NASA: 2009 second warmest year on record
Jeremy Hancemongabay.com
January 24, 2010
"There's always interest in the annual temperature numbers and a given year's ranking, but the ranking often misses the point," James Hansen, GISS director, said in a press release. "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."
 The map shows temperature changes for the last decade -- January 2000 to December 2009 -- relative to the 1951-1980 mean. Warmer areas are in red, cooler areas in blue. The largest temperature increases occurred in the Arctic and a portion of Antarctica. Map by: NASA. |
"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 explained.
While the United States, Europe, and China may have been colder than usual this winter, the Arctic and the Southern Hemisphere remained significantly warm. Climatologists have pointed out recently the importance of understanding the difference between weather (day-to-day localized events) and climate (longterm trends).
Overall GISS has measured an upward trend in the global temperature of about 0.36 degrees Fahrenheit (0.2 degrees Celsius) every ten years over the past three decades. Since 1880, temperatures have risen about 1.5 degrees Fahrenheit (0.8 degrees Celsius).
The GISS uses slightly different temperature analysis than other temperature research groups, such as the Met Office Hadley Centre in the UK, which omits temperature readings from large parts of the Arctic and Antarctic because monitoring stations are sparse. Despite these small differences both GISS and Met Office Hadley Centre record that the 2000s was clearly the warmest decade on record.
"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."
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