It is summer in the northern hemisphere and given the Americans and Europeans are pretty obsessed with temperatures records at the moment, and some with a fear that the Arctic might go ice free this northern summer, it was with some anticipation that the June 2008 temperature records were released.
According to the US National Climatic Data Centre (NCDC) the Northern Hemisphere Arctic sea ice extent for June 2008 ranked third lowest for June since records began in 1979 while Southern Hemisphere Antarctic sea ice extent for June 2008 was above the 1979-2000 mean, ranking as the second largest June extent.
So there is still ice in the Arctic and more ice than usual in the Antarctic.
As regards the US, according to the NCDC, June 2008 was the 27th warmest June based on records dating back to 1895. Globally though June 2008 ranked eighth warmest for June since worldwide records began in 1880.
But according to Joe D’Aleo a meteorologist with a blog: Don’t believe a word of it.
Joe prefers the NASA satellite data compiled by Roy Spencer at the University of Alabama, Huntsville, and it shows June 2008 was the 22nd warmest in its 30 years of records, Figure 1. According to Joe, this satellite data indicated the globe was a full 1.1F degrees colder than the NCDC guesstimate.
Figure 1. The NASA MSU June Temperatures since 1979 via Joe D’Aleo.
Joe explains that he prefers the satellite data because: the thermometer global data bases suffer from major station dropout after 1990 (number dropped from 6000 to less than 2000) and a ten fold increase in the number of missing months in the stations that report. Furthermore, there are serious problems with algorithms for assessing whether a station is urban or rural and adjusting for local land use changes. And there are major siting issues. You can find more information here: http://icecap.us/images/uploads/DATA_ISSUES.pdf
Interestingly though, even James Hansen’s monthly data for the last ten years to June 2008, shows some recent cooling and it looks like global temperaturs have plateaued, Figure 2.
Figure 2. The NASA GISS Monthly Mean Surface Temperature Analysis since 1998, (see http://data.giss.nasa.gov/gistemp/graphs/Fig.C.lrg.gif ).