The observed lack of change in global annual average surface temperature over the past 15-years or so is a fact that is being increasingly debated within the scientific literature and in the wider world. It is fair to say there is no consensus over its cause, or about how long it may continue.
Although we have only a quarter, and in one case a third, of the annual global surface temperature data available for 2013 it is interesting to look at how things are going, particularly since the world is currently El Nino neutral and has been for the past ten months. So far we have no El Nino pushing temperatures slightly up, or La Nina doing the converse.
The major global temperature databases are all telling the same story about 2013 so far.
According to NOAA January, February and March were the 9th-10th warmest on record, although when errors are taken into account it could almost have been 15th or thereabouts. Nasa Giss gives January as the 6th warmest, February as the 11th, March as the 12th and April as the 13th. Hadcrut4 has January at 10th, February at 9th and March at 12th.
So far 2013 is proving to be statistically identical to the past 15-years or so, and if it is destined to be a record year then the monthly averages for the rest of the year will have to behave abnormally to make up the increasing shortfall when compared to the ‘warm’ years of 2010 and 2007. In Nasa Giss for example there is 0.88 deg C to make up after only four months.
One has to be careful in looking at the global annual average temperature for the past 15-years or so. I would go no further than saying that it is remarkably flat with no statistically significant change. But something to look out for comes from NOAA data as reproduced below. It shows 0.1 deg C decline in global temperatures for March data in the past decade! What would it have been like if the 2010 El Nino had not taken place? Won’t the next five years of data prove interesting.Click on image to enlarge.
The next two graphs show January and February data. Both show significant declines.
The annual data is also interesting. Looking at the global land only data shows no statistically significant change over the past decade. The global ocean however shows a cooling that is more significant, 0.07 degrees.