Spherical Chicken

An entirely normal El Nino SST decline should occur soon.

Year-to-Year weekly comparison of El Nino cycles

This is a comparison of El Nino events for the past 7 El Nino events, where there is weekly El Nino 3.4 data that is available:

http://www.cpc.noaa.gov/data/indices/wksst.for

All that this picture intends to show is that this El Nino is running stronger than 4 out of the past 6 El Nino’s and every single one of the prior El Nino’s had peaked by this time, so it is unlikely that the current one would strengthen.  It is also likely that the current El Nino will start to cool.  It would not be too surprising if roughly 3 months from now there is a transition to ENSO-neutral SSTs (+0.5C or cooler) in the equatorial pacific.

I fully expect to hear wails from the denialsphere at that time that any weakness in the El Nino means that global warming is wrong and we’re heading for a new ice age, when all that will be occurring is a normal transition after an El Nino.  This graph attempts to show that El Nino cycles are simply behaving normally and any decline from this peak would be normal.

The warming pulse from the El Nino will still take 4 months to arrive, as will the transition to ENSO-neutral or weak La Nina conditions, so I still expect that 2010 will set a global surface temperature record.

The graph does show that there is at least a slight chance that the El Nino might “linger” the way that the 1991 El Nino did.  It was a bit of a late bloomer, with a rapid run-up, and appears to be peaking later than the 1994/2002/2004/2006 El Nino’s and visually appears more similar to 1991.  If I had to bet, though, I’d have to bet we’re closer to +0.5C than +1.5C 3 months from now.