Global Temperature Trend Update—August, 2010

Every month University of Alabama in Huntsville climatologists John Christy and Roy Spencer report the latest global temperature trends from satellite data. Below are the newest data updated through July, 2010.

The accompanying UAH press release notes:

Second hottest July on record as El Nino continues to fade

Global climate trend since Nov. 16, 1978: +0.14 C per decade

July temperatures (preliminary)

Global composite temp.: +0.49 C (about 0.88 degrees Fahrenheit) above 20-year average for July.

Northern Hemisphere: +0.63 C (about 1.13 degrees Fahrenheit) above 20-year average for July.

Southern Hemisphere: +0.34 C (about 0.58 degrees Fahrenheit) above 20-year average for July.

Tropics: +0.48 C (about 0.61 degrees Fahrenheit) above 20-year average for July.

June temperatures (revised):

Global Composite: +0.44 C above 20-year average

Northern Hemisphere: +0.55 C above 20-year average

Southern Hemisphere: +0.32 C above 20-year average

Tropics: +0.48 C above 20-year average

(All temperature anomalies are based on a 20-year average (1979-1998) for the month reported.)

Notes on data released Aug. 3, 2010:

July 2010 was the second hottest July in the 32-year satellite temperature dataset, with a global average temperature that was only 0.03 C cooler than the record set in July 1998, according to Dr. John Christy, professor of atmospheric science and director of the Earth System Science Center at The University of Alabama in Huntsville.

July Temperature Anomalies
    Year  Mo  Degrees C
 1.  1998  7   +0.52
 2.  2010  7   +0.49
 3.  2009  7   +0.44
 4.  2005  7   +0.35
 5.  2002  7   +0.3
 6.  2007  7   +0.26
 7.  2006  7   +0.22
 8.  1991  7   +0.2
 9.  1988  7   +0.19
10.  2003  7   +0.18

Average temperatures for the globe, as well as the northern and southern hemispheres, went up in July despite the continued cooling of the El Nino Pacific Ocean warming event and the apparent transition to a La Nina Pacific Ocean cooling event.

"If you look at how much sea surface temperatures are falling, no one would have predicted this," Christy said.

July 2010 was the second hottest July globally and in the Northern Hemisphere; third hottest in the Southern Hemisphere; and fourth hottest in the tropics.

Compared to seasonal norms, July 2010 was also the 17th warmest of all of the months since the satellite temperature dataset began in December 1978.

Warmest months, global
    Year  Mth  Anomaly
 1.  1998   2   +0.76
 2.  1998   4   +0.76
 3.  2010   3   +0.66
 4.  1998   5   +0.65
 5.  2010   1   +0.64
 6.  2010   2   +0.61
 7.  1998   1   +0.58
 8.  1998   6   +0.57
 9.  2010   5   +0.54
10.  1998   3   +0.53
11.  1998   7   +0.52
12.  1998   8   +0.52
13.  2007   1   +0.51
14.  2009   9   +0.5
15.  2009  11   +0.5
16.  2010   4   +0.5
17.* 2010   7   +0.49
18.  2005  10   +0.47
19.  2005   4   +0.46
20.  1998   9   +0.45

The first seven months of 2010 were only 0.07 C (about 0.13 degrees Fahrenheit) cooler than the record set in 1998 during another El Nino Pacific Ocean warming event.

  Jan-July Temp Anomalies
            GL      NH      SH      TRP
1998  +0.62  +0.73  +0.51  +0.90
2010  +0.55  +0.74  +0.36  +0.63