Global Temperature Report: July 2010
Second hottest July on record as El Nino fade continues
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: +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 TheUniversity 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 +0.1910. 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 +0.5410. 1998 3 +0.5311. 1998 7 +0.5212. 1998 8 +0.5213. 2007 1 +0.5114. 2009 9 +0.515. 2009 11 +0.516. 2010 4 +0.517.* 2010 7 +0.4918. 2005 10 +0.4719. 2005 4 +0.4620. 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 TRP1998 +0.62 +0.73 +0.51 +0.902010 +0.55 +0.74 +0.36 +0.63
As part of an ongoing joint project between UAHuntsville, NOAA and NASA, Christy and Dr. Roy Spencer, a principal research scientist in the ESSC, use data gathered by advanced microwave sounding units on NOAA and NASA satellites to get accurate temperature readings for almost all regions of the Earth. This includes remote desert, ocean and rain forest areas where reliable climate data are not otherwise available.
The satellite-based instruments measure the temperature of the atmosphere from the surface up to an altitude of about eight kilometers above sea level. Once the monthly temperature data is collected and processed, it is placed in a "public" computer file for immediate access by atmospheric scientists in the U.S. and abroad.
Neither Christy nor Spencer receives any research support or funding from oil, coal or industrial companies or organizations, or from any private or special interest groups. All of their climate research funding comes from federal and state grants or contracts.
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