The Goddard Institute of Space Studies at the National Aeronautics and Space Administration has now released its analysis of world temperatures for the first seven months of this year showing that the global average July 2010 temperature was 0.55°C warmer than climatology (the long-run average) in the GISS analysis, which puts 2010 in practically a three-way tie for third warmest July. July 1998 was the warmest in the GISS analysis, at 0.68°C.
The July 2010 global map of surface temperature anomalies (figure 1), relative to the average July in the 1951-1980 period, was more than 5°C (about 10°F) warmer than climatology in the eastern European region including Moscow. There was an area in eastern Asia that was similarly unusually hot. The eastern part of the United States was unusually warm, although not to the degree of the hot spots in Eurasia. There were also substantial areas cooler than climatology, including a region in central Asia and the southern part of South America. The emerging La Nina is now moderately strong, as evidenced by the region cooler than climatology along the equator in the eastern and central Pacific Ocean.
The 12-month running mean of global temperature (figure 2) achieved a record high level during the past few months. Because the current La Nina will continue at least several months, and likely strengthen somewhat, the 12-month running mean temperature is expected to decline during the second half of 2010.
The GISS analysis poses the question of whether calendar year 2010 be the warmest in the period of instrumental data?
Figure 3 shows that through the first seven months 2010 is warmer than prior warm years. The difference of +0.08°C compared with 2005, the prior warmest year, is large enough that 2010 is likely, but not certain, to be the warmest year in the GISS record. However, because of the cooling effect of La Nina in the remainder of the year, there is a strong possibility that the 2005 and 2010 global temperatures will be sufficiently close that they will be practically indistinguishable.
The Intrade prediction market where people put a price on such matters has the probability of 2010 being warmer than prior years at about a 90% probability.