NEW YORK, Jan. 22 (UPI) -- An analysis of global surface temperatures shows the last decade was the warmest on record, officials at New York's Goddard Institute for Space Studies said.
The rankings were determined by averaging temperatures to include fluctuations caused by the tropical El Nino-La Nina weather cycle, said James Hanson, the institute's director.
"When we average temperature ... to minimize that variability, we find global warming is continuing unabated," Hansen said.
Worldwide, 2009 tied for the second-warmest year since 1880, when records first were kept, while 2009 was the warmest year on record for the southern hemisphere, said James Hansen, the institute's director.
Globally, last year was a fraction of a degree cooler than 2005, the warmest on record, putting 2009 in a virtual tie for the second warmest year with 1998, 2002, 2003, 2006, and 2007.
Average global temperatures have increased by about 1.5 degrees Fahrenheit since 1880, Hansen said in a release.