December Was 7th Warmest of the Past 31 Years

December temperatures (preliminary)

Global composite temp.: +0.28 C (about 0.50 degrees Fahrenheit) above
20-year average for December.
Northern Hemisphere: +0.32 C (about 0.58 degrees Fahrenheit) above 20-year
average for December.
Southern Hemisphere: +0.24 C (about 0.43 degrees Fahreneheit) above
20-year average for December.
November temperatures (revised):
Global Composite: +0.50 C above 20-year average
Northern Hemisphere: +0.42 C above 20-year average
Southern Hemisphere: +0.57 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 Jan. 6, 2009:
An El Nino Pacific Ocean warming event kept global temperatures warmer than seasonal norms through December, with temperatures in the tropics a full 0.50 C (0.9 degrees Fahrenheit) warmer than seasonal norms, according to Dr. John Christy, professor of atmospheric science and director of the Earth System Science Center (ESSC) at The University of Alabama in Huntsville.

Powered by the El Nino, temperatures throughout 2009 were warmer than seasonal norms, making it the seventh warmest year in the 31-year satellite-based temperature record.

Year Temp Anomaly
1. 1998 +0.512 C
2. 2005 +0.338 C
3. 2002 +0.311 C
4. 2007 +0.282 C
5. 2003 +0.275 C
6. 2006 +0.260 C
7. 2009 +0.259 C
8. 2001 +0.198 C
9. 2004 +0.193 C
10. 1991 +0.117 C
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 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.

For Additional Information:
Dr. John Christy, (256) 961-7763
john.christy@nsstc.uah.edu
Dr. Roy Spencer, (256) 961-7960
roy.spencer@nsstc.uah.edu