In all probability 2014 will continue the global surface temperature standstill in a statistically perfect manner.
Articles are starting to appear discussing the global average surface temperature of 2014. I am always reluctant to say too much about the final temperature of 2014 until its final month though my reservations are not shared by others. Part of the motivation for the current speculation is that August was a very hot month globally.
John Vidal writing in the Guardian points out August’s figures in Nasa’s Giss dataset. August has a temperature anomaly of 70, technically the highest August on record although four other Augusts are within 0.05 deg C of 2014 with 2011 being 0.69. However Vidal gets his one of his figures wrong when he says that August’s figure was very close to those of 2011 (69), 2008 (39), 2006 (66) and 2003 (65). After this Vidal cherry-picks his figures. According to the dataset he starts off with, Nasa’s Giss, May and August are the warmest months on record. May’s anomaly of 79 is the warmest by a considerable margin. However Vidal changes to the NOAA dataset to claim that May and June were the hottest ever.
NOAA’s dataset differs from Giss. NOAA has May the warmest on record with a temperature anomaly of 0.74 deg C. This was made up of land data (fourth highest May on record) and ocean data (highest May on record). NOAA has June as the hottest on record comprising the seventh highest land temperature for June on record, and the warmest June ocean temperature on record. In Giss June was third and equal to 2013 and 2009.
NOAA’s year to date record shows 2014 is in the top three but nothing particularly unusual. Note, error bars on NOAA’s graph would show the differences to be statistically insignificant.
According to Giss for 2014 to be a record year, and technically beat 2010, the average temperature anomaly for the rest of the year must by 65. This is not impossible as the final four months of 2012 and 2013 achieved this because of warm Septembers and Novembers.
Regarding HadCrut4 August’s data has yet to be released. May and June were record months but May by only 0.002 deg C. July was not a record month being 0.549 against 2010′s 0.607. For 2014 to technically exceed 2010 the months August – December must have an average temperature anomaly of 0.562. Last year that average was 0.525.
Many have been waiting for an El Nino to start. This would certainly boost global temperatures possibly enough to provide a record this year and an accelerated start to 2015. But it would be wrong to equate this to overall global warming, it’s a different effect though to many looking for a record to attribute to global warming any record, however obtained, will do.
2014 is a warm year and the ocean over the past few months have broken records. Some have tweeted that this is what global warming looks like but in reality it’s not possible to say that. 2014 will probably be in the top five warmest but at the moment it will probably not turn out to be warmer than 2010. It is impossible for it to beat 2010 by a statistically significant margin, even if we define that as only one standard deviation above the decadal mean. Even if 2014 does beat 2010 it will only be by a statistically insignificant margin and well within the inter-annual error bars. In all probability 2014 will continue the global surface temperature standstill in a statistically perfect manner. When will the global surface annual temperature start to rise out of the error bars of the past 18 years?