Global warming saw the past decade become the warmest ever on Earth, a new analysis

of global surface temperatures released by NASA showed Thursday.
The US space agency also found that 2009 was the second-warmest year on
record since modern temperature measurements began in 1880. Last year was
only a small fraction of a degree cooler than 2005, the warmest yet, putting
2009 in a virtual tie with the other hottest years, which have all occurred
since 1998.

According to James Hansen, who heads NASA's Goddard Institute for Space
Studies, global temperatures change due to variations in ocean heating and
cooling.

"When we average temperature over five or 10 years to minimize that
variability, we find global warming is continuing unabated," Hansen said in
a statement.

A strong La Nina effect that cooled the tropical Pacific Ocean made 2008 the
coolest year of the decade, according to the New York-based institute.

In analyzing the data, NASA scientists found a clear warming trend, although
a leveling off took place in the 1940s and 1970s.

The records showed that temperatures trended upward by about 0.36 degrees
Fahrenheit (0.2 Celsius) per decade over the past 30 years. Average global
temperatures have increased a total of about 1.5 degrees Fahrenheit (0.8
Celsius) since 1880.