From sci space news
Jan. 19, 2012
Steve Cole
Headquarters, Washington
202-358-0918


Leslie McCarthy Goddard Institute for Space Studies, New York 212-678-5507


RELEASE: 12-020

NASA FINDS 2011 NINTH WARMEST YEAR ON RECORD

WASHINGTON -- The global average surface temperature in 2011 was the ninth
warmest since 1880, according to NASA scientists. The finding continues a
trend in which nine of the 10 warmest years in the modern meteorological
record have occurred since the year 2000.

NASA's Goddard Institute for Space Studies (GISS) in New York, which
monitors global surface temperatures on an ongoing basis, released an
updated analysis that shows temperatures around the globe in 2011 compared
to the average global temperature from the mid-20th century. The comparison
shows how Earth continues to experience warmer temperatures than several
decades ago. The average temperature around the globe in 2011 was 0.92
degrees F (0.51 C) warmer than the mid-20th century baseline.

"We know the planet is absorbing more energy than it is emitting," said
GISS director James E. Hansen. "So we are continuing to see a trend toward
higher temperatures. Even with the cooling effects of a strong La Nina
influence and low solar activity for the past several years, 2011 was one
of the 10 warmest years on record."

The difference between 2011 and the warmest year in the GISS record
(2010) is 0.22 degrees F (0.12 C). This underscores the emphasis scientists
put on the long-term trend of global temperature rise. Because of the large
natural variability of climate, scientists do not expect temperatures to
rise consistently year after year. However, they do expect a continuing
temperature rise over decades.

The first 11 years of the 21st century experienced notably higher
temperatures compared to the middle and late 20th century, Hansen said. The
only year from the 20th century in the top 10 warmest years on record is
1998.

Higher temperatures today are largely sustained by increased atmospheric
concentrations of greenhouse gases, especially carbon dioxide. These gases
absorb infrared radiation emitted by Earth and release that energy into the
atmosphere rather than allowing it to escape to space. As their atmospheric
concentration has increased, the amount of energy "trapped" by these gases
has led to higher temperatures.

The carbon dioxide level in the atmosphere was about 285 parts per million
in 1880, when the GISS global temperature record begins. By 1960, the
average concentration had risen to about 315 parts per million. Today it
exceeds 390 parts per million and continues to rise at an accelerating
pace.

The temperature analysis produced at GISS is compiled from weather data
from more than 1,000 meteorological stations around the world, satellite
observations of sea surface temperature and Antarctic research station
measurements. A publicly available computer program is used to calculate
the difference between surface temperature in a given month and the average
temperature for the same place during 1951 to 1980. This three-decade
period functions as a baseline for the analysis.

The resulting temperature record is very close to analyses by the Met
Office Hadley Centre in the United Kingdom and the National Oceanic and
Atmospheric Administration's National Climatic Data Center in Asheville,
N.C.

Hansen said he expects record-breaking global average temperature in the
next two to three years because solar activity is on the upswing and the
next El Nino will increase tropical Pacific temperatures. The warmest years
on record were 2005 and 2010, in a virtual tie.

"It's always dangerous to make predictions about El Nino, but it's safe to
say we'll see one in the next three years," Hansen said. "It won't take a
very strong El Nino to push temperatures above 2010."

For more information on the GISS temperature analysis, visit:

http://data.giss.nasa.gov/gistemp

-end-