusion without some evidence as to why this rise needs to be treated with suspicion. I don't see that as too much to ask .

 I wonder if we should note April is the month just before the northen hemisphere spring really gets going? Or, perhaps, why the rise in March was small? Or perhaps that over the two months the rise look less extraordinary? Or that the graph over the past few years looks to be painting a consistent picture?

I'm not suggesting we draw any conclusions or dismiss it Peter, just that we raise our eyebrows and try to work out what would cause such a sudden jump. It would seem logical however that sudden changes in concentration are most likely to be localised events, only adding a small amount overall to the background average. It could be something like N hemisphere spring kicking in as you imply... plant respiration kicking in again at the altitude of the observatory and creating a localised step in CO2 levels.

EDIT: Worth bearing in mind too that that area is rather volcanic too I guess... though spikes in the increase wouldn't be regular and should be quite easily mapped if that were the cause... 

Fair enough Sam  

I also wonder if the mild January in the US, the cold late winter in Europe have played a part? But, looking again, perhaps it's the March figure that might be odd more than April?

I updated the temperature of graph (see above) CO2 still needs to be added as CDIAC hasn't updated, I must digitise from the NOAA preliminary data 2004-20060509:

done

see also

http://home.casema.nl/errenwijlens/co2/maunaloa_co2_200605.txt

a bit of photoshopping overlaying 2004, 2005 and 2006 yields nothing special, march was anomalously low (so no sensor hickup ) :