2013 was world's fourth warmest year on record: US

Last year was the world's fourth warmest since modern records began in 1880, according to US government figures released Tuesday that provide more evidence that the planet is heating up.

The average of combined land and ocean surface temperatures in 2013 was 1.12 degrees Fahrenheit (0.62 Celsius) above the 20th century average of 57 degrees Fahrenheit (13.9 Celsius).

"This temperature departure for 2013 tied with 2003 as the fourth warmest year since records began in 1880," said a statement from the National Oceanic and Atmospheric Administration (NOAA).

Last year also marked the 37th year in a row with higher than average global temperatures.

All 13 years of the 21st century have been among the warmest on record, NOAA said, with the hottest being 2010, 2005, and 1998.

COOLER THAN AVERAGE

While most of the world experienced above-average annual temperatures, a few small regions in the central United States, eastern Pacific and South America were cooler than average.

The NOAA figures were released as part of the agency's yearly temperature analysis.

NASA also issued its own data on Tuesday that showed slightly different outcomes, with last year ranking as the seventh warmest globally on average.

However, experts said the actual temperature differences between years are very small, and that the overall trend toward a warming globe is clear.

"Long-term trends in surface temperatures are unusual and 2013 adds to the evidence for ongoing climate change," NASA climatologist Gavin Schmidt said.

"While one year or one season can be affected by random weather events, this analysis shows the necessity for continued, long-term monitoring."