Global Temperature Report – December 2008

Global temperatures during 2008 were influenced by a La Nina Pacific Ocean cooling event.

Global trend since Nov. 16, 1978: +0.13 C per decade

December temperatures (preliminary)

Global composite temp.: +0.18 C (about 0.32 degrees Fahrenheit) above
20-year average for December.
Northern Hemisphere: +0.41 C (about 0.74 degrees Fahrenheit) above 20-year
average for December.
Southern Hemisphere: -0.05 C (about 0.09 degrees Fahrenheit) below 20-year
average for December.
November temperatures (revised):
Global Composite: +0.25 C above 20-year average
Northern Hemisphere: +0.34 C above 20-year average
Southern Hemisphere: +0.16 C above 20-year average
(All temperature variations are based on a 20-year average (1979-1998) for
the month reported.)
Notes on data released Jan. 12, 2009:
The eleventh warmest global December in 31 years was also the fifth warmest
in the Northern Hemisphere, according to Dr. John Christy, a professor of
atmospheric science and director of the Earth System Science Center (ESSC)
at The University of Alabama in Huntsville. At the same time, the Southern
Hemisphere saw its tenth coolest of the past 31 Decembers.
WARMEST DECEMBERS, NH
2003 +0.62 C
2006 +0.54 C
1987 +0.52 C
1998 +0.42 C
2008 +0.41 C
2005 +0.40 C
Since November 1978, the Northern Hemisphere atmosphere has warmed more than
three times as fast as the Southern Hemisphere atmosphere (+0.19 C to +0.06
C per decade).
With a global average temperature that was 0.05 C warmer than seasonal
norms, 2008 goes into the books as the coolest year since 2000. Global
temperatures during 2008 were influenced by a La Nina Pacific Ocean cooling
event.
Another La Nina appears to be forming in the Pacific, which could chill
temperatures through 2009.
Color maps of local temperature anomalies may soon be available on-line at:
http://climate.uah.edu/
The processed temperature data is available on-line at:
vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt
As part of an ongoing joint project between The University of Alabama in
Huntsville, 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 for which 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 Spencer nor Christy 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
state and federal grants or contracts.
Dr. John Christy, UAH, (256) 961-7763
john.christy@nsstc.uah.edu
Dr. Roy Spencer, UAH, (256) 961-7960
roy.spencer@nsstc.uah.edu