Infonugget: NASA confirms it’s still toasty out there

Last decade was warmest on record, 2009 one of warmest years, NASA research finds (emphasis added):

A new analysis of global surface temperatures by NASA scientists finds the past year was tied for the second warmest since 1880. In the Southern Hemisphere, 2009 was the warmest year on record.

Although 2008 was the coolest year of the decade because of a strong La Nina that cooled the tropical Pacific Ocean, 2009 saw a return to a near-record global temperatures as the La Nina diminished, according to the new analysis by NASA’s Goddard Institute for Space Studies (GISS) in New York. The past year was a small fraction of a degree cooler than 2005, the warmest on record, putting 2009 in a virtual tie with a cluster of other years –1998, 2002, 2003, 2006, and 2007 — for the second warmest on record.

“There’s always interest in the annual temperature numbers and a given year’s ranking, but the ranking often misses the point,” said James Hansen, GISS director. “There’s substantial year-to-year variability of global temperature caused by the tropical El Nino-La Nina cycle. When we average temperature over five or ten years to minimize that variability, we find global warming is continuing unabated.”

January 2000 to December 2009 was the warmest decade on record. Looking back to 1880, when modern scientific instrumentation became available to monitor temperatures precisely, a clear warming trend is present, although there was a leveling off between the 1940s and 1970s.

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The near-record global temperatures of 2009 occurred despite an unseasonably cool December in much of North America. High air pressures from the Arctic decreased the east-west flow of the jet stream, while increasing its tendency to blow from north to south. The result was an unusual effect that caused frigid air from the Arctic to rush into North America and warmer mid-latitude air to shift toward the north. This left North America cooler than normal, while the Arctic was warmer than normal.

“The contiguous 48 states cover only 1.5 percent of the world area, so the United States’ temperature does not affect the global temperature much,” Hansen said.

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Other research groups also track global temperature trends but use different analysis techniques. The Met Office Hadley Centre in the United Kingdom uses similar input measurements as GISS, for example, but it omits large areas of the Arctic and Antarctic where monitoring stations are sparse.

Although the two methods produce slightly differing results in the annual rankings, the decadal trends in the two records are essentially identical.

“There’s a contradiction between the results shown here and popular perceptions about climate trends,” Hansen said. “In the last decade, global warming has not stopped.”

For more information about GISS’s surface temperature record, visit: http://data.giss.nasa.gov/gistemp/

For related video and still images, visit: http://svs.gsfc.nasa.gov/goto?010557

In particular, see the page GISS Surface Temperature Analysis: Global Maps from GHCN Data for a web interface that lets you generate maps of temperature trends and anomalies. More fun for a science geek than should be legal, if you ask me.